第一次提交

.gitignore

+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+
+.idea
+build
+cmake-build-debug

CMakeLists.txt

+cmake_minimum_required(VERSION 2.7)
+set(CMAKE_VERBOSE_MAKEFILE on)
+
+project(clock_gettime_testor)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -g -O0")
+include_directories(.)
+aux_source_directory(. SRC_LIST)
+
+add_executable(spdlog_sample ${SRC_LIST})
+TARGET_LINK_LIBRARIES(spdlog_sample pthread)
+

spdlog/async.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+//
+// Async logging using global thread pool
+// All loggers created here share same global thread pool.
+// Each log message is pushed to a queue along with a shared pointer to the
+// logger.
+// If a logger deleted while having pending messages in the queue, it's actual
+// destruction will defer
+// until all its messages are processed by the thread pool.
+// This is because each message in the queue holds a shared_ptr to the
+// originating logger.
+
+#include <spdlog/async_logger.h>
+#include <spdlog/details/registry.h>
+#include <spdlog/details/thread_pool.h>
+
+#include <memory>
+#include <mutex>
+#include <functional>
+
+namespace spdlog {
+
+namespace details {
+static const size_t default_async_q_size = 8192;
+}
+
+// async logger factory - creates async loggers backed with thread pool.
+// if a global thread pool doesn't already exist, create it with default queue
+// size of 8192 items and single thread.
+template<async_overflow_policy OverflowPolicy = async_overflow_policy::block>
+struct async_factory_impl
+{
+    template<typename Sink, typename... SinkArgs>
+    static std::shared_ptr<async_logger> create(std::string logger_name, SinkArgs &&...args)
+    {
+        auto &registry_inst = details::registry::instance();
+
+        // create global thread pool if not already exists..
+
+        auto &mutex = registry_inst.tp_mutex();
+        std::lock_guard<std::recursive_mutex> tp_lock(mutex);
+        auto tp = registry_inst.get_tp();
+        if (tp == nullptr)
+        {
+            tp = std::make_shared<details::thread_pool>(details::default_async_q_size, 1);
+            registry_inst.set_tp(tp);
+        }
+
+        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
+        auto new_logger = std::make_shared<async_logger>(std::move(logger_name), std::move(sink), std::move(tp), OverflowPolicy);
+        registry_inst.initialize_logger(new_logger);
+        return new_logger;
+    }
+};
+
+using async_factory = async_factory_impl<async_overflow_policy::block>;
+using async_factory_nonblock = async_factory_impl<async_overflow_policy::overrun_oldest>;
+
+template<typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create_async(std::string logger_name, SinkArgs &&...sink_args)
+{
+    return async_factory::create<Sink>(std::move(logger_name), std::forward<SinkArgs>(sink_args)...);
+}
+
+template<typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create_async_nb(std::string logger_name, SinkArgs &&...sink_args)
+{
+    return async_factory_nonblock::create<Sink>(std::move(logger_name), std::forward<SinkArgs>(sink_args)...);
+}
+
+// set global thread pool.
+inline void init_thread_pool(size_t q_size, size_t thread_count, std::function<void()> on_thread_start)
+{
+    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start);
+    details::registry::instance().set_tp(std::move(tp));
+}
+
+// set global thread pool.
+inline void init_thread_pool(size_t q_size, size_t thread_count)
+{
+    init_thread_pool(q_size, thread_count, [] {});
+}
+
+// get the global thread pool.
+inline std::shared_ptr<spdlog::details::thread_pool> thread_pool()
+{
+    return details::registry::instance().get_tp();
+}
+} // namespace spdlog

spdlog/async_logger-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/async_logger.h>
+#endif
+
+#include <spdlog/sinks/sink.h>
+#include <spdlog/details/thread_pool.h>
+
+#include <memory>
+#include <string>
+
+SPDLOG_INLINE spdlog::async_logger::async_logger(
+    std::string logger_name, sinks_init_list sinks_list, std::weak_ptr<details::thread_pool> tp, async_overflow_policy overflow_policy)
+    : async_logger(std::move(logger_name), sinks_list.begin(), sinks_list.end(), std::move(tp), overflow_policy)
+{}
+
+SPDLOG_INLINE spdlog::async_logger::async_logger(
+    std::string logger_name, sink_ptr single_sink, std::weak_ptr<details::thread_pool> tp, async_overflow_policy overflow_policy)
+    : async_logger(std::move(logger_name), {std::move(single_sink)}, std::move(tp), overflow_policy)
+{}
+
+// send the log message to the thread pool
+SPDLOG_INLINE void spdlog::async_logger::sink_it_(const details::log_msg &msg)
+{
+    if (auto pool_ptr = thread_pool_.lock())
+    {
+        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
+    }
+    else
+    {
+        throw_spdlog_ex("async log: thread pool doesn't exist anymore");
+    }
+}
+
+// send flush request to the thread pool
+SPDLOG_INLINE void spdlog::async_logger::flush_()
+{
+    if (auto pool_ptr = thread_pool_.lock())
+    {
+        pool_ptr->post_flush(shared_from_this(), overflow_policy_);
+    }
+    else
+    {
+        throw_spdlog_ex("async flush: thread pool doesn't exist anymore");
+    }
+}
+
+//
+// backend functions - called from the thread pool to do the actual job
+//
+SPDLOG_INLINE void spdlog::async_logger::backend_sink_it_(const details::log_msg &msg)
+{
+    for (auto &sink : sinks_)
+    {
+        if (sink->should_log(msg.level))
+        {
+            SPDLOG_TRY
+            {
+                sink->log(msg);
+            }
+            SPDLOG_LOGGER_CATCH()
+        }
+    }
+
+    if (should_flush_(msg))
+    {
+        backend_flush_();
+    }
+}
+
+SPDLOG_INLINE void spdlog::async_logger::backend_flush_()
+{
+    for (auto &sink : sinks_)
+    {
+        SPDLOG_TRY
+        {
+            sink->flush();
+        }
+        SPDLOG_LOGGER_CATCH()
+    }
+}
+
+SPDLOG_INLINE std::shared_ptr<spdlog::logger> spdlog::async_logger::clone(std::string new_name)
+{
+    auto cloned = std::make_shared<spdlog::async_logger>(*this);
+    cloned->name_ = std::move(new_name);
+    return cloned;
+}

spdlog/async_logger.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Fast asynchronous logger.
+// Uses pre allocated queue.
+// Creates a single back thread to pop messages from the queue and log them.
+//
+// Upon each log write the logger:
+//    1. Checks if its log level is enough to log the message
+//    2. Push a new copy of the message to a queue (or block the caller until
+//    space is available in the queue)
+// Upon destruction, logs all remaining messages in the queue before
+// destructing..
+
+#include <spdlog/logger.h>
+
+namespace spdlog {
+
+// Async overflow policy - block by default.
+enum class async_overflow_policy
+{
+    block,         // Block until message can be enqueued
+    overrun_oldest // Discard oldest message in the queue if full when trying to
+                   // add new item.
+};
+
+namespace details {
+class thread_pool;
+}
+
+class SPDLOG_API async_logger final : public std::enable_shared_from_this<async_logger>, public logger
+{
+    friend class details::thread_pool;
+
+public:
+    template<typename It>
+    async_logger(std::string logger_name, It begin, It end, std::weak_ptr<details::thread_pool> tp,
+        async_overflow_policy overflow_policy = async_overflow_policy::block)
+        : logger(std::move(logger_name), begin, end)
+        , thread_pool_(std::move(tp))
+        , overflow_policy_(overflow_policy)
+    {}
+
+    async_logger(std::string logger_name, sinks_init_list sinks_list, std::weak_ptr<details::thread_pool> tp,
+        async_overflow_policy overflow_policy = async_overflow_policy::block);
+
+    async_logger(std::string logger_name, sink_ptr single_sink, std::weak_ptr<details::thread_pool> tp,
+        async_overflow_policy overflow_policy = async_overflow_policy::block);
+
+    std::shared_ptr<logger> clone(std::string new_name) override;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+    void backend_sink_it_(const details::log_msg &incoming_log_msg);
+    void backend_flush_();
+
+private:
+    std::weak_ptr<details::thread_pool> thread_pool_;
+    async_overflow_policy overflow_policy_;
+};
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "async_logger-inl.h"
+#endif

spdlog/cfg/argv.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+#include <spdlog/cfg/helpers.h>
+#include <spdlog/details/registry.h>
+
+//
+// Init log levels using each argv entry that starts with "SPDLOG_LEVEL="
+//
+// set all loggers to debug level:
+// example.exe "SPDLOG_LEVEL=debug"
+
+// set logger1 to trace level
+// example.exe "SPDLOG_LEVEL=logger1=trace"
+
+// turn off all logging except for logger1 and logger2:
+// example.exe "SPDLOG_LEVEL=off,logger1=debug,logger2=info"
+
+namespace spdlog {
+namespace cfg {
+
+// search for SPDLOG_LEVEL= in the args and use it to init the levels
+inline void load_argv_levels(int argc, const char **argv)
+{
+    const std::string spdlog_level_prefix = "SPDLOG_LEVEL=";
+    for (int i = 1; i < argc; i++)
+    {
+        std::string arg = argv[i];
+        if (arg.find(spdlog_level_prefix) == 0)
+        {
+            auto levels_string = arg.substr(spdlog_level_prefix.size());
+            helpers::load_levels(levels_string);
+        }
+    }
+}
+
+inline void load_argv_levels(int argc, char **argv)
+{
+    load_argv_levels(argc, const_cast<const char **>(argv));
+}
+
+} // namespace cfg
+} // namespace spdlog

spdlog/cfg/env.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+#include <spdlog/cfg/helpers.h>
+#include <spdlog/details/registry.h>
+#include <spdlog/details/os.h>
+
+//
+// Init levels and patterns from env variables SPDLOG_LEVEL
+// Inspired from Rust's "env_logger" crate (https://crates.io/crates/env_logger).
+// Note - fallback to "info" level on unrecognized levels
+//
+// Examples:
+//
+// set global level to debug:
+// export SPDLOG_LEVEL=debug
+//
+// turn off all logging except for logger1:
+// export SPDLOG_LEVEL="*=off,logger1=debug"
+//
+
+// turn off all logging except for logger1 and logger2:
+// export SPDLOG_LEVEL="off,logger1=debug,logger2=info"
+
+namespace spdlog {
+namespace cfg {
+inline void load_env_levels()
+{
+    auto env_val = details::os::getenv("SPDLOG_LEVEL");
+    if (!env_val.empty())
+    {
+        helpers::load_levels(env_val);
+    }
+}
+
+} // namespace cfg
+} // namespace spdlog

spdlog/cfg/helpers-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/cfg/helpers.h>
+#endif
+
+#include <spdlog/spdlog.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/registry.h>
+
+#include <algorithm>
+#include <string>
+#include <utility>
+#include <sstream>
+
+namespace spdlog {
+namespace cfg {
+namespace helpers {
+
+// inplace convert to lowercase
+inline std::string &to_lower_(std::string &str)
+{
+    std::transform(
+        str.begin(), str.end(), str.begin(), [](char ch) { return static_cast<char>((ch >= 'A' && ch <= 'Z') ? ch + ('a' - 'A') : ch); });
+    return str;
+}
+
+// inplace trim spaces
+inline std::string &trim_(std::string &str)
+{
+    const char *spaces = " \n\r\t";
+    str.erase(str.find_last_not_of(spaces) + 1);
+    str.erase(0, str.find_first_not_of(spaces));
+    return str;
+}
+
+// return (name,value) trimmed pair from given "name=value" string.
+// return empty string on missing parts
+// "key=val" => ("key", "val")
+// " key  =  val " => ("key", "val")
+// "key=" => ("key", "")
+// "val" => ("", "val")
+
+inline std::pair<std::string, std::string> extract_kv_(char sep, const std::string &str)
+{
+    auto n = str.find(sep);
+    std::string k, v;
+    if (n == std::string::npos)
+    {
+        v = str;
+    }
+    else
+    {
+        k = str.substr(0, n);
+        v = str.substr(n + 1);
+    }
+    return std::make_pair(trim_(k), trim_(v));
+}
+
+// return vector of key/value pairs from sequence of "K1=V1,K2=V2,.."
+// "a=AAA,b=BBB,c=CCC,.." => {("a","AAA"),("b","BBB"),("c", "CCC"),...}
+inline std::unordered_map<std::string, std::string> extract_key_vals_(const std::string &str)
+{
+    std::string token;
+    std::istringstream token_stream(str);
+    std::unordered_map<std::string, std::string> rv{};
+    while (std::getline(token_stream, token, ','))
+    {
+        if (token.empty())
+        {
+            continue;
+        }
+        auto kv = extract_kv_('=', token);
+        rv[kv.first] = kv.second;
+    }
+    return rv;
+}
+
+SPDLOG_INLINE void load_levels(const std::string &input)
+{
+    if (input.empty() || input.size() > 512)
+    {
+        return;
+    }
+
+    auto key_vals = extract_key_vals_(input);
+    std::unordered_map<std::string, level::level_enum> levels;
+    level::level_enum global_level = level::info;
+    bool global_level_found = false;
+
+    for (auto &name_level : key_vals)
+    {
+        auto &logger_name = name_level.first;
+        auto level_name = to_lower_(name_level.second);
+        auto level = level::from_str(level_name);
+        // ignore unrecognized level names
+        if (level == level::off && level_name != "off")
+        {
+            continue;
+        }
+        if (logger_name.empty()) // no logger name indicate global level
+        {
+            global_level_found = true;
+            global_level = level;
+        }
+        else
+        {
+            levels[logger_name] = level;
+        }
+    }
+
+    details::registry::instance().set_levels(std::move(levels), global_level_found ? &global_level : nullptr);
+}
+
+} // namespace helpers
+} // namespace cfg
+} // namespace spdlog

spdlog/cfg/helpers.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <unordered_map>
+
+namespace spdlog {
+namespace cfg {
+namespace helpers {
+//
+// Init levels from given string
+//
+// Examples:
+//
+// set global level to debug: "debug"
+// turn off all logging except for logger1: "off,logger1=debug"
+// turn off all logging except for logger1 and logger2: "off,logger1=debug,logger2=info"
+//
+SPDLOG_API void load_levels(const std::string &txt);
+} // namespace helpers
+
+} // namespace cfg
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "helpers-inl.h"
+#endif // SPDLOG_HEADER_ONLY

spdlog/common-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/common.h>
+#endif
+
+namespace spdlog {
+namespace level {
+static string_view_t level_string_views[] SPDLOG_LEVEL_NAMES;
+
+static const char *short_level_names[] SPDLOG_SHORT_LEVEL_NAMES;
+
+SPDLOG_INLINE string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT
+{
+    return level_string_views[l];
+}
+
+SPDLOG_INLINE const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT
+{
+    return short_level_names[l];
+}
+
+SPDLOG_INLINE spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT
+{
+    int level = 0;
+    for (const auto &level_str : level_string_views)
+    {
+        if (level_str == name)
+        {
+            return static_cast<level::level_enum>(level);
+        }
+        level++;
+    }
+    // check also for "warn" and "err" before giving up..
+    if (name == "warn")
+    {
+        return level::warn;
+    }
+    if (name == "err")
+    {
+        return level::err;
+    }
+    return level::off;
+}
+} // namespace level
+
+SPDLOG_INLINE spdlog_ex::spdlog_ex(std::string msg)
+    : msg_(std::move(msg))
+{}
+
+SPDLOG_INLINE spdlog_ex::spdlog_ex(const std::string &msg, int last_errno)
+{
+    memory_buf_t outbuf;
+    fmt::format_system_error(outbuf, last_errno, msg);
+    msg_ = fmt::to_string(outbuf);
+}
+
+SPDLOG_INLINE const char *spdlog_ex::what() const SPDLOG_NOEXCEPT
+{
+    return msg_.c_str();
+}
+
+SPDLOG_INLINE void throw_spdlog_ex(const std::string &msg, int last_errno)
+{
+    SPDLOG_THROW(spdlog_ex(msg, last_errno));
+}
+
+SPDLOG_INLINE void throw_spdlog_ex(std::string msg)
+{
+    SPDLOG_THROW(spdlog_ex(std::move(msg)));
+}
+
+} // namespace spdlog

spdlog/common.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/tweakme.h>
+#include <spdlog/details/null_mutex.h>
+
+#include <atomic>
+#include <chrono>
+#include <initializer_list>
+#include <memory>
+#include <exception>
+#include <string>
+#include <type_traits>
+#include <functional>
+
+#ifdef SPDLOG_COMPILED_LIB
+#undef SPDLOG_HEADER_ONLY
+#if defined(_WIN32) && defined(SPDLOG_SHARED_LIB)
+#ifdef spdlog_EXPORTS
+#define SPDLOG_API __declspec(dllexport)
+#else
+#define SPDLOG_API __declspec(dllimport)
+#endif
+#else // !defined(_WIN32) || !defined(SPDLOG_SHARED_LIB)
+#define SPDLOG_API
+#endif
+#define SPDLOG_INLINE
+#else // !defined(SPDLOG_COMPILED_LIB)
+#define SPDLOG_API
+#define SPDLOG_HEADER_ONLY
+#define SPDLOG_INLINE inline
+#endif // #ifdef SPDLOG_COMPILED_LIB
+
+#include <spdlog/fmt/fmt.h>
+
+// visual studio upto 2013 does not support noexcept nor constexpr
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+#define SPDLOG_NOEXCEPT _NOEXCEPT
+#define SPDLOG_CONSTEXPR
+#else
+#define SPDLOG_NOEXCEPT noexcept
+#define SPDLOG_CONSTEXPR constexpr
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+#define SPDLOG_DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+#define SPDLOG_DEPRECATED __declspec(deprecated)
+#else
+#define SPDLOG_DEPRECATED
+#endif
+
+// disable thread local on msvc 2013
+#ifndef SPDLOG_NO_TLS
+#if (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt)
+#define SPDLOG_NO_TLS 1
+#endif
+#endif
+
+#ifndef SPDLOG_FUNCTION
+#define SPDLOG_FUNCTION static_cast<const char *>(__FUNCTION__)
+#endif
+
+#ifdef SPDLOG_NO_EXCEPTIONS
+#define SPDLOG_TRY
+#define SPDLOG_THROW(ex)                                                                                                                   \
+    do                                                                                                                                     \
+    {                                                                                                                                      \
+        printf("spdlog fatal error: %s\n", ex.what());                                                                                     \
+        std::abort();                                                                                                                      \
+    } while (0)
+#define SPDLOG_CATCH_ALL()
+#else
+#define SPDLOG_TRY try
+#define SPDLOG_THROW(ex) throw(ex)
+#define SPDLOG_CATCH_ALL() catch (...)
+#endif
+
+namespace spdlog {
+
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+using filename_t = std::wstring;
+#define SPDLOG_FILENAME_T(s) L##s
+#else
+using filename_t = std::string;
+#define SPDLOG_FILENAME_T(s) s
+#endif
+
+using log_clock = std::chrono::system_clock;
+using sink_ptr = std::shared_ptr<sinks::sink>;
+using sinks_init_list = std::initializer_list<sink_ptr>;
+using err_handler = std::function<void(const std::string &err_msg)>;
+using string_view_t = fmt::basic_string_view<char>;
+using wstring_view_t = fmt::basic_string_view<wchar_t>;
+using memory_buf_t = fmt::basic_memory_buffer<char, 250>;
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+#ifndef _WIN32
+#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+#else
+template<typename T>
+struct is_convertible_to_wstring_view : std::is_convertible<T, wstring_view_t>
+{};
+#endif // _WIN32
+#else
+template<typename>
+struct is_convertible_to_wstring_view : std::false_type
+{};
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+#if defined(SPDLOG_NO_ATOMIC_LEVELS)
+using level_t = details::null_atomic_int;
+#else
+using level_t = std::atomic<int>;
+#endif
+
+#define SPDLOG_LEVEL_TRACE 0
+#define SPDLOG_LEVEL_DEBUG 1
+#define SPDLOG_LEVEL_INFO 2
+#define SPDLOG_LEVEL_WARN 3
+#define SPDLOG_LEVEL_ERROR 4
+#define SPDLOG_LEVEL_CRITICAL 5
+#define SPDLOG_LEVEL_OFF 6
+
+#if !defined(SPDLOG_ACTIVE_LEVEL)
+#define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
+#endif
+
+// Log level enum
+namespace level {
+enum level_enum
+{
+    trace = SPDLOG_LEVEL_TRACE,
+    debug = SPDLOG_LEVEL_DEBUG,
+    info = SPDLOG_LEVEL_INFO,
+    warn = SPDLOG_LEVEL_WARN,
+    err = SPDLOG_LEVEL_ERROR,
+    critical = SPDLOG_LEVEL_CRITICAL,
+    off = SPDLOG_LEVEL_OFF,
+    n_levels
+};
+
+#if !defined(SPDLOG_LEVEL_NAMES)
+#define SPDLOG_LEVEL_NAMES                                                                                                                 \
+    {                                                                                                                                      \
+        "TRACE", "DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL", "off"                                                                    \
+    }
+#endif
+
+#if !defined(SPDLOG_SHORT_LEVEL_NAMES)
+
+#define SPDLOG_SHORT_LEVEL_NAMES                                                                                                           \
+    {                                                                                                                                      \
+        "T", "D", "I", "W", "E", "C", "O"                                                                                                  \
+    }
+#endif
+
+SPDLOG_API string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+SPDLOG_API const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+SPDLOG_API spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT;
+
+} // namespace level
+
+//
+// Color mode used by sinks with color support.
+//
+enum class color_mode
+{
+    always,
+    automatic,
+    never
+};
+
+//
+// Pattern time - specific time getting to use for pattern_formatter.
+// local time by default
+//
+enum class pattern_time_type
+{
+    local, // log localtime
+    utc    // log utc
+};
+
+//
+// Log exception
+//
+class SPDLOG_API spdlog_ex : public std::exception
+{
+public:
+    explicit spdlog_ex(std::string msg);
+    spdlog_ex(const std::string &msg, int last_errno);
+    const char *what() const SPDLOG_NOEXCEPT override;
+
+private:
+    std::string msg_;
+};
+
+SPDLOG_API void throw_spdlog_ex(const std::string &msg, int last_errno);
+SPDLOG_API void throw_spdlog_ex(std::string msg);
+
+struct source_loc
+{
+    SPDLOG_CONSTEXPR source_loc() = default;
+    SPDLOG_CONSTEXPR source_loc(const char *filename_in, int line_in, const char *funcname_in)
+        : filename{filename_in}
+        , line{line_in}
+        , funcname{funcname_in}
+    {}
+
+    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT
+    {
+        return line == 0;
+    }
+    const char *filename{nullptr};
+    int line{0};
+    const char *funcname{nullptr};
+};
+
+namespace details {
+// make_unique support for pre c++14
+
+#if __cplusplus >= 201402L // C++14 and beyond
+using std::make_unique;
+#else
+template<typename T, typename... Args>
+std::unique_ptr<T> make_unique(Args &&...args)
+{
+    static_assert(!std::is_array<T>::value, "arrays not supported");
+    return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
+#endif
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "common-inl.h"
+#endif

spdlog/details/backtracer-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/backtracer.h>
+#endif
+namespace spdlog {
+namespace details {
+SPDLOG_INLINE backtracer::backtracer(const backtracer &other)
+{
+    std::lock_guard<std::mutex> lock(other.mutex_);
+    enabled_ = other.enabled();
+    messages_ = other.messages_;
+}
+
+SPDLOG_INLINE backtracer::backtracer(backtracer &&other) SPDLOG_NOEXCEPT
+{
+    std::lock_guard<std::mutex> lock(other.mutex_);
+    enabled_ = other.enabled();
+    messages_ = std::move(other.messages_);
+}
+
+SPDLOG_INLINE backtracer &backtracer::operator=(backtracer other)
+{
+    std::lock_guard<std::mutex> lock(mutex_);
+    enabled_ = other.enabled();
+    messages_ = std::move(other.messages_);
+    return *this;
+}
+
+SPDLOG_INLINE void backtracer::enable(size_t size)
+{
+    std::lock_guard<std::mutex> lock{mutex_};
+    enabled_.store(true, std::memory_order_relaxed);
+    messages_ = circular_q<log_msg_buffer>{size};
+}
+
+SPDLOG_INLINE void backtracer::disable()
+{
+    std::lock_guard<std::mutex> lock{mutex_};
+    enabled_.store(false, std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE bool backtracer::enabled() const
+{
+    return enabled_.load(std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE void backtracer::push_back(const log_msg &msg)
+{
+    std::lock_guard<std::mutex> lock{mutex_};
+    messages_.push_back(log_msg_buffer{msg});
+}
+
+// pop all items in the q and apply the given fun on each of them.
+SPDLOG_INLINE void backtracer::foreach_pop(std::function<void(const details::log_msg &)> fun)
+{
+    std::lock_guard<std::mutex> lock{mutex_};
+    while (!messages_.empty())
+    {
+        auto &front_msg = messages_.front();
+        fun(front_msg);
+        messages_.pop_front();
+    }
+}
+} // namespace details
+} // namespace spdlog

spdlog/details/backtracer.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg_buffer.h>
+#include <spdlog/details/circular_q.h>
+
+#include <atomic>
+#include <mutex>
+#include <functional>
+
+// Store log messages in circular buffer.
+// Useful for storing debug data in case of error/warning happens.
+
+namespace spdlog {
+namespace details {
+class SPDLOG_API backtracer
+{
+    mutable std::mutex mutex_;
+    std::atomic<bool> enabled_{false};
+    circular_q<log_msg_buffer> messages_;
+
+public:
+    backtracer() = default;
+    backtracer(const backtracer &other);
+
+    backtracer(backtracer &&other) SPDLOG_NOEXCEPT;
+    backtracer &operator=(backtracer other);
+
+    void enable(size_t size);
+    void disable();
+    bool enabled() const;
+    void push_back(const log_msg &msg);
+
+    // pop all items in the q and apply the given fun on each of them.
+    void foreach_pop(std::function<void(const details::log_msg &)> fun);
+};
+
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "backtracer-inl.h"
+#endif
\ No newline at end of file

spdlog/details/circular_q.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+// circular q view of std::vector.
+#pragma once
+
+#include <vector>
+#include <cassert>
+
+namespace spdlog {
+namespace details {
+template<typename T>
+class circular_q
+{
+    size_t max_items_ = 0;
+    typename std::vector<T>::size_type head_ = 0;
+    typename std::vector<T>::size_type tail_ = 0;
+    size_t overrun_counter_ = 0;
+    std::vector<T> v_;
+
+public:
+    using value_type = T;
+
+    // empty ctor - create a disabled queue with no elements allocated at all
+    circular_q() = default;
+
+    explicit circular_q(size_t max_items)
+        : max_items_(max_items + 1) // one item is reserved as marker for full q
+        , v_(max_items_)
+    {}
+
+    circular_q(const circular_q &) = default;
+    circular_q &operator=(const circular_q &) = default;
+
+    // move cannot be default,
+    // since we need to reset head_, tail_, etc to zero in the moved object
+    circular_q(circular_q &&other) SPDLOG_NOEXCEPT
+    {
+        copy_moveable(std::move(other));
+    }
+
+    circular_q &operator=(circular_q &&other) SPDLOG_NOEXCEPT
+    {
+        copy_moveable(std::move(other));
+        return *this;
+    }
+
+    // push back, overrun (oldest) item if no room left
+    void push_back(T &&item)
+    {
+        if (max_items_ > 0)
+        {
+            v_[tail_] = std::move(item);
+            tail_ = (tail_ + 1) % max_items_;
+
+            if (tail_ == head_) // overrun last item if full
+            {
+                head_ = (head_ + 1) % max_items_;
+                ++overrun_counter_;
+            }
+        }
+    }
+
+    // Return reference to the front item.
+    // If there are no elements in the container, the behavior is undefined.
+    const T &front() const
+    {
+        return v_[head_];
+    }
+
+    T &front()
+    {
+        return v_[head_];
+    }
+
+    // Return number of elements actually stored
+    size_t size() const
+    {
+        if (tail_ >= head_)
+        {
+            return tail_ - head_;
+        }
+        else
+        {
+            return max_items_ - (head_ - tail_);
+        }
+    }
+
+    // Return const reference to item by index.
+    // If index is out of range 0…size()-1, the behavior is undefined.
+    const T &at(size_t i) const
+    {
+        assert(i < size());
+        return v_[(head_ + i) % max_items_];
+    }
+
+    // Pop item from front.
+    // If there are no elements in the container, the behavior is undefined.
+    void pop_front()
+    {
+        head_ = (head_ + 1) % max_items_;
+    }
+
+    bool empty() const
+    {
+        return tail_ == head_;
+    }
+
+    bool full() const
+    {
+        // head is ahead of the tail by 1
+        if (max_items_ > 0)
+        {
+            return ((tail_ + 1) % max_items_) == head_;
+        }
+        return false;
+    }
+
+    size_t overrun_counter() const
+    {
+        return overrun_counter_;
+    }
+
+private:
+    // copy from other&& and reset it to disabled state
+    void copy_moveable(circular_q &&other) SPDLOG_NOEXCEPT
+    {
+        max_items_ = other.max_items_;
+        head_ = other.head_;
+        tail_ = other.tail_;
+        overrun_counter_ = other.overrun_counter_;
+        v_ = std::move(other.v_);
+
+        // put &&other in disabled, but valid state
+        other.max_items_ = 0;
+        other.head_ = other.tail_ = 0;
+        other.overrun_counter_ = 0;
+    }
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/console_globals.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <mutex>
+
+namespace spdlog {
+namespace details {
+
+struct console_mutex
+{
+    using mutex_t = std::mutex;
+    static mutex_t &mutex()
+    {
+        static mutex_t s_mutex;
+        return s_mutex;
+    }
+};
+
+struct console_nullmutex
+{
+    using mutex_t = null_mutex;
+    static mutex_t &mutex()
+    {
+        static mutex_t s_mutex;
+        return s_mutex;
+    }
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/file_helper-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/file_helper.h>
+#endif
+
+#include <spdlog/details/os.h>
+#include <spdlog/common.h>
+
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <string>
+#include <thread>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE file_helper::~file_helper()
+{
+    close();
+}
+
+SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate)
+{
+    close();
+    filename_ = fname;
+    auto *mode = truncate ? SPDLOG_FILENAME_T("wb") : SPDLOG_FILENAME_T("ab");
+
+    for (int tries = 0; tries < open_tries_; ++tries)
+    {
+        // create containing folder if not exists already.
+        os::create_dir(os::dir_name(fname));
+        if (!os::fopen_s(&fd_, fname, mode))
+        {
+            return;
+        }
+
+        details::os::sleep_for_millis(open_interval_);
+    }
+
+    throw_spdlog_ex("Failed opening file " + os::filename_to_str(filename_) + " for writing", errno);
+}
+
+SPDLOG_INLINE void file_helper::reopen(bool truncate)
+{
+    if (filename_.empty())
+    {
+        throw_spdlog_ex("Failed re opening file - was not opened before");
+    }
+    this->open(filename_, truncate);
+}
+
+SPDLOG_INLINE void file_helper::flush()
+{
+    std::fflush(fd_);
+}
+
+SPDLOG_INLINE void file_helper::close()
+{
+    if (fd_ != nullptr)
+    {
+        std::fclose(fd_);
+        fd_ = nullptr;
+    }
+}
+
+SPDLOG_INLINE void file_helper::write(const memory_buf_t &buf)
+{
+    size_t msg_size = buf.size();
+    auto data = buf.data();
+    if (std::fwrite(data, 1, msg_size, fd_) != msg_size)
+    {
+        throw_spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno);
+    }
+}
+
+SPDLOG_INLINE size_t file_helper::size() const
+{
+    if (fd_ == nullptr)
+    {
+        throw_spdlog_ex("Cannot use size() on closed file " + os::filename_to_str(filename_));
+    }
+    return os::filesize(fd_);
+}
+
+SPDLOG_INLINE const filename_t &file_helper::filename() const
+{
+    return filename_;
+}
+
+//
+// return file path and its extension:
+//
+// "mylog.txt" => ("mylog", ".txt")
+// "mylog" => ("mylog", "")
+// "mylog." => ("mylog.", "")
+// "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
+//
+// the starting dot in filenames is ignored (hidden files):
+//
+// ".mylog" => (".mylog". "")
+// "my_folder/.mylog" => ("my_folder/.mylog", "")
+// "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
+SPDLOG_INLINE std::tuple<filename_t, filename_t> file_helper::split_by_extension(const filename_t &fname)
+{
+    auto ext_index = fname.rfind('.');
+
+    // no valid extension found - return whole path and empty string as
+    // extension
+    if (ext_index == filename_t::npos || ext_index == 0 || ext_index == fname.size() - 1)
+    {
+        return std::make_tuple(fname, filename_t());
+    }
+
+    // treat cases like "/etc/rc.d/somelogfile or "/abc/.hiddenfile"
+    auto folder_index = fname.rfind(details::os::folder_sep);
+    if (folder_index != filename_t::npos && folder_index >= ext_index - 1)
+    {
+        return std::make_tuple(fname, filename_t());
+    }
+
+    // finally - return a valid base and extension tuple
+    return std::make_tuple(fname.substr(0, ext_index), fname.substr(ext_index));
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/file_helper.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+// Helper class for file sinks.
+// When failing to open a file, retry several times(5) with a delay interval(10 ms).
+// Throw spdlog_ex exception on errors.
+
+class SPDLOG_API file_helper
+{
+public:
+    explicit file_helper() = default;
+
+    file_helper(const file_helper &) = delete;
+    file_helper &operator=(const file_helper &) = delete;
+    ~file_helper();
+
+    void open(const filename_t &fname, bool truncate = false);
+    void reopen(bool truncate);
+    void flush();
+    void close();
+    void write(const memory_buf_t &buf);
+    size_t size() const;
+    const filename_t &filename() const;
+
+    //
+    // return file path and its extension:
+    //
+    // "mylog.txt" => ("mylog", ".txt")
+    // "mylog" => ("mylog", "")
+    // "mylog." => ("mylog.", "")
+    // "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
+    //
+    // the starting dot in filenames is ignored (hidden files):
+    //
+    // ".mylog" => (".mylog". "")
+    // "my_folder/.mylog" => ("my_folder/.mylog", "")
+    // "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
+    static std::tuple<filename_t, filename_t> split_by_extension(const filename_t &fname);
+
+private:
+    const int open_tries_ = 5;
+    const int open_interval_ = 10;
+    std::FILE *fd_{nullptr};
+    filename_t filename_;
+};
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "file_helper-inl.h"
+#endif

spdlog/details/fmt_helper.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+#pragma once
+
+#include <chrono>
+#include <type_traits>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/common.h>
+
+// Some fmt helpers to efficiently format and pad ints and strings
+namespace spdlog {
+namespace details {
+namespace fmt_helper {
+
+inline spdlog::string_view_t to_string_view(const memory_buf_t &buf) SPDLOG_NOEXCEPT
+{
+    return spdlog::string_view_t{buf.data(), buf.size()};
+}
+
+inline void append_string_view(spdlog::string_view_t view, memory_buf_t &dest)
+{
+    auto *buf_ptr = view.data();
+    dest.append(buf_ptr, buf_ptr + view.size());
+}
+
+template<typename T>
+inline void append_int(T n, memory_buf_t &dest)
+{
+    fmt::format_int i(n);
+    dest.append(i.data(), i.data() + i.size());
+}
+
+template<typename T>
+inline unsigned int count_digits(T n)
+{
+    using count_type = typename std::conditional<(sizeof(T) > sizeof(uint32_t)), uint64_t, uint32_t>::type;
+    return static_cast<unsigned int>(fmt::
+// fmt 7.0.0 renamed the internal namespace to detail.
+// See: https://github.com/fmtlib/fmt/issues/1538
+#if FMT_VERSION < 70000
+            internal
+#else
+            detail
+#endif
+        ::count_digits(static_cast<count_type>(n)));
+}
+
+inline void pad2(int n, memory_buf_t &dest)
+{
+    if (n >= 0 && n < 100) // 0-99
+    {
+        dest.push_back(static_cast<char>('0' + n / 10));
+        dest.push_back(static_cast<char>('0' + n % 10));
+    }
+    else // unlikely, but just in case, let fmt deal with it
+    {
+        fmt::format_to(dest, "{:02}", n);
+    }
+}
+
+template<typename T>
+inline void pad_uint(T n, unsigned int width, memory_buf_t &dest)
+{
+    static_assert(std::is_unsigned<T>::value, "pad_uint must get unsigned T");
+    for (auto digits = count_digits(n); digits < width; digits++)
+    {
+        dest.push_back('0');
+    }
+    append_int(n, dest);
+}
+
+template<typename T>
+inline void pad3(T n, memory_buf_t &dest)
+{
+    static_assert(std::is_unsigned<T>::value, "pad3 must get unsigned T");
+    if (n < 1000)
+    {
+        dest.push_back(static_cast<char>(n / 100 + '0'));
+        n = n % 100;
+        dest.push_back(static_cast<char>((n / 10) + '0'));
+        dest.push_back(static_cast<char>((n % 10) + '0'));
+    }
+    else
+    {
+        append_int(n, dest);
+    }
+}
+
+template<typename T>
+inline void pad6(T n, memory_buf_t &dest)
+{
+    pad_uint(n, 6, dest);
+}
+
+template<typename T>
+inline void pad9(T n, memory_buf_t &dest)
+{
+    pad_uint(n, 9, dest);
+}
+
+// return fraction of a second of the given time_point.
+// e.g.
+// fraction<std::milliseconds>(tp) -> will return the millis part of the second
+template<typename ToDuration>
+inline ToDuration time_fraction(log_clock::time_point tp)
+{
+    using std::chrono::duration_cast;
+    using std::chrono::seconds;
+    auto duration = tp.time_since_epoch();
+    auto secs = duration_cast<seconds>(duration);
+    return duration_cast<ToDuration>(duration) - duration_cast<ToDuration>(secs);
+}
+
+} // namespace fmt_helper
+} // namespace details
+} // namespace spdlog

spdlog/details/log_msg-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/log_msg.h>
+#endif
+
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE log_msg::log_msg(spdlog::log_clock::time_point log_time, spdlog::source_loc loc, string_view_t a_logger_name,
+    spdlog::level::level_enum lvl, spdlog::string_view_t msg)
+    : logger_name(a_logger_name)
+    , level(lvl)
+    , time(log_time)
+#ifndef SPDLOG_NO_THREAD_ID
+    , thread_id(os::thread_id())
+#endif
+    , source(loc)
+    , payload(msg)
+{}
+
+SPDLOG_INLINE log_msg::log_msg(
+    spdlog::source_loc loc, string_view_t a_logger_name, spdlog::level::level_enum lvl, spdlog::string_view_t msg)
+    : log_msg(os::now(), loc, a_logger_name, lvl, msg)
+{}
+
+SPDLOG_INLINE log_msg::log_msg(string_view_t a_logger_name, spdlog::level::level_enum lvl, spdlog::string_view_t msg)
+    : log_msg(os::now(), source_loc{}, a_logger_name, lvl, msg)
+{}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/log_msg.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <string>
+
+namespace spdlog {
+namespace details {
+struct SPDLOG_API log_msg
+{
+    log_msg() = default;
+    log_msg(log_clock::time_point log_time, source_loc loc, string_view_t logger_name, level::level_enum lvl, string_view_t msg);
+    log_msg(source_loc loc, string_view_t logger_name, level::level_enum lvl, string_view_t msg);
+    log_msg(string_view_t logger_name, level::level_enum lvl, string_view_t msg);
+    log_msg(const log_msg &other) = default;
+
+    string_view_t logger_name;
+    level::level_enum level{level::off};
+    log_clock::time_point time;
+    size_t thread_id{0};
+
+    // wrapping the formatted text with color (updated by pattern_formatter).
+    mutable size_t color_range_start{0};
+    mutable size_t color_range_end{0};
+
+    source_loc source;
+    string_view_t payload;
+};
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "log_msg-inl.h"
+#endif

spdlog/details/log_msg_buffer-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/log_msg_buffer.h>
+#endif
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(const log_msg &orig_msg)
+    : log_msg{orig_msg}
+{
+    buffer.append(logger_name.begin(), logger_name.end());
+    buffer.append(payload.begin(), payload.end());
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(const log_msg_buffer &other)
+    : log_msg{other}
+{
+    buffer.append(logger_name.begin(), logger_name.end());
+    buffer.append(payload.begin(), payload.end());
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT : log_msg{other}, buffer{std::move(other.buffer)}
+{
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer &log_msg_buffer::operator=(const log_msg_buffer &other)
+{
+    log_msg::operator=(other);
+    buffer.clear();
+    buffer.append(other.buffer.data(), other.buffer.data() + other.buffer.size());
+    update_string_views();
+    return *this;
+}
+
+SPDLOG_INLINE log_msg_buffer &log_msg_buffer::operator=(log_msg_buffer &&other) SPDLOG_NOEXCEPT
+{
+    log_msg::operator=(other);
+    buffer = std::move(other.buffer);
+    update_string_views();
+    return *this;
+}
+
+SPDLOG_INLINE void log_msg_buffer::update_string_views()
+{
+    logger_name = string_view_t{buffer.data(), logger_name.size()};
+    payload = string_view_t{buffer.data() + logger_name.size(), payload.size()};
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/log_msg_buffer.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg.h>
+
+namespace spdlog {
+namespace details {
+
+// Extend log_msg with internal buffer to store its payload.
+// This is needed since log_msg holds string_views that points to stack data.
+
+class SPDLOG_API log_msg_buffer : public log_msg
+{
+    memory_buf_t buffer;
+    void update_string_views();
+
+public:
+    log_msg_buffer() = default;
+    explicit log_msg_buffer(const log_msg &orig_msg);
+    log_msg_buffer(const log_msg_buffer &other);
+    log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT;
+    log_msg_buffer &operator=(const log_msg_buffer &other);
+    log_msg_buffer &operator=(log_msg_buffer &&other) SPDLOG_NOEXCEPT;
+};
+
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "log_msg_buffer-inl.h"
+#endif

spdlog/details/mpmc_blocking_q.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// multi producer-multi consumer blocking queue.
+// enqueue(..) - will block until room found to put the new message.
+// enqueue_nowait(..) - will return immediately with false if no room left in
+// the queue.
+// dequeue_for(..) - will block until the queue is not empty or timeout have
+// passed.
+
+#include <spdlog/details/circular_q.h>
+
+#include <condition_variable>
+#include <mutex>
+
+namespace spdlog {
+namespace details {
+
+template<typename T>
+class mpmc_blocking_queue
+{
+public:
+    using item_type = T;
+    explicit mpmc_blocking_queue(size_t max_items)
+        : q_(max_items)
+    {}
+
+#ifndef __MINGW32__
+    // try to enqueue and block if no room left
+    void enqueue(T &&item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            pop_cv_.wait(lock, [this] { return !this->q_.full(); });
+            q_.push_back(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    // enqueue immediately. overrun oldest message in the queue if no room left.
+    void enqueue_nowait(T &&item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            q_.push_back(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    // try to dequeue item. if no item found. wait upto timeout and try again
+    // Return true, if succeeded dequeue item, false otherwise
+    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
+            {
+                return false;
+            }
+            popped_item = std::move(q_.front());
+            q_.pop_front();
+        }
+        pop_cv_.notify_one();
+        return true;
+    }
+
+#else
+    // apparently mingw deadlocks if the mutex is released before cv.notify_one(),
+    // so release the mutex at the very end each function.
+
+    // try to enqueue and block if no room left
+    void enqueue(T &&item)
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        pop_cv_.wait(lock, [this] { return !this->q_.full(); });
+        q_.push_back(std::move(item));
+        push_cv_.notify_one();
+    }
+
+    // enqueue immediately. overrun oldest message in the queue if no room left.
+    void enqueue_nowait(T &&item)
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        q_.push_back(std::move(item));
+        push_cv_.notify_one();
+    }
+
+    // try to dequeue item. if no item found. wait upto timeout and try again
+    // Return true, if succeeded dequeue item, false otherwise
+    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
+        {
+            return false;
+        }
+        popped_item = std::move(q_.front());
+        q_.pop_front();
+        pop_cv_.notify_one();
+        return true;
+    }
+
+#endif
+
+    size_t overrun_counter()
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        return q_.overrun_counter();
+    }
+
+    size_t size()
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        return q_.size();
+    }
+
+private:
+    std::mutex queue_mutex_;
+    std::condition_variable push_cv_;
+    std::condition_variable pop_cv_;
+    spdlog::details::circular_q<T> q_;
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/null_mutex.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <atomic>
+#include <utility>
+// null, no cost dummy "mutex" and dummy "atomic" int
+
+namespace spdlog {
+namespace details {
+struct null_mutex
+{
+    void lock() const {}
+    void unlock() const {}
+    bool try_lock() const
+    {
+        return true;
+    }
+};
+
+struct null_atomic_int
+{
+    int value;
+    null_atomic_int() = default;
+
+    explicit null_atomic_int(int new_value)
+        : value(new_value)
+    {}
+
+    int load(std::memory_order = std::memory_order_relaxed) const
+    {
+        return value;
+    }
+
+    void store(int new_value, std::memory_order = std::memory_order_relaxed)
+    {
+        value = new_value;
+    }
+
+    int exchange(int new_value, std::memory_order = std::memory_order_relaxed)
+    {
+        std::swap(new_value, value);
+        return new_value; // return value before the call
+    }
+};
+
+} // namespace details
+} // namespace spdlog

spdlog/details/os-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/os.h>
+#endif
+
+#include <spdlog/common.h>
+
+#include <algorithm>
+#include <chrono>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <string>
+#include <thread>
+#include <array>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#ifdef _WIN32
+
+#include <io.h>      // _get_osfhandle and _isatty support
+#include <process.h> //  _get_pid support
+#include <spdlog/details/windows_include.h>
+
+#ifdef __MINGW32__
+#include <share.h>
+#endif
+
+#if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)
+#include <limits>
+#endif
+
+#include <direct.h> // for _mkdir/_wmkdir
+
+#else // unix
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#ifdef __linux__
+#include <sys/syscall.h> //Use gettid() syscall under linux to get thread id
+
+#elif defined(_AIX)
+#include <pthread.h> // for pthread_getthreadid_np
+
+#elif defined(__DragonFly__) || defined(__FreeBSD__)
+#include <pthread_np.h> // for pthread_getthreadid_np
+
+#elif defined(__NetBSD__)
+#include <lwp.h> // for _lwp_self
+
+#elif defined(__sun)
+#include <thread.h> // for thr_self
+#endif
+
+#endif // unix
+
+#ifndef __has_feature      // Clang - feature checking macros.
+#define __has_feature(x) 0 // Compatibility with non-clang compilers.
+#endif
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+SPDLOG_INLINE spdlog::log_clock::time_point now() SPDLOG_NOEXCEPT
+{
+
+#if defined __linux__ && defined SPDLOG_CLOCK_COARSE
+    timespec ts;
+    ::clock_gettime(CLOCK_REALTIME_COARSE, &ts);
+    return std::chrono::time_point<log_clock, typename log_clock::duration>(
+        std::chrono::duration_cast<typename log_clock::duration>(std::chrono::seconds(ts.tv_sec) + std::chrono::nanoseconds(ts.tv_nsec)));
+
+#else
+    return log_clock::now();
+#endif
+}
+SPDLOG_INLINE std::tm localtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT
+{
+
+#ifdef _WIN32
+    std::tm tm;
+    ::localtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    ::localtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+SPDLOG_INLINE std::tm localtime() SPDLOG_NOEXCEPT
+{
+    std::time_t now_t = ::time(nullptr);
+    return localtime(now_t);
+}
+
+SPDLOG_INLINE std::tm gmtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT
+{
+
+#ifdef _WIN32
+    std::tm tm;
+    ::gmtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    ::gmtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+SPDLOG_INLINE std::tm gmtime() SPDLOG_NOEXCEPT
+{
+    std::time_t now_t = ::time(nullptr);
+    return gmtime(now_t);
+}
+
+// fopen_s on non windows for writing
+SPDLOG_INLINE bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode)
+{
+#ifdef _WIN32
+#ifdef SPDLOG_WCHAR_FILENAMES
+    *fp = ::_wfsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
+#else
+    *fp = ::_fsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
+#endif
+#if defined(SPDLOG_PREVENT_CHILD_FD)
+    if (*fp != nullptr)
+    {
+        auto file_handle = reinterpret_cast<HANDLE>(_get_osfhandle(::_fileno(*fp)));
+        if (!::SetHandleInformation(file_handle, HANDLE_FLAG_INHERIT, 0))
+        {
+            ::fclose(*fp);
+            *fp = nullptr;
+        }
+    }
+#endif
+#else // unix
+#if defined(SPDLOG_PREVENT_CHILD_FD)
+    const int mode_flag = mode == SPDLOG_FILENAME_T("ab") ? O_APPEND : O_TRUNC;
+    const int fd = ::open((filename.c_str()), O_CREAT | O_WRONLY | O_CLOEXEC | mode_flag, mode_t(0644));
+    if (fd == -1)
+    {
+        return false;
+    }
+    *fp = ::fdopen(fd, mode.c_str());
+    if (*fp == nullptr)
+    {
+        ::close(fd);
+    }
+#else
+    *fp = ::fopen((filename.c_str()), mode.c_str());
+#endif
+#endif
+
+    return *fp == nullptr;
+}
+
+SPDLOG_INLINE int remove(const filename_t &filename) SPDLOG_NOEXCEPT
+{
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return ::_wremove(filename.c_str());
+#else
+    return std::remove(filename.c_str());
+#endif
+}
+
+SPDLOG_INLINE int remove_if_exists(const filename_t &filename) SPDLOG_NOEXCEPT
+{
+    return path_exists(filename) ? remove(filename) : 0;
+}
+
+SPDLOG_INLINE int rename(const filename_t &filename1, const filename_t &filename2) SPDLOG_NOEXCEPT
+{
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return ::_wrename(filename1.c_str(), filename2.c_str());
+#else
+    return std::rename(filename1.c_str(), filename2.c_str());
+#endif
+}
+
+// Return true if path exists (file or directory)
+SPDLOG_INLINE bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT
+{
+#ifdef _WIN32
+#ifdef SPDLOG_WCHAR_FILENAMES
+    auto attribs = ::GetFileAttributesW(filename.c_str());
+#else
+    auto attribs = ::GetFileAttributesA(filename.c_str());
+#endif
+    return attribs != INVALID_FILE_ATTRIBUTES;
+#else // common linux/unix all have the stat system call
+    struct stat buffer;
+    return (::stat(filename.c_str(), &buffer) == 0);
+#endif
+}
+
+// Return file size according to open FILE* object
+SPDLOG_INLINE size_t filesize(FILE *f)
+{
+    if (f == nullptr)
+    {
+        throw_spdlog_ex("Failed getting file size. fd is null");
+    }
+#if defined(_WIN32) && !defined(__CYGWIN__)
+    int fd = ::_fileno(f);
+#if _WIN64 // 64 bits
+    __int64 ret = ::_filelengthi64(fd);
+    if (ret >= 0)
+    {
+        return static_cast<size_t>(ret);
+    }
+
+#else // windows 32 bits
+    long ret = ::_filelength(fd);
+    if (ret >= 0)
+    {
+        return static_cast<size_t>(ret);
+    }
+#endif
+
+#else // unix
+// OpenBSD doesn't compile with :: before the fileno(..)
+#if defined(__OpenBSD__)
+    int fd = fileno(f);
+#else
+    int fd = ::fileno(f);
+#endif
+// 64 bits(but not in osx or cygwin, where fstat64 is deprecated)
+#if (defined(__linux__) || defined(__sun) || defined(_AIX)) && (defined(__LP64__) || defined(_LP64))
+    struct stat64 st;
+    if (::fstat64(fd, &st) == 0)
+    {
+        return static_cast<size_t>(st.st_size);
+    }
+#else // other unix or linux 32 bits or cygwin
+    struct stat st;
+    if (::fstat(fd, &st) == 0)
+    {
+        return static_cast<size_t>(st.st_size);
+    }
+#endif
+#endif
+    throw_spdlog_ex("Failed getting file size from fd", errno);
+    return 0; // will not be reached.
+}
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm)
+{
+
+#ifdef _WIN32
+#if _WIN32_WINNT < _WIN32_WINNT_WS08
+    TIME_ZONE_INFORMATION tzinfo;
+    auto rv = ::GetTimeZoneInformation(&tzinfo);
+#else
+    DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
+    auto rv = ::GetDynamicTimeZoneInformation(&tzinfo);
+#endif
+    if (rv == TIME_ZONE_ID_INVALID)
+        throw_spdlog_ex("Failed getting timezone info. ", errno);
+
+    int offset = -tzinfo.Bias;
+    if (tm.tm_isdst)
+    {
+        offset -= tzinfo.DaylightBias;
+    }
+    else
+    {
+        offset -= tzinfo.StandardBias;
+    }
+    return offset;
+#else
+
+#if defined(sun) || defined(__sun) || defined(_AIX) || (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
+    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
+    struct helper
+    {
+        static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(), const std::tm &gmtm = details::os::gmtime())
+        {
+            int local_year = localtm.tm_year + (1900 - 1);
+            int gmt_year = gmtm.tm_year + (1900 - 1);
+
+            long int days = (
+                // difference in day of year
+                localtm.tm_yday -
+                gmtm.tm_yday
+
+                // + intervening leap days
+                + ((local_year >> 2) - (gmt_year >> 2)) - (local_year / 100 - gmt_year / 100) +
+                ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
+
+                // + difference in years * 365 */
+                + (long int)(local_year - gmt_year) * 365);
+
+            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
+            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
+            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);
+
+            return secs;
+        }
+    };
+
+    auto offset_seconds = helper::calculate_gmt_offset(tm);
+#else
+    auto offset_seconds = tm.tm_gmtoff;
+#endif
+
+    return static_cast<int>(offset_seconds / 60);
+#endif
+}
+
+// Return current thread id as size_t
+// It exists because the std::this_thread::get_id() is much slower(especially
+// under VS 2013)
+SPDLOG_INLINE size_t _thread_id() SPDLOG_NOEXCEPT
+{
+#ifdef _WIN32
+    return static_cast<size_t>(::GetCurrentThreadId());
+#elif defined(__linux__)
+#if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
+#define SYS_gettid __NR_gettid
+#endif
+    return static_cast<size_t>(::syscall(SYS_gettid));
+#elif defined(_AIX) || defined(__DragonFly__) || defined(__FreeBSD__)
+    return static_cast<size_t>(::pthread_getthreadid_np());
+#elif defined(__NetBSD__)
+    return static_cast<size_t>(::_lwp_self());
+#elif defined(__OpenBSD__)
+    return static_cast<size_t>(::getthrid());
+#elif defined(__sun)
+    return static_cast<size_t>(::thr_self());
+#elif __APPLE__
+    uint64_t tid;
+    pthread_threadid_np(nullptr, &tid);
+    return static_cast<size_t>(tid);
+#else // Default to standard C++11 (other Unix)
+    return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
+#endif
+}
+
+// Return current thread id as size_t (from thread local storage)
+SPDLOG_INLINE size_t thread_id() SPDLOG_NOEXCEPT
+{
+#if defined(SPDLOG_NO_TLS)
+    return _thread_id();
+#else // cache thread id in tls
+    static thread_local const size_t tid = _thread_id();
+    return tid;
+#endif
+}
+
+// This is avoid msvc issue in sleep_for that happens if the clock changes.
+// See https://github.com/gabime/spdlog/issues/609
+SPDLOG_INLINE void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT
+{
+#if defined(_WIN32)
+    ::Sleep(milliseconds);
+#else
+    std::this_thread::sleep_for(std::chrono::milliseconds(milliseconds));
+#endif
+}
+
+// wchar support for windows file names (SPDLOG_WCHAR_FILENAMES must be defined)
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
+{
+    memory_buf_t buf;
+    wstr_to_utf8buf(filename, buf);
+    return fmt::to_string(buf);
+}
+#else
+SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
+{
+    return filename;
+}
+#endif
+
+SPDLOG_INLINE int pid() SPDLOG_NOEXCEPT
+{
+
+#ifdef _WIN32
+    return static_cast<int>(::GetCurrentProcessId());
+#else
+    return static_cast<int>(::getpid());
+#endif
+}
+
+// Determine if the terminal supports colors
+// Based on: https://github.com/agauniyal/rang/
+SPDLOG_INLINE bool is_color_terminal() SPDLOG_NOEXCEPT
+{
+#ifdef _WIN32
+    return true;
+#else
+    static constexpr std::array<const char *, 14> terms = {
+        {"ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm", "linux", "msys", "putty", "rxvt", "screen", "vt100", "xterm"}};
+
+    const char *env_p = std::getenv("TERM");
+    if (env_p == nullptr)
+    {
+        return false;
+    }
+
+    static const bool result =
+        std::any_of(terms.begin(), terms.end(), [&](const char *term) { return std::strstr(env_p, term) != nullptr; });
+    return result;
+#endif
+}
+
+// Determine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_INLINE bool in_terminal(FILE *file) SPDLOG_NOEXCEPT
+{
+
+#ifdef _WIN32
+    return ::_isatty(_fileno(file)) != 0;
+#else
+    return ::isatty(fileno(file)) != 0;
+#endif
+}
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target)
+{
+    if (wstr.size() > static_cast<size_t>((std::numeric_limits<int>::max)()))
+    {
+        throw_spdlog_ex("UTF-16 string is too big to be converted to UTF-8");
+    }
+
+    int wstr_size = static_cast<int>(wstr.size());
+    if (wstr_size == 0)
+    {
+        target.resize(0);
+        return;
+    }
+
+    int result_size = static_cast<int>(target.capacity());
+    if ((wstr_size + 1) * 2 > result_size)
+    {
+        result_size = ::WideCharToMultiByte(CP_UTF8, 0, wstr.data(), wstr_size, NULL, 0, NULL, NULL);
+    }
+
+    if (result_size > 0)
+    {
+        target.resize(result_size);
+        result_size = ::WideCharToMultiByte(CP_UTF8, 0, wstr.data(), wstr_size, target.data(), result_size, NULL, NULL);
+
+        if (result_size > 0)
+        {
+            target.resize(result_size);
+            return;
+        }
+    }
+
+    throw_spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
+}
+#endif // (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+
+// return true on success
+static SPDLOG_INLINE bool mkdir_(const filename_t &path)
+{
+#ifdef _WIN32
+#ifdef SPDLOG_WCHAR_FILENAMES
+    return ::_wmkdir(path.c_str()) == 0;
+#else
+    return ::_mkdir(path.c_str()) == 0;
+#endif
+#else
+    return ::mkdir(path.c_str(), mode_t(0755)) == 0;
+#endif
+}
+
+// create the given directory - and all directories leading to it
+// return true on success or if the directory already exists
+SPDLOG_INLINE bool create_dir(filename_t path)
+{
+    if (path_exists(path))
+    {
+        return true;
+    }
+
+    if (path.empty())
+    {
+        return false;
+    }
+
+#ifdef _WIN32
+    // support forward slash in windows
+    std::replace(path.begin(), path.end(), '/', folder_sep);
+#endif
+
+    size_t search_offset = 0;
+    do
+    {
+        auto token_pos = path.find(folder_sep, search_offset);
+        // treat the entire path as a folder if no folder separator not found
+        if (token_pos == filename_t::npos)
+        {
+            token_pos = path.size();
+        }
+
+        auto subdir = path.substr(0, token_pos);
+
+        if (!subdir.empty() && !path_exists(subdir) && !mkdir_(subdir))
+        {
+            return false; // return error if failed creating dir
+        }
+        search_offset = token_pos + 1;
+    } while (search_offset < path.size());
+
+    return true;
+}
+
+// Return directory name from given path or empty string
+// "abc/file" => "abc"
+// "abc/" => "abc"
+// "abc" => ""
+// "abc///" => "abc//"
+SPDLOG_INLINE filename_t dir_name(filename_t path)
+{
+#ifdef _WIN32
+    // support forward slash in windows
+    std::replace(path.begin(), path.end(), '/', folder_sep);
+#endif
+    auto pos = path.find_last_of(folder_sep);
+    return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
+}
+
+std::string SPDLOG_INLINE getenv(const char *field)
+{
+
+#if defined(_MSC_VER)
+#if defined(__cplusplus_winrt)
+    return std::string{}; // not supported under uwp
+#else
+    size_t len = 0;
+    char buf[128];
+    bool ok = ::getenv_s(&len, buf, sizeof(buf), field) == 0;
+    return ok ? buf : std::string{};
+#endif
+#else // revert to getenv
+    char *buf = ::getenv(field);
+    return buf ? buf : std::string{};
+#endif
+}
+
+} // namespace os
+} // namespace details
+} // namespace spdlog

spdlog/details/os.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <ctime> // std::time_t
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+SPDLOG_API spdlog::log_clock::time_point now() SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm localtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm localtime() SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm gmtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm gmtime() SPDLOG_NOEXCEPT;
+
+// eol definition
+#if !defined(SPDLOG_EOL)
+#ifdef _WIN32
+#define SPDLOG_EOL "\r\n"
+#else
+#define SPDLOG_EOL "\n"
+#endif
+#endif
+
+SPDLOG_CONSTEXPR static const char *default_eol = SPDLOG_EOL;
+
+// folder separator
+#ifdef _WIN32
+static const char folder_sep = '\\';
+#else
+SPDLOG_CONSTEXPR static const char folder_sep = '/';
+#endif
+
+// fopen_s on non windows for writing
+SPDLOG_API bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode);
+
+// Remove filename. return 0 on success
+SPDLOG_API int remove(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+// Remove file if exists. return 0 on success
+// Note: Non atomic (might return failure to delete if concurrently deleted by other process/thread)
+SPDLOG_API int remove_if_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+SPDLOG_API int rename(const filename_t &filename1, const filename_t &filename2) SPDLOG_NOEXCEPT;
+
+// Return if file exists.
+SPDLOG_API bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+// Return file size according to open FILE* object
+SPDLOG_API size_t filesize(FILE *f);
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+SPDLOG_API int utc_minutes_offset(const std::tm &tm = details::os::localtime());
+
+// Return current thread id as size_t
+// It exists because the std::this_thread::get_id() is much slower(especially
+// under VS 2013)
+SPDLOG_API size_t _thread_id() SPDLOG_NOEXCEPT;
+
+// Return current thread id as size_t (from thread local storage)
+SPDLOG_API size_t thread_id() SPDLOG_NOEXCEPT;
+
+// This is avoid msvc issue in sleep_for that happens if the clock changes.
+// See https://github.com/gabime/spdlog/issues/609
+SPDLOG_API void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::string filename_to_str(const filename_t &filename);
+
+SPDLOG_API int pid() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal supports colors
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_API bool is_color_terminal() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_API bool in_terminal(FILE *file) SPDLOG_NOEXCEPT;
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+SPDLOG_API void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target);
+#endif
+
+// Return directory name from given path or empty string
+// "abc/file" => "abc"
+// "abc/" => "abc"
+// "abc" => ""
+// "abc///" => "abc//"
+SPDLOG_API filename_t dir_name(filename_t path);
+
+// Create a dir from the given path.
+// Return true if succeeded or if this dir already exists.
+SPDLOG_API bool create_dir(filename_t path);
+
+// non thread safe, cross platform getenv/getenv_s
+// return empty string if field not found
+SPDLOG_API std::string getenv(const char *field);
+
+} // namespace os
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "os-inl.h"
+#endif

spdlog/details/periodic_worker-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/periodic_worker.h>
+#endif
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE periodic_worker::periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval)
+{
+    active_ = (interval > std::chrono::seconds::zero());
+    if (!active_)
+    {
+        return;
+    }
+
+    worker_thread_ = std::thread([this, callback_fun, interval]() {
+        for (;;)
+        {
+            std::unique_lock<std::mutex> lock(this->mutex_);
+            if (this->cv_.wait_for(lock, interval, [this] { return !this->active_; }))
+            {
+                return; // active_ == false, so exit this thread
+            }
+            callback_fun();
+        }
+    });
+}
+
+// stop the worker thread and join it
+SPDLOG_INLINE periodic_worker::~periodic_worker()
+{
+    if (worker_thread_.joinable())
+    {
+        {
+            std::lock_guard<std::mutex> lock(mutex_);
+            active_ = false;
+        }
+        cv_.notify_one();
+        worker_thread_.join();
+    }
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/periodic_worker.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// periodic worker thread - periodically executes the given callback function.
+//
+// RAII over the owned thread:
+//    creates the thread on construction.
+//    stops and joins the thread on destruction (if the thread is executing a callback, wait for it to finish first).
+
+#include <chrono>
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+#include <thread>
+namespace spdlog {
+namespace details {
+
+class SPDLOG_API periodic_worker
+{
+public:
+    periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval);
+    periodic_worker(const periodic_worker &) = delete;
+    periodic_worker &operator=(const periodic_worker &) = delete;
+    // stop the worker thread and join it
+    ~periodic_worker();
+
+private:
+    bool active_;
+    std::thread worker_thread_;
+    std::mutex mutex_;
+    std::condition_variable cv_;
+};
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "periodic_worker-inl.h"
+#endif

spdlog/details/registry-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/registry.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/periodic_worker.h>
+#include <spdlog/logger.h>
+#include <spdlog/pattern_formatter.h>
+
+#ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
+// support for the default stdout color logger
+#ifdef _WIN32
+#include <spdlog/sinks/wincolor_sink.h>
+#else
+#include <spdlog/sinks/ansicolor_sink.h>
+#endif
+#endif // SPDLOG_DISABLE_DEFAULT_LOGGER
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+#include <unordered_map>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE registry::registry()
+    : formatter_(new pattern_formatter())
+{
+
+#ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
+    // create default logger (ansicolor_stdout_sink_mt or wincolor_stdout_sink_mt in windows).
+#ifdef _WIN32
+    auto color_sink = std::make_shared<sinks::wincolor_stdout_sink_mt>();
+#else
+    auto color_sink = std::make_shared<sinks::ansicolor_stdout_sink_mt>();
+#endif
+
+    const char *default_logger_name = "";
+    default_logger_ = std::make_shared<spdlog::logger>(default_logger_name, std::move(color_sink));
+    loggers_[default_logger_name] = default_logger_;
+
+#endif // SPDLOG_DISABLE_DEFAULT_LOGGER
+}
+
+SPDLOG_INLINE registry::~registry() = default;
+
+SPDLOG_INLINE void registry::register_logger(std::shared_ptr<logger> new_logger)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    register_logger_(std::move(new_logger));
+}
+
+SPDLOG_INLINE void registry::initialize_logger(std::shared_ptr<logger> new_logger)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    new_logger->set_formatter(formatter_->clone());
+
+    if (err_handler_)
+    {
+        new_logger->set_error_handler(err_handler_);
+    }
+
+    // set new level according to previously configured level or default level
+    auto it = log_levels_.find(new_logger->name());
+    auto new_level = it != log_levels_.end() ? it->second : global_log_level_;
+    new_logger->set_level(new_level);
+
+    new_logger->flush_on(flush_level_);
+
+    if (backtrace_n_messages_ > 0)
+    {
+        new_logger->enable_backtrace(backtrace_n_messages_);
+    }
+
+    if (automatic_registration_)
+    {
+        register_logger_(std::move(new_logger));
+    }
+}
+
+SPDLOG_INLINE std::shared_ptr<logger> registry::get(const std::string &logger_name)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto found = loggers_.find(logger_name);
+    return found == loggers_.end() ? nullptr : found->second;
+}
+
+SPDLOG_INLINE std::shared_ptr<logger> registry::default_logger()
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    return default_logger_;
+}
+
+// Return raw ptr to the default logger.
+// To be used directly by the spdlog default api (e.g. spdlog::info)
+// This make the default API faster, but cannot be used concurrently with set_default_logger().
+// e.g do not call set_default_logger() from one thread while calling spdlog::info() from another.
+SPDLOG_INLINE logger *registry::get_default_raw()
+{
+    return default_logger_.get();
+}
+
+// set default logger.
+// default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+SPDLOG_INLINE void registry::set_default_logger(std::shared_ptr<logger> new_default_logger)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    // remove previous default logger from the map
+    if (default_logger_ != nullptr)
+    {
+        loggers_.erase(default_logger_->name());
+    }
+    if (new_default_logger != nullptr)
+    {
+        loggers_[new_default_logger->name()] = new_default_logger;
+    }
+    default_logger_ = std::move(new_default_logger);
+}
+
+SPDLOG_INLINE void registry::set_tp(std::shared_ptr<thread_pool> tp)
+{
+    std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+    tp_ = std::move(tp);
+}
+
+SPDLOG_INLINE std::shared_ptr<thread_pool> registry::get_tp()
+{
+    std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+    return tp_;
+}
+
+// Set global formatter. Each sink in each logger will get a clone of this object
+SPDLOG_INLINE void registry::set_formatter(std::unique_ptr<formatter> formatter)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    formatter_ = std::move(formatter);
+    for (auto &l : loggers_)
+    {
+        l.second->set_formatter(formatter_->clone());
+    }
+}
+
+SPDLOG_INLINE void registry::enable_backtrace(size_t n_messages)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    backtrace_n_messages_ = n_messages;
+
+    for (auto &l : loggers_)
+    {
+        l.second->enable_backtrace(n_messages);
+    }
+}
+
+SPDLOG_INLINE void registry::disable_backtrace()
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    backtrace_n_messages_ = 0;
+    for (auto &l : loggers_)
+    {
+        l.second->disable_backtrace();
+    }
+}
+
+SPDLOG_INLINE void registry::set_level(level::level_enum log_level)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        l.second->set_level(log_level);
+    }
+    global_log_level_ = log_level;
+}
+
+SPDLOG_INLINE void registry::flush_on(level::level_enum log_level)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        l.second->flush_on(log_level);
+    }
+    flush_level_ = log_level;
+}
+
+SPDLOG_INLINE void registry::flush_every(std::chrono::seconds interval)
+{
+    std::lock_guard<std::mutex> lock(flusher_mutex_);
+    auto clbk = [this]() { this->flush_all(); };
+    periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
+}
+
+SPDLOG_INLINE void registry::set_error_handler(void (*handler)(const std::string &msg))
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        l.second->set_error_handler(handler);
+    }
+    err_handler_ = handler;
+}
+
+SPDLOG_INLINE void registry::apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        fun(l.second);
+    }
+}
+
+SPDLOG_INLINE void registry::flush_all()
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        l.second->flush();
+    }
+}
+
+SPDLOG_INLINE void registry::drop(const std::string &logger_name)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    loggers_.erase(logger_name);
+    if (default_logger_ && default_logger_->name() == logger_name)
+    {
+        default_logger_.reset();
+    }
+}
+
+SPDLOG_INLINE void registry::drop_all()
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    loggers_.clear();
+    default_logger_.reset();
+}
+
+// clean all resources and threads started by the registry
+SPDLOG_INLINE void registry::shutdown()
+{
+    {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        periodic_flusher_.reset();
+    }
+
+    drop_all();
+
+    {
+        std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+        tp_.reset();
+    }
+}
+
+SPDLOG_INLINE std::recursive_mutex &registry::tp_mutex()
+{
+    return tp_mutex_;
+}
+
+SPDLOG_INLINE void registry::set_automatic_registration(bool automatic_registration)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    automatic_registration_ = automatic_registration;
+}
+
+SPDLOG_INLINE void registry::set_levels(log_levels levels, level::level_enum *global_level)
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    log_levels_ = std::move(levels);
+    auto global_level_requested = global_level != nullptr;
+    global_log_level_ = global_level_requested ? *global_level : global_log_level_;
+
+    for (auto &logger : loggers_)
+    {
+        auto logger_entry = log_levels_.find(logger.first);
+        if (logger_entry != log_levels_.end())
+        {
+            logger.second->set_level(logger_entry->second);
+        }
+        else if (global_level_requested)
+        {
+            logger.second->set_level(*global_level);
+        }
+    }
+}
+
+SPDLOG_INLINE registry &registry::instance()
+{
+    static registry s_instance;
+    return s_instance;
+}
+
+SPDLOG_INLINE void registry::throw_if_exists_(const std::string &logger_name)
+{
+    if (loggers_.find(logger_name) != loggers_.end())
+    {
+        throw_spdlog_ex("logger with name '" + logger_name + "' already exists");
+    }
+}
+
+SPDLOG_INLINE void registry::register_logger_(std::shared_ptr<logger> new_logger)
+{
+    auto logger_name = new_logger->name();
+    throw_if_exists_(logger_name);
+    loggers_[logger_name] = std::move(new_logger);
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/registry.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Loggers registry of unique name->logger pointer
+// An attempt to create a logger with an already existing name will result with spdlog_ex exception.
+// If user requests a non existing logger, nullptr will be returned
+// This class is thread safe
+
+#include <spdlog/common.h>
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <mutex>
+
+namespace spdlog {
+class logger;
+
+namespace details {
+class thread_pool;
+class periodic_worker;
+
+class SPDLOG_API registry
+{
+public:
+    using log_levels = std::unordered_map<std::string, level::level_enum>;
+    registry(const registry &) = delete;
+    registry &operator=(const registry &) = delete;
+
+    void register_logger(std::shared_ptr<logger> new_logger);
+    void initialize_logger(std::shared_ptr<logger> new_logger);
+    std::shared_ptr<logger> get(const std::string &logger_name);
+    std::shared_ptr<logger> default_logger();
+
+    // Return raw ptr to the default logger.
+    // To be used directly by the spdlog default api (e.g. spdlog::info)
+    // This make the default API faster, but cannot be used concurrently with set_default_logger().
+    // e.g do not call set_default_logger() from one thread while calling spdlog::info() from another.
+    logger *get_default_raw();
+
+    // set default logger.
+    // default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+    void set_default_logger(std::shared_ptr<logger> new_default_logger);
+
+    void set_tp(std::shared_ptr<thread_pool> tp);
+
+    std::shared_ptr<thread_pool> get_tp();
+
+    // Set global formatter. Each sink in each logger will get a clone of this object
+    void set_formatter(std::unique_ptr<formatter> formatter);
+
+    void enable_backtrace(size_t n_messages);
+
+    void disable_backtrace();
+
+    void set_level(level::level_enum log_level);
+
+    void flush_on(level::level_enum log_level);
+
+    void flush_every(std::chrono::seconds interval);
+
+    void set_error_handler(void (*handler)(const std::string &msg));
+
+    void apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun);
+
+    void flush_all();
+
+    void drop(const std::string &logger_name);
+
+    void drop_all();
+
+    // clean all resources and threads started by the registry
+    void shutdown();
+
+    std::recursive_mutex &tp_mutex();
+
+    void set_automatic_registration(bool automatic_registration);
+
+    // set levels for all existing/future loggers. global_level can be null if should not set.
+    void set_levels(log_levels levels, level::level_enum *global_level);
+
+    static registry &instance();
+
+private:
+    registry();
+    ~registry();
+
+    void throw_if_exists_(const std::string &logger_name);
+    void register_logger_(std::shared_ptr<logger> new_logger);
+    bool set_level_from_cfg_(logger *logger);
+    std::mutex logger_map_mutex_, flusher_mutex_;
+    std::recursive_mutex tp_mutex_;
+    std::unordered_map<std::string, std::shared_ptr<logger>> loggers_;
+    log_levels log_levels_;
+    std::unique_ptr<formatter> formatter_;
+    spdlog::level::level_enum global_log_level_ = level::info;
+    level::level_enum flush_level_ = level::off;
+    void (*err_handler_)(const std::string &msg);
+    std::shared_ptr<thread_pool> tp_;
+    std::unique_ptr<periodic_worker> periodic_flusher_;
+    std::shared_ptr<logger> default_logger_;
+    bool automatic_registration_ = true;
+    size_t backtrace_n_messages_ = 0;
+};
+
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "registry-inl.h"
+#endif

spdlog/details/synchronous_factory.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "registry.h"
+
+namespace spdlog {
+
+// Default logger factory-  creates synchronous loggers
+class logger;
+
+struct synchronous_factory
+{
+    template<typename Sink, typename... SinkArgs>
+    static std::shared_ptr<spdlog::logger> create(std::string logger_name, SinkArgs &&...args)
+    {
+        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
+        auto new_logger = std::make_shared<spdlog::logger>(std::move(logger_name), std::move(sink));
+        details::registry::instance().initialize_logger(new_logger);
+        return new_logger;
+    }
+};
+} // namespace spdlog
\ No newline at end of file

spdlog/details/tcp_client-windows.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN
+// tcp client helper
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+#include <winsock2.h>
+#include <windows.h>
+#include <ws2tcpip.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string>
+
+#pragma comment(lib, "Ws2_32.lib")
+#pragma comment(lib, "Mswsock.lib")
+#pragma comment(lib, "AdvApi32.lib")
+
+namespace spdlog {
+namespace details {
+class tcp_client
+{
+    SOCKET socket_ = INVALID_SOCKET;
+
+    static bool winsock_initialized_()
+    {
+        SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+        if (s == INVALID_SOCKET)
+        {
+            return false;
+        }
+        else
+        {
+            closesocket(s);
+            return true;
+        }
+    }
+
+    static void init_winsock_()
+    {
+        WSADATA wsaData;
+        auto rv = WSAStartup(MAKEWORD(2, 2), &wsaData);
+        if (rv != 0)
+        {
+            throw_winsock_error_("WSAStartup failed", ::WSAGetLastError());
+        }
+    }
+
+    static void throw_winsock_error_(const std::string &msg, int last_error)
+    {
+        char buf[512];
+        ::FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error,
+            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, (sizeof(buf) / sizeof(char)), NULL);
+
+        throw_spdlog_ex(fmt::format("tcp_sink - {}: {}", msg, buf));
+    }
+
+public:
+    bool is_connected() const
+    {
+        return socket_ != INVALID_SOCKET;
+    }
+
+    void close()
+    {
+        ::closesocket(socket_);
+        socket_ = INVALID_SOCKET;
+        WSACleanup();
+    }
+
+    SOCKET fd() const
+    {
+        return socket_;
+    }
+
+    ~tcp_client()
+    {
+        close();
+    }
+
+    // try to connect or throw on failure
+    void connect(const std::string &host, int port)
+    {
+        // initialize winsock if needed
+        if (!winsock_initialized_())
+        {
+            init_winsock_();
+        }
+
+        if (is_connected())
+        {
+            close();
+        }
+        struct addrinfo hints
+        {};
+        ZeroMemory(&hints, sizeof(hints));
+
+        hints.ai_family = AF_INET;       // IPv4
+        hints.ai_socktype = SOCK_STREAM; // TCP
+        hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
+        hints.ai_protocol = 0;
+
+        auto port_str = std::to_string(port);
+        struct addrinfo *addrinfo_result;
+        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
+        int last_error = 0;
+        if (rv != 0)
+        {
+            last_error = ::WSAGetLastError();
+            WSACleanup();
+            throw_winsock_error_("getaddrinfo failed", last_error);
+        }
+
+        // Try each address until we successfully connect(2).
+
+        for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next)
+        {
+            socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+            if (socket_ == INVALID_SOCKET)
+            {
+                last_error = ::WSAGetLastError();
+                WSACleanup();
+                continue;
+            }
+            if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0)
+            {
+                break;
+            }
+            else
+            {
+                last_error = ::WSAGetLastError();
+                close();
+            }
+        }
+        ::freeaddrinfo(addrinfo_result);
+        if (socket_ == INVALID_SOCKET)
+        {
+            WSACleanup();
+            throw_winsock_error_("connect failed", last_error);
+        }
+
+        // set TCP_NODELAY
+        int enable_flag = 1;
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, (char *)&enable_flag, sizeof(enable_flag));
+    }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes)
+    {
+        size_t bytes_sent = 0;
+        while (bytes_sent < n_bytes)
+        {
+            const int send_flags = 0;
+            auto write_result = ::send(socket_, data + bytes_sent, (int)(n_bytes - bytes_sent), send_flags);
+            if (write_result == SOCKET_ERROR)
+            {
+                int last_error = ::WSAGetLastError();
+                close();
+                throw_winsock_error_("send failed", last_error);
+            }
+
+            if (write_result == 0) // (probably should not happen but in any case..)
+            {
+                break;
+            }
+            bytes_sent += static_cast<size_t>(write_result);
+        }
+    }
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/tcp_client.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifdef _WIN32
+#error include tcp_client-windows.h instead
+#endif
+
+// tcp client helper
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <netinet/tcp.h>
+
+#include <string>
+
+namespace spdlog {
+namespace details {
+class tcp_client
+{
+    int socket_ = -1;
+
+public:
+    bool is_connected() const
+    {
+        return socket_ != -1;
+    }
+
+    void close()
+    {
+        if (is_connected())
+        {
+            ::close(socket_);
+            socket_ = -1;
+        }
+    }
+
+    int fd() const
+    {
+        return socket_;
+    }
+
+    ~tcp_client()
+    {
+        close();
+    }
+
+    // try to connect or throw on failure
+    void connect(const std::string &host, int port)
+    {
+        close();
+        struct addrinfo hints
+        {};
+        memset(&hints, 0, sizeof(struct addrinfo));
+        hints.ai_family = AF_INET;       // IPv4
+        hints.ai_socktype = SOCK_STREAM; // TCP
+        hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
+        hints.ai_protocol = 0;
+
+        auto port_str = std::to_string(port);
+        struct addrinfo *addrinfo_result;
+        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
+        if (rv != 0)
+        {
+            auto msg = fmt::format("::getaddrinfo failed: {}", gai_strerror(rv));
+            throw_spdlog_ex(msg);
+        }
+
+        // Try each address until we successfully connect(2).
+        int last_errno = 0;
+        for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next)
+        {
+#if defined(SOCK_CLOEXEC)
+            const int flags = SOCK_CLOEXEC;
+#else
+            const int flags = 0;
+#endif
+            socket_ = ::socket(rp->ai_family, rp->ai_socktype | flags, rp->ai_protocol);
+            if (socket_ == -1)
+            {
+                last_errno = errno;
+                continue;
+            }
+            rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
+            if (rv == 0)
+            {
+                break;
+            }
+            last_errno = errno;
+            ::close(socket_);
+            socket_ = -1;
+        }
+        ::freeaddrinfo(addrinfo_result);
+        if (socket_ == -1)
+        {
+            throw_spdlog_ex("::connect failed", last_errno);
+        }
+
+        // set TCP_NODELAY
+        int enable_flag = 1;
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, (char *)&enable_flag, sizeof(enable_flag));
+
+        // prevent sigpipe on systems where MSG_NOSIGNAL is not available
+#if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
+        ::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, (char *)&enable_flag, sizeof(enable_flag));
+#endif
+
+#if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
+#error "tcp_sink would raise SIGPIPE since niether SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
+#endif
+    }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes)
+    {
+        size_t bytes_sent = 0;
+        while (bytes_sent < n_bytes)
+        {
+#if defined(MSG_NOSIGNAL)
+            const int send_flags = MSG_NOSIGNAL;
+#else
+            const int send_flags = 0;
+#endif
+            auto write_result = ::send(socket_, data + bytes_sent, n_bytes - bytes_sent, send_flags);
+            if (write_result < 0)
+            {
+                close();
+                throw_spdlog_ex("write(2) failed", errno);
+            }
+
+            if (write_result == 0) // (probably should not happen but in any case..)
+            {
+                break;
+            }
+            bytes_sent += static_cast<size_t>(write_result);
+        }
+    }
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/thread_pool-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/details/thread_pool.h>
+#endif
+
+#include <spdlog/common.h>
+#include <cassert>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start)
+    : q_(q_max_items)
+{
+    if (threads_n == 0 || threads_n > 1000)
+    {
+        throw_spdlog_ex("spdlog::thread_pool(): invalid threads_n param (valid "
+                        "range is 1-1000)");
+    }
+    for (size_t i = 0; i < threads_n; i++)
+    {
+        threads_.emplace_back([this, on_thread_start] {
+            on_thread_start();
+            this->thread_pool::worker_loop_();
+        });
+    }
+}
+
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n)
+    : thread_pool(q_max_items, threads_n, [] {})
+{}
+
+// message all threads to terminate gracefully join them
+SPDLOG_INLINE thread_pool::~thread_pool()
+{
+    SPDLOG_TRY
+    {
+        for (size_t i = 0; i < threads_.size(); i++)
+        {
+            post_async_msg_(async_msg(async_msg_type::terminate), async_overflow_policy::block);
+        }
+
+        for (auto &t : threads_)
+        {
+            t.join();
+        }
+    }
+    SPDLOG_CATCH_ALL() {}
+}
+
+void SPDLOG_INLINE thread_pool::post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy)
+{
+    async_msg async_m(std::move(worker_ptr), async_msg_type::log, msg);
+    post_async_msg_(std::move(async_m), overflow_policy);
+}
+
+void SPDLOG_INLINE thread_pool::post_flush(async_logger_ptr &&worker_ptr, async_overflow_policy overflow_policy)
+{
+    post_async_msg_(async_msg(std::move(worker_ptr), async_msg_type::flush), overflow_policy);
+}
+
+size_t SPDLOG_INLINE thread_pool::overrun_counter()
+{
+    return q_.overrun_counter();
+}
+
+size_t SPDLOG_INLINE thread_pool::queue_size()
+{
+    return q_.size();
+}
+
+void SPDLOG_INLINE thread_pool::post_async_msg_(async_msg &&new_msg, async_overflow_policy overflow_policy)
+{
+    if (overflow_policy == async_overflow_policy::block)
+    {
+        q_.enqueue(std::move(new_msg));
+    }
+    else
+    {
+        q_.enqueue_nowait(std::move(new_msg));
+    }
+}
+
+void SPDLOG_INLINE thread_pool::worker_loop_()
+{
+    while (process_next_msg_()) {}
+}
+
+// process next message in the queue
+// return true if this thread should still be active (while no terminate msg
+// was received)
+bool SPDLOG_INLINE thread_pool::process_next_msg_()
+{
+    async_msg incoming_async_msg;
+    bool dequeued = q_.dequeue_for(incoming_async_msg, std::chrono::seconds(10));
+    if (!dequeued)
+    {
+        return true;
+    }
+
+    switch (incoming_async_msg.msg_type)
+    {
+    case async_msg_type::log: {
+        incoming_async_msg.worker_ptr->backend_sink_it_(incoming_async_msg);
+        return true;
+    }
+    case async_msg_type::flush: {
+        incoming_async_msg.worker_ptr->backend_flush_();
+        return true;
+    }
+
+    case async_msg_type::terminate: {
+        return false;
+    }
+
+    default: {
+        assert(false);
+    }
+    }
+
+    return true;
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/thread_pool.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg_buffer.h>
+#include <spdlog/details/mpmc_blocking_q.h>
+#include <spdlog/details/os.h>
+
+#include <chrono>
+#include <memory>
+#include <thread>
+#include <vector>
+#include <functional>
+
+namespace spdlog {
+class async_logger;
+
+namespace details {
+
+using async_logger_ptr = std::shared_ptr<spdlog::async_logger>;
+
+enum class async_msg_type
+{
+    log,
+    flush,
+    terminate
+};
+
+#include <spdlog/details/log_msg_buffer.h>
+// Async msg to move to/from the queue
+// Movable only. should never be copied
+struct async_msg : log_msg_buffer
+{
+    async_msg_type msg_type{async_msg_type::log};
+    async_logger_ptr worker_ptr;
+
+    async_msg() = default;
+    ~async_msg() = default;
+
+    // should only be moved in or out of the queue..
+    async_msg(const async_msg &) = delete;
+
+// support for vs2013 move
+#if defined(_MSC_VER) && _MSC_VER <= 1800
+    async_msg(async_msg &&other)
+        : log_msg_buffer(std::move(other))
+        , msg_type(other.msg_type)
+        , worker_ptr(std::move(other.worker_ptr))
+    {}
+
+    async_msg &operator=(async_msg &&other)
+    {
+        *static_cast<log_msg_buffer *>(this) = std::move(other);
+        msg_type = other.msg_type;
+        worker_ptr = std::move(other.worker_ptr);
+        return *this;
+    }
+#else // (_MSC_VER) && _MSC_VER <= 1800
+    async_msg(async_msg &&) = default;
+    async_msg &operator=(async_msg &&) = default;
+#endif
+
+    // construct from log_msg with given type
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type, const details::log_msg &m)
+        : log_msg_buffer{m}
+        , msg_type{the_type}
+        , worker_ptr{std::move(worker)}
+    {}
+
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type)
+        : log_msg_buffer{}
+        , msg_type{the_type}
+        , worker_ptr{std::move(worker)}
+    {}
+
+    explicit async_msg(async_msg_type the_type)
+        : async_msg{nullptr, the_type}
+    {}
+};
+
+class SPDLOG_API thread_pool
+{
+public:
+    using item_type = async_msg;
+    using q_type = details::mpmc_blocking_queue<item_type>;
+
+    thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start);
+    thread_pool(size_t q_max_items, size_t threads_n);
+
+    // message all threads to terminate gracefully join them
+    ~thread_pool();
+
+    thread_pool(const thread_pool &) = delete;
+    thread_pool &operator=(thread_pool &&) = delete;
+
+    void post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy);
+    void post_flush(async_logger_ptr &&worker_ptr, async_overflow_policy overflow_policy);
+    size_t overrun_counter();
+    size_t queue_size();
+
+private:
+    q_type q_;
+
+    std::vector<std::thread> threads_;
+
+    void post_async_msg_(async_msg &&new_msg, async_overflow_policy overflow_policy);
+    void worker_loop_();
+
+    // process next message in the queue
+    // return true if this thread should still be active (while no terminate msg
+    // was received)
+    bool process_next_msg_();
+};
+
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "thread_pool-inl.h"
+#endif

spdlog/details/windows_include.h

+#pragma once
+
+#ifndef NOMINMAX
+#define NOMINMAX // prevent windows redefining min/max
+#endif
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>

spdlog/fmt/bin_to_hex.h

+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include <cctype>
+
+//
+// Support for logging binary data as hex
+// format flags, any combination of the followng:
+// {:X} - print in uppercase.
+// {:s} - don't separate each byte with space.
+// {:p} - don't print the position on each line start.
+// {:n} - don't split the output to lines.
+// {:a} - show ASCII if :n is not set
+
+//
+// Examples:
+//
+// std::vector<char> v(200, 0x0b);
+// logger->info("Some buffer {}", spdlog::to_hex(v));
+// char buf[128];
+// logger->info("Some buffer {:X}", spdlog::to_hex(std::begin(buf), std::end(buf)));
+// logger->info("Some buffer {:X}", spdlog::to_hex(std::begin(buf), std::end(buf), 16));
+
+namespace spdlog {
+namespace details {
+
+template<typename It>
+class dump_info
+{
+public:
+    dump_info(It range_begin, It range_end, size_t size_per_line)
+        : begin_(range_begin)
+        , end_(range_end)
+        , size_per_line_(size_per_line)
+    {}
+
+    It begin() const
+    {
+        return begin_;
+    }
+    It end() const
+    {
+        return end_;
+    }
+    size_t size_per_line() const
+    {
+        return size_per_line_;
+    }
+
+private:
+    It begin_, end_;
+    size_t size_per_line_;
+};
+} // namespace details
+
+// create a dump_info that wraps the given container
+template<typename Container>
+inline details::dump_info<typename Container::const_iterator> to_hex(const Container &container, size_t size_per_line = 32)
+{
+    static_assert(sizeof(typename Container::value_type) == 1, "sizeof(Container::value_type) != 1");
+    using Iter = typename Container::const_iterator;
+    return details::dump_info<Iter>(std::begin(container), std::end(container), size_per_line);
+}
+
+// create dump_info from ranges
+template<typename It>
+inline details::dump_info<It> to_hex(const It range_begin, const It range_end, size_t size_per_line = 32)
+{
+    return details::dump_info<It>(range_begin, range_end, size_per_line);
+}
+
+} // namespace spdlog
+
+namespace fmt {
+
+template<typename T>
+struct formatter<spdlog::details::dump_info<T>>
+{
+    const char delimiter = ' ';
+    bool put_newlines = true;
+    bool put_delimiters = true;
+    bool use_uppercase = false;
+    bool put_positions = true; // position on start of each line
+    bool show_ascii = false;
+
+    // parse the format string flags
+    template<typename ParseContext>
+    auto parse(ParseContext &ctx) -> decltype(ctx.begin())
+    {
+        auto it = ctx.begin();
+        while (it != ctx.end() && *it != '}')
+        {
+            switch (*it)
+            {
+            case 'X':
+                use_uppercase = true;
+                break;
+            case 's':
+                put_delimiters = false;
+                break;
+            case 'p':
+                put_positions = false;
+                break;
+            case 'n':
+                put_newlines = false;
+                show_ascii = false;
+                break;
+            case 'a':
+                if (put_newlines)
+                {
+                    show_ascii = true;
+                }
+                break;
+            }
+
+            ++it;
+        }
+        return it;
+    }
+
+    // format the given bytes range as hex
+    template<typename FormatContext, typename Container>
+    auto format(const spdlog::details::dump_info<Container> &the_range, FormatContext &ctx) -> decltype(ctx.out())
+    {
+        SPDLOG_CONSTEXPR const char *hex_upper = "0123456789ABCDEF";
+        SPDLOG_CONSTEXPR const char *hex_lower = "0123456789abcdef";
+        const char *hex_chars = use_uppercase ? hex_upper : hex_lower;
+
+#if FMT_VERSION < 60000
+        auto inserter = ctx.begin();
+#else
+        auto inserter = ctx.out();
+#endif
+
+        int size_per_line = static_cast<int>(the_range.size_per_line());
+        auto start_of_line = the_range.begin();
+        for (auto i = the_range.begin(); i != the_range.end(); i++)
+        {
+            auto ch = static_cast<unsigned char>(*i);
+
+            if (put_newlines && (i == the_range.begin() || i - start_of_line >= size_per_line))
+            {
+                if (show_ascii && i != the_range.begin())
+                {
+                    *inserter++ = delimiter;
+                    *inserter++ = delimiter;
+                    for (auto j = start_of_line; j < i; j++)
+                    {
+                        auto pc = static_cast<unsigned char>(*j);
+                        *inserter++ = std::isprint(pc) ? static_cast<char>(*j) : '.';
+                    }
+                }
+
+                put_newline(inserter, static_cast<size_t>(i - the_range.begin()));
+
+                // put first byte without delimiter in front of it
+                *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+                *inserter++ = hex_chars[ch & 0x0f];
+                start_of_line = i;
+                continue;
+            }
+
+            if (put_delimiters)
+            {
+                *inserter++ = delimiter;
+            }
+
+            *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+            *inserter++ = hex_chars[ch & 0x0f];
+        }
+        if (show_ascii) // add ascii to last line
+        {
+            if (the_range.end() - the_range.begin() > size_per_line)
+            {
+                auto blank_num = size_per_line - (the_range.end() - start_of_line);
+                while (blank_num-- > 0)
+                {
+                    *inserter++ = delimiter;
+                    *inserter++ = delimiter;
+                    if (put_delimiters)
+                    {
+                        *inserter++ = delimiter;
+                    }
+                }
+            }
+            *inserter++ = delimiter;
+            *inserter++ = delimiter;
+            for (auto j = start_of_line; j != the_range.end(); j++)
+            {
+                auto pc = static_cast<unsigned char>(*j);
+                *inserter++ = std::isprint(pc) ? static_cast<char>(*j) : '.';
+            }
+        }
+        return inserter;
+    }
+
+    // put newline(and position header)
+    template<typename It>
+    void put_newline(It inserter, std::size_t pos)
+    {
+#ifdef _WIN32
+        *inserter++ = '\r';
+#endif
+        *inserter++ = '\n';
+
+        if (put_positions)
+        {
+            fmt::format_to(inserter, "{:<04X}: ", pos);
+        }
+    }
+};
+} // namespace fmt

spdlog/fmt/bundled/LICENSE.rst

+Copyright (c) 2012 - present, Victor Zverovich
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+--- Optional exception to the license ---
+
+As an exception, if, as a result of your compiling your source code, portions
+of this Software are embedded into a machine-executable object form of such
+source code, you may redistribute such embedded portions in such object form
+without including the above copyright and permission notices.

spdlog/fmt/bundled/chrono.h

+// Formatting library for C++ - chrono support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_CHRONO_H_
+#define FMT_CHRONO_H_
+
+#include <chrono>
+#include <ctime>
+#include <locale>
+#include <sstream>
+
+#include "format.h"
+#include "locale.h"
+
+FMT_BEGIN_NAMESPACE
+
+// Enable safe chrono durations, unless explicitly disabled.
+#ifndef FMT_SAFE_DURATION_CAST
+#  define FMT_SAFE_DURATION_CAST 1
+#endif
+#if FMT_SAFE_DURATION_CAST
+
+// For conversion between std::chrono::durations without undefined
+// behaviour or erroneous results.
+// This is a stripped down version of duration_cast, for inclusion in fmt.
+// See https://github.com/pauldreik/safe_duration_cast
+//
+// Copyright Paul Dreik 2019
+namespace safe_duration_cast {
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
+                        std::numeric_limits<From>::is_signed ==
+                            std::numeric_limits<To>::is_signed)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  using F = std::numeric_limits<From>;
+  using T = std::numeric_limits<To>;
+  static_assert(F::is_integer, "From must be integral");
+  static_assert(T::is_integer, "To must be integral");
+
+  // A and B are both signed, or both unsigned.
+  if (F::digits <= T::digits) {
+    // From fits in To without any problem.
+  } else {
+    // From does not always fit in To, resort to a dynamic check.
+    if (from < (T::min)() || from > (T::max)()) {
+      // outside range.
+      ec = 1;
+      return {};
+    }
+  }
+  return static_cast<To>(from);
+}
+
+/**
+ * converts From to To, without loss. If the dynamic value of from
+ * can't be converted to To without loss, ec is set.
+ */
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
+                        std::numeric_limits<From>::is_signed !=
+                            std::numeric_limits<To>::is_signed)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  using F = std::numeric_limits<From>;
+  using T = std::numeric_limits<To>;
+  static_assert(F::is_integer, "From must be integral");
+  static_assert(T::is_integer, "To must be integral");
+
+  if (F::is_signed && !T::is_signed) {
+    // From may be negative, not allowed!
+    if (fmt::detail::is_negative(from)) {
+      ec = 1;
+      return {};
+    }
+
+    // From is positive. Can it always fit in To?
+    if (F::digits <= T::digits) {
+      // yes, From always fits in To.
+    } else {
+      // from may not fit in To, we have to do a dynamic check
+      if (from > static_cast<From>((T::max)())) {
+        ec = 1;
+        return {};
+      }
+    }
+  }
+
+  if (!F::is_signed && T::is_signed) {
+    // can from be held in To?
+    if (F::digits < T::digits) {
+      // yes, From always fits in To.
+    } else {
+      // from may not fit in To, we have to do a dynamic check
+      if (from > static_cast<From>((T::max)())) {
+        // outside range.
+        ec = 1;
+        return {};
+      }
+    }
+  }
+
+  // reaching here means all is ok for lossless conversion.
+  return static_cast<To>(from);
+
+}  // function
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(std::is_same<From, To>::value)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  return from;
+}  // function
+
+// clang-format off
+/**
+ * converts From to To if possible, otherwise ec is set.
+ *
+ * input                            |    output
+ * ---------------------------------|---------------
+ * NaN                              | NaN
+ * Inf                              | Inf
+ * normal, fits in output           | converted (possibly lossy)
+ * normal, does not fit in output   | ec is set
+ * subnormal                        | best effort
+ * -Inf                             | -Inf
+ */
+// clang-format on
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value)>
+FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
+  ec = 0;
+  using T = std::numeric_limits<To>;
+  static_assert(std::is_floating_point<From>::value, "From must be floating");
+  static_assert(std::is_floating_point<To>::value, "To must be floating");
+
+  // catch the only happy case
+  if (std::isfinite(from)) {
+    if (from >= T::lowest() && from <= (T::max)()) {
+      return static_cast<To>(from);
+    }
+    // not within range.
+    ec = 1;
+    return {};
+  }
+
+  // nan and inf will be preserved
+  return static_cast<To>(from);
+}  // function
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(std::is_same<From, To>::value)>
+FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
+  ec = 0;
+  static_assert(std::is_floating_point<From>::value, "From must be floating");
+  return from;
+}
+
+/**
+ * safe duration cast between integral durations
+ */
+template <typename To, typename FromRep, typename FromPeriod,
+          FMT_ENABLE_IF(std::is_integral<FromRep>::value),
+          FMT_ENABLE_IF(std::is_integral<typename To::rep>::value)>
+To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
+                      int& ec) {
+  using From = std::chrono::duration<FromRep, FromPeriod>;
+  ec = 0;
+  // the basic idea is that we need to convert from count() in the from type
+  // to count() in the To type, by multiplying it with this:
+  struct Factor
+      : std::ratio_divide<typename From::period, typename To::period> {};
+
+  static_assert(Factor::num > 0, "num must be positive");
+  static_assert(Factor::den > 0, "den must be positive");
+
+  // the conversion is like this: multiply from.count() with Factor::num
+  // /Factor::den and convert it to To::rep, all this without
+  // overflow/underflow. let's start by finding a suitable type that can hold
+  // both To, From and Factor::num
+  using IntermediateRep =
+      typename std::common_type<typename From::rep, typename To::rep,
+                                decltype(Factor::num)>::type;
+
+  // safe conversion to IntermediateRep
+  IntermediateRep count =
+      lossless_integral_conversion<IntermediateRep>(from.count(), ec);
+  if (ec) {
+    return {};
+  }
+  // multiply with Factor::num without overflow or underflow
+  if (Factor::num != 1) {
+    const auto max1 = detail::max_value<IntermediateRep>() / Factor::num;
+    if (count > max1) {
+      ec = 1;
+      return {};
+    }
+    const auto min1 =
+        (std::numeric_limits<IntermediateRep>::min)() / Factor::num;
+    if (count < min1) {
+      ec = 1;
+      return {};
+    }
+    count *= Factor::num;
+  }
+
+  // this can't go wrong, right? den>0 is checked earlier.
+  if (Factor::den != 1) {
+    count /= Factor::den;
+  }
+  // convert to the to type, safely
+  using ToRep = typename To::rep;
+  const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
+  if (ec) {
+    return {};
+  }
+  return To{tocount};
+}
+
+/**
+ * safe duration_cast between floating point durations
+ */
+template <typename To, typename FromRep, typename FromPeriod,
+          FMT_ENABLE_IF(std::is_floating_point<FromRep>::value),
+          FMT_ENABLE_IF(std::is_floating_point<typename To::rep>::value)>
+To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
+                      int& ec) {
+  using From = std::chrono::duration<FromRep, FromPeriod>;
+  ec = 0;
+  if (std::isnan(from.count())) {
+    // nan in, gives nan out. easy.
+    return To{std::numeric_limits<typename To::rep>::quiet_NaN()};
+  }
+  // maybe we should also check if from is denormal, and decide what to do about
+  // it.
+
+  // +-inf should be preserved.
+  if (std::isinf(from.count())) {
+    return To{from.count()};
+  }
+
+  // the basic idea is that we need to convert from count() in the from type
+  // to count() in the To type, by multiplying it with this:
+  struct Factor
+      : std::ratio_divide<typename From::period, typename To::period> {};
+
+  static_assert(Factor::num > 0, "num must be positive");
+  static_assert(Factor::den > 0, "den must be positive");
+
+  // the conversion is like this: multiply from.count() with Factor::num
+  // /Factor::den and convert it to To::rep, all this without
+  // overflow/underflow. let's start by finding a suitable type that can hold
+  // both To, From and Factor::num
+  using IntermediateRep =
+      typename std::common_type<typename From::rep, typename To::rep,
+                                decltype(Factor::num)>::type;
+
+  // force conversion of From::rep -> IntermediateRep to be safe,
+  // even if it will never happen be narrowing in this context.
+  IntermediateRep count =
+      safe_float_conversion<IntermediateRep>(from.count(), ec);
+  if (ec) {
+    return {};
+  }
+
+  // multiply with Factor::num without overflow or underflow
+  if (Factor::num != 1) {
+    constexpr auto max1 = detail::max_value<IntermediateRep>() /
+                          static_cast<IntermediateRep>(Factor::num);
+    if (count > max1) {
+      ec = 1;
+      return {};
+    }
+    constexpr auto min1 = std::numeric_limits<IntermediateRep>::lowest() /
+                          static_cast<IntermediateRep>(Factor::num);
+    if (count < min1) {
+      ec = 1;
+      return {};
+    }
+    count *= static_cast<IntermediateRep>(Factor::num);
+  }
+
+  // this can't go wrong, right? den>0 is checked earlier.
+  if (Factor::den != 1) {
+    using common_t = typename std::common_type<IntermediateRep, intmax_t>::type;
+    count /= static_cast<common_t>(Factor::den);
+  }
+
+  // convert to the to type, safely
+  using ToRep = typename To::rep;
+
+  const ToRep tocount = safe_float_conversion<ToRep>(count, ec);
+  if (ec) {
+    return {};
+  }
+  return To{tocount};
+}
+}  // namespace safe_duration_cast
+#endif
+
+// Prevents expansion of a preceding token as a function-style macro.
+// Usage: f FMT_NOMACRO()
+#define FMT_NOMACRO
+
+namespace detail {
+inline null<> localtime_r FMT_NOMACRO(...) { return null<>(); }
+inline null<> localtime_s(...) { return null<>(); }
+inline null<> gmtime_r(...) { return null<>(); }
+inline null<> gmtime_s(...) { return null<>(); }
+}  // namespace detail
+
+// Thread-safe replacement for std::localtime
+inline std::tm localtime(std::time_t time) {
+  struct dispatcher {
+    std::time_t time_;
+    std::tm tm_;
+
+    dispatcher(std::time_t t) : time_(t) {}
+
+    bool run() {
+      using namespace fmt::detail;
+      return handle(localtime_r(&time_, &tm_));
+    }
+
+    bool handle(std::tm* tm) { return tm != nullptr; }
+
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
+      return fallback(localtime_s(&tm_, &time_));
+    }
+
+    bool fallback(int res) { return res == 0; }
+
+#if !FMT_MSC_VER
+    bool fallback(detail::null<>) {
+      using namespace fmt::detail;
+      std::tm* tm = std::localtime(&time_);
+      if (tm) tm_ = *tm;
+      return tm != nullptr;
+    }
+#endif
+  };
+  dispatcher lt(time);
+  // Too big time values may be unsupported.
+  if (!lt.run()) FMT_THROW(format_error("time_t value out of range"));
+  return lt.tm_;
+}
+
+// Thread-safe replacement for std::gmtime
+inline std::tm gmtime(std::time_t time) {
+  struct dispatcher {
+    std::time_t time_;
+    std::tm tm_;
+
+    dispatcher(std::time_t t) : time_(t) {}
+
+    bool run() {
+      using namespace fmt::detail;
+      return handle(gmtime_r(&time_, &tm_));
+    }
+
+    bool handle(std::tm* tm) { return tm != nullptr; }
+
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
+      return fallback(gmtime_s(&tm_, &time_));
+    }
+
+    bool fallback(int res) { return res == 0; }
+
+#if !FMT_MSC_VER
+    bool fallback(detail::null<>) {
+      std::tm* tm = std::gmtime(&time_);
+      if (tm) tm_ = *tm;
+      return tm != nullptr;
+    }
+#endif
+  };
+  dispatcher gt(time);
+  // Too big time values may be unsupported.
+  if (!gt.run()) FMT_THROW(format_error("time_t value out of range"));
+  return gt.tm_;
+}
+
+namespace detail {
+inline size_t strftime(char* str, size_t count, const char* format,
+                       const std::tm* time) {
+  return std::strftime(str, count, format, time);
+}
+
+inline size_t strftime(wchar_t* str, size_t count, const wchar_t* format,
+                       const std::tm* time) {
+  return std::wcsftime(str, count, format, time);
+}
+}  // namespace detail
+
+template <typename Char> struct formatter<std::tm, Char> {
+  template <typename ParseContext>
+  auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it == ':') ++it;
+    auto end = it;
+    while (end != ctx.end() && *end != '}') ++end;
+    tm_format.reserve(detail::to_unsigned(end - it + 1));
+    tm_format.append(it, end);
+    tm_format.push_back('\0');
+    return end;
+  }
+
+  template <typename FormatContext>
+  auto format(const std::tm& tm, FormatContext& ctx) -> decltype(ctx.out()) {
+    basic_memory_buffer<Char> buf;
+    size_t start = buf.size();
+    for (;;) {
+      size_t size = buf.capacity() - start;
+      size_t count = detail::strftime(&buf[start], size, &tm_format[0], &tm);
+      if (count != 0) {
+        buf.resize(start + count);
+        break;
+      }
+      if (size >= tm_format.size() * 256) {
+        // If the buffer is 256 times larger than the format string, assume
+        // that `strftime` gives an empty result. There doesn't seem to be a
+        // better way to distinguish the two cases:
+        // https://github.com/fmtlib/fmt/issues/367
+        break;
+      }
+      const size_t MIN_GROWTH = 10;
+      buf.reserve(buf.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
+    }
+    return std::copy(buf.begin(), buf.end(), ctx.out());
+  }
+
+  basic_memory_buffer<Char> tm_format;
+};
+
+namespace detail {
+template <typename Period> FMT_CONSTEXPR const char* get_units() {
+  return nullptr;
+}
+template <> FMT_CONSTEXPR const char* get_units<std::atto>() { return "as"; }
+template <> FMT_CONSTEXPR const char* get_units<std::femto>() { return "fs"; }
+template <> FMT_CONSTEXPR const char* get_units<std::pico>() { return "ps"; }
+template <> FMT_CONSTEXPR const char* get_units<std::nano>() { return "ns"; }
+template <> FMT_CONSTEXPR const char* get_units<std::micro>() { return "µs"; }
+template <> FMT_CONSTEXPR const char* get_units<std::milli>() { return "ms"; }
+template <> FMT_CONSTEXPR const char* get_units<std::centi>() { return "cs"; }
+template <> FMT_CONSTEXPR const char* get_units<std::deci>() { return "ds"; }
+template <> FMT_CONSTEXPR const char* get_units<std::ratio<1>>() { return "s"; }
+template <> FMT_CONSTEXPR const char* get_units<std::deca>() { return "das"; }
+template <> FMT_CONSTEXPR const char* get_units<std::hecto>() { return "hs"; }
+template <> FMT_CONSTEXPR const char* get_units<std::kilo>() { return "ks"; }
+template <> FMT_CONSTEXPR const char* get_units<std::mega>() { return "Ms"; }
+template <> FMT_CONSTEXPR const char* get_units<std::giga>() { return "Gs"; }
+template <> FMT_CONSTEXPR const char* get_units<std::tera>() { return "Ts"; }
+template <> FMT_CONSTEXPR const char* get_units<std::peta>() { return "Ps"; }
+template <> FMT_CONSTEXPR const char* get_units<std::exa>() { return "Es"; }
+template <> FMT_CONSTEXPR const char* get_units<std::ratio<60>>() {
+  return "m";
+}
+template <> FMT_CONSTEXPR const char* get_units<std::ratio<3600>>() {
+  return "h";
+}
+
+enum class numeric_system {
+  standard,
+  // Alternative numeric system, e.g. 十二 instead of 12 in ja_JP locale.
+  alternative
+};
+
+// Parses a put_time-like format string and invokes handler actions.
+template <typename Char, typename Handler>
+FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
+                                              const Char* end,
+                                              Handler&& handler) {
+  auto ptr = begin;
+  while (ptr != end) {
+    auto c = *ptr;
+    if (c == '}') break;
+    if (c != '%') {
+      ++ptr;
+      continue;
+    }
+    if (begin != ptr) handler.on_text(begin, ptr);
+    ++ptr;  // consume '%'
+    if (ptr == end) FMT_THROW(format_error("invalid format"));
+    c = *ptr++;
+    switch (c) {
+    case '%':
+      handler.on_text(ptr - 1, ptr);
+      break;
+    case 'n': {
+      const Char newline[] = {'\n'};
+      handler.on_text(newline, newline + 1);
+      break;
+    }
+    case 't': {
+      const Char tab[] = {'\t'};
+      handler.on_text(tab, tab + 1);
+      break;
+    }
+    // Day of the week:
+    case 'a':
+      handler.on_abbr_weekday();
+      break;
+    case 'A':
+      handler.on_full_weekday();
+      break;
+    case 'w':
+      handler.on_dec0_weekday(numeric_system::standard);
+      break;
+    case 'u':
+      handler.on_dec1_weekday(numeric_system::standard);
+      break;
+    // Month:
+    case 'b':
+      handler.on_abbr_month();
+      break;
+    case 'B':
+      handler.on_full_month();
+      break;
+    // Hour, minute, second:
+    case 'H':
+      handler.on_24_hour(numeric_system::standard);
+      break;
+    case 'I':
+      handler.on_12_hour(numeric_system::standard);
+      break;
+    case 'M':
+      handler.on_minute(numeric_system::standard);
+      break;
+    case 'S':
+      handler.on_second(numeric_system::standard);
+      break;
+    // Other:
+    case 'c':
+      handler.on_datetime(numeric_system::standard);
+      break;
+    case 'x':
+      handler.on_loc_date(numeric_system::standard);
+      break;
+    case 'X':
+      handler.on_loc_time(numeric_system::standard);
+      break;
+    case 'D':
+      handler.on_us_date();
+      break;
+    case 'F':
+      handler.on_iso_date();
+      break;
+    case 'r':
+      handler.on_12_hour_time();
+      break;
+    case 'R':
+      handler.on_24_hour_time();
+      break;
+    case 'T':
+      handler.on_iso_time();
+      break;
+    case 'p':
+      handler.on_am_pm();
+      break;
+    case 'Q':
+      handler.on_duration_value();
+      break;
+    case 'q':
+      handler.on_duration_unit();
+      break;
+    case 'z':
+      handler.on_utc_offset();
+      break;
+    case 'Z':
+      handler.on_tz_name();
+      break;
+    // Alternative representation:
+    case 'E': {
+      if (ptr == end) FMT_THROW(format_error("invalid format"));
+      c = *ptr++;
+      switch (c) {
+      case 'c':
+        handler.on_datetime(numeric_system::alternative);
+        break;
+      case 'x':
+        handler.on_loc_date(numeric_system::alternative);
+        break;
+      case 'X':
+        handler.on_loc_time(numeric_system::alternative);
+        break;
+      default:
+        FMT_THROW(format_error("invalid format"));
+      }
+      break;
+    }
+    case 'O':
+      if (ptr == end) FMT_THROW(format_error("invalid format"));
+      c = *ptr++;
+      switch (c) {
+      case 'w':
+        handler.on_dec0_weekday(numeric_system::alternative);
+        break;
+      case 'u':
+        handler.on_dec1_weekday(numeric_system::alternative);
+        break;
+      case 'H':
+        handler.on_24_hour(numeric_system::alternative);
+        break;
+      case 'I':
+        handler.on_12_hour(numeric_system::alternative);
+        break;
+      case 'M':
+        handler.on_minute(numeric_system::alternative);
+        break;
+      case 'S':
+        handler.on_second(numeric_system::alternative);
+        break;
+      default:
+        FMT_THROW(format_error("invalid format"));
+      }
+      break;
+    default:
+      FMT_THROW(format_error("invalid format"));
+    }
+    begin = ptr;
+  }
+  if (begin != ptr) handler.on_text(begin, ptr);
+  return ptr;
+}
+
+struct chrono_format_checker {
+  FMT_NORETURN void report_no_date() { FMT_THROW(format_error("no date")); }
+
+  template <typename Char> void on_text(const Char*, const Char*) {}
+  FMT_NORETURN void on_abbr_weekday() { report_no_date(); }
+  FMT_NORETURN void on_full_weekday() { report_no_date(); }
+  FMT_NORETURN void on_dec0_weekday(numeric_system) { report_no_date(); }
+  FMT_NORETURN void on_dec1_weekday(numeric_system) { report_no_date(); }
+  FMT_NORETURN void on_abbr_month() { report_no_date(); }
+  FMT_NORETURN void on_full_month() { report_no_date(); }
+  void on_24_hour(numeric_system) {}
+  void on_12_hour(numeric_system) {}
+  void on_minute(numeric_system) {}
+  void on_second(numeric_system) {}
+  FMT_NORETURN void on_datetime(numeric_system) { report_no_date(); }
+  FMT_NORETURN void on_loc_date(numeric_system) { report_no_date(); }
+  FMT_NORETURN void on_loc_time(numeric_system) { report_no_date(); }
+  FMT_NORETURN void on_us_date() { report_no_date(); }
+  FMT_NORETURN void on_iso_date() { report_no_date(); }
+  void on_12_hour_time() {}
+  void on_24_hour_time() {}
+  void on_iso_time() {}
+  void on_am_pm() {}
+  void on_duration_value() {}
+  void on_duration_unit() {}
+  FMT_NORETURN void on_utc_offset() { report_no_date(); }
+  FMT_NORETURN void on_tz_name() { report_no_date(); }
+};
+
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline bool isnan(T) {
+  return false;
+}
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+inline bool isnan(T value) {
+  return std::isnan(value);
+}
+
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline bool isfinite(T) {
+  return true;
+}
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+inline bool isfinite(T value) {
+  return std::isfinite(value);
+}
+
+// Converts value to int and checks that it's in the range [0, upper).
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline int to_nonnegative_int(T value, int upper) {
+  FMT_ASSERT(value >= 0 && value <= upper, "invalid value");
+  (void)upper;
+  return static_cast<int>(value);
+}
+template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+inline int to_nonnegative_int(T value, int upper) {
+  FMT_ASSERT(
+      std::isnan(value) || (value >= 0 && value <= static_cast<T>(upper)),
+      "invalid value");
+  (void)upper;
+  return static_cast<int>(value);
+}
+
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline T mod(T x, int y) {
+  return x % static_cast<T>(y);
+}
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+inline T mod(T x, int y) {
+  return std::fmod(x, static_cast<T>(y));
+}
+
+// If T is an integral type, maps T to its unsigned counterpart, otherwise
+// leaves it unchanged (unlike std::make_unsigned).
+template <typename T, bool INTEGRAL = std::is_integral<T>::value>
+struct make_unsigned_or_unchanged {
+  using type = T;
+};
+
+template <typename T> struct make_unsigned_or_unchanged<T, true> {
+  using type = typename std::make_unsigned<T>::type;
+};
+
+#if FMT_SAFE_DURATION_CAST
+// throwing version of safe_duration_cast
+template <typename To, typename FromRep, typename FromPeriod>
+To fmt_safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from) {
+  int ec;
+  To to = safe_duration_cast::safe_duration_cast<To>(from, ec);
+  if (ec) FMT_THROW(format_error("cannot format duration"));
+  return to;
+}
+#endif
+
+template <typename Rep, typename Period,
+          FMT_ENABLE_IF(std::is_integral<Rep>::value)>
+inline std::chrono::duration<Rep, std::milli> get_milliseconds(
+    std::chrono::duration<Rep, Period> d) {
+  // this may overflow and/or the result may not fit in the
+  // target type.
+#if FMT_SAFE_DURATION_CAST
+  using CommonSecondsType =
+      typename std::common_type<decltype(d), std::chrono::seconds>::type;
+  const auto d_as_common = fmt_safe_duration_cast<CommonSecondsType>(d);
+  const auto d_as_whole_seconds =
+      fmt_safe_duration_cast<std::chrono::seconds>(d_as_common);
+  // this conversion should be nonproblematic
+  const auto diff = d_as_common - d_as_whole_seconds;
+  const auto ms =
+      fmt_safe_duration_cast<std::chrono::duration<Rep, std::milli>>(diff);
+  return ms;
+#else
+  auto s = std::chrono::duration_cast<std::chrono::seconds>(d);
+  return std::chrono::duration_cast<std::chrono::milliseconds>(d - s);
+#endif
+}
+
+template <typename Rep, typename Period,
+          FMT_ENABLE_IF(std::is_floating_point<Rep>::value)>
+inline std::chrono::duration<Rep, std::milli> get_milliseconds(
+    std::chrono::duration<Rep, Period> d) {
+  using common_type = typename std::common_type<Rep, std::intmax_t>::type;
+  auto ms = mod(d.count() * static_cast<common_type>(Period::num) /
+                    static_cast<common_type>(Period::den) * 1000,
+                1000);
+  return std::chrono::duration<Rep, std::milli>(static_cast<Rep>(ms));
+}
+
+template <typename Char, typename Rep, typename OutputIt>
+OutputIt format_duration_value(OutputIt out, Rep val, int precision) {
+  const Char pr_f[] = {'{', ':', '.', '{', '}', 'f', '}', 0};
+  if (precision >= 0) return format_to(out, pr_f, val, precision);
+  const Char fp_f[] = {'{', ':', 'g', '}', 0};
+  const Char format[] = {'{', '}', 0};
+  return format_to(out, std::is_floating_point<Rep>::value ? fp_f : format,
+                   val);
+}
+template <typename Char, typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, Char) {
+  return std::copy(unit.begin(), unit.end(), out);
+}
+
+template <typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, wchar_t) {
+  // This works when wchar_t is UTF-32 because units only contain characters
+  // that have the same representation in UTF-16 and UTF-32.
+  utf8_to_utf16 u(unit);
+  return std::copy(u.c_str(), u.c_str() + u.size(), out);
+}
+
+template <typename Char, typename Period, typename OutputIt>
+OutputIt format_duration_unit(OutputIt out) {
+  if (const char* unit = get_units<Period>())
+    return copy_unit(string_view(unit), out, Char());
+  const Char num_f[] = {'[', '{', '}', ']', 's', 0};
+  if (const_check(Period::den == 1)) return format_to(out, num_f, Period::num);
+  const Char num_def_f[] = {'[', '{', '}', '/', '{', '}', ']', 's', 0};
+  return format_to(out, num_def_f, Period::num, Period::den);
+}
+
+template <typename FormatContext, typename OutputIt, typename Rep,
+          typename Period>
+struct chrono_formatter {
+  FormatContext& context;
+  OutputIt out;
+  int precision;
+  // rep is unsigned to avoid overflow.
+  using rep =
+      conditional_t<std::is_integral<Rep>::value && sizeof(Rep) < sizeof(int),
+                    unsigned, typename make_unsigned_or_unchanged<Rep>::type>;
+  rep val;
+  using seconds = std::chrono::duration<rep>;
+  seconds s;
+  using milliseconds = std::chrono::duration<rep, std::milli>;
+  bool negative;
+
+  using char_type = typename FormatContext::char_type;
+
+  explicit chrono_formatter(FormatContext& ctx, OutputIt o,
+                            std::chrono::duration<Rep, Period> d)
+      : context(ctx),
+        out(o),
+        val(static_cast<rep>(d.count())),
+        negative(false) {
+    if (d.count() < 0) {
+      val = 0 - val;
+      negative = true;
+    }
+
+    // this may overflow and/or the result may not fit in the
+    // target type.
+#if FMT_SAFE_DURATION_CAST
+    // might need checked conversion (rep!=Rep)
+    auto tmpval = std::chrono::duration<rep, Period>(val);
+    s = fmt_safe_duration_cast<seconds>(tmpval);
+#else
+    s = std::chrono::duration_cast<seconds>(
+        std::chrono::duration<rep, Period>(val));
+#endif
+  }
+
+  // returns true if nan or inf, writes to out.
+  bool handle_nan_inf() {
+    if (isfinite(val)) {
+      return false;
+    }
+    if (isnan(val)) {
+      write_nan();
+      return true;
+    }
+    // must be +-inf
+    if (val > 0) {
+      write_pinf();
+    } else {
+      write_ninf();
+    }
+    return true;
+  }
+
+  Rep hour() const { return static_cast<Rep>(mod((s.count() / 3600), 24)); }
+
+  Rep hour12() const {
+    Rep hour = static_cast<Rep>(mod((s.count() / 3600), 12));
+    return hour <= 0 ? 12 : hour;
+  }
+
+  Rep minute() const { return static_cast<Rep>(mod((s.count() / 60), 60)); }
+  Rep second() const { return static_cast<Rep>(mod(s.count(), 60)); }
+
+  std::tm time() const {
+    auto time = std::tm();
+    time.tm_hour = to_nonnegative_int(hour(), 24);
+    time.tm_min = to_nonnegative_int(minute(), 60);
+    time.tm_sec = to_nonnegative_int(second(), 60);
+    return time;
+  }
+
+  void write_sign() {
+    if (negative) {
+      *out++ = '-';
+      negative = false;
+    }
+  }
+
+  void write(Rep value, int width) {
+    write_sign();
+    if (isnan(value)) return write_nan();
+    uint32_or_64_or_128_t<int> n =
+        to_unsigned(to_nonnegative_int(value, max_value<int>()));
+    int num_digits = detail::count_digits(n);
+    if (width > num_digits) out = std::fill_n(out, width - num_digits, '0');
+    out = format_decimal<char_type>(out, n, num_digits).end;
+  }
+
+  void write_nan() { std::copy_n("nan", 3, out); }
+  void write_pinf() { std::copy_n("inf", 3, out); }
+  void write_ninf() { std::copy_n("-inf", 4, out); }
+
+  void format_localized(const tm& time, char format, char modifier = 0) {
+    if (isnan(val)) return write_nan();
+    auto locale = context.locale().template get<std::locale>();
+    auto& facet = std::use_facet<std::time_put<char_type>>(locale);
+    std::basic_ostringstream<char_type> os;
+    os.imbue(locale);
+    facet.put(os, os, ' ', &time, format, modifier);
+    auto str = os.str();
+    std::copy(str.begin(), str.end(), out);
+  }
+
+  void on_text(const char_type* begin, const char_type* end) {
+    std::copy(begin, end, out);
+  }
+
+  // These are not implemented because durations don't have date information.
+  void on_abbr_weekday() {}
+  void on_full_weekday() {}
+  void on_dec0_weekday(numeric_system) {}
+  void on_dec1_weekday(numeric_system) {}
+  void on_abbr_month() {}
+  void on_full_month() {}
+  void on_datetime(numeric_system) {}
+  void on_loc_date(numeric_system) {}
+  void on_loc_time(numeric_system) {}
+  void on_us_date() {}
+  void on_iso_date() {}
+  void on_utc_offset() {}
+  void on_tz_name() {}
+
+  void on_24_hour(numeric_system ns) {
+    if (handle_nan_inf()) return;
+
+    if (ns == numeric_system::standard) return write(hour(), 2);
+    auto time = tm();
+    time.tm_hour = to_nonnegative_int(hour(), 24);
+    format_localized(time, 'H', 'O');
+  }
+
+  void on_12_hour(numeric_system ns) {
+    if (handle_nan_inf()) return;
+
+    if (ns == numeric_system::standard) return write(hour12(), 2);
+    auto time = tm();
+    time.tm_hour = to_nonnegative_int(hour12(), 12);
+    format_localized(time, 'I', 'O');
+  }
+
+  void on_minute(numeric_system ns) {
+    if (handle_nan_inf()) return;
+
+    if (ns == numeric_system::standard) return write(minute(), 2);
+    auto time = tm();
+    time.tm_min = to_nonnegative_int(minute(), 60);
+    format_localized(time, 'M', 'O');
+  }
+
+  void on_second(numeric_system ns) {
+    if (handle_nan_inf()) return;
+
+    if (ns == numeric_system::standard) {
+      write(second(), 2);
+#if FMT_SAFE_DURATION_CAST
+      // convert rep->Rep
+      using duration_rep = std::chrono::duration<rep, Period>;
+      using duration_Rep = std::chrono::duration<Rep, Period>;
+      auto tmpval = fmt_safe_duration_cast<duration_Rep>(duration_rep{val});
+#else
+      auto tmpval = std::chrono::duration<Rep, Period>(val);
+#endif
+      auto ms = get_milliseconds(tmpval);
+      if (ms != std::chrono::milliseconds(0)) {
+        *out++ = '.';
+        write(ms.count(), 3);
+      }
+      return;
+    }
+    auto time = tm();
+    time.tm_sec = to_nonnegative_int(second(), 60);
+    format_localized(time, 'S', 'O');
+  }
+
+  void on_12_hour_time() {
+    if (handle_nan_inf()) return;
+    format_localized(time(), 'r');
+  }
+
+  void on_24_hour_time() {
+    if (handle_nan_inf()) {
+      *out++ = ':';
+      handle_nan_inf();
+      return;
+    }
+
+    write(hour(), 2);
+    *out++ = ':';
+    write(minute(), 2);
+  }
+
+  void on_iso_time() {
+    on_24_hour_time();
+    *out++ = ':';
+    if (handle_nan_inf()) return;
+    write(second(), 2);
+  }
+
+  void on_am_pm() {
+    if (handle_nan_inf()) return;
+    format_localized(time(), 'p');
+  }
+
+  void on_duration_value() {
+    if (handle_nan_inf()) return;
+    write_sign();
+    out = format_duration_value<char_type>(out, val, precision);
+  }
+
+  void on_duration_unit() {
+    out = format_duration_unit<char_type, Period>(out);
+  }
+};
+}  // namespace detail
+
+template <typename Rep, typename Period, typename Char>
+struct formatter<std::chrono::duration<Rep, Period>, Char> {
+ private:
+  basic_format_specs<Char> specs;
+  int precision;
+  using arg_ref_type = detail::arg_ref<Char>;
+  arg_ref_type width_ref;
+  arg_ref_type precision_ref;
+  mutable basic_string_view<Char> format_str;
+  using duration = std::chrono::duration<Rep, Period>;
+
+  struct spec_handler {
+    formatter& f;
+    basic_format_parse_context<Char>& context;
+    basic_string_view<Char> format_str;
+
+    template <typename Id> FMT_CONSTEXPR arg_ref_type make_arg_ref(Id arg_id) {
+      context.check_arg_id(arg_id);
+      return arg_ref_type(arg_id);
+    }
+
+    FMT_CONSTEXPR arg_ref_type make_arg_ref(basic_string_view<Char> arg_id) {
+      context.check_arg_id(arg_id);
+      return arg_ref_type(arg_id);
+    }
+
+    FMT_CONSTEXPR arg_ref_type make_arg_ref(detail::auto_id) {
+      return arg_ref_type(context.next_arg_id());
+    }
+
+    void on_error(const char* msg) { FMT_THROW(format_error(msg)); }
+    void on_fill(basic_string_view<Char> fill) { f.specs.fill = fill; }
+    void on_align(align_t align) { f.specs.align = align; }
+    void on_width(int width) { f.specs.width = width; }
+    void on_precision(int _precision) { f.precision = _precision; }
+    void end_precision() {}
+
+    template <typename Id> void on_dynamic_width(Id arg_id) {
+      f.width_ref = make_arg_ref(arg_id);
+    }
+
+    template <typename Id> void on_dynamic_precision(Id arg_id) {
+      f.precision_ref = make_arg_ref(arg_id);
+    }
+  };
+
+  using iterator = typename basic_format_parse_context<Char>::iterator;
+  struct parse_range {
+    iterator begin;
+    iterator end;
+  };
+
+  FMT_CONSTEXPR parse_range do_parse(basic_format_parse_context<Char>& ctx) {
+    auto begin = ctx.begin(), end = ctx.end();
+    if (begin == end || *begin == '}') return {begin, begin};
+    spec_handler handler{*this, ctx, format_str};
+    begin = detail::parse_align(begin, end, handler);
+    if (begin == end) return {begin, begin};
+    begin = detail::parse_width(begin, end, handler);
+    if (begin == end) return {begin, begin};
+    if (*begin == '.') {
+      if (std::is_floating_point<Rep>::value)
+        begin = detail::parse_precision(begin, end, handler);
+      else
+        handler.on_error("precision not allowed for this argument type");
+    }
+    end = parse_chrono_format(begin, end, detail::chrono_format_checker());
+    return {begin, end};
+  }
+
+ public:
+  formatter() : precision(-1) {}
+
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    auto range = do_parse(ctx);
+    format_str = basic_string_view<Char>(
+        &*range.begin, detail::to_unsigned(range.end - range.begin));
+    return range.end;
+  }
+
+  template <typename FormatContext>
+  auto format(const duration& d, FormatContext& ctx) -> decltype(ctx.out()) {
+    auto begin = format_str.begin(), end = format_str.end();
+    // As a possible future optimization, we could avoid extra copying if width
+    // is not specified.
+    basic_memory_buffer<Char> buf;
+    auto out = std::back_inserter(buf);
+    detail::handle_dynamic_spec<detail::width_checker>(specs.width, width_ref,
+                                                       ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(precision,
+                                                           precision_ref, ctx);
+    if (begin == end || *begin == '}') {
+      out = detail::format_duration_value<Char>(out, d.count(), precision);
+      detail::format_duration_unit<Char, Period>(out);
+    } else {
+      detail::chrono_formatter<FormatContext, decltype(out), Rep, Period> f(
+          ctx, out, d);
+      f.precision = precision;
+      parse_chrono_format(begin, end, f);
+    }
+    return detail::write(
+        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs);
+  }
+};
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_CHRONO_H_

spdlog/fmt/bundled/color.h

+// Formatting library for C++ - color support
+//
+// Copyright (c) 2018 - present, Victor Zverovich and fmt contributors
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_COLOR_H_
+#define FMT_COLOR_H_
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+enum class color : uint32_t {
+  alice_blue = 0xF0F8FF,               // rgb(240,248,255)
+  antique_white = 0xFAEBD7,            // rgb(250,235,215)
+  aqua = 0x00FFFF,                     // rgb(0,255,255)
+  aquamarine = 0x7FFFD4,               // rgb(127,255,212)
+  azure = 0xF0FFFF,                    // rgb(240,255,255)
+  beige = 0xF5F5DC,                    // rgb(245,245,220)
+  bisque = 0xFFE4C4,                   // rgb(255,228,196)
+  black = 0x000000,                    // rgb(0,0,0)
+  blanched_almond = 0xFFEBCD,          // rgb(255,235,205)
+  blue = 0x0000FF,                     // rgb(0,0,255)
+  blue_violet = 0x8A2BE2,              // rgb(138,43,226)
+  brown = 0xA52A2A,                    // rgb(165,42,42)
+  burly_wood = 0xDEB887,               // rgb(222,184,135)
+  cadet_blue = 0x5F9EA0,               // rgb(95,158,160)
+  chartreuse = 0x7FFF00,               // rgb(127,255,0)
+  chocolate = 0xD2691E,                // rgb(210,105,30)
+  coral = 0xFF7F50,                    // rgb(255,127,80)
+  cornflower_blue = 0x6495ED,          // rgb(100,149,237)
+  cornsilk = 0xFFF8DC,                 // rgb(255,248,220)
+  crimson = 0xDC143C,                  // rgb(220,20,60)
+  cyan = 0x00FFFF,                     // rgb(0,255,255)
+  dark_blue = 0x00008B,                // rgb(0,0,139)
+  dark_cyan = 0x008B8B,                // rgb(0,139,139)
+  dark_golden_rod = 0xB8860B,          // rgb(184,134,11)
+  dark_gray = 0xA9A9A9,                // rgb(169,169,169)
+  dark_green = 0x006400,               // rgb(0,100,0)
+  dark_khaki = 0xBDB76B,               // rgb(189,183,107)
+  dark_magenta = 0x8B008B,             // rgb(139,0,139)
+  dark_olive_green = 0x556B2F,         // rgb(85,107,47)
+  dark_orange = 0xFF8C00,              // rgb(255,140,0)
+  dark_orchid = 0x9932CC,              // rgb(153,50,204)
+  dark_red = 0x8B0000,                 // rgb(139,0,0)
+  dark_salmon = 0xE9967A,              // rgb(233,150,122)
+  dark_sea_green = 0x8FBC8F,           // rgb(143,188,143)
+  dark_slate_blue = 0x483D8B,          // rgb(72,61,139)
+  dark_slate_gray = 0x2F4F4F,          // rgb(47,79,79)
+  dark_turquoise = 0x00CED1,           // rgb(0,206,209)
+  dark_violet = 0x9400D3,              // rgb(148,0,211)
+  deep_pink = 0xFF1493,                // rgb(255,20,147)
+  deep_sky_blue = 0x00BFFF,            // rgb(0,191,255)
+  dim_gray = 0x696969,                 // rgb(105,105,105)
+  dodger_blue = 0x1E90FF,              // rgb(30,144,255)
+  fire_brick = 0xB22222,               // rgb(178,34,34)
+  floral_white = 0xFFFAF0,             // rgb(255,250,240)
+  forest_green = 0x228B22,             // rgb(34,139,34)
+  fuchsia = 0xFF00FF,                  // rgb(255,0,255)
+  gainsboro = 0xDCDCDC,                // rgb(220,220,220)
+  ghost_white = 0xF8F8FF,              // rgb(248,248,255)
+  gold = 0xFFD700,                     // rgb(255,215,0)
+  golden_rod = 0xDAA520,               // rgb(218,165,32)
+  gray = 0x808080,                     // rgb(128,128,128)
+  green = 0x008000,                    // rgb(0,128,0)
+  green_yellow = 0xADFF2F,             // rgb(173,255,47)
+  honey_dew = 0xF0FFF0,                // rgb(240,255,240)
+  hot_pink = 0xFF69B4,                 // rgb(255,105,180)
+  indian_red = 0xCD5C5C,               // rgb(205,92,92)
+  indigo = 0x4B0082,                   // rgb(75,0,130)
+  ivory = 0xFFFFF0,                    // rgb(255,255,240)
+  khaki = 0xF0E68C,                    // rgb(240,230,140)
+  lavender = 0xE6E6FA,                 // rgb(230,230,250)
+  lavender_blush = 0xFFF0F5,           // rgb(255,240,245)
+  lawn_green = 0x7CFC00,               // rgb(124,252,0)
+  lemon_chiffon = 0xFFFACD,            // rgb(255,250,205)
+  light_blue = 0xADD8E6,               // rgb(173,216,230)
+  light_coral = 0xF08080,              // rgb(240,128,128)
+  light_cyan = 0xE0FFFF,               // rgb(224,255,255)
+  light_golden_rod_yellow = 0xFAFAD2,  // rgb(250,250,210)
+  light_gray = 0xD3D3D3,               // rgb(211,211,211)
+  light_green = 0x90EE90,              // rgb(144,238,144)
+  light_pink = 0xFFB6C1,               // rgb(255,182,193)
+  light_salmon = 0xFFA07A,             // rgb(255,160,122)
+  light_sea_green = 0x20B2AA,          // rgb(32,178,170)
+  light_sky_blue = 0x87CEFA,           // rgb(135,206,250)
+  light_slate_gray = 0x778899,         // rgb(119,136,153)
+  light_steel_blue = 0xB0C4DE,         // rgb(176,196,222)
+  light_yellow = 0xFFFFE0,             // rgb(255,255,224)
+  lime = 0x00FF00,                     // rgb(0,255,0)
+  lime_green = 0x32CD32,               // rgb(50,205,50)
+  linen = 0xFAF0E6,                    // rgb(250,240,230)
+  magenta = 0xFF00FF,                  // rgb(255,0,255)
+  maroon = 0x800000,                   // rgb(128,0,0)
+  medium_aquamarine = 0x66CDAA,        // rgb(102,205,170)
+  medium_blue = 0x0000CD,              // rgb(0,0,205)
+  medium_orchid = 0xBA55D3,            // rgb(186,85,211)
+  medium_purple = 0x9370DB,            // rgb(147,112,219)
+  medium_sea_green = 0x3CB371,         // rgb(60,179,113)
+  medium_slate_blue = 0x7B68EE,        // rgb(123,104,238)
+  medium_spring_green = 0x00FA9A,      // rgb(0,250,154)
+  medium_turquoise = 0x48D1CC,         // rgb(72,209,204)
+  medium_violet_red = 0xC71585,        // rgb(199,21,133)
+  midnight_blue = 0x191970,            // rgb(25,25,112)
+  mint_cream = 0xF5FFFA,               // rgb(245,255,250)
+  misty_rose = 0xFFE4E1,               // rgb(255,228,225)
+  moccasin = 0xFFE4B5,                 // rgb(255,228,181)
+  navajo_white = 0xFFDEAD,             // rgb(255,222,173)
+  navy = 0x000080,                     // rgb(0,0,128)
+  old_lace = 0xFDF5E6,                 // rgb(253,245,230)
+  olive = 0x808000,                    // rgb(128,128,0)
+  olive_drab = 0x6B8E23,               // rgb(107,142,35)
+  orange = 0xFFA500,                   // rgb(255,165,0)
+  orange_red = 0xFF4500,               // rgb(255,69,0)
+  orchid = 0xDA70D6,                   // rgb(218,112,214)
+  pale_golden_rod = 0xEEE8AA,          // rgb(238,232,170)
+  pale_green = 0x98FB98,               // rgb(152,251,152)
+  pale_turquoise = 0xAFEEEE,           // rgb(175,238,238)
+  pale_violet_red = 0xDB7093,          // rgb(219,112,147)
+  papaya_whip = 0xFFEFD5,              // rgb(255,239,213)
+  peach_puff = 0xFFDAB9,               // rgb(255,218,185)
+  peru = 0xCD853F,                     // rgb(205,133,63)
+  pink = 0xFFC0CB,                     // rgb(255,192,203)
+  plum = 0xDDA0DD,                     // rgb(221,160,221)
+  powder_blue = 0xB0E0E6,              // rgb(176,224,230)
+  purple = 0x800080,                   // rgb(128,0,128)
+  rebecca_purple = 0x663399,           // rgb(102,51,153)
+  red = 0xFF0000,                      // rgb(255,0,0)
+  rosy_brown = 0xBC8F8F,               // rgb(188,143,143)
+  royal_blue = 0x4169E1,               // rgb(65,105,225)
+  saddle_brown = 0x8B4513,             // rgb(139,69,19)
+  salmon = 0xFA8072,                   // rgb(250,128,114)
+  sandy_brown = 0xF4A460,              // rgb(244,164,96)
+  sea_green = 0x2E8B57,                // rgb(46,139,87)
+  sea_shell = 0xFFF5EE,                // rgb(255,245,238)
+  sienna = 0xA0522D,                   // rgb(160,82,45)
+  silver = 0xC0C0C0,                   // rgb(192,192,192)
+  sky_blue = 0x87CEEB,                 // rgb(135,206,235)
+  slate_blue = 0x6A5ACD,               // rgb(106,90,205)
+  slate_gray = 0x708090,               // rgb(112,128,144)
+  snow = 0xFFFAFA,                     // rgb(255,250,250)
+  spring_green = 0x00FF7F,             // rgb(0,255,127)
+  steel_blue = 0x4682B4,               // rgb(70,130,180)
+  tan = 0xD2B48C,                      // rgb(210,180,140)
+  teal = 0x008080,                     // rgb(0,128,128)
+  thistle = 0xD8BFD8,                  // rgb(216,191,216)
+  tomato = 0xFF6347,                   // rgb(255,99,71)
+  turquoise = 0x40E0D0,                // rgb(64,224,208)
+  violet = 0xEE82EE,                   // rgb(238,130,238)
+  wheat = 0xF5DEB3,                    // rgb(245,222,179)
+  white = 0xFFFFFF,                    // rgb(255,255,255)
+  white_smoke = 0xF5F5F5,              // rgb(245,245,245)
+  yellow = 0xFFFF00,                   // rgb(255,255,0)
+  yellow_green = 0x9ACD32              // rgb(154,205,50)
+};                                     // enum class color
+
+enum class terminal_color : uint8_t {
+  black = 30,
+  red,
+  green,
+  yellow,
+  blue,
+  magenta,
+  cyan,
+  white,
+  bright_black = 90,
+  bright_red,
+  bright_green,
+  bright_yellow,
+  bright_blue,
+  bright_magenta,
+  bright_cyan,
+  bright_white
+};
+
+enum class emphasis : uint8_t {
+  bold = 1,
+  italic = 1 << 1,
+  underline = 1 << 2,
+  strikethrough = 1 << 3
+};
+
+// rgb is a struct for red, green and blue colors.
+// Using the name "rgb" makes some editors show the color in a tooltip.
+struct rgb {
+  FMT_CONSTEXPR rgb() : r(0), g(0), b(0) {}
+  FMT_CONSTEXPR rgb(uint8_t r_, uint8_t g_, uint8_t b_) : r(r_), g(g_), b(b_) {}
+  FMT_CONSTEXPR rgb(uint32_t hex)
+      : r((hex >> 16) & 0xFF), g((hex >> 8) & 0xFF), b(hex & 0xFF) {}
+  FMT_CONSTEXPR rgb(color hex)
+      : r((uint32_t(hex) >> 16) & 0xFF),
+        g((uint32_t(hex) >> 8) & 0xFF),
+        b(uint32_t(hex) & 0xFF) {}
+  uint8_t r;
+  uint8_t g;
+  uint8_t b;
+};
+
+namespace detail {
+
+// color is a struct of either a rgb color or a terminal color.
+struct color_type {
+  FMT_CONSTEXPR color_type() FMT_NOEXCEPT : is_rgb(), value{} {}
+  FMT_CONSTEXPR color_type(color rgb_color) FMT_NOEXCEPT : is_rgb(true),
+                                                           value{} {
+    value.rgb_color = static_cast<uint32_t>(rgb_color);
+  }
+  FMT_CONSTEXPR color_type(rgb rgb_color) FMT_NOEXCEPT : is_rgb(true), value{} {
+    value.rgb_color = (static_cast<uint32_t>(rgb_color.r) << 16) |
+                      (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b;
+  }
+  FMT_CONSTEXPR color_type(terminal_color term_color) FMT_NOEXCEPT : is_rgb(),
+                                                                     value{} {
+    value.term_color = static_cast<uint8_t>(term_color);
+  }
+  bool is_rgb;
+  union color_union {
+    uint8_t term_color;
+    uint32_t rgb_color;
+  } value;
+};
+}  // namespace detail
+
+// Experimental text formatting support.
+class text_style {
+ public:
+  FMT_CONSTEXPR text_style(emphasis em = emphasis()) FMT_NOEXCEPT
+      : set_foreground_color(),
+        set_background_color(),
+        ems(em) {}
+
+  FMT_CONSTEXPR text_style& operator|=(const text_style& rhs) {
+    if (!set_foreground_color) {
+      set_foreground_color = rhs.set_foreground_color;
+      foreground_color = rhs.foreground_color;
+    } else if (rhs.set_foreground_color) {
+      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
+        FMT_THROW(format_error("can't OR a terminal color"));
+      foreground_color.value.rgb_color |= rhs.foreground_color.value.rgb_color;
+    }
+
+    if (!set_background_color) {
+      set_background_color = rhs.set_background_color;
+      background_color = rhs.background_color;
+    } else if (rhs.set_background_color) {
+      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
+        FMT_THROW(format_error("can't OR a terminal color"));
+      background_color.value.rgb_color |= rhs.background_color.value.rgb_color;
+    }
+
+    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) |
+                                static_cast<uint8_t>(rhs.ems));
+    return *this;
+  }
+
+  friend FMT_CONSTEXPR text_style operator|(text_style lhs,
+                                            const text_style& rhs) {
+    return lhs |= rhs;
+  }
+
+  FMT_CONSTEXPR text_style& operator&=(const text_style& rhs) {
+    if (!set_foreground_color) {
+      set_foreground_color = rhs.set_foreground_color;
+      foreground_color = rhs.foreground_color;
+    } else if (rhs.set_foreground_color) {
+      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
+        FMT_THROW(format_error("can't AND a terminal color"));
+      foreground_color.value.rgb_color &= rhs.foreground_color.value.rgb_color;
+    }
+
+    if (!set_background_color) {
+      set_background_color = rhs.set_background_color;
+      background_color = rhs.background_color;
+    } else if (rhs.set_background_color) {
+      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
+        FMT_THROW(format_error("can't AND a terminal color"));
+      background_color.value.rgb_color &= rhs.background_color.value.rgb_color;
+    }
+
+    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) &
+                                static_cast<uint8_t>(rhs.ems));
+    return *this;
+  }
+
+  friend FMT_CONSTEXPR text_style operator&(text_style lhs,
+                                            const text_style& rhs) {
+    return lhs &= rhs;
+  }
+
+  FMT_CONSTEXPR bool has_foreground() const FMT_NOEXCEPT {
+    return set_foreground_color;
+  }
+  FMT_CONSTEXPR bool has_background() const FMT_NOEXCEPT {
+    return set_background_color;
+  }
+  FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
+    return static_cast<uint8_t>(ems) != 0;
+  }
+  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
+    FMT_ASSERT(has_foreground(), "no foreground specified for this style");
+    return foreground_color;
+  }
+  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
+    FMT_ASSERT(has_background(), "no background specified for this style");
+    return background_color;
+  }
+  FMT_CONSTEXPR emphasis get_emphasis() const FMT_NOEXCEPT {
+    FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
+    return ems;
+  }
+
+ private:
+  FMT_CONSTEXPR text_style(bool is_foreground,
+                           detail::color_type text_color) FMT_NOEXCEPT
+      : set_foreground_color(),
+        set_background_color(),
+        ems() {
+    if (is_foreground) {
+      foreground_color = text_color;
+      set_foreground_color = true;
+    } else {
+      background_color = text_color;
+      set_background_color = true;
+    }
+  }
+
+  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
+      FMT_NOEXCEPT;
+  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
+      FMT_NOEXCEPT;
+
+  detail::color_type foreground_color;
+  detail::color_type background_color;
+  bool set_foreground_color;
+  bool set_background_color;
+  emphasis ems;
+};
+
+FMT_CONSTEXPR text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
+  return text_style(/*is_foreground=*/true, foreground);
+}
+
+FMT_CONSTEXPR text_style bg(detail::color_type background) FMT_NOEXCEPT {
+  return text_style(/*is_foreground=*/false, background);
+}
+
+FMT_CONSTEXPR text_style operator|(emphasis lhs, emphasis rhs) FMT_NOEXCEPT {
+  return text_style(lhs) | rhs;
+}
+
+namespace detail {
+
+template <typename Char> struct ansi_color_escape {
+  FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
+                                  const char* esc) FMT_NOEXCEPT {
+    // If we have a terminal color, we need to output another escape code
+    // sequence.
+    if (!text_color.is_rgb) {
+      bool is_background = esc == detail::data::background_color;
+      uint32_t value = text_color.value.term_color;
+      // Background ASCII codes are the same as the foreground ones but with
+      // 10 more.
+      if (is_background) value += 10u;
+
+      size_t index = 0;
+      buffer[index++] = static_cast<Char>('\x1b');
+      buffer[index++] = static_cast<Char>('[');
+
+      if (value >= 100u) {
+        buffer[index++] = static_cast<Char>('1');
+        value %= 100u;
+      }
+      buffer[index++] = static_cast<Char>('0' + value / 10u);
+      buffer[index++] = static_cast<Char>('0' + value % 10u);
+
+      buffer[index++] = static_cast<Char>('m');
+      buffer[index++] = static_cast<Char>('\0');
+      return;
+    }
+
+    for (int i = 0; i < 7; i++) {
+      buffer[i] = static_cast<Char>(esc[i]);
+    }
+    rgb color(text_color.value.rgb_color);
+    to_esc(color.r, buffer + 7, ';');
+    to_esc(color.g, buffer + 11, ';');
+    to_esc(color.b, buffer + 15, 'm');
+    buffer[19] = static_cast<Char>(0);
+  }
+  FMT_CONSTEXPR ansi_color_escape(emphasis em) FMT_NOEXCEPT {
+    uint8_t em_codes[4] = {};
+    uint8_t em_bits = static_cast<uint8_t>(em);
+    if (em_bits & static_cast<uint8_t>(emphasis::bold)) em_codes[0] = 1;
+    if (em_bits & static_cast<uint8_t>(emphasis::italic)) em_codes[1] = 3;
+    if (em_bits & static_cast<uint8_t>(emphasis::underline)) em_codes[2] = 4;
+    if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
+      em_codes[3] = 9;
+
+    size_t index = 0;
+    for (int i = 0; i < 4; ++i) {
+      if (!em_codes[i]) continue;
+      buffer[index++] = static_cast<Char>('\x1b');
+      buffer[index++] = static_cast<Char>('[');
+      buffer[index++] = static_cast<Char>('0' + em_codes[i]);
+      buffer[index++] = static_cast<Char>('m');
+    }
+    buffer[index++] = static_cast<Char>(0);
+  }
+  FMT_CONSTEXPR operator const Char*() const FMT_NOEXCEPT { return buffer; }
+
+  FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
+  FMT_CONSTEXPR const Char* end() const FMT_NOEXCEPT {
+    return buffer + std::char_traits<Char>::length(buffer);
+  }
+
+ private:
+  Char buffer[7u + 3u * 4u + 1u];
+
+  static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
+                                   char delimiter) FMT_NOEXCEPT {
+    out[0] = static_cast<Char>('0' + c / 100);
+    out[1] = static_cast<Char>('0' + c / 10 % 10);
+    out[2] = static_cast<Char>('0' + c % 10);
+    out[3] = static_cast<Char>(delimiter);
+  }
+};
+
+template <typename Char>
+FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
+    detail::color_type foreground) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(foreground, detail::data::foreground_color);
+}
+
+template <typename Char>
+FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
+    detail::color_type background) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(background, detail::data::background_color);
+}
+
+template <typename Char>
+FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(em);
+}
+
+template <typename Char>
+inline void fputs(const Char* chars, FILE* stream) FMT_NOEXCEPT {
+  std::fputs(chars, stream);
+}
+
+template <>
+inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
+  std::fputws(chars, stream);
+}
+
+template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
+  fputs(detail::data::reset_color, stream);
+}
+
+template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
+  fputs(detail::data::wreset_color, stream);
+}
+
+template <typename Char>
+inline void reset_color(basic_memory_buffer<Char>& buffer) FMT_NOEXCEPT {
+  const char* begin = data::reset_color;
+  const char* end = begin + sizeof(data::reset_color) - 1;
+  buffer.append(begin, end);
+}
+
+template <typename Char>
+void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
+                basic_string_view<Char> format_str,
+                basic_format_args<buffer_context<Char>> args) {
+  bool has_style = false;
+  if (ts.has_emphasis()) {
+    has_style = true;
+    auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+    buf.append(emphasis.begin(), emphasis.end());
+  }
+  if (ts.has_foreground()) {
+    has_style = true;
+    auto foreground = detail::make_foreground_color<Char>(ts.get_foreground());
+    buf.append(foreground.begin(), foreground.end());
+  }
+  if (ts.has_background()) {
+    has_style = true;
+    auto background = detail::make_background_color<Char>(ts.get_background());
+    buf.append(background.begin(), background.end());
+  }
+  detail::vformat_to(buf, format_str, args);
+  if (has_style) detail::reset_color<Char>(buf);
+}
+}  // namespace detail
+
+template <typename S, typename Char = char_t<S>>
+void vprint(std::FILE* f, const text_style& ts, const S& format,
+            basic_format_args<buffer_context<Char>> args) {
+  basic_memory_buffer<Char> buf;
+  detail::vformat_to(buf, ts, to_string_view(format), args);
+  buf.push_back(Char(0));
+  detail::fputs(buf.data(), f);
+}
+
+/**
+  Formats a string and prints it to the specified file stream using ANSI
+  escape sequences to specify text formatting.
+  Example:
+    fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+               "Elapsed time: {0:.2f} seconds", 1.23);
+ */
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
+void print(std::FILE* f, const text_style& ts, const S& format_str,
+           const Args&... args) {
+  detail::check_format_string<Args...>(format_str);
+  using context = buffer_context<char_t<S>>;
+  format_arg_store<context, Args...> as{args...};
+  vprint(f, ts, format_str, basic_format_args<context>(as));
+}
+
+/**
+  Formats a string and prints it to stdout using ANSI escape sequences to
+  specify text formatting.
+  Example:
+    fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+               "Elapsed time: {0:.2f} seconds", 1.23);
+ */
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
+void print(const text_style& ts, const S& format_str, const Args&... args) {
+  return print(stdout, ts, format_str, args...);
+}
+
+template <typename S, typename Char = char_t<S>>
+inline std::basic_string<Char> vformat(
+    const text_style& ts, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buf;
+  detail::vformat_to(buf, ts, to_string_view(format_str), args);
+  return fmt::to_string(buf);
+}
+
+/**
+  \rst
+  Formats arguments and returns the result as a string using ANSI
+  escape sequences to specify text formatting.
+
+  **Example**::
+
+    #include <fmt/color.h>
+    std::string message = fmt::format(fmt::emphasis::bold | fg(fmt::color::red),
+                                      "The answer is {}", 42);
+  \endrst
+*/
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
+                                      const Args&... args) {
+  return vformat(ts, to_string_view(format_str),
+                 detail::make_args_checked<Args...>(format_str, args...));
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_COLOR_H_

spdlog/fmt/bundled/compile.h

+// Formatting library for C++ - experimental format string compilation
+//
+// Copyright (c) 2012 - present, Victor Zverovich and fmt contributors
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_COMPILE_H_
+#define FMT_COMPILE_H_
+
+#include <vector>
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+// A compile-time string which is compiled into fast formatting code.
+class compiled_string {};
+
+template <typename S>
+struct is_compiled_string : std::is_base_of<compiled_string, S> {};
+
+/**
+  \rst
+  Converts a string literal *s* into a format string that will be parsed at
+  compile time and converted into efficient formatting code. Requires C++17
+  ``constexpr if`` compiler support.
+
+  **Example**::
+
+    // Converts 42 into std::string using the most efficient method and no
+    // runtime format string processing.
+    std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+  \endrst
+ */
+#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
+
+template <typename T, typename... Tail>
+const T& first(const T& value, const Tail&...) {
+  return value;
+}
+
+// Part of a compiled format string. It can be either literal text or a
+// replacement field.
+template <typename Char> struct format_part {
+  enum class kind { arg_index, arg_name, text, replacement };
+
+  struct replacement {
+    arg_ref<Char> arg_id;
+    dynamic_format_specs<Char> specs;
+  };
+
+  kind part_kind;
+  union value {
+    int arg_index;
+    basic_string_view<Char> str;
+    replacement repl;
+
+    FMT_CONSTEXPR value(int index = 0) : arg_index(index) {}
+    FMT_CONSTEXPR value(basic_string_view<Char> s) : str(s) {}
+    FMT_CONSTEXPR value(replacement r) : repl(r) {}
+  } val;
+  // Position past the end of the argument id.
+  const Char* arg_id_end = nullptr;
+
+  FMT_CONSTEXPR format_part(kind k = kind::arg_index, value v = {})
+      : part_kind(k), val(v) {}
+
+  static FMT_CONSTEXPR format_part make_arg_index(int index) {
+    return format_part(kind::arg_index, index);
+  }
+  static FMT_CONSTEXPR format_part make_arg_name(basic_string_view<Char> name) {
+    return format_part(kind::arg_name, name);
+  }
+  static FMT_CONSTEXPR format_part make_text(basic_string_view<Char> text) {
+    return format_part(kind::text, text);
+  }
+  static FMT_CONSTEXPR format_part make_replacement(replacement repl) {
+    return format_part(kind::replacement, repl);
+  }
+};
+
+template <typename Char> struct part_counter {
+  unsigned num_parts = 0;
+
+  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
+    if (begin != end) ++num_parts;
+  }
+
+  FMT_CONSTEXPR int on_arg_id() { return ++num_parts, 0; }
+  FMT_CONSTEXPR int on_arg_id(int) { return ++num_parts, 0; }
+  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
+    return ++num_parts, 0;
+  }
+
+  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
+
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
+                                            const Char* end) {
+    // Find the matching brace.
+    unsigned brace_counter = 0;
+    for (; begin != end; ++begin) {
+      if (*begin == '{') {
+        ++brace_counter;
+      } else if (*begin == '}') {
+        if (brace_counter == 0u) break;
+        --brace_counter;
+      }
+    }
+    return begin;
+  }
+
+  FMT_CONSTEXPR void on_error(const char*) {}
+};
+
+// Counts the number of parts in a format string.
+template <typename Char>
+FMT_CONSTEXPR unsigned count_parts(basic_string_view<Char> format_str) {
+  part_counter<Char> counter;
+  parse_format_string<true>(format_str, counter);
+  return counter.num_parts;
+}
+
+template <typename Char, typename PartHandler>
+class format_string_compiler : public error_handler {
+ private:
+  using part = format_part<Char>;
+
+  PartHandler handler_;
+  part part_;
+  basic_string_view<Char> format_str_;
+  basic_format_parse_context<Char> parse_context_;
+
+ public:
+  FMT_CONSTEXPR format_string_compiler(basic_string_view<Char> format_str,
+                                       PartHandler handler)
+      : handler_(handler),
+        format_str_(format_str),
+        parse_context_(format_str) {}
+
+  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
+    if (begin != end)
+      handler_(part::make_text({begin, to_unsigned(end - begin)}));
+  }
+
+  FMT_CONSTEXPR int on_arg_id() {
+    part_ = part::make_arg_index(parse_context_.next_arg_id());
+    return 0;
+  }
+
+  FMT_CONSTEXPR int on_arg_id(int id) {
+    parse_context_.check_arg_id(id);
+    part_ = part::make_arg_index(id);
+    return 0;
+  }
+
+  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char> id) {
+    part_ = part::make_arg_name(id);
+    return 0;
+  }
+
+  FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
+    part_.arg_id_end = ptr;
+    handler_(part_);
+  }
+
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
+                                            const Char* end) {
+    auto repl = typename part::replacement();
+    dynamic_specs_handler<basic_format_parse_context<Char>> handler(
+        repl.specs, parse_context_);
+    auto it = parse_format_specs(begin, end, handler);
+    if (*it != '}') on_error("missing '}' in format string");
+    repl.arg_id = part_.part_kind == part::kind::arg_index
+                      ? arg_ref<Char>(part_.val.arg_index)
+                      : arg_ref<Char>(part_.val.str);
+    auto part = part::make_replacement(repl);
+    part.arg_id_end = begin;
+    handler_(part);
+    return it;
+  }
+};
+
+// Compiles a format string and invokes handler(part) for each parsed part.
+template <bool IS_CONSTEXPR, typename Char, typename PartHandler>
+FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str,
+                                         PartHandler handler) {
+  parse_format_string<IS_CONSTEXPR>(
+      format_str,
+      format_string_compiler<Char, PartHandler>(format_str, handler));
+}
+
+template <typename OutputIt, typename Context, typename Id>
+void format_arg(
+    basic_format_parse_context<typename Context::char_type>& parse_ctx,
+    Context& ctx, Id arg_id) {
+  ctx.advance_to(visit_format_arg(
+      arg_formatter<OutputIt, typename Context::char_type>(ctx, &parse_ctx),
+      ctx.arg(arg_id)));
+}
+
+// vformat_to is defined in a subnamespace to prevent ADL.
+namespace cf {
+template <typename Context, typename OutputIt, typename CompiledFormat>
+auto vformat_to(OutputIt out, CompiledFormat& cf,
+                basic_format_args<Context> args) -> typename Context::iterator {
+  using char_type = typename Context::char_type;
+  basic_format_parse_context<char_type> parse_ctx(
+      to_string_view(cf.format_str_));
+  Context ctx(out, args);
+
+  const auto& parts = cf.parts();
+  for (auto part_it = std::begin(parts); part_it != std::end(parts);
+       ++part_it) {
+    const auto& part = *part_it;
+    const auto& value = part.val;
+
+    using format_part_t = format_part<char_type>;
+    switch (part.part_kind) {
+    case format_part_t::kind::text: {
+      const auto text = value.str;
+      auto output = ctx.out();
+      auto&& it = reserve(output, text.size());
+      it = std::copy_n(text.begin(), text.size(), it);
+      ctx.advance_to(output);
+      break;
+    }
+
+    case format_part_t::kind::arg_index:
+      advance_to(parse_ctx, part.arg_id_end);
+      detail::format_arg<OutputIt>(parse_ctx, ctx, value.arg_index);
+      break;
+
+    case format_part_t::kind::arg_name:
+      advance_to(parse_ctx, part.arg_id_end);
+      detail::format_arg<OutputIt>(parse_ctx, ctx, value.str);
+      break;
+
+    case format_part_t::kind::replacement: {
+      const auto& arg_id_value = value.repl.arg_id.val;
+      const auto arg = value.repl.arg_id.kind == arg_id_kind::index
+                           ? ctx.arg(arg_id_value.index)
+                           : ctx.arg(arg_id_value.name);
+
+      auto specs = value.repl.specs;
+
+      handle_dynamic_spec<width_checker>(specs.width, specs.width_ref, ctx);
+      handle_dynamic_spec<precision_checker>(specs.precision,
+                                             specs.precision_ref, ctx);
+
+      error_handler h;
+      numeric_specs_checker<error_handler> checker(h, arg.type());
+      if (specs.align == align::numeric) checker.require_numeric_argument();
+      if (specs.sign != sign::none) checker.check_sign();
+      if (specs.alt) checker.require_numeric_argument();
+      if (specs.precision >= 0) checker.check_precision();
+
+      advance_to(parse_ctx, part.arg_id_end);
+      ctx.advance_to(
+          visit_format_arg(arg_formatter<OutputIt, typename Context::char_type>(
+                               ctx, nullptr, &specs),
+                           arg));
+      break;
+    }
+    }
+  }
+  return ctx.out();
+}
+}  // namespace cf
+
+struct basic_compiled_format {};
+
+template <typename S, typename = void>
+struct compiled_format_base : basic_compiled_format {
+  using char_type = char_t<S>;
+  using parts_container = std::vector<detail::format_part<char_type>>;
+
+  parts_container compiled_parts;
+
+  explicit compiled_format_base(basic_string_view<char_type> format_str) {
+    compile_format_string<false>(format_str,
+                                 [this](const format_part<char_type>& part) {
+                                   compiled_parts.push_back(part);
+                                 });
+  }
+
+  const parts_container& parts() const { return compiled_parts; }
+};
+
+template <typename Char, unsigned N> struct format_part_array {
+  format_part<Char> data[N] = {};
+  FMT_CONSTEXPR format_part_array() = default;
+};
+
+template <typename Char, unsigned N>
+FMT_CONSTEXPR format_part_array<Char, N> compile_to_parts(
+    basic_string_view<Char> format_str) {
+  format_part_array<Char, N> parts;
+  unsigned counter = 0;
+  // This is not a lambda for compatibility with older compilers.
+  struct {
+    format_part<Char>* parts;
+    unsigned* counter;
+    FMT_CONSTEXPR void operator()(const format_part<Char>& part) {
+      parts[(*counter)++] = part;
+    }
+  } collector{parts.data, &counter};
+  compile_format_string<true>(format_str, collector);
+  if (counter < N) {
+    parts.data[counter] =
+        format_part<Char>::make_text(basic_string_view<Char>());
+  }
+  return parts;
+}
+
+template <typename T> constexpr const T& constexpr_max(const T& a, const T& b) {
+  return (a < b) ? b : a;
+}
+
+template <typename S>
+struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>>
+    : basic_compiled_format {
+  using char_type = char_t<S>;
+
+  FMT_CONSTEXPR explicit compiled_format_base(basic_string_view<char_type>) {}
+
+// Workaround for old compilers. Format string compilation will not be
+// performed there anyway.
+#if FMT_USE_CONSTEXPR
+  static FMT_CONSTEXPR_DECL const unsigned num_format_parts =
+      constexpr_max(count_parts(to_string_view(S())), 1u);
+#else
+  static const unsigned num_format_parts = 1;
+#endif
+
+  using parts_container = format_part<char_type>[num_format_parts];
+
+  const parts_container& parts() const {
+    static FMT_CONSTEXPR_DECL const auto compiled_parts =
+        compile_to_parts<char_type, num_format_parts>(
+            detail::to_string_view(S()));
+    return compiled_parts.data;
+  }
+};
+
+template <typename S, typename... Args>
+class compiled_format : private compiled_format_base<S> {
+ public:
+  using typename compiled_format_base<S>::char_type;
+
+ private:
+  basic_string_view<char_type> format_str_;
+
+  template <typename Context, typename OutputIt, typename CompiledFormat>
+  friend auto cf::vformat_to(OutputIt out, CompiledFormat& cf,
+                             basic_format_args<Context> args) ->
+      typename Context::iterator;
+
+ public:
+  compiled_format() = delete;
+  explicit constexpr compiled_format(basic_string_view<char_type> format_str)
+      : compiled_format_base<S>(format_str), format_str_(format_str) {}
+};
+
+#ifdef __cpp_if_constexpr
+template <typename... Args> struct type_list {};
+
+// Returns a reference to the argument at index N from [first, rest...].
+template <int N, typename T, typename... Args>
+constexpr const auto& get(const T& first, const Args&... rest) {
+  static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
+  if constexpr (N == 0)
+    return first;
+  else
+    return get<N - 1>(rest...);
+}
+
+template <int N, typename> struct get_type_impl;
+
+template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
+  using type = remove_cvref_t<decltype(get<N>(std::declval<Args>()...))>;
+};
+
+template <int N, typename T>
+using get_type = typename get_type_impl<N, T>::type;
+
+template <typename T> struct is_compiled_format : std::false_type {};
+
+template <typename Char> struct text {
+  basic_string_view<Char> data;
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&...) const {
+    return write<Char>(out, data);
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<text<Char>> : std::true_type {};
+
+template <typename Char>
+constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
+                               size_t size) {
+  return {{&s[pos], size}};
+}
+
+// A replacement field that refers to argument N.
+template <typename Char, typename T, int N> struct field {
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&... args) const {
+    // This ensures that the argument type is convertile to `const T&`.
+    const T& arg = get<N>(args...);
+    return write<Char>(out, arg);
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<field<Char, T, N>> : std::true_type {};
+
+// A replacement field that refers to argument N and has format specifiers.
+template <typename Char, typename T, int N> struct spec_field {
+  using char_type = Char;
+  mutable formatter<T, Char> fmt;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&... args) const {
+    // This ensures that the argument type is convertile to `const T&`.
+    const T& arg = get<N>(args...);
+    basic_format_context<OutputIt, Char> ctx(out, {});
+    return fmt.format(arg, ctx);
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};
+
+template <typename L, typename R> struct concat {
+  L lhs;
+  R rhs;
+  using char_type = typename L::char_type;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&... args) const {
+    out = lhs.format(out, args...);
+    return rhs.format(out, args...);
+  }
+};
+
+template <typename L, typename R>
+struct is_compiled_format<concat<L, R>> : std::true_type {};
+
+template <typename L, typename R>
+constexpr concat<L, R> make_concat(L lhs, R rhs) {
+  return {lhs, rhs};
+}
+
+struct unknown_format {};
+
+template <typename Char>
+constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
+  for (size_t size = str.size(); pos != size; ++pos) {
+    if (str[pos] == '{' || str[pos] == '}') break;
+  }
+  return pos;
+}
+
+template <typename Args, size_t POS, int ID, typename S>
+constexpr auto compile_format_string(S format_str);
+
+template <typename Args, size_t POS, int ID, typename T, typename S>
+constexpr auto parse_tail(T head, S format_str) {
+  if constexpr (POS !=
+                basic_string_view<typename S::char_type>(format_str).size()) {
+    constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
+    if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
+                               unknown_format>())
+      return tail;
+    else
+      return make_concat(head, tail);
+  } else {
+    return head;
+  }
+}
+
+template <typename T, typename Char> struct parse_specs_result {
+  formatter<T, Char> fmt;
+  size_t end;
+};
+
+template <typename T, typename Char>
+constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
+                                                  size_t pos) {
+  str.remove_prefix(pos);
+  auto ctx = basic_format_parse_context<Char>(str);
+  auto f = formatter<T, Char>();
+  auto end = f.parse(ctx);
+  return {f, pos + (end - str.data()) + 1};
+}
+
+// Compiles a non-empty format string and returns the compiled representation
+// or unknown_format() on unrecognized input.
+template <typename Args, size_t POS, int ID, typename S>
+constexpr auto compile_format_string(S format_str) {
+  using char_type = typename S::char_type;
+  constexpr basic_string_view<char_type> str = format_str;
+  if constexpr (str[POS] == '{') {
+    if (POS + 1 == str.size())
+      throw format_error("unmatched '{' in format string");
+    if constexpr (str[POS + 1] == '{') {
+      return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
+    } else if constexpr (str[POS + 1] == '}') {
+      using type = get_type<ID, Args>;
+      return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
+                                               format_str);
+    } else if constexpr (str[POS + 1] == ':') {
+      using type = get_type<ID, Args>;
+      constexpr auto result = parse_specs<type>(str, POS + 2);
+      return parse_tail<Args, result.end, ID + 1>(
+          spec_field<char_type, type, ID>{result.fmt}, format_str);
+    } else {
+      return unknown_format();
+    }
+  } else if constexpr (str[POS] == '}') {
+    if (POS + 1 == str.size())
+      throw format_error("unmatched '}' in format string");
+    return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
+  } else {
+    constexpr auto end = parse_text(str, POS + 1);
+    return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
+                                     format_str);
+  }
+}
+
+template <typename... Args, typename S,
+          FMT_ENABLE_IF(is_compile_string<S>::value ||
+                        detail::is_compiled_string<S>::value)>
+constexpr auto compile(S format_str) {
+  constexpr basic_string_view<typename S::char_type> str = format_str;
+  if constexpr (str.size() == 0) {
+    return detail::make_text(str, 0, 0);
+  } else {
+    constexpr auto result =
+        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
+            format_str);
+    if constexpr (std::is_same<remove_cvref_t<decltype(result)>,
+                               detail::unknown_format>()) {
+      return detail::compiled_format<S, Args...>(to_string_view(format_str));
+    } else {
+      return result;
+    }
+  }
+}
+#else
+template <typename... Args, typename S,
+          FMT_ENABLE_IF(is_compile_string<S>::value)>
+constexpr auto compile(S format_str) -> detail::compiled_format<S, Args...> {
+  return detail::compiled_format<S, Args...>(to_string_view(format_str));
+}
+#endif  // __cpp_if_constexpr
+
+// Compiles the format string which must be a string literal.
+template <typename... Args, typename Char, size_t N>
+auto compile(const Char (&format_str)[N])
+    -> detail::compiled_format<const Char*, Args...> {
+  return detail::compiled_format<const Char*, Args...>(
+      basic_string_view<Char>(format_str, N - 1));
+}
+}  // namespace detail
+
+// DEPRECATED! use FMT_COMPILE instead.
+template <typename... Args>
+FMT_DEPRECATED auto compile(const Args&... args)
+    -> decltype(detail::compile(args...)) {
+  return detail::compile(args...);
+}
+
+#if FMT_USE_CONSTEXPR
+#  ifdef __cpp_if_constexpr
+
+template <typename CompiledFormat, typename... Args,
+          typename Char = typename CompiledFormat::char_type,
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
+                                          const Args&... args) {
+  basic_memory_buffer<Char> buffer;
+  detail::buffer<Char>& base = buffer;
+  cf.format(std::back_inserter(base), args...);
+  return to_string(buffer);
+}
+
+template <typename OutputIt, typename CompiledFormat, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+OutputIt format_to(OutputIt out, const CompiledFormat& cf,
+                   const Args&... args) {
+  return cf.format(out, args...);
+}
+#  endif  // __cpp_if_constexpr
+#endif    // FMT_USE_CONSTEXPR
+
+template <typename CompiledFormat, typename... Args,
+          typename Char = typename CompiledFormat::char_type,
+          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
+                                        CompiledFormat>::value)>
+std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
+  basic_memory_buffer<Char> buffer;
+  using context = buffer_context<Char>;
+  detail::buffer<Char>& base = buffer;
+  detail::cf::vformat_to<context>(std::back_inserter(base), cf,
+                                  make_format_args<context>(args...));
+  return to_string(buffer);
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
+                                                           Args&&... args) {
+  constexpr basic_string_view<typename S::char_type> str = S();
+  if (str.size() == 2 && str[0] == '{' && str[1] == '}')
+    return fmt::to_string(detail::first(args...));
+  constexpr auto compiled = detail::compile<Args...>(S());
+  return format(compiled, std::forward<Args>(args)...);
+}
+
+template <typename OutputIt, typename CompiledFormat, typename... Args,
+          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
+                                        CompiledFormat>::value)>
+OutputIt format_to(OutputIt out, const CompiledFormat& cf,
+                   const Args&... args) {
+  using char_type = typename CompiledFormat::char_type;
+  using context = format_context_t<OutputIt, char_type>;
+  return detail::cf::vformat_to<context>(out, cf,
+                                         make_format_args<context>(args...));
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+OutputIt format_to(OutputIt out, const S&, const Args&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  return format_to(out, compiled, args...);
+}
+
+template <
+    typename OutputIt, typename CompiledFormat, typename... Args,
+    FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&& std::is_base_of<
+                  detail::basic_compiled_format, CompiledFormat>::value)>
+format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
+                                         const CompiledFormat& cf,
+                                         const Args&... args) {
+  auto it =
+      format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
+  return {it.base(), it.count()};
+}
+
+template <typename CompiledFormat, typename... Args>
+size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
+  return format_to(detail::counting_iterator(), cf, args...).count();
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_COMPILE_H_

spdlog/fmt/bundled/core.h

+// Formatting library for C++ - the core API
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_CORE_H_
+#define FMT_CORE_H_
+
+#include <cstdio>  // std::FILE
+#include <cstring>
+#include <functional>
+#include <iterator>
+#include <memory>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+// The fmt library version in the form major * 10000 + minor * 100 + patch.
+#define FMT_VERSION 70003
+
+#ifdef __clang__
+#  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
+#else
+#  define FMT_CLANG_VERSION 0
+#endif
+
+#if defined(__GNUC__) && !defined(__clang__)
+#  define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
+#else
+#  define FMT_GCC_VERSION 0
+#endif
+
+#if defined(__INTEL_COMPILER)
+#  define FMT_ICC_VERSION __INTEL_COMPILER
+#else
+#  define FMT_ICC_VERSION 0
+#endif
+
+#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  define FMT_HAS_GXX_CXX11 FMT_GCC_VERSION
+#else
+#  define FMT_HAS_GXX_CXX11 0
+#endif
+
+#ifdef __NVCC__
+#  define FMT_NVCC __NVCC__
+#else
+#  define FMT_NVCC 0
+#endif
+
+#ifdef _MSC_VER
+#  define FMT_MSC_VER _MSC_VER
+#  define FMT_SUPPRESS_MSC_WARNING(n) __pragma(warning(suppress : n))
+#else
+#  define FMT_MSC_VER 0
+#  define FMT_SUPPRESS_MSC_WARNING(n)
+#endif
+#ifdef __has_feature
+#  define FMT_HAS_FEATURE(x) __has_feature(x)
+#else
+#  define FMT_HAS_FEATURE(x) 0
+#endif
+
+#if defined(__has_include) && !defined(__INTELLISENSE__) && \
+    !(FMT_ICC_VERSION && FMT_ICC_VERSION < 1600)
+#  define FMT_HAS_INCLUDE(x) __has_include(x)
+#else
+#  define FMT_HAS_INCLUDE(x) 0
+#endif
+
+#ifdef __has_cpp_attribute
+#  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
+#else
+#  define FMT_HAS_CPP_ATTRIBUTE(x) 0
+#endif
+
+#define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
+  (__cplusplus >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))
+
+#define FMT_HAS_CPP17_ATTRIBUTE(attribute) \
+  (__cplusplus >= 201703L && FMT_HAS_CPP_ATTRIBUTE(attribute))
+
+// Check if relaxed C++14 constexpr is supported.
+// GCC doesn't allow throw in constexpr until version 6 (bug 67371).
+#ifndef FMT_USE_CONSTEXPR
+#  define FMT_USE_CONSTEXPR                                           \
+    (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1910 || \
+     (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
+        !FMT_NVCC && !FMT_ICC_VERSION
+#endif
+#if FMT_USE_CONSTEXPR
+#  define FMT_CONSTEXPR constexpr
+#  define FMT_CONSTEXPR_DECL constexpr
+#else
+#  define FMT_CONSTEXPR inline
+#  define FMT_CONSTEXPR_DECL
+#endif
+
+#ifndef FMT_OVERRIDE
+#  if FMT_HAS_FEATURE(cxx_override) || \
+      (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
+#    define FMT_OVERRIDE override
+#  else
+#    define FMT_OVERRIDE
+#  endif
+#endif
+
+// Check if exceptions are disabled.
+#ifndef FMT_EXCEPTIONS
+#  if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
+      FMT_MSC_VER && !_HAS_EXCEPTIONS
+#    define FMT_EXCEPTIONS 0
+#  else
+#    define FMT_EXCEPTIONS 1
+#  endif
+#endif
+
+// Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
+#ifndef FMT_USE_NOEXCEPT
+#  define FMT_USE_NOEXCEPT 0
+#endif
+
+#if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || \
+    (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
+#  define FMT_DETECTED_NOEXCEPT noexcept
+#  define FMT_HAS_CXX11_NOEXCEPT 1
+#else
+#  define FMT_DETECTED_NOEXCEPT throw()
+#  define FMT_HAS_CXX11_NOEXCEPT 0
+#endif
+
+#ifndef FMT_NOEXCEPT
+#  if FMT_EXCEPTIONS || FMT_HAS_CXX11_NOEXCEPT
+#    define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
+#  else
+#    define FMT_NOEXCEPT
+#  endif
+#endif
+
+// [[noreturn]] is disabled on MSVC and NVCC because of bogus unreachable code
+// warnings.
+#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER && \
+    !FMT_NVCC
+#  define FMT_NORETURN [[noreturn]]
+#else
+#  define FMT_NORETURN
+#endif
+
+#ifndef FMT_DEPRECATED
+#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
+#    define FMT_DEPRECATED [[deprecated]]
+#  else
+#    if defined(__GNUC__) || defined(__clang__)
+#      define FMT_DEPRECATED __attribute__((deprecated))
+#    elif FMT_MSC_VER
+#      define FMT_DEPRECATED __declspec(deprecated)
+#    else
+#      define FMT_DEPRECATED /* deprecated */
+#    endif
+#  endif
+#endif
+
+// Workaround broken [[deprecated]] in the Intel, PGI and NVCC compilers.
+#if FMT_ICC_VERSION || defined(__PGI) || FMT_NVCC
+#  define FMT_DEPRECATED_ALIAS
+#else
+#  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
+#endif
+
+#ifndef FMT_INLINE
+#  if FMT_GCC_VERSION || FMT_CLANG_VERSION
+#    define FMT_INLINE inline __attribute__((always_inline))
+#  else
+#    define FMT_INLINE inline
+#  endif
+#endif
+
+#ifndef FMT_BEGIN_NAMESPACE
+#  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
+      FMT_MSC_VER >= 1900
+#    define FMT_INLINE_NAMESPACE inline namespace
+#    define FMT_END_NAMESPACE \
+      }                       \
+      }
+#  else
+#    define FMT_INLINE_NAMESPACE namespace
+#    define FMT_END_NAMESPACE \
+      }                       \
+      using namespace v7;     \
+      }
+#  endif
+#  define FMT_BEGIN_NAMESPACE \
+    namespace fmt {           \
+    FMT_INLINE_NAMESPACE v7 {
+#endif
+
+#if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
+#  define FMT_CLASS_API FMT_SUPPRESS_MSC_WARNING(4275)
+#  ifdef FMT_EXPORT
+#    define FMT_API __declspec(dllexport)
+#    define FMT_EXTERN_TEMPLATE_API FMT_API
+#    define FMT_EXPORTED
+#  elif defined(FMT_SHARED)
+#    define FMT_API __declspec(dllimport)
+#    define FMT_EXTERN_TEMPLATE_API FMT_API
+#  endif
+#else
+#  define FMT_CLASS_API
+#endif
+#ifndef FMT_API
+#  define FMT_API
+#endif
+#ifndef FMT_EXTERN_TEMPLATE_API
+#  define FMT_EXTERN_TEMPLATE_API
+#endif
+#ifndef FMT_INSTANTIATION_DEF_API
+#  define FMT_INSTANTIATION_DEF_API FMT_API
+#endif
+
+#ifndef FMT_HEADER_ONLY
+#  define FMT_EXTERN extern
+#else
+#  define FMT_EXTERN
+#endif
+
+// libc++ supports string_view in pre-c++17.
+#if (FMT_HAS_INCLUDE(<string_view>) &&                       \
+     (__cplusplus > 201402L || defined(_LIBCPP_VERSION))) || \
+    (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
+#  include <string_view>
+#  define FMT_USE_STRING_VIEW
+#elif FMT_HAS_INCLUDE("experimental/string_view") && __cplusplus >= 201402L
+#  include <experimental/string_view>
+#  define FMT_USE_EXPERIMENTAL_STRING_VIEW
+#endif
+
+#ifndef FMT_UNICODE
+#  define FMT_UNICODE !FMT_MSC_VER
+#endif
+#if FMT_UNICODE && FMT_MSC_VER
+#  pragma execution_character_set("utf-8")
+#endif
+
+FMT_BEGIN_NAMESPACE
+
+// Implementations of enable_if_t and other metafunctions for older systems.
+template <bool B, class T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+template <bool B, class T, class F>
+using conditional_t = typename std::conditional<B, T, F>::type;
+template <bool B> using bool_constant = std::integral_constant<bool, B>;
+template <typename T>
+using remove_reference_t = typename std::remove_reference<T>::type;
+template <typename T>
+using remove_const_t = typename std::remove_const<T>::type;
+template <typename T>
+using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
+template <typename T> struct type_identity { using type = T; };
+template <typename T> using type_identity_t = typename type_identity<T>::type;
+
+struct monostate {};
+
+// An enable_if helper to be used in template parameters which results in much
+// shorter symbols: https://godbolt.org/z/sWw4vP. Extra parentheses are needed
+// to workaround a bug in MSVC 2019 (see #1140 and #1186).
+#define FMT_ENABLE_IF(...) enable_if_t<(__VA_ARGS__), int> = 0
+
+namespace detail {
+
+// A helper function to suppress bogus "conditional expression is constant"
+// warnings.
+template <typename T> constexpr T const_check(T value) { return value; }
+
+FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
+                                      const char* message);
+
+#ifndef FMT_ASSERT
+#  ifdef NDEBUG
+// FMT_ASSERT is not empty to avoid -Werror=empty-body.
+#    define FMT_ASSERT(condition, message) ((void)0)
+#  else
+#    define FMT_ASSERT(condition, message)                                    \
+      ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
+           ? (void)0                                                          \
+           : ::fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
+#  endif
+#endif
+
+#if defined(FMT_USE_STRING_VIEW)
+template <typename Char> using std_string_view = std::basic_string_view<Char>;
+#elif defined(FMT_USE_EXPERIMENTAL_STRING_VIEW)
+template <typename Char>
+using std_string_view = std::experimental::basic_string_view<Char>;
+#else
+template <typename T> struct std_string_view {};
+#endif
+
+#ifdef FMT_USE_INT128
+// Do nothing.
+#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && !(FMT_CLANG_VERSION && FMT_MSC_VER)
+#  define FMT_USE_INT128 1
+using int128_t = __int128_t;
+using uint128_t = __uint128_t;
+#else
+#  define FMT_USE_INT128 0
+#endif
+#if !FMT_USE_INT128
+struct int128_t {};
+struct uint128_t {};
+#endif
+
+// Casts a nonnegative integer to unsigned.
+template <typename Int>
+FMT_CONSTEXPR typename std::make_unsigned<Int>::type to_unsigned(Int value) {
+  FMT_ASSERT(value >= 0, "negative value");
+  return static_cast<typename std::make_unsigned<Int>::type>(value);
+}
+
+FMT_SUPPRESS_MSC_WARNING(4566) constexpr unsigned char micro[] = "\u00B5";
+
+template <typename Char> constexpr bool is_unicode() {
+  return FMT_UNICODE || sizeof(Char) != 1 ||
+         (sizeof(micro) == 3 && micro[0] == 0xC2 && micro[1] == 0xB5);
+}
+
+#ifdef __cpp_char8_t
+using char8_type = char8_t;
+#else
+enum char8_type : unsigned char {};
+#endif
+}  // namespace detail
+
+#ifdef FMT_USE_INTERNAL
+namespace internal = detail;  // DEPRECATED
+#endif
+
+/**
+  An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
+  subset of the API. ``fmt::basic_string_view`` is used for format strings even
+  if ``std::string_view`` is available to prevent issues when a library is
+  compiled with a different ``-std`` option than the client code (which is not
+  recommended).
+ */
+template <typename Char> class basic_string_view {
+ private:
+  const Char* data_;
+  size_t size_;
+
+ public:
+  using value_type = Char;
+  using iterator = const Char*;
+
+  constexpr basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
+
+  /** Constructs a string reference object from a C string and a size. */
+  constexpr basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
+      : data_(s),
+        size_(count) {}
+
+  /**
+    \rst
+    Constructs a string reference object from a C string computing
+    the size with ``std::char_traits<Char>::length``.
+    \endrst
+   */
+#if __cplusplus >= 201703L  // C++17's char_traits::length() is constexpr.
+  FMT_CONSTEXPR
+#endif
+  basic_string_view(const Char* s)
+      : data_(s), size_(std::char_traits<Char>::length(s)) {}
+
+  /** Constructs a string reference from a ``std::basic_string`` object. */
+  template <typename Traits, typename Alloc>
+  FMT_CONSTEXPR basic_string_view(
+      const std::basic_string<Char, Traits, Alloc>& s) FMT_NOEXCEPT
+      : data_(s.data()),
+        size_(s.size()) {}
+
+  template <typename S, FMT_ENABLE_IF(std::is_same<
+                                      S, detail::std_string_view<Char>>::value)>
+  FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
+                                                      size_(s.size()) {}
+
+  /** Returns a pointer to the string data. */
+  constexpr const Char* data() const { return data_; }
+
+  /** Returns the string size. */
+  constexpr size_t size() const { return size_; }
+
+  constexpr iterator begin() const { return data_; }
+  constexpr iterator end() const { return data_ + size_; }
+
+  constexpr const Char& operator[](size_t pos) const { return data_[pos]; }
+
+  FMT_CONSTEXPR void remove_prefix(size_t n) {
+    data_ += n;
+    size_ -= n;
+  }
+
+  // Lexicographically compare this string reference to other.
+  int compare(basic_string_view other) const {
+    size_t str_size = size_ < other.size_ ? size_ : other.size_;
+    int result = std::char_traits<Char>::compare(data_, other.data_, str_size);
+    if (result == 0)
+      result = size_ == other.size_ ? 0 : (size_ < other.size_ ? -1 : 1);
+    return result;
+  }
+
+  friend bool operator==(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) == 0;
+  }
+  friend bool operator!=(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) != 0;
+  }
+  friend bool operator<(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) < 0;
+  }
+  friend bool operator<=(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) <= 0;
+  }
+  friend bool operator>(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) > 0;
+  }
+  friend bool operator>=(basic_string_view lhs, basic_string_view rhs) {
+    return lhs.compare(rhs) >= 0;
+  }
+};
+
+using string_view = basic_string_view<char>;
+using wstring_view = basic_string_view<wchar_t>;
+
+/** Specifies if ``T`` is a character type. Can be specialized by users. */
+template <typename T> struct is_char : std::false_type {};
+template <> struct is_char<char> : std::true_type {};
+template <> struct is_char<wchar_t> : std::true_type {};
+template <> struct is_char<detail::char8_type> : std::true_type {};
+template <> struct is_char<char16_t> : std::true_type {};
+template <> struct is_char<char32_t> : std::true_type {};
+
+/**
+  \rst
+  Returns a string view of `s`. In order to add custom string type support to
+  {fmt} provide an overload of `to_string_view` for it in the same namespace as
+  the type for the argument-dependent lookup to work.
+
+  **Example**::
+
+    namespace my_ns {
+    inline string_view to_string_view(const my_string& s) {
+      return {s.data(), s.length()};
+    }
+    }
+    std::string message = fmt::format(my_string("The answer is {}"), 42);
+  \endrst
+ */
+template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
+inline basic_string_view<Char> to_string_view(const Char* s) {
+  return s;
+}
+
+template <typename Char, typename Traits, typename Alloc>
+inline basic_string_view<Char> to_string_view(
+    const std::basic_string<Char, Traits, Alloc>& s) {
+  return s;
+}
+
+template <typename Char>
+inline basic_string_view<Char> to_string_view(basic_string_view<Char> s) {
+  return s;
+}
+
+template <typename Char,
+          FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
+inline basic_string_view<Char> to_string_view(detail::std_string_view<Char> s) {
+  return s;
+}
+
+// A base class for compile-time strings. It is defined in the fmt namespace to
+// make formatting functions visible via ADL, e.g. format(FMT_STRING("{}"), 42).
+struct compile_string {};
+
+template <typename S>
+struct is_compile_string : std::is_base_of<compile_string, S> {};
+
+template <typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
+constexpr basic_string_view<typename S::char_type> to_string_view(const S& s) {
+  return s;
+}
+
+namespace detail {
+void to_string_view(...);
+using fmt::v7::to_string_view;
+
+// Specifies whether S is a string type convertible to fmt::basic_string_view.
+// It should be a constexpr function but MSVC 2017 fails to compile it in
+// enable_if and MSVC 2015 fails to compile it as an alias template.
+template <typename S>
+struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
+};
+
+template <typename S, typename = void> struct char_t_impl {};
+template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
+  using result = decltype(to_string_view(std::declval<S>()));
+  using type = typename result::value_type;
+};
+
+struct error_handler {
+  constexpr error_handler() = default;
+  constexpr error_handler(const error_handler&) = default;
+
+  // This function is intentionally not constexpr to give a compile-time error.
+  FMT_NORETURN FMT_API void on_error(const char* message);
+};
+}  // namespace detail
+
+/** String's character type. */
+template <typename S> using char_t = typename detail::char_t_impl<S>::type;
+
+/**
+  \rst
+  Parsing context consisting of a format string range being parsed and an
+  argument counter for automatic indexing.
+
+  You can use one of the following type aliases for common character types:
+
+  +-----------------------+-------------------------------------+
+  | Type                  | Definition                          |
+  +=======================+=====================================+
+  | format_parse_context  | basic_format_parse_context<char>    |
+  +-----------------------+-------------------------------------+
+  | wformat_parse_context | basic_format_parse_context<wchar_t> |
+  +-----------------------+-------------------------------------+
+  \endrst
+ */
+template <typename Char, typename ErrorHandler = detail::error_handler>
+class basic_format_parse_context : private ErrorHandler {
+ private:
+  basic_string_view<Char> format_str_;
+  int next_arg_id_;
+
+ public:
+  using char_type = Char;
+  using iterator = typename basic_string_view<Char>::iterator;
+
+  explicit constexpr basic_format_parse_context(
+      basic_string_view<Char> format_str, ErrorHandler eh = {})
+      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(0) {}
+
+  /**
+    Returns an iterator to the beginning of the format string range being
+    parsed.
+   */
+  constexpr iterator begin() const FMT_NOEXCEPT { return format_str_.begin(); }
+
+  /**
+    Returns an iterator past the end of the format string range being parsed.
+   */
+  constexpr iterator end() const FMT_NOEXCEPT { return format_str_.end(); }
+
+  /** Advances the begin iterator to ``it``. */
+  FMT_CONSTEXPR void advance_to(iterator it) {
+    format_str_.remove_prefix(detail::to_unsigned(it - begin()));
+  }
+
+  /**
+    Reports an error if using the manual argument indexing; otherwise returns
+    the next argument index and switches to the automatic indexing.
+   */
+  FMT_CONSTEXPR int next_arg_id() {
+    // Don't check if the argument id is valid to avoid overhead and because it
+    // will be checked during formatting anyway.
+    if (next_arg_id_ >= 0) return next_arg_id_++;
+    on_error("cannot switch from manual to automatic argument indexing");
+    return 0;
+  }
+
+  /**
+    Reports an error if using the automatic argument indexing; otherwise
+    switches to the manual indexing.
+   */
+  FMT_CONSTEXPR void check_arg_id(int) {
+    if (next_arg_id_ > 0)
+      on_error("cannot switch from automatic to manual argument indexing");
+    else
+      next_arg_id_ = -1;
+  }
+
+  FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
+
+  FMT_CONSTEXPR void on_error(const char* message) {
+    ErrorHandler::on_error(message);
+  }
+
+  constexpr ErrorHandler error_handler() const { return *this; }
+};
+
+using format_parse_context = basic_format_parse_context<char>;
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+
+template <typename Context> class basic_format_arg;
+template <typename Context> class basic_format_args;
+template <typename Context> class dynamic_format_arg_store;
+
+// A formatter for objects of type T.
+template <typename T, typename Char = char, typename Enable = void>
+struct formatter {
+  // A deleted default constructor indicates a disabled formatter.
+  formatter() = delete;
+};
+
+// Specifies if T has an enabled formatter specialization. A type can be
+// formattable even if it doesn't have a formatter e.g. via a conversion.
+template <typename T, typename Context>
+using has_formatter =
+    std::is_constructible<typename Context::template formatter_type<T>>;
+
+namespace detail {
+
+/**
+  \rst
+  A contiguous memory buffer with an optional growing ability. It is an internal
+  class and shouldn't be used directly, only via `~fmt::basic_memory_buffer`.
+  \endrst
+ */
+template <typename T> class buffer {
+ private:
+  T* ptr_;
+  size_t size_;
+  size_t capacity_;
+
+ protected:
+  // Don't initialize ptr_ since it is not accessed to save a few cycles.
+  FMT_SUPPRESS_MSC_WARNING(26495)
+  buffer(size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
+
+  buffer(T* p = nullptr, size_t sz = 0, size_t cap = 0) FMT_NOEXCEPT
+      : ptr_(p),
+        size_(sz),
+        capacity_(cap) {}
+
+  /** Sets the buffer data and capacity. */
+  void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
+    ptr_ = buf_data;
+    capacity_ = buf_capacity;
+  }
+
+  /** Increases the buffer capacity to hold at least *capacity* elements. */
+  virtual void grow(size_t capacity) = 0;
+
+ public:
+  using value_type = T;
+  using const_reference = const T&;
+
+  buffer(const buffer&) = delete;
+  void operator=(const buffer&) = delete;
+  virtual ~buffer() = default;
+
+  T* begin() FMT_NOEXCEPT { return ptr_; }
+  T* end() FMT_NOEXCEPT { return ptr_ + size_; }
+
+  const T* begin() const FMT_NOEXCEPT { return ptr_; }
+  const T* end() const FMT_NOEXCEPT { return ptr_ + size_; }
+
+  /** Returns the size of this buffer. */
+  size_t size() const FMT_NOEXCEPT { return size_; }
+
+  /** Returns the capacity of this buffer. */
+  size_t capacity() const FMT_NOEXCEPT { return capacity_; }
+
+  /** Returns a pointer to the buffer data. */
+  T* data() FMT_NOEXCEPT { return ptr_; }
+
+  /** Returns a pointer to the buffer data. */
+  const T* data() const FMT_NOEXCEPT { return ptr_; }
+
+  /**
+    Resizes the buffer. If T is a POD type new elements may not be initialized.
+   */
+  void resize(size_t new_size) {
+    reserve(new_size);
+    size_ = new_size;
+  }
+
+  /** Clears this buffer. */
+  void clear() { size_ = 0; }
+
+  /** Reserves space to store at least *capacity* elements. */
+  void reserve(size_t new_capacity) {
+    if (new_capacity > capacity_) grow(new_capacity);
+  }
+
+  void push_back(const T& value) {
+    reserve(size_ + 1);
+    ptr_[size_++] = value;
+  }
+
+  /** Appends data to the end of the buffer. */
+  template <typename U> void append(const U* begin, const U* end);
+
+  template <typename I> T& operator[](I index) { return ptr_[index]; }
+  template <typename I> const T& operator[](I index) const {
+    return ptr_[index];
+  }
+};
+
+// A container-backed buffer.
+template <typename Container>
+class container_buffer : public buffer<typename Container::value_type> {
+ private:
+  Container& container_;
+
+ protected:
+  void grow(size_t capacity) FMT_OVERRIDE {
+    container_.resize(capacity);
+    this->set(&container_[0], capacity);
+  }
+
+ public:
+  explicit container_buffer(Container& c)
+      : buffer<typename Container::value_type>(c.size()), container_(c) {}
+};
+
+// Extracts a reference to the container from back_insert_iterator.
+template <typename Container>
+inline Container& get_container(std::back_insert_iterator<Container> it) {
+  using bi_iterator = std::back_insert_iterator<Container>;
+  struct accessor : bi_iterator {
+    accessor(bi_iterator iter) : bi_iterator(iter) {}
+    using bi_iterator::container;
+  };
+  return *accessor(it).container;
+}
+
+template <typename T, typename Char = char, typename Enable = void>
+struct fallback_formatter {
+  fallback_formatter() = delete;
+};
+
+// Specifies if T has an enabled fallback_formatter specialization.
+template <typename T, typename Context>
+using has_fallback_formatter =
+    std::is_constructible<fallback_formatter<T, typename Context::char_type>>;
+
+struct view {};
+
+template <typename Char, typename T> struct named_arg : view {
+  const Char* name;
+  const T& value;
+  named_arg(const Char* n, const T& v) : name(n), value(v) {}
+};
+
+template <typename Char> struct named_arg_info {
+  const Char* name;
+  int id;
+};
+
+template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
+struct arg_data {
+  // args_[0].named_args points to named_args_ to avoid bloating format_args.
+  T args_[1 + (NUM_ARGS != 0 ? NUM_ARGS : 1)];
+  named_arg_info<Char> named_args_[NUM_NAMED_ARGS];
+
+  template <typename... U>
+  arg_data(const U&... init) : args_{T(named_args_, NUM_NAMED_ARGS), init...} {}
+  arg_data(const arg_data& other) = delete;
+  const T* args() const { return args_ + 1; }
+  named_arg_info<Char>* named_args() { return named_args_; }
+};
+
+template <typename T, typename Char, size_t NUM_ARGS>
+struct arg_data<T, Char, NUM_ARGS, 0> {
+  T args_[NUM_ARGS != 0 ? NUM_ARGS : 1];
+
+  template <typename... U>
+  FMT_INLINE arg_data(const U&... init) : args_{init...} {}
+  FMT_INLINE const T* args() const { return args_; }
+  FMT_INLINE std::nullptr_t named_args() { return nullptr; }
+};
+
+template <typename Char>
+inline void init_named_args(named_arg_info<Char>*, int, int) {}
+
+template <typename Char, typename T, typename... Tail>
+void init_named_args(named_arg_info<Char>* named_args, int arg_count,
+                     int named_arg_count, const T&, const Tail&... args) {
+  init_named_args(named_args, arg_count + 1, named_arg_count, args...);
+}
+
+template <typename Char, typename T, typename... Tail>
+void init_named_args(named_arg_info<Char>* named_args, int arg_count,
+                     int named_arg_count, const named_arg<Char, T>& arg,
+                     const Tail&... args) {
+  named_args[named_arg_count++] = {arg.name, arg_count};
+  init_named_args(named_args, arg_count + 1, named_arg_count, args...);
+}
+
+template <typename... Args>
+FMT_INLINE void init_named_args(std::nullptr_t, int, int, const Args&...) {}
+
+template <typename T> struct is_named_arg : std::false_type {};
+
+template <typename T, typename Char>
+struct is_named_arg<named_arg<Char, T>> : std::true_type {};
+
+template <bool B = false> constexpr size_t count() { return B ? 1 : 0; }
+template <bool B1, bool B2, bool... Tail> constexpr size_t count() {
+  return (B1 ? 1 : 0) + count<B2, Tail...>();
+}
+
+template <typename... Args> constexpr size_t count_named_args() {
+  return count<is_named_arg<Args>::value...>();
+}
+
+enum class type {
+  none_type,
+  // Integer types should go first,
+  int_type,
+  uint_type,
+  long_long_type,
+  ulong_long_type,
+  int128_type,
+  uint128_type,
+  bool_type,
+  char_type,
+  last_integer_type = char_type,
+  // followed by floating-point types.
+  float_type,
+  double_type,
+  long_double_type,
+  last_numeric_type = long_double_type,
+  cstring_type,
+  string_type,
+  pointer_type,
+  custom_type
+};
+
+// Maps core type T to the corresponding type enum constant.
+template <typename T, typename Char>
+struct type_constant : std::integral_constant<type, type::custom_type> {};
+
+#define FMT_TYPE_CONSTANT(Type, constant) \
+  template <typename Char>                \
+  struct type_constant<Type, Char>        \
+      : std::integral_constant<type, type::constant> {}
+
+FMT_TYPE_CONSTANT(int, int_type);
+FMT_TYPE_CONSTANT(unsigned, uint_type);
+FMT_TYPE_CONSTANT(long long, long_long_type);
+FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
+FMT_TYPE_CONSTANT(int128_t, int128_type);
+FMT_TYPE_CONSTANT(uint128_t, uint128_type);
+FMT_TYPE_CONSTANT(bool, bool_type);
+FMT_TYPE_CONSTANT(Char, char_type);
+FMT_TYPE_CONSTANT(float, float_type);
+FMT_TYPE_CONSTANT(double, double_type);
+FMT_TYPE_CONSTANT(long double, long_double_type);
+FMT_TYPE_CONSTANT(const Char*, cstring_type);
+FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
+FMT_TYPE_CONSTANT(const void*, pointer_type);
+
+constexpr bool is_integral_type(type t) {
+  return t > type::none_type && t <= type::last_integer_type;
+}
+
+constexpr bool is_arithmetic_type(type t) {
+  return t > type::none_type && t <= type::last_numeric_type;
+}
+
+template <typename Char> struct string_value {
+  const Char* data;
+  size_t size;
+};
+
+template <typename Char> struct named_arg_value {
+  const named_arg_info<Char>* data;
+  size_t size;
+};
+
+template <typename Context> struct custom_value {
+  using parse_context = typename Context::parse_context_type;
+  const void* value;
+  void (*format)(const void* arg, parse_context& parse_ctx, Context& ctx);
+};
+
+// A formatting argument value.
+template <typename Context> class value {
+ public:
+  using char_type = typename Context::char_type;
+
+  union {
+    int int_value;
+    unsigned uint_value;
+    long long long_long_value;
+    unsigned long long ulong_long_value;
+    int128_t int128_value;
+    uint128_t uint128_value;
+    bool bool_value;
+    char_type char_value;
+    float float_value;
+    double double_value;
+    long double long_double_value;
+    const void* pointer;
+    string_value<char_type> string;
+    custom_value<Context> custom;
+    named_arg_value<char_type> named_args;
+  };
+
+  constexpr FMT_INLINE value(int val = 0) : int_value(val) {}
+  constexpr FMT_INLINE value(unsigned val) : uint_value(val) {}
+  FMT_INLINE value(long long val) : long_long_value(val) {}
+  FMT_INLINE value(unsigned long long val) : ulong_long_value(val) {}
+  FMT_INLINE value(int128_t val) : int128_value(val) {}
+  FMT_INLINE value(uint128_t val) : uint128_value(val) {}
+  FMT_INLINE value(float val) : float_value(val) {}
+  FMT_INLINE value(double val) : double_value(val) {}
+  FMT_INLINE value(long double val) : long_double_value(val) {}
+  FMT_INLINE value(bool val) : bool_value(val) {}
+  FMT_INLINE value(char_type val) : char_value(val) {}
+  FMT_INLINE value(const char_type* val) { string.data = val; }
+  FMT_INLINE value(basic_string_view<char_type> val) {
+    string.data = val.data();
+    string.size = val.size();
+  }
+  FMT_INLINE value(const void* val) : pointer(val) {}
+  FMT_INLINE value(const named_arg_info<char_type>* args, size_t size)
+      : named_args{args, size} {}
+
+  template <typename T> FMT_INLINE value(const T& val) {
+    custom.value = &val;
+    // Get the formatter type through the context to allow different contexts
+    // have different extension points, e.g. `formatter<T>` for `format` and
+    // `printf_formatter<T>` for `printf`.
+    custom.format = format_custom_arg<
+        T, conditional_t<has_formatter<T, Context>::value,
+                         typename Context::template formatter_type<T>,
+                         fallback_formatter<T, char_type>>>;
+  }
+
+ private:
+  // Formats an argument of a custom type, such as a user-defined class.
+  template <typename T, typename Formatter>
+  static void format_custom_arg(const void* arg,
+                                typename Context::parse_context_type& parse_ctx,
+                                Context& ctx) {
+    Formatter f;
+    parse_ctx.advance_to(f.parse(parse_ctx));
+    ctx.advance_to(f.format(*static_cast<const T*>(arg), ctx));
+  }
+};
+
+template <typename Context, typename T>
+FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value);
+
+// To minimize the number of types we need to deal with, long is translated
+// either to int or to long long depending on its size.
+enum { long_short = sizeof(long) == sizeof(int) };
+using long_type = conditional_t<long_short, int, long long>;
+using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
+
+// Maps formatting arguments to core types.
+template <typename Context> struct arg_mapper {
+  using char_type = typename Context::char_type;
+
+  FMT_CONSTEXPR int map(signed char val) { return val; }
+  FMT_CONSTEXPR unsigned map(unsigned char val) { return val; }
+  FMT_CONSTEXPR int map(short val) { return val; }
+  FMT_CONSTEXPR unsigned map(unsigned short val) { return val; }
+  FMT_CONSTEXPR int map(int val) { return val; }
+  FMT_CONSTEXPR unsigned map(unsigned val) { return val; }
+  FMT_CONSTEXPR long_type map(long val) { return val; }
+  FMT_CONSTEXPR ulong_type map(unsigned long val) { return val; }
+  FMT_CONSTEXPR long long map(long long val) { return val; }
+  FMT_CONSTEXPR unsigned long long map(unsigned long long val) { return val; }
+  FMT_CONSTEXPR int128_t map(int128_t val) { return val; }
+  FMT_CONSTEXPR uint128_t map(uint128_t val) { return val; }
+  FMT_CONSTEXPR bool map(bool val) { return val; }
+
+  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
+  FMT_CONSTEXPR char_type map(T val) {
+    static_assert(
+        std::is_same<T, char>::value || std::is_same<T, char_type>::value,
+        "mixing character types is disallowed");
+    return val;
+  }
+
+  FMT_CONSTEXPR float map(float val) { return val; }
+  FMT_CONSTEXPR double map(double val) { return val; }
+  FMT_CONSTEXPR long double map(long double val) { return val; }
+
+  FMT_CONSTEXPR const char_type* map(char_type* val) { return val; }
+  FMT_CONSTEXPR const char_type* map(const char_type* val) { return val; }
+  template <typename T, FMT_ENABLE_IF(is_string<T>::value)>
+  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
+    static_assert(std::is_same<char_type, char_t<T>>::value,
+                  "mixing character types is disallowed");
+    return to_string_view(val);
+  }
+  template <typename T,
+            FMT_ENABLE_IF(
+                std::is_constructible<basic_string_view<char_type>, T>::value &&
+                !is_string<T>::value && !has_formatter<T, Context>::value &&
+                !has_fallback_formatter<T, Context>::value)>
+  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
+    return basic_string_view<char_type>(val);
+  }
+  template <
+      typename T,
+      FMT_ENABLE_IF(
+          std::is_constructible<std_string_view<char_type>, T>::value &&
+          !std::is_constructible<basic_string_view<char_type>, T>::value &&
+          !is_string<T>::value && !has_formatter<T, Context>::value &&
+          !has_fallback_formatter<T, Context>::value)>
+  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
+    return std_string_view<char_type>(val);
+  }
+  FMT_CONSTEXPR const char* map(const signed char* val) {
+    static_assert(std::is_same<char_type, char>::value, "invalid string type");
+    return reinterpret_cast<const char*>(val);
+  }
+  FMT_CONSTEXPR const char* map(const unsigned char* val) {
+    static_assert(std::is_same<char_type, char>::value, "invalid string type");
+    return reinterpret_cast<const char*>(val);
+  }
+  FMT_CONSTEXPR const char* map(signed char* val) {
+    const auto* const_val = val;
+    return map(const_val);
+  }
+  FMT_CONSTEXPR const char* map(unsigned char* val) {
+    const auto* const_val = val;
+    return map(const_val);
+  }
+
+  FMT_CONSTEXPR const void* map(void* val) { return val; }
+  FMT_CONSTEXPR const void* map(const void* val) { return val; }
+  FMT_CONSTEXPR const void* map(std::nullptr_t val) { return val; }
+  template <typename T> FMT_CONSTEXPR int map(const T*) {
+    // Formatting of arbitrary pointers is disallowed. If you want to output
+    // a pointer cast it to "void *" or "const void *". In particular, this
+    // forbids formatting of "[const] volatile char *" which is printed as bool
+    // by iostreams.
+    static_assert(!sizeof(T), "formatting of non-void pointers is disallowed");
+    return 0;
+  }
+
+  template <typename T,
+            FMT_ENABLE_IF(std::is_enum<T>::value &&
+                          !has_formatter<T, Context>::value &&
+                          !has_fallback_formatter<T, Context>::value)>
+  FMT_CONSTEXPR auto map(const T& val)
+      -> decltype(std::declval<arg_mapper>().map(
+          static_cast<typename std::underlying_type<T>::type>(val))) {
+    return map(static_cast<typename std::underlying_type<T>::type>(val));
+  }
+  template <typename T,
+            FMT_ENABLE_IF(!is_string<T>::value && !is_char<T>::value &&
+                          (has_formatter<T, Context>::value ||
+                           has_fallback_formatter<T, Context>::value))>
+  FMT_CONSTEXPR const T& map(const T& val) {
+    return val;
+  }
+
+  template <typename T>
+  FMT_CONSTEXPR auto map(const named_arg<char_type, T>& val)
+      -> decltype(std::declval<arg_mapper>().map(val.value)) {
+    return map(val.value);
+  }
+
+  int map(...) {
+    constexpr bool formattable = sizeof(Context) == 0;
+    static_assert(
+        formattable,
+        "Cannot format argument. To make type T formattable provide a "
+        "formatter<T> specialization: "
+        "https://fmt.dev/latest/api.html#formatting-user-defined-types");
+    return 0;
+  }
+};
+
+// A type constant after applying arg_mapper<Context>.
+template <typename T, typename Context>
+using mapped_type_constant =
+    type_constant<decltype(arg_mapper<Context>().map(std::declval<const T&>())),
+                  typename Context::char_type>;
+
+enum { packed_arg_bits = 4 };
+// Maximum number of arguments with packed types.
+enum { max_packed_args = 62 / packed_arg_bits };
+enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
+enum : unsigned long long { has_named_args_bit = 1ULL << 62 };
+}  // namespace detail
+
+// A formatting argument. It is a trivially copyable/constructible type to
+// allow storage in basic_memory_buffer.
+template <typename Context> class basic_format_arg {
+ private:
+  detail::value<Context> value_;
+  detail::type type_;
+
+  template <typename ContextType, typename T>
+  friend FMT_CONSTEXPR basic_format_arg<ContextType> detail::make_arg(
+      const T& value);
+
+  template <typename Visitor, typename Ctx>
+  friend FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
+                                             const basic_format_arg<Ctx>& arg)
+      -> decltype(vis(0));
+
+  friend class basic_format_args<Context>;
+  friend class dynamic_format_arg_store<Context>;
+
+  using char_type = typename Context::char_type;
+
+  template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
+  friend struct detail::arg_data;
+
+  basic_format_arg(const detail::named_arg_info<char_type>* args, size_t size)
+      : value_(args, size) {}
+
+ public:
+  class handle {
+   public:
+    explicit handle(detail::custom_value<Context> custom) : custom_(custom) {}
+
+    void format(typename Context::parse_context_type& parse_ctx,
+                Context& ctx) const {
+      custom_.format(custom_.value, parse_ctx, ctx);
+    }
+
+   private:
+    detail::custom_value<Context> custom_;
+  };
+
+  constexpr basic_format_arg() : type_(detail::type::none_type) {}
+
+  constexpr explicit operator bool() const FMT_NOEXCEPT {
+    return type_ != detail::type::none_type;
+  }
+
+  detail::type type() const { return type_; }
+
+  bool is_integral() const { return detail::is_integral_type(type_); }
+  bool is_arithmetic() const { return detail::is_arithmetic_type(type_); }
+};
+
+/**
+  \rst
+  Visits an argument dispatching to the appropriate visit method based on
+  the argument type. For example, if the argument type is ``double`` then
+  ``vis(value)`` will be called with the value of type ``double``.
+  \endrst
+ */
+template <typename Visitor, typename Context>
+FMT_CONSTEXPR_DECL FMT_INLINE auto visit_format_arg(
+    Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
+  using char_type = typename Context::char_type;
+  switch (arg.type_) {
+  case detail::type::none_type:
+    break;
+  case detail::type::int_type:
+    return vis(arg.value_.int_value);
+  case detail::type::uint_type:
+    return vis(arg.value_.uint_value);
+  case detail::type::long_long_type:
+    return vis(arg.value_.long_long_value);
+  case detail::type::ulong_long_type:
+    return vis(arg.value_.ulong_long_value);
+#if FMT_USE_INT128
+  case detail::type::int128_type:
+    return vis(arg.value_.int128_value);
+  case detail::type::uint128_type:
+    return vis(arg.value_.uint128_value);
+#else
+  case detail::type::int128_type:
+  case detail::type::uint128_type:
+    break;
+#endif
+  case detail::type::bool_type:
+    return vis(arg.value_.bool_value);
+  case detail::type::char_type:
+    return vis(arg.value_.char_value);
+  case detail::type::float_type:
+    return vis(arg.value_.float_value);
+  case detail::type::double_type:
+    return vis(arg.value_.double_value);
+  case detail::type::long_double_type:
+    return vis(arg.value_.long_double_value);
+  case detail::type::cstring_type:
+    return vis(arg.value_.string.data);
+  case detail::type::string_type:
+    return vis(basic_string_view<char_type>(arg.value_.string.data,
+                                            arg.value_.string.size));
+  case detail::type::pointer_type:
+    return vis(arg.value_.pointer);
+  case detail::type::custom_type:
+    return vis(typename basic_format_arg<Context>::handle(arg.value_.custom));
+  }
+  return vis(monostate());
+}
+
+// Checks whether T is a container with contiguous storage.
+template <typename T> struct is_contiguous : std::false_type {};
+template <typename Char>
+struct is_contiguous<std::basic_string<Char>> : std::true_type {};
+template <typename Char>
+struct is_contiguous<detail::buffer<Char>> : std::true_type {};
+
+namespace detail {
+
+template <typename OutputIt>
+struct is_back_insert_iterator : std::false_type {};
+template <typename Container>
+struct is_back_insert_iterator<std::back_insert_iterator<Container>>
+    : std::true_type {};
+
+template <typename OutputIt>
+struct is_contiguous_back_insert_iterator : std::false_type {};
+template <typename Container>
+struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
+    : is_contiguous<Container> {};
+
+// A type-erased reference to an std::locale to avoid heavy <locale> include.
+class locale_ref {
+ private:
+  const void* locale_;  // A type-erased pointer to std::locale.
+
+ public:
+  locale_ref() : locale_(nullptr) {}
+  template <typename Locale> explicit locale_ref(const Locale& loc);
+
+  explicit operator bool() const FMT_NOEXCEPT { return locale_ != nullptr; }
+
+  template <typename Locale> Locale get() const;
+};
+
+template <typename> constexpr unsigned long long encode_types() { return 0; }
+
+template <typename Context, typename Arg, typename... Args>
+constexpr unsigned long long encode_types() {
+  return static_cast<unsigned>(mapped_type_constant<Arg, Context>::value) |
+         (encode_types<Context, Args...>() << packed_arg_bits);
+}
+
+template <typename Context, typename T>
+FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value) {
+  basic_format_arg<Context> arg;
+  arg.type_ = mapped_type_constant<T, Context>::value;
+  arg.value_ = arg_mapper<Context>().map(value);
+  return arg;
+}
+
+// The type template parameter is there to avoid an ODR violation when using
+// a fallback formatter in one translation unit and an implicit conversion in
+// another (not recommended).
+template <bool IS_PACKED, typename Context, type, typename T,
+          FMT_ENABLE_IF(IS_PACKED)>
+inline value<Context> make_arg(const T& val) {
+  return arg_mapper<Context>().map(val);
+}
+
+template <bool IS_PACKED, typename Context, type, typename T,
+          FMT_ENABLE_IF(!IS_PACKED)>
+inline basic_format_arg<Context> make_arg(const T& value) {
+  return make_arg<Context>(value);
+}
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> const T& unwrap(const T& v) { return v; }
+template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+  return static_cast<const T&>(v);
+}
+
+class dynamic_arg_list {
+  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+  // templates it doesn't complain about inability to deduce single translation
+  // unit for placing vtable. So storage_node_base is made a fake template.
+  template <typename = void> struct node {
+    virtual ~node() = default;
+    std::unique_ptr<node<>> next;
+  };
+
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> const T& push(const Arg& arg) {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
+
+// Formatting context.
+template <typename OutputIt, typename Char> class basic_format_context {
+ public:
+  /** The character type for the output. */
+  using char_type = Char;
+
+ private:
+  OutputIt out_;
+  basic_format_args<basic_format_context> args_;
+  detail::locale_ref loc_;
+
+ public:
+  using iterator = OutputIt;
+  using format_arg = basic_format_arg<basic_format_context>;
+  using parse_context_type = basic_format_parse_context<Char>;
+  template <typename T> using formatter_type = formatter<T, char_type>;
+
+  basic_format_context(const basic_format_context&) = delete;
+  void operator=(const basic_format_context&) = delete;
+  /**
+   Constructs a ``basic_format_context`` object. References to the arguments are
+   stored in the object so make sure they have appropriate lifetimes.
+   */
+  basic_format_context(OutputIt out,
+                       basic_format_args<basic_format_context> ctx_args,
+                       detail::locale_ref loc = detail::locale_ref())
+      : out_(out), args_(ctx_args), loc_(loc) {}
+
+  format_arg arg(int id) const { return args_.get(id); }
+  format_arg arg(basic_string_view<char_type> name) { return args_.get(name); }
+  int arg_id(basic_string_view<char_type> name) { return args_.get_id(name); }
+  const basic_format_args<basic_format_context>& args() const { return args_; }
+
+  detail::error_handler error_handler() { return {}; }
+  void on_error(const char* message) { error_handler().on_error(message); }
+
+  // Returns an iterator to the beginning of the output range.
+  iterator out() { return out_; }
+
+  // Advances the begin iterator to ``it``.
+  void advance_to(iterator it) {
+    if (!detail::is_back_insert_iterator<iterator>()) out_ = it;
+  }
+
+  detail::locale_ref locale() { return loc_; }
+};
+
+template <typename Char>
+using buffer_context =
+    basic_format_context<std::back_insert_iterator<detail::buffer<Char>>, Char>;
+using format_context = buffer_context<char>;
+using wformat_context = buffer_context<wchar_t>;
+
+// Workaround a bug in gcc: https://stackoverflow.com/q/62767544/471164.
+#define FMT_BUFFER_CONTEXT(Char) \
+  basic_format_context<std::back_insert_iterator<detail::buffer<Char>>, Char>
+
+/**
+  \rst
+  An array of references to arguments. It can be implicitly converted into
+  `~fmt::basic_format_args` for passing into type-erased formatting functions
+  such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context, typename... Args>
+class format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  static const size_t num_args = sizeof...(Args);
+  static const size_t num_named_args = detail::count_named_args<Args...>();
+  static const bool is_packed = num_args <= detail::max_packed_args;
+
+  using value_type = conditional_t<is_packed, detail::value<Context>,
+                                   basic_format_arg<Context>>;
+
+  detail::arg_data<value_type, typename Context::char_type, num_args,
+                   num_named_args>
+      data_;
+
+  friend class basic_format_args<Context>;
+
+  static constexpr unsigned long long desc =
+      (is_packed ? detail::encode_types<Context, Args...>()
+                 : detail::is_unpacked_bit | num_args) |
+      (num_named_args != 0
+           ? static_cast<unsigned long long>(detail::has_named_args_bit)
+           : 0);
+
+ public:
+  format_arg_store(const Args&... args)
+      :
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+        basic_format_args<Context>(*this),
+#endif
+        data_{detail::make_arg<
+            is_packed, Context,
+            detail::mapped_type_constant<Args, Context>::value>(args)...} {
+    detail::init_named_args(data_.named_args(), 0, 0, args...);
+  }
+};
+
+/**
+  \rst
+  Constructs an `~fmt::format_arg_store` object that contains references to
+  arguments and can be implicitly converted to `~fmt::format_args`. `Context`
+  can be omitted in which case it defaults to `~fmt::context`.
+  See `~fmt::arg` for lifetime considerations.
+  \endrst
+ */
+template <typename Context = format_context, typename... Args>
+inline format_arg_store<Context, Args...> make_format_args(
+    const Args&... args) {
+  return {args...};
+}
+
+/**
+  \rst
+  Returns a named argument to be used in a formatting function. It should only
+  be used in a call to a formatting function.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {s:.2f} seconds", fmt::arg("s", 1.23));
+  \endrst
+ */
+template <typename Char, typename T>
+inline detail::named_arg<Char, T> arg(const Char* name, const T& arg) {
+  static_assert(!detail::is_named_arg<T>(), "nested named arguments");
+  return {name, arg};
+}
+
+/**
+  \rst
+  A dynamic version of `fmt::format_arg_store`.
+  It's equipped with a storage to potentially temporary objects which lifetimes
+  could be shorter than the format arguments object.
+
+  It can be implicitly converted into `~fmt::basic_format_args` for passing
+  into type-erased formatting functions such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context>
+class dynamic_format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, Context>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_type = conditional_t<detail::is_string<T>::value,
+                                    std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  unsigned long long get_types() const {
+    return detail::is_unpacked_bit | data_.size() |
+           (named_info_.empty()
+                ? 0ULL
+                : static_cast<unsigned long long>(detail::has_named_args_bit));
+  }
+
+  const basic_format_arg<Context>* data() const {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(detail::make_arg<Context>(arg));
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty()) {
+      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
+      data_.insert(data_.begin(), {zero_ptr, 0});
+    }
+    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  /**
+    \rst
+    Adds an argument into the dynamic store for later passing to a formatting
+    function.
+
+    Note that custom types and string types (but not string views) are copied
+    into the store dynamically allocating memory if necessary.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      store.push_back(42);
+      store.push_back("abc");
+      store.push_back(1.5f);
+      std::string result = fmt::vformat("{} and {} and {}", store);
+    \endrst
+  */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+    \rst
+    Adds a reference to the argument into the dynamic store for later passing to
+    a formatting function. Supports named arguments wrapped in
+    ``std::reference_wrapper`` via ``std::ref()``/``std::cref()``.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      char str[] = "1234567890";
+      store.push_back(std::cref(str));
+      int a1_val{42};
+      auto a1 = fmt::arg("a1_", a1_val);
+      store.push_back(std::cref(a1));
+
+      // Changing str affects the output but only for string and custom types.
+      str[0] = 'X';
+
+      std::string result = fmt::vformat("{} and {a1_}");
+      assert(result == "X234567890 and 42");
+    \endrst
+  */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        detail::is_named_arg<typename std::remove_cv<T>::type>::value ||
+            need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+    Adds named argument into the dynamic store for later passing to a formatting
+    function. ``std::reference_wrapper`` is supported to avoid copying of the
+    argument.
+  */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /** Erase all elements from the store */
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = detail::dynamic_arg_list();
+  }
+
+  /**
+    \rst
+    Reserves space to store at least *new_cap* arguments including
+    *new_cap_named* named arguments.
+    \endrst
+  */
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "Set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+};
+
+/**
+  \rst
+  A view of a collection of formatting arguments. To avoid lifetime issues it
+  should only be used as a parameter type in type-erased functions such as
+  ``vformat``::
+
+    void vlog(string_view format_str, format_args args);  // OK
+    format_args args = make_format_args(42);  // Error: dangling reference
+  \endrst
+ */
+template <typename Context> class basic_format_args {
+ public:
+  using size_type = int;
+  using format_arg = basic_format_arg<Context>;
+
+ private:
+  // A descriptor that contains information about formatting arguments.
+  // If the number of arguments is less or equal to max_packed_args then
+  // argument types are passed in the descriptor. This reduces binary code size
+  // per formatting function call.
+  unsigned long long desc_;
+  union {
+    // If is_packed() returns true then argument values are stored in values_;
+    // otherwise they are stored in args_. This is done to improve cache
+    // locality and reduce compiled code size since storing larger objects
+    // may require more code (at least on x86-64) even if the same amount of
+    // data is actually copied to stack. It saves ~10% on the bloat test.
+    const detail::value<Context>* values_;
+    const format_arg* args_;
+  };
+
+  bool is_packed() const { return (desc_ & detail::is_unpacked_bit) == 0; }
+  bool has_named_args() const {
+    return (desc_ & detail::has_named_args_bit) != 0;
+  }
+
+  detail::type type(int index) const {
+    int shift = index * detail::packed_arg_bits;
+    unsigned int mask = (1 << detail::packed_arg_bits) - 1;
+    return static_cast<detail::type>((desc_ >> shift) & mask);
+  }
+
+  basic_format_args(unsigned long long desc,
+                    const detail::value<Context>* values)
+      : desc_(desc), values_(values) {}
+  basic_format_args(unsigned long long desc, const format_arg* args)
+      : desc_(desc), args_(args) {}
+
+ public:
+  basic_format_args() : desc_(0) {}
+
+  /**
+   \rst
+   Constructs a `basic_format_args` object from `~fmt::format_arg_store`.
+   \endrst
+   */
+  template <typename... Args>
+  FMT_INLINE basic_format_args(const format_arg_store<Context, Args...>& store)
+      : basic_format_args(store.desc, store.data_.args()) {}
+
+  /**
+   \rst
+   Constructs a `basic_format_args` object from
+   `~fmt::dynamic_format_arg_store`.
+   \endrst
+   */
+  FMT_INLINE basic_format_args(const dynamic_format_arg_store<Context>& store)
+      : basic_format_args(store.get_types(), store.data()) {}
+
+  /**
+   \rst
+   Constructs a `basic_format_args` object from a dynamic set of arguments.
+   \endrst
+   */
+  basic_format_args(const format_arg* args, int count)
+      : basic_format_args(detail::is_unpacked_bit | detail::to_unsigned(count),
+                          args) {}
+
+  /** Returns the argument with the specified id. */
+  format_arg get(int id) const {
+    format_arg arg;
+    if (!is_packed()) {
+      if (id < max_size()) arg = args_[id];
+      return arg;
+    }
+    if (id >= detail::max_packed_args) return arg;
+    arg.type_ = type(id);
+    if (arg.type_ == detail::type::none_type) return arg;
+    arg.value_ = values_[id];
+    return arg;
+  }
+
+  template <typename Char> format_arg get(basic_string_view<Char> name) const {
+    int id = get_id(name);
+    return id >= 0 ? get(id) : format_arg();
+  }
+
+  template <typename Char> int get_id(basic_string_view<Char> name) const {
+    if (!has_named_args()) return -1;
+    const auto& named_args =
+        (is_packed() ? values_[-1] : args_[-1].value_).named_args;
+    for (size_t i = 0; i < named_args.size; ++i) {
+      if (named_args.data[i].name == name) return named_args.data[i].id;
+    }
+    return -1;
+  }
+
+  int max_size() const {
+    unsigned long long max_packed = detail::max_packed_args;
+    return static_cast<int>(is_packed() ? max_packed
+                                        : desc_ & ~detail::is_unpacked_bit);
+  }
+};
+
+/** An alias to ``basic_format_args<context>``. */
+// It is a separate type rather than an alias to make symbols readable.
+struct format_args : basic_format_args<format_context> {
+  template <typename... Args>
+  FMT_INLINE format_args(const Args&... args) : basic_format_args(args...) {}
+};
+struct wformat_args : basic_format_args<wformat_context> {
+  using basic_format_args::basic_format_args;
+};
+
+namespace detail {
+
+// Reports a compile-time error if S is not a valid format string.
+template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
+FMT_INLINE void check_format_string(const S&) {
+#ifdef FMT_ENFORCE_COMPILE_STRING
+  static_assert(is_compile_string<S>::value,
+                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
+                "FMT_STRING.");
+#endif
+}
+template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
+void check_format_string(S);
+
+template <typename... Args, typename S, typename Char = char_t<S>>
+inline format_arg_store<buffer_context<Char>, remove_reference_t<Args>...>
+make_args_checked(const S& format_str,
+                  const remove_reference_t<Args>&... args) {
+  static_assert(count<(std::is_base_of<view, remove_reference_t<Args>>::value &&
+                       std::is_reference<Args>::value)...>() == 0,
+                "passing views as lvalues is disallowed");
+  check_format_string<Args...>(format_str);
+  return {args...};
+}
+
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+std::basic_string<Char> vformat(
+    basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args);
+
+FMT_API std::string vformat(string_view format_str, format_args args);
+
+template <typename Char>
+typename FMT_BUFFER_CONTEXT(Char)::iterator vformat_to(
+    buffer<Char>& buf, basic_string_view<Char> format_str,
+    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args);
+
+template <typename Char, typename Args,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+inline void vprint_mojibake(std::FILE*, basic_string_view<Char>, const Args&) {}
+
+FMT_API void vprint_mojibake(std::FILE*, string_view, format_args);
+#ifndef _WIN32
+inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
+#endif
+}  // namespace detail
+
+/** Formats a string and writes the output to ``out``. */
+// GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
+// vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
+template <
+    typename OutputIt, typename S, typename Char = char_t<S>,
+    FMT_ENABLE_IF(detail::is_contiguous_back_insert_iterator<OutputIt>::value)>
+OutputIt vformat_to(
+    OutputIt out, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  auto& c = detail::get_container(out);
+  detail::container_buffer<remove_reference_t<decltype(c)>> buf(c);
+  detail::vformat_to(buf, to_string_view(format_str), args);
+  return out;
+}
+
+template <typename Container, typename S, typename... Args,
+          FMT_ENABLE_IF(
+              is_contiguous<Container>::value&& detail::is_string<S>::value)>
+inline std::back_insert_iterator<Container> format_to(
+    std::back_insert_iterator<Container> out, const S& format_str,
+    Args&&... args) {
+  return vformat_to(out, to_string_view(format_str),
+                    detail::make_args_checked<Args...>(format_str, args...));
+}
+
+template <typename S, typename Char = char_t<S>>
+FMT_INLINE std::basic_string<Char> vformat(
+    const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  return detail::vformat(to_string_view(format_str), args);
+}
+
+/**
+  \rst
+  Formats arguments and returns the result as a string.
+
+  **Example**::
+
+    #include <fmt/core.h>
+    std::string message = fmt::format("The answer is {}", 42);
+  \endrst
+*/
+// Pass char_t as a default template parameter instead of using
+// std::basic_string<char_t<S>> to reduce the symbol size.
+template <typename S, typename... Args, typename Char = char_t<S>>
+FMT_INLINE std::basic_string<Char> format(const S& format_str, Args&&... args) {
+  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  return detail::vformat(to_string_view(format_str), vargs);
+}
+
+FMT_API void vprint(string_view, format_args);
+FMT_API void vprint(std::FILE*, string_view, format_args);
+
+/**
+  \rst
+  Formats ``args`` according to specifications in ``format_str`` and writes the
+  output to the file ``f``. Strings are assumed to be Unicode-encoded unless the
+  ``FMT_UNICODE`` macro is set to 0.
+
+  **Example**::
+
+    fmt::print(stderr, "Don't {}!", "panic");
+  \endrst
+ */
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline void print(std::FILE* f, const S& format_str, Args&&... args) {
+  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  return detail::is_unicode<Char>()
+             ? vprint(f, to_string_view(format_str), vargs)
+             : detail::vprint_mojibake(f, to_string_view(format_str), vargs);
+}
+
+/**
+  \rst
+  Formats ``args`` according to specifications in ``format_str`` and writes
+  the output to ``stdout``. Strings are assumed to be Unicode-encoded unless
+  the ``FMT_UNICODE`` macro is set to 0.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
+ */
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline void print(const S& format_str, Args&&... args) {
+  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  return detail::is_unicode<Char>()
+             ? vprint(to_string_view(format_str), vargs)
+             : detail::vprint_mojibake(stdout, to_string_view(format_str),
+                                       vargs);
+}
+FMT_END_NAMESPACE
+
+#endif  // FMT_CORE_H_

spdlog/fmt/bundled/format-inl.h

+// Formatting library for C++ - implementation
+//
+// Copyright (c) 2012 - 2016, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_FORMAT_INL_H_
+#define FMT_FORMAT_INL_H_
+
+#include <cassert>
+#include <cctype>
+#include <climits>
+#include <cmath>
+#include <cstdarg>
+#include <cstring>  // for std::memmove
+#include <cwchar>
+#include <exception>
+
+#include "format.h"
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
+#  include <locale>
+#endif
+
+#ifdef _WIN32
+#  if !defined(NOMINMAX) && !defined(WIN32_LEAN_AND_MEAN)
+#    define NOMINMAX
+#    define WIN32_LEAN_AND_MEAN
+#    include <windows.h>
+#    undef WIN32_LEAN_AND_MEAN
+#    undef NOMINMAX
+#  else
+#    include <windows.h>
+#  endif
+#  include <io.h>
+#endif
+
+#ifdef _MSC_VER
+#  pragma warning(push)
+#  pragma warning(disable : 4702)  // unreachable code
+#endif
+
+// Dummy implementations of strerror_r and strerror_s called if corresponding
+// system functions are not available.
+inline fmt::detail::null<> strerror_r(int, char*, ...) { return {}; }
+inline fmt::detail::null<> strerror_s(char*, size_t, ...) { return {}; }
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
+  // Use unchecked std::fprintf to avoid triggering another assertion when
+  // writing to stderr fails
+  std::fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message);
+  // Chosen instead of std::abort to satisfy Clang in CUDA mode during device
+  // code pass.
+  std::terminate();
+}
+
+#ifndef _MSC_VER
+#  define FMT_SNPRINTF snprintf
+#else  // _MSC_VER
+inline int fmt_snprintf(char* buffer, size_t size, const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+  int result = vsnprintf_s(buffer, size, _TRUNCATE, format, args);
+  va_end(args);
+  return result;
+}
+#  define FMT_SNPRINTF fmt_snprintf
+#endif  // _MSC_VER
+
+// A portable thread-safe version of strerror.
+// Sets buffer to point to a string describing the error code.
+// This can be either a pointer to a string stored in buffer,
+// or a pointer to some static immutable string.
+// Returns one of the following values:
+//   0      - success
+//   ERANGE - buffer is not large enough to store the error message
+//   other  - failure
+// Buffer should be at least of size 1.
+FMT_FUNC int safe_strerror(int error_code, char*& buffer,
+                           size_t buffer_size) FMT_NOEXCEPT {
+  FMT_ASSERT(buffer != nullptr && buffer_size != 0, "invalid buffer");
+
+  class dispatcher {
+   private:
+    int error_code_;
+    char*& buffer_;
+    size_t buffer_size_;
+
+    // A noop assignment operator to avoid bogus warnings.
+    void operator=(const dispatcher&) {}
+
+    // Handle the result of XSI-compliant version of strerror_r.
+    int handle(int result) {
+      // glibc versions before 2.13 return result in errno.
+      return result == -1 ? errno : result;
+    }
+
+    // Handle the result of GNU-specific version of strerror_r.
+    FMT_MAYBE_UNUSED
+    int handle(char* message) {
+      // If the buffer is full then the message is probably truncated.
+      if (message == buffer_ && strlen(buffer_) == buffer_size_ - 1)
+        return ERANGE;
+      buffer_ = message;
+      return 0;
+    }
+
+    // Handle the case when strerror_r is not available.
+    FMT_MAYBE_UNUSED
+    int handle(detail::null<>) {
+      return fallback(strerror_s(buffer_, buffer_size_, error_code_));
+    }
+
+    // Fallback to strerror_s when strerror_r is not available.
+    FMT_MAYBE_UNUSED
+    int fallback(int result) {
+      // If the buffer is full then the message is probably truncated.
+      return result == 0 && strlen(buffer_) == buffer_size_ - 1 ? ERANGE
+                                                                : result;
+    }
+
+#if !FMT_MSC_VER
+    // Fallback to strerror if strerror_r and strerror_s are not available.
+    int fallback(detail::null<>) {
+      errno = 0;
+      buffer_ = strerror(error_code_);
+      return errno;
+    }
+#endif
+
+   public:
+    dispatcher(int err_code, char*& buf, size_t buf_size)
+        : error_code_(err_code), buffer_(buf), buffer_size_(buf_size) {}
+
+    int run() { return handle(strerror_r(error_code_, buffer_, buffer_size_)); }
+  };
+  return dispatcher(error_code, buffer, buffer_size).run();
+}
+
+FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
+                                string_view message) FMT_NOEXCEPT {
+  // Report error code making sure that the output fits into
+  // inline_buffer_size to avoid dynamic memory allocation and potential
+  // bad_alloc.
+  out.resize(0);
+  static const char SEP[] = ": ";
+  static const char ERROR_STR[] = "error ";
+  // Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
+  size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
+  auto abs_value = static_cast<uint32_or_64_or_128_t<int>>(error_code);
+  if (detail::is_negative(error_code)) {
+    abs_value = 0 - abs_value;
+    ++error_code_size;
+  }
+  error_code_size += detail::to_unsigned(detail::count_digits(abs_value));
+  auto it = std::back_inserter(out);
+  if (message.size() <= inline_buffer_size - error_code_size)
+    format_to(it, "{}{}", message, SEP);
+  format_to(it, "{}{}", ERROR_STR, error_code);
+  assert(out.size() <= inline_buffer_size);
+}
+
+FMT_FUNC void report_error(format_func func, int error_code,
+                           string_view message) FMT_NOEXCEPT {
+  memory_buffer full_message;
+  func(full_message, error_code, message);
+  // Don't use fwrite_fully because the latter may throw.
+  (void)std::fwrite(full_message.data(), full_message.size(), 1, stderr);
+  std::fputc('\n', stderr);
+}
+
+// A wrapper around fwrite that throws on error.
+FMT_FUNC void fwrite_fully(const void* ptr, size_t size, size_t count,
+                           FILE* stream) {
+  size_t written = std::fwrite(ptr, size, count, stream);
+  if (written < count) FMT_THROW(system_error(errno, "cannot write to file"));
+}
+}  // namespace detail
+
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
+namespace detail {
+
+template <typename Locale>
+locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
+  static_assert(std::is_same<Locale, std::locale>::value, "");
+}
+
+template <typename Locale> Locale locale_ref::get() const {
+  static_assert(std::is_same<Locale, std::locale>::value, "");
+  return locale_ ? *static_cast<const std::locale*>(locale_) : std::locale();
+}
+
+template <typename Char> FMT_FUNC std::string grouping_impl(locale_ref loc) {
+  return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>()).grouping();
+}
+template <typename Char> FMT_FUNC Char thousands_sep_impl(locale_ref loc) {
+  return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
+      .thousands_sep();
+}
+template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref loc) {
+  return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
+      .decimal_point();
+}
+}  // namespace detail
+#else
+template <typename Char>
+FMT_FUNC std::string detail::grouping_impl(locale_ref) {
+  return "\03";
+}
+template <typename Char> FMT_FUNC Char detail::thousands_sep_impl(locale_ref) {
+  return FMT_STATIC_THOUSANDS_SEPARATOR;
+}
+template <typename Char> FMT_FUNC Char detail::decimal_point_impl(locale_ref) {
+  return '.';
+}
+#endif
+
+FMT_API FMT_FUNC format_error::~format_error() FMT_NOEXCEPT = default;
+FMT_API FMT_FUNC system_error::~system_error() FMT_NOEXCEPT = default;
+
+FMT_FUNC void system_error::init(int err_code, string_view format_str,
+                                 format_args args) {
+  error_code_ = err_code;
+  memory_buffer buffer;
+  format_system_error(buffer, err_code, vformat(format_str, args));
+  std::runtime_error& base = *this;
+  base = std::runtime_error(to_string(buffer));
+}
+
+namespace detail {
+
+template <> FMT_FUNC int count_digits<4>(detail::fallback_uintptr n) {
+  // fallback_uintptr is always stored in little endian.
+  int i = static_cast<int>(sizeof(void*)) - 1;
+  while (i > 0 && n.value[i] == 0) --i;
+  auto char_digits = std::numeric_limits<unsigned char>::digits / 4;
+  return i >= 0 ? i * char_digits + count_digits<4, unsigned>(n.value[i]) : 1;
+}
+
+template <typename T>
+const typename basic_data<T>::digit_pair basic_data<T>::digits[] = {
+    {'0', '0'},  {'0', '1'},  {'0', '2'},  {'0', '3'},  {'0', '4'},
+    {'0', '5'},  {'0', '6'},  {'0', '7'},  {'0', '8'},  {'0', '9'},
+    {'1', '0'},  {'1', '1'},  {'1', '2'},  {'1', '3'},  {'1', '4'},
+    {'1', '5'},  {'1', '6'},  {'1', '7'},  {'1', '8'},  {'1', '9'},
+    {'2', '0'},  {'2', '1'},  {'2', '2'},  {'2', '3'},  {'2', '4'},
+    {'2', '5'},  {'2', '6'},  {'2', '7'},  {'2', '8'},  {'2', '9'},
+    {'3', '0'},  {'3', '1'},  {'3', '2'},  {'3', '3'},  {'3', '4'},
+    {'3', '5'},  {'3', '6'},  {'3', '7'},  {'3', '8'},  {'3', '9'},
+    {'4', '0'},  {'4', '1'},  {'4', '2'},  {'4', '3'},  {'4', '4'},
+    {'4', '5'},  {'4', '6'},  {'4', '7'},  {'4', '8'},  {'4', '9'},
+    {'5', '0'},  {'5', '1'},  {'5', '2'},  {'5', '3'},  {'5', '4'},
+    {'5', '5'},  {'5', '6'},  {'5', '7'},  {'5', '8'},  {'5', '9'},
+    {'6', '0'},  {'6', '1'},  {'6', '2'},  {'6', '3'},  {'6', '4'},
+    {'6', '5'},  {'6', '6'},  {'6', '7'},  {'6', '8'},  {'6', '9'},
+    {'7', '0'},  {'7', '1'},  {'7', '2'},  {'7', '3'},  {'7', '4'},
+    {'7', '5'},  {'7', '6'},  {'7', '7'},  {'7', '8'},  {'7', '9'},
+    {'8', '0'},  {'8', '1'},  {'8', '2'},  {'8', '3'},  {'8', '4'},
+    {'8', '5'},  {'8', '6'},  {'8', '7'},  {'8', '8'},  {'8', '9'},
+    {'9', '0'},  {'9', '1'},  {'9', '2'},  {'9', '3'},  {'9', '4'},
+    {'9', '5'},  {'9', '6'},  {'9', '7'},  {'9', '8'},  {'9', '9'}};
+
+template <typename T>
+const char basic_data<T>::hex_digits[] = "0123456789abcdef";
+
+#define FMT_POWERS_OF_10(factor)                                             \
+  factor * 10, (factor)*100, (factor)*1000, (factor)*10000, (factor)*100000, \
+      (factor)*1000000, (factor)*10000000, (factor)*100000000,               \
+      (factor)*1000000000
+
+template <typename T>
+const uint64_t basic_data<T>::powers_of_10_64[] = {
+    1, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
+    10000000000000000000ULL};
+
+template <typename T>
+const uint32_t basic_data<T>::zero_or_powers_of_10_32[] = {0,
+                                                           FMT_POWERS_OF_10(1)};
+
+template <typename T>
+const uint64_t basic_data<T>::zero_or_powers_of_10_64[] = {
+    0, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
+    10000000000000000000ULL};
+
+// Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
+// These are generated by support/compute-powers.py.
+template <typename T>
+const uint64_t basic_data<T>::pow10_significands[] = {
+    0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
+    0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
+    0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
+    0x8dd01fad907ffc3c, 0xd3515c2831559a83, 0x9d71ac8fada6c9b5,
+    0xea9c227723ee8bcb, 0xaecc49914078536d, 0x823c12795db6ce57,
+    0xc21094364dfb5637, 0x9096ea6f3848984f, 0xd77485cb25823ac7,
+    0xa086cfcd97bf97f4, 0xef340a98172aace5, 0xb23867fb2a35b28e,
+    0x84c8d4dfd2c63f3b, 0xc5dd44271ad3cdba, 0x936b9fcebb25c996,
+    0xdbac6c247d62a584, 0xa3ab66580d5fdaf6, 0xf3e2f893dec3f126,
+    0xb5b5ada8aaff80b8, 0x87625f056c7c4a8b, 0xc9bcff6034c13053,
+    0x964e858c91ba2655, 0xdff9772470297ebd, 0xa6dfbd9fb8e5b88f,
+    0xf8a95fcf88747d94, 0xb94470938fa89bcf, 0x8a08f0f8bf0f156b,
+    0xcdb02555653131b6, 0x993fe2c6d07b7fac, 0xe45c10c42a2b3b06,
+    0xaa242499697392d3, 0xfd87b5f28300ca0e, 0xbce5086492111aeb,
+    0x8cbccc096f5088cc, 0xd1b71758e219652c, 0x9c40000000000000,
+    0xe8d4a51000000000, 0xad78ebc5ac620000, 0x813f3978f8940984,
+    0xc097ce7bc90715b3, 0x8f7e32ce7bea5c70, 0xd5d238a4abe98068,
+    0x9f4f2726179a2245, 0xed63a231d4c4fb27, 0xb0de65388cc8ada8,
+    0x83c7088e1aab65db, 0xc45d1df942711d9a, 0x924d692ca61be758,
+    0xda01ee641a708dea, 0xa26da3999aef774a, 0xf209787bb47d6b85,
+    0xb454e4a179dd1877, 0x865b86925b9bc5c2, 0xc83553c5c8965d3d,
+    0x952ab45cfa97a0b3, 0xde469fbd99a05fe3, 0xa59bc234db398c25,
+    0xf6c69a72a3989f5c, 0xb7dcbf5354e9bece, 0x88fcf317f22241e2,
+    0xcc20ce9bd35c78a5, 0x98165af37b2153df, 0xe2a0b5dc971f303a,
+    0xa8d9d1535ce3b396, 0xfb9b7cd9a4a7443c, 0xbb764c4ca7a44410,
+    0x8bab8eefb6409c1a, 0xd01fef10a657842c, 0x9b10a4e5e9913129,
+    0xe7109bfba19c0c9d, 0xac2820d9623bf429, 0x80444b5e7aa7cf85,
+    0xbf21e44003acdd2d, 0x8e679c2f5e44ff8f, 0xd433179d9c8cb841,
+    0x9e19db92b4e31ba9, 0xeb96bf6ebadf77d9, 0xaf87023b9bf0ee6b,
+};
+
+// Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
+// to significands above.
+template <typename T>
+const int16_t basic_data<T>::pow10_exponents[] = {
+    -1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
+    -927,  -901,  -874,  -847,  -821,  -794,  -768,  -741,  -715,  -688, -661,
+    -635,  -608,  -582,  -555,  -529,  -502,  -475,  -449,  -422,  -396, -369,
+    -343,  -316,  -289,  -263,  -236,  -210,  -183,  -157,  -130,  -103, -77,
+    -50,   -24,   3,     30,    56,    83,    109,   136,   162,   189,  216,
+    242,   269,   295,   322,   348,   375,   402,   428,   455,   481,  508,
+    534,   561,   588,   614,   641,   667,   694,   720,   747,   774,  800,
+    827,   853,   880,   907,   933,   960,   986,   1013,  1039,  1066};
+
+template <typename T>
+const char basic_data<T>::foreground_color[] = "\x1b[38;2;";
+template <typename T>
+const char basic_data<T>::background_color[] = "\x1b[48;2;";
+template <typename T> const char basic_data<T>::reset_color[] = "\x1b[0m";
+template <typename T> const wchar_t basic_data<T>::wreset_color[] = L"\x1b[0m";
+template <typename T> const char basic_data<T>::signs[] = {0, '-', '+', ' '};
+template <typename T>
+const char basic_data<T>::left_padding_shifts[] = {31, 31, 0, 1, 0};
+template <typename T>
+const char basic_data<T>::right_padding_shifts[] = {0, 31, 0, 1, 0};
+
+template <typename T> struct bits {
+  static FMT_CONSTEXPR_DECL const int value =
+      static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
+};
+
+class fp;
+template <int SHIFT = 0> fp normalize(fp value);
+
+// Lower (upper) boundary is a value half way between a floating-point value
+// and its predecessor (successor). Boundaries have the same exponent as the
+// value so only significands are stored.
+struct boundaries {
+  uint64_t lower;
+  uint64_t upper;
+};
+
+// A handmade floating-point number f * pow(2, e).
+class fp {
+ private:
+  using significand_type = uint64_t;
+
+ public:
+  significand_type f;
+  int e;
+
+  // All sizes are in bits.
+  // Subtract 1 to account for an implicit most significant bit in the
+  // normalized form.
+  static FMT_CONSTEXPR_DECL const int double_significand_size =
+      std::numeric_limits<double>::digits - 1;
+  static FMT_CONSTEXPR_DECL const uint64_t implicit_bit =
+      1ULL << double_significand_size;
+  static FMT_CONSTEXPR_DECL const int significand_size =
+      bits<significand_type>::value;
+
+  fp() : f(0), e(0) {}
+  fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
+
+  // Constructs fp from an IEEE754 double. It is a template to prevent compile
+  // errors on platforms where double is not IEEE754.
+  template <typename Double> explicit fp(Double d) { assign(d); }
+
+  // Assigns d to this and return true iff predecessor is closer than successor.
+  template <typename Double, FMT_ENABLE_IF(sizeof(Double) == sizeof(uint64_t))>
+  bool assign(Double d) {
+    // Assume double is in the format [sign][exponent][significand].
+    using limits = std::numeric_limits<Double>;
+    const int exponent_size =
+        bits<Double>::value - double_significand_size - 1;  // -1 for sign
+    const uint64_t significand_mask = implicit_bit - 1;
+    const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
+    const int exponent_bias = (1 << exponent_size) - limits::max_exponent - 1;
+    auto u = bit_cast<uint64_t>(d);
+    f = u & significand_mask;
+    int biased_e =
+        static_cast<int>((u & exponent_mask) >> double_significand_size);
+    // Predecessor is closer if d is a normalized power of 2 (f == 0) other than
+    // the smallest normalized number (biased_e > 1).
+    bool is_predecessor_closer = f == 0 && biased_e > 1;
+    if (biased_e != 0)
+      f += implicit_bit;
+    else
+      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
+    e = biased_e - exponent_bias - double_significand_size;
+    return is_predecessor_closer;
+  }
+
+  template <typename Double, FMT_ENABLE_IF(sizeof(Double) != sizeof(uint64_t))>
+  bool assign(Double) {
+    *this = fp();
+    return false;
+  }
+
+  // Assigns d to this together with computing lower and upper boundaries,
+  // where a boundary is a value half way between the number and its predecessor
+  // (lower) or successor (upper). The upper boundary is normalized and lower
+  // has the same exponent but may be not normalized.
+  template <typename Double> boundaries assign_with_boundaries(Double d) {
+    bool is_lower_closer = assign(d);
+    fp lower =
+        is_lower_closer ? fp((f << 2) - 1, e - 2) : fp((f << 1) - 1, e - 1);
+    // 1 in normalize accounts for the exponent shift above.
+    fp upper = normalize<1>(fp((f << 1) + 1, e - 1));
+    lower.f <<= lower.e - upper.e;
+    return boundaries{lower.f, upper.f};
+  }
+
+  template <typename Double> boundaries assign_float_with_boundaries(Double d) {
+    assign(d);
+    constexpr int min_normal_e = std::numeric_limits<float>::min_exponent -
+                                 std::numeric_limits<double>::digits;
+    significand_type half_ulp = 1 << (std::numeric_limits<double>::digits -
+                                      std::numeric_limits<float>::digits - 1);
+    if (min_normal_e > e) half_ulp <<= min_normal_e - e;
+    fp upper = normalize<0>(fp(f + half_ulp, e));
+    fp lower = fp(
+        f - (half_ulp >> ((f == implicit_bit && e > min_normal_e) ? 1 : 0)), e);
+    lower.f <<= lower.e - upper.e;
+    return boundaries{lower.f, upper.f};
+  }
+};
+
+// Normalizes the value converted from double and multiplied by (1 << SHIFT).
+template <int SHIFT> fp normalize(fp value) {
+  // Handle subnormals.
+  const auto shifted_implicit_bit = fp::implicit_bit << SHIFT;
+  while ((value.f & shifted_implicit_bit) == 0) {
+    value.f <<= 1;
+    --value.e;
+  }
+  // Subtract 1 to account for hidden bit.
+  const auto offset =
+      fp::significand_size - fp::double_significand_size - SHIFT - 1;
+  value.f <<= offset;
+  value.e -= offset;
+  return value;
+}
+
+inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
+
+// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
+inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
+#if FMT_USE_INT128
+  auto product = static_cast<__uint128_t>(lhs) * rhs;
+  auto f = static_cast<uint64_t>(product >> 64);
+  return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
+#else
+  // Multiply 32-bit parts of significands.
+  uint64_t mask = (1ULL << 32) - 1;
+  uint64_t a = lhs >> 32, b = lhs & mask;
+  uint64_t c = rhs >> 32, d = rhs & mask;
+  uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
+  // Compute mid 64-bit of result and round.
+  uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
+  return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
+#endif
+}
+
+inline fp operator*(fp x, fp y) { return {multiply(x.f, y.f), x.e + y.e + 64}; }
+
+// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
+// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
+inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
+  const int64_t one_over_log2_10 = 0x4d104d42;  // round(pow(2, 32) / log2(10))
+  int index = static_cast<int>(
+      ((min_exponent + fp::significand_size - 1) * one_over_log2_10 +
+       ((int64_t(1) << 32) - 1))  // ceil
+      >> 32                       // arithmetic shift
+  );
+  // Decimal exponent of the first (smallest) cached power of 10.
+  const int first_dec_exp = -348;
+  // Difference between 2 consecutive decimal exponents in cached powers of 10.
+  const int dec_exp_step = 8;
+  index = (index - first_dec_exp - 1) / dec_exp_step + 1;
+  pow10_exponent = first_dec_exp + index * dec_exp_step;
+  return {data::pow10_significands[index], data::pow10_exponents[index]};
+}
+
+// A simple accumulator to hold the sums of terms in bigint::square if uint128_t
+// is not available.
+struct accumulator {
+  uint64_t lower;
+  uint64_t upper;
+
+  accumulator() : lower(0), upper(0) {}
+  explicit operator uint32_t() const { return static_cast<uint32_t>(lower); }
+
+  void operator+=(uint64_t n) {
+    lower += n;
+    if (lower < n) ++upper;
+  }
+  void operator>>=(int shift) {
+    assert(shift == 32);
+    (void)shift;
+    lower = (upper << 32) | (lower >> 32);
+    upper >>= 32;
+  }
+};
+
+class bigint {
+ private:
+  // A bigint is stored as an array of bigits (big digits), with bigit at index
+  // 0 being the least significant one.
+  using bigit = uint32_t;
+  using double_bigit = uint64_t;
+  enum { bigits_capacity = 32 };
+  basic_memory_buffer<bigit, bigits_capacity> bigits_;
+  int exp_;
+
+  bigit operator[](int index) const { return bigits_[to_unsigned(index)]; }
+  bigit& operator[](int index) { return bigits_[to_unsigned(index)]; }
+
+  static FMT_CONSTEXPR_DECL const int bigit_bits = bits<bigit>::value;
+
+  friend struct formatter<bigint>;
+
+  void subtract_bigits(int index, bigit other, bigit& borrow) {
+    auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
+    (*this)[index] = static_cast<bigit>(result);
+    borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
+  }
+
+  void remove_leading_zeros() {
+    int num_bigits = static_cast<int>(bigits_.size()) - 1;
+    while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
+    bigits_.resize(to_unsigned(num_bigits + 1));
+  }
+
+  // Computes *this -= other assuming aligned bigints and *this >= other.
+  void subtract_aligned(const bigint& other) {
+    FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
+    FMT_ASSERT(compare(*this, other) >= 0, "");
+    bigit borrow = 0;
+    int i = other.exp_ - exp_;
+    for (size_t j = 0, n = other.bigits_.size(); j != n; ++i, ++j) {
+      subtract_bigits(i, other.bigits_[j], borrow);
+    }
+    while (borrow > 0) subtract_bigits(i, 0, borrow);
+    remove_leading_zeros();
+  }
+
+  void multiply(uint32_t value) {
+    const double_bigit wide_value = value;
+    bigit carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      double_bigit result = bigits_[i] * wide_value + carry;
+      bigits_[i] = static_cast<bigit>(result);
+      carry = static_cast<bigit>(result >> bigit_bits);
+    }
+    if (carry != 0) bigits_.push_back(carry);
+  }
+
+  void multiply(uint64_t value) {
+    const bigit mask = ~bigit(0);
+    const double_bigit lower = value & mask;
+    const double_bigit upper = value >> bigit_bits;
+    double_bigit carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      double_bigit result = bigits_[i] * lower + (carry & mask);
+      carry =
+          bigits_[i] * upper + (result >> bigit_bits) + (carry >> bigit_bits);
+      bigits_[i] = static_cast<bigit>(result);
+    }
+    while (carry != 0) {
+      bigits_.push_back(carry & mask);
+      carry >>= bigit_bits;
+    }
+  }
+
+ public:
+  bigint() : exp_(0) {}
+  explicit bigint(uint64_t n) { assign(n); }
+  ~bigint() { assert(bigits_.capacity() <= bigits_capacity); }
+
+  bigint(const bigint&) = delete;
+  void operator=(const bigint&) = delete;
+
+  void assign(const bigint& other) {
+    auto size = other.bigits_.size();
+    bigits_.resize(size);
+    auto data = other.bigits_.data();
+    std::copy(data, data + size, make_checked(bigits_.data(), size));
+    exp_ = other.exp_;
+  }
+
+  void assign(uint64_t n) {
+    size_t num_bigits = 0;
+    do {
+      bigits_[num_bigits++] = n & ~bigit(0);
+      n >>= bigit_bits;
+    } while (n != 0);
+    bigits_.resize(num_bigits);
+    exp_ = 0;
+  }
+
+  int num_bigits() const { return static_cast<int>(bigits_.size()) + exp_; }
+
+  FMT_NOINLINE bigint& operator<<=(int shift) {
+    assert(shift >= 0);
+    exp_ += shift / bigit_bits;
+    shift %= bigit_bits;
+    if (shift == 0) return *this;
+    bigit carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      bigit c = bigits_[i] >> (bigit_bits - shift);
+      bigits_[i] = (bigits_[i] << shift) + carry;
+      carry = c;
+    }
+    if (carry != 0) bigits_.push_back(carry);
+    return *this;
+  }
+
+  template <typename Int> bigint& operator*=(Int value) {
+    FMT_ASSERT(value > 0, "");
+    multiply(uint32_or_64_or_128_t<Int>(value));
+    return *this;
+  }
+
+  friend int compare(const bigint& lhs, const bigint& rhs) {
+    int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
+    if (num_lhs_bigits != num_rhs_bigits)
+      return num_lhs_bigits > num_rhs_bigits ? 1 : -1;
+    int i = static_cast<int>(lhs.bigits_.size()) - 1;
+    int j = static_cast<int>(rhs.bigits_.size()) - 1;
+    int end = i - j;
+    if (end < 0) end = 0;
+    for (; i >= end; --i, --j) {
+      bigit lhs_bigit = lhs[i], rhs_bigit = rhs[j];
+      if (lhs_bigit != rhs_bigit) return lhs_bigit > rhs_bigit ? 1 : -1;
+    }
+    if (i != j) return i > j ? 1 : -1;
+    return 0;
+  }
+
+  // Returns compare(lhs1 + lhs2, rhs).
+  friend int add_compare(const bigint& lhs1, const bigint& lhs2,
+                         const bigint& rhs) {
+    int max_lhs_bigits = (std::max)(lhs1.num_bigits(), lhs2.num_bigits());
+    int num_rhs_bigits = rhs.num_bigits();
+    if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
+    if (max_lhs_bigits > num_rhs_bigits) return 1;
+    auto get_bigit = [](const bigint& n, int i) -> bigit {
+      return i >= n.exp_ && i < n.num_bigits() ? n[i - n.exp_] : 0;
+    };
+    double_bigit borrow = 0;
+    int min_exp = (std::min)((std::min)(lhs1.exp_, lhs2.exp_), rhs.exp_);
+    for (int i = num_rhs_bigits - 1; i >= min_exp; --i) {
+      double_bigit sum =
+          static_cast<double_bigit>(get_bigit(lhs1, i)) + get_bigit(lhs2, i);
+      bigit rhs_bigit = get_bigit(rhs, i);
+      if (sum > rhs_bigit + borrow) return 1;
+      borrow = rhs_bigit + borrow - sum;
+      if (borrow > 1) return -1;
+      borrow <<= bigit_bits;
+    }
+    return borrow != 0 ? -1 : 0;
+  }
+
+  // Assigns pow(10, exp) to this bigint.
+  void assign_pow10(int exp) {
+    assert(exp >= 0);
+    if (exp == 0) return assign(1);
+    // Find the top bit.
+    int bitmask = 1;
+    while (exp >= bitmask) bitmask <<= 1;
+    bitmask >>= 1;
+    // pow(10, exp) = pow(5, exp) * pow(2, exp). First compute pow(5, exp) by
+    // repeated squaring and multiplication.
+    assign(5);
+    bitmask >>= 1;
+    while (bitmask != 0) {
+      square();
+      if ((exp & bitmask) != 0) *this *= 5;
+      bitmask >>= 1;
+    }
+    *this <<= exp;  // Multiply by pow(2, exp) by shifting.
+  }
+
+  void square() {
+    basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
+    int num_bigits = static_cast<int>(bigits_.size());
+    int num_result_bigits = 2 * num_bigits;
+    bigits_.resize(to_unsigned(num_result_bigits));
+    using accumulator_t = conditional_t<FMT_USE_INT128, uint128_t, accumulator>;
+    auto sum = accumulator_t();
+    for (int bigit_index = 0; bigit_index < num_bigits; ++bigit_index) {
+      // Compute bigit at position bigit_index of the result by adding
+      // cross-product terms n[i] * n[j] such that i + j == bigit_index.
+      for (int i = 0, j = bigit_index; j >= 0; ++i, --j) {
+        // Most terms are multiplied twice which can be optimized in the future.
+        sum += static_cast<double_bigit>(n[i]) * n[j];
+      }
+      (*this)[bigit_index] = static_cast<bigit>(sum);
+      sum >>= bits<bigit>::value;  // Compute the carry.
+    }
+    // Do the same for the top half.
+    for (int bigit_index = num_bigits; bigit_index < num_result_bigits;
+         ++bigit_index) {
+      for (int j = num_bigits - 1, i = bigit_index - j; i < num_bigits;)
+        sum += static_cast<double_bigit>(n[i++]) * n[j--];
+      (*this)[bigit_index] = static_cast<bigit>(sum);
+      sum >>= bits<bigit>::value;
+    }
+    --num_result_bigits;
+    remove_leading_zeros();
+    exp_ *= 2;
+  }
+
+  // Divides this bignum by divisor, assigning the remainder to this and
+  // returning the quotient.
+  int divmod_assign(const bigint& divisor) {
+    FMT_ASSERT(this != &divisor, "");
+    if (compare(*this, divisor) < 0) return 0;
+    int num_bigits = static_cast<int>(bigits_.size());
+    FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");
+    int exp_difference = exp_ - divisor.exp_;
+    if (exp_difference > 0) {
+      // Align bigints by adding trailing zeros to simplify subtraction.
+      bigits_.resize(to_unsigned(num_bigits + exp_difference));
+      for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
+        bigits_[j] = bigits_[i];
+      std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
+      exp_ -= exp_difference;
+    }
+    int quotient = 0;
+    do {
+      subtract_aligned(divisor);
+      ++quotient;
+    } while (compare(*this, divisor) >= 0);
+    return quotient;
+  }
+};
+
+enum class round_direction { unknown, up, down };
+
+// Given the divisor (normally a power of 10), the remainder = v % divisor for
+// some number v and the error, returns whether v should be rounded up, down, or
+// whether the rounding direction can't be determined due to error.
+// error should be less than divisor / 2.
+inline round_direction get_round_direction(uint64_t divisor, uint64_t remainder,
+                                           uint64_t error) {
+  FMT_ASSERT(remainder < divisor, "");  // divisor - remainder won't overflow.
+  FMT_ASSERT(error < divisor, "");      // divisor - error won't overflow.
+  FMT_ASSERT(error < divisor - error, "");  // error * 2 won't overflow.
+  // Round down if (remainder + error) * 2 <= divisor.
+  if (remainder <= divisor - remainder && error * 2 <= divisor - remainder * 2)
+    return round_direction::down;
+  // Round up if (remainder - error) * 2 >= divisor.
+  if (remainder >= error &&
+      remainder - error >= divisor - (remainder - error)) {
+    return round_direction::up;
+  }
+  return round_direction::unknown;
+}
+
+namespace digits {
+enum result {
+  more,  // Generate more digits.
+  done,  // Done generating digits.
+  error  // Digit generation cancelled due to an error.
+};
+}
+
+// A version of count_digits optimized for grisu_gen_digits.
+inline int grisu_count_digits(uint32_t n) {
+  if (n < 10) return 1;
+  if (n < 100) return 2;
+  if (n < 1000) return 3;
+  if (n < 10000) return 4;
+  if (n < 100000) return 5;
+  if (n < 1000000) return 6;
+  if (n < 10000000) return 7;
+  if (n < 100000000) return 8;
+  if (n < 1000000000) return 9;
+  return 10;
+}
+
+// Generates output using the Grisu digit-gen algorithm.
+// error: the size of the region (lower, upper) outside of which numbers
+// definitely do not round to value (Delta in Grisu3).
+template <typename Handler>
+FMT_ALWAYS_INLINE digits::result grisu_gen_digits(fp value, uint64_t error,
+                                                  int& exp, Handler& handler) {
+  const fp one(1ULL << -value.e, value.e);
+  // The integral part of scaled value (p1 in Grisu) = value / one. It cannot be
+  // zero because it contains a product of two 64-bit numbers with MSB set (due
+  // to normalization) - 1, shifted right by at most 60 bits.
+  auto integral = static_cast<uint32_t>(value.f >> -one.e);
+  FMT_ASSERT(integral != 0, "");
+  FMT_ASSERT(integral == value.f >> -one.e, "");
+  // The fractional part of scaled value (p2 in Grisu) c = value % one.
+  uint64_t fractional = value.f & (one.f - 1);
+  exp = grisu_count_digits(integral);  // kappa in Grisu.
+  // Divide by 10 to prevent overflow.
+  auto result = handler.on_start(data::powers_of_10_64[exp - 1] << -one.e,
+                                 value.f / 10, error * 10, exp);
+  if (result != digits::more) return result;
+  // Generate digits for the integral part. This can produce up to 10 digits.
+  do {
+    uint32_t digit = 0;
+    auto divmod_integral = [&](uint32_t divisor) {
+      digit = integral / divisor;
+      integral %= divisor;
+    };
+    // This optimization by Milo Yip reduces the number of integer divisions by
+    // one per iteration.
+    switch (exp) {
+    case 10:
+      divmod_integral(1000000000);
+      break;
+    case 9:
+      divmod_integral(100000000);
+      break;
+    case 8:
+      divmod_integral(10000000);
+      break;
+    case 7:
+      divmod_integral(1000000);
+      break;
+    case 6:
+      divmod_integral(100000);
+      break;
+    case 5:
+      divmod_integral(10000);
+      break;
+    case 4:
+      divmod_integral(1000);
+      break;
+    case 3:
+      divmod_integral(100);
+      break;
+    case 2:
+      divmod_integral(10);
+      break;
+    case 1:
+      digit = integral;
+      integral = 0;
+      break;
+    default:
+      FMT_ASSERT(false, "invalid number of digits");
+    }
+    --exp;
+    uint64_t remainder =
+        (static_cast<uint64_t>(integral) << -one.e) + fractional;
+    result = handler.on_digit(static_cast<char>('0' + digit),
+                              data::powers_of_10_64[exp] << -one.e, remainder,
+                              error, exp, true);
+    if (result != digits::more) return result;
+  } while (exp > 0);
+  // Generate digits for the fractional part.
+  for (;;) {
+    fractional *= 10;
+    error *= 10;
+    char digit =
+        static_cast<char>('0' + static_cast<char>(fractional >> -one.e));
+    fractional &= one.f - 1;
+    --exp;
+    result = handler.on_digit(digit, one.f, fractional, error, exp, false);
+    if (result != digits::more) return result;
+  }
+}
+
+// The fixed precision digit handler.
+struct fixed_handler {
+  char* buf;
+  int size;
+  int precision;
+  int exp10;
+  bool fixed;
+
+  digits::result on_start(uint64_t divisor, uint64_t remainder, uint64_t error,
+                          int& exp) {
+    // Non-fixed formats require at least one digit and no precision adjustment.
+    if (!fixed) return digits::more;
+    // Adjust fixed precision by exponent because it is relative to decimal
+    // point.
+    precision += exp + exp10;
+    // Check if precision is satisfied just by leading zeros, e.g.
+    // format("{:.2f}", 0.001) gives "0.00" without generating any digits.
+    if (precision > 0) return digits::more;
+    if (precision < 0) return digits::done;
+    auto dir = get_round_direction(divisor, remainder, error);
+    if (dir == round_direction::unknown) return digits::error;
+    buf[size++] = dir == round_direction::up ? '1' : '0';
+    return digits::done;
+  }
+
+  digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
+                          uint64_t error, int, bool integral) {
+    FMT_ASSERT(remainder < divisor, "");
+    buf[size++] = digit;
+    if (size < precision) return digits::more;
+    if (!integral) {
+      // Check if error * 2 < divisor with overflow prevention.
+      // The check is not needed for the integral part because error = 1
+      // and divisor > (1 << 32) there.
+      if (error >= divisor || error >= divisor - error) return digits::error;
+    } else {
+      FMT_ASSERT(error == 1 && divisor > 2, "");
+    }
+    auto dir = get_round_direction(divisor, remainder, error);
+    if (dir != round_direction::up)
+      return dir == round_direction::down ? digits::done : digits::error;
+    ++buf[size - 1];
+    for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
+      buf[i] = '0';
+      ++buf[i - 1];
+    }
+    if (buf[0] > '9') {
+      buf[0] = '1';
+      buf[size++] = '0';
+    }
+    return digits::done;
+  }
+};
+
+// The shortest representation digit handler.
+struct grisu_shortest_handler {
+  char* buf;
+  int size;
+  // Distance between scaled value and upper bound (wp_W in Grisu3).
+  uint64_t diff;
+
+  digits::result on_start(uint64_t, uint64_t, uint64_t, int&) {
+    return digits::more;
+  }
+
+  // Decrement the generated number approaching value from above.
+  void round(uint64_t d, uint64_t divisor, uint64_t& remainder,
+             uint64_t error) {
+    while (
+        remainder < d && error - remainder >= divisor &&
+        (remainder + divisor < d || d - remainder >= remainder + divisor - d)) {
+      --buf[size - 1];
+      remainder += divisor;
+    }
+  }
+
+  // Implements Grisu's round_weed.
+  digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
+                          uint64_t error, int exp, bool integral) {
+    buf[size++] = digit;
+    if (remainder >= error) return digits::more;
+    uint64_t unit = integral ? 1 : data::powers_of_10_64[-exp];
+    uint64_t up = (diff - 1) * unit;  // wp_Wup
+    round(up, divisor, remainder, error);
+    uint64_t down = (diff + 1) * unit;  // wp_Wdown
+    if (remainder < down && error - remainder >= divisor &&
+        (remainder + divisor < down ||
+         down - remainder > remainder + divisor - down)) {
+      return digits::error;
+    }
+    return 2 * unit <= remainder && remainder <= error - 4 * unit
+               ? digits::done
+               : digits::error;
+  }
+};
+
+// Formats value using a variation of the Fixed-Precision Positive
+// Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
+// https://fmt.dev/p372-steele.pdf.
+template <typename Double>
+void fallback_format(Double d, buffer<char>& buf, int& exp10) {
+  bigint numerator;    // 2 * R in (FPP)^2.
+  bigint denominator;  // 2 * S in (FPP)^2.
+  // lower and upper are differences between value and corresponding boundaries.
+  bigint lower;             // (M^- in (FPP)^2).
+  bigint upper_store;       // upper's value if different from lower.
+  bigint* upper = nullptr;  // (M^+ in (FPP)^2).
+  fp value;
+  // Shift numerator and denominator by an extra bit or two (if lower boundary
+  // is closer) to make lower and upper integers. This eliminates multiplication
+  // by 2 during later computations.
+  // TODO: handle float
+  int shift = value.assign(d) ? 2 : 1;
+  uint64_t significand = value.f << shift;
+  if (value.e >= 0) {
+    numerator.assign(significand);
+    numerator <<= value.e;
+    lower.assign(1);
+    lower <<= value.e;
+    if (shift != 1) {
+      upper_store.assign(1);
+      upper_store <<= value.e + 1;
+      upper = &upper_store;
+    }
+    denominator.assign_pow10(exp10);
+    denominator <<= 1;
+  } else if (exp10 < 0) {
+    numerator.assign_pow10(-exp10);
+    lower.assign(numerator);
+    if (shift != 1) {
+      upper_store.assign(numerator);
+      upper_store <<= 1;
+      upper = &upper_store;
+    }
+    numerator *= significand;
+    denominator.assign(1);
+    denominator <<= shift - value.e;
+  } else {
+    numerator.assign(significand);
+    denominator.assign_pow10(exp10);
+    denominator <<= shift - value.e;
+    lower.assign(1);
+    if (shift != 1) {
+      upper_store.assign(1ULL << 1);
+      upper = &upper_store;
+    }
+  }
+  if (!upper) upper = &lower;
+  // Invariant: value == (numerator / denominator) * pow(10, exp10).
+  bool even = (value.f & 1) == 0;
+  int num_digits = 0;
+  char* data = buf.data();
+  for (;;) {
+    int digit = numerator.divmod_assign(denominator);
+    bool low = compare(numerator, lower) - even < 0;  // numerator <[=] lower.
+    // numerator + upper >[=] pow10:
+    bool high = add_compare(numerator, *upper, denominator) + even > 0;
+    data[num_digits++] = static_cast<char>('0' + digit);
+    if (low || high) {
+      if (!low) {
+        ++data[num_digits - 1];
+      } else if (high) {
+        int result = add_compare(numerator, numerator, denominator);
+        // Round half to even.
+        if (result > 0 || (result == 0 && (digit % 2) != 0))
+          ++data[num_digits - 1];
+      }
+      buf.resize(to_unsigned(num_digits));
+      exp10 -= num_digits - 1;
+      return;
+    }
+    numerator *= 10;
+    lower *= 10;
+    if (upper != &lower) *upper *= 10;
+  }
+}
+
+// Formats value using the Grisu algorithm
+// (https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf)
+// if T is a IEEE754 binary32 or binary64 and snprintf otherwise.
+template <typename T>
+int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
+  static_assert(!std::is_same<T, float>::value, "");
+  FMT_ASSERT(value >= 0, "value is negative");
+
+  const bool fixed = specs.format == float_format::fixed;
+  if (value <= 0) {  // <= instead of == to silence a warning.
+    if (precision <= 0 || !fixed) {
+      buf.push_back('0');
+      return 0;
+    }
+    buf.resize(to_unsigned(precision));
+    std::uninitialized_fill_n(buf.data(), precision, '0');
+    return -precision;
+  }
+
+  if (!specs.use_grisu) return snprintf_float(value, precision, specs, buf);
+
+  int exp = 0;
+  const int min_exp = -60;  // alpha in Grisu.
+  int cached_exp10 = 0;     // K in Grisu.
+  if (precision < 0) {
+    fp fp_value;
+    auto boundaries = specs.binary32
+                          ? fp_value.assign_float_with_boundaries(value)
+                          : fp_value.assign_with_boundaries(value);
+    fp_value = normalize(fp_value);
+    // Find a cached power of 10 such that multiplying value by it will bring
+    // the exponent in the range [min_exp, -32].
+    const fp cached_pow = get_cached_power(
+        min_exp - (fp_value.e + fp::significand_size), cached_exp10);
+    // Multiply value and boundaries by the cached power of 10.
+    fp_value = fp_value * cached_pow;
+    boundaries.lower = multiply(boundaries.lower, cached_pow.f);
+    boundaries.upper = multiply(boundaries.upper, cached_pow.f);
+    assert(min_exp <= fp_value.e && fp_value.e <= -32);
+    --boundaries.lower;  // \tilde{M}^- - 1 ulp -> M^-_{\downarrow}.
+    ++boundaries.upper;  // \tilde{M}^+ + 1 ulp -> M^+_{\uparrow}.
+    // Numbers outside of (lower, upper) definitely do not round to value.
+    grisu_shortest_handler handler{buf.data(), 0,
+                                   boundaries.upper - fp_value.f};
+    auto result =
+        grisu_gen_digits(fp(boundaries.upper, fp_value.e),
+                         boundaries.upper - boundaries.lower, exp, handler);
+    if (result == digits::error) {
+      exp += handler.size - cached_exp10 - 1;
+      fallback_format(value, buf, exp);
+      return exp;
+    }
+    buf.resize(to_unsigned(handler.size));
+  } else {
+    if (precision > 17) return snprintf_float(value, precision, specs, buf);
+    fp normalized = normalize(fp(value));
+    const auto cached_pow = get_cached_power(
+        min_exp - (normalized.e + fp::significand_size), cached_exp10);
+    normalized = normalized * cached_pow;
+    fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
+    if (grisu_gen_digits(normalized, 1, exp, handler) == digits::error)
+      return snprintf_float(value, precision, specs, buf);
+    int num_digits = handler.size;
+    if (!fixed) {
+      // Remove trailing zeros.
+      while (num_digits > 0 && buf[num_digits - 1] == '0') {
+        --num_digits;
+        ++exp;
+      }
+    }
+    buf.resize(to_unsigned(num_digits));
+  }
+  return exp - cached_exp10;
+}
+
+template <typename T>
+int snprintf_float(T value, int precision, float_specs specs,
+                   buffer<char>& buf) {
+  // Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
+  FMT_ASSERT(buf.capacity() > buf.size(), "empty buffer");
+  static_assert(!std::is_same<T, float>::value, "");
+
+  // Subtract 1 to account for the difference in precision since we use %e for
+  // both general and exponent format.
+  if (specs.format == float_format::general ||
+      specs.format == float_format::exp)
+    precision = (precision >= 0 ? precision : 6) - 1;
+
+  // Build the format string.
+  enum { max_format_size = 7 };  // The longest format is "%#.*Le".
+  char format[max_format_size];
+  char* format_ptr = format;
+  *format_ptr++ = '%';
+  if (specs.showpoint && specs.format == float_format::hex) *format_ptr++ = '#';
+  if (precision >= 0) {
+    *format_ptr++ = '.';
+    *format_ptr++ = '*';
+  }
+  if (std::is_same<T, long double>()) *format_ptr++ = 'L';
+  *format_ptr++ = specs.format != float_format::hex
+                      ? (specs.format == float_format::fixed ? 'f' : 'e')
+                      : (specs.upper ? 'A' : 'a');
+  *format_ptr = '\0';
+
+  // Format using snprintf.
+  auto offset = buf.size();
+  for (;;) {
+    auto begin = buf.data() + offset;
+    auto capacity = buf.capacity() - offset;
+#ifdef FMT_FUZZ
+    if (precision > 100000)
+      throw std::runtime_error(
+          "fuzz mode - avoid large allocation inside snprintf");
+#endif
+    // Suppress the warning about a nonliteral format string.
+    // Cannot use auto because of a bug in MinGW (#1532).
+    int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF;
+    int result = precision >= 0
+                     ? snprintf_ptr(begin, capacity, format, precision, value)
+                     : snprintf_ptr(begin, capacity, format, value);
+    if (result < 0) {
+      buf.reserve(buf.capacity() + 1);  // The buffer will grow exponentially.
+      continue;
+    }
+    auto size = to_unsigned(result);
+    // Size equal to capacity means that the last character was truncated.
+    if (size >= capacity) {
+      buf.reserve(size + offset + 1);  // Add 1 for the terminating '\0'.
+      continue;
+    }
+    auto is_digit = [](char c) { return c >= '0' && c <= '9'; };
+    if (specs.format == float_format::fixed) {
+      if (precision == 0) {
+        buf.resize(size);
+        return 0;
+      }
+      // Find and remove the decimal point.
+      auto end = begin + size, p = end;
+      do {
+        --p;
+      } while (is_digit(*p));
+      int fraction_size = static_cast<int>(end - p - 1);
+      std::memmove(p, p + 1, to_unsigned(fraction_size));
+      buf.resize(size - 1);
+      return -fraction_size;
+    }
+    if (specs.format == float_format::hex) {
+      buf.resize(size + offset);
+      return 0;
+    }
+    // Find and parse the exponent.
+    auto end = begin + size, exp_pos = end;
+    do {
+      --exp_pos;
+    } while (*exp_pos != 'e');
+    char sign = exp_pos[1];
+    assert(sign == '+' || sign == '-');
+    int exp = 0;
+    auto p = exp_pos + 2;  // Skip 'e' and sign.
+    do {
+      assert(is_digit(*p));
+      exp = exp * 10 + (*p++ - '0');
+    } while (p != end);
+    if (sign == '-') exp = -exp;
+    int fraction_size = 0;
+    if (exp_pos != begin + 1) {
+      // Remove trailing zeros.
+      auto fraction_end = exp_pos - 1;
+      while (*fraction_end == '0') --fraction_end;
+      // Move the fractional part left to get rid of the decimal point.
+      fraction_size = static_cast<int>(fraction_end - begin - 1);
+      std::memmove(begin + 1, begin + 2, to_unsigned(fraction_size));
+    }
+    buf.resize(to_unsigned(fraction_size) + offset + 1);
+    return exp - fraction_size;
+  }
+}
+
+// A public domain branchless UTF-8 decoder by Christopher Wellons:
+// https://github.com/skeeto/branchless-utf8
+/* Decode the next character, c, from buf, reporting errors in e.
+ *
+ * Since this is a branchless decoder, four bytes will be read from the
+ * buffer regardless of the actual length of the next character. This
+ * means the buffer _must_ have at least three bytes of zero padding
+ * following the end of the data stream.
+ *
+ * Errors are reported in e, which will be non-zero if the parsed
+ * character was somehow invalid: invalid byte sequence, non-canonical
+ * encoding, or a surrogate half.
+ *
+ * The function returns a pointer to the next character. When an error
+ * occurs, this pointer will be a guess that depends on the particular
+ * error, but it will always advance at least one byte.
+ */
+FMT_FUNC const char* utf8_decode(const char* buf, uint32_t* c, int* e) {
+  static const char lengths[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+                                 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+                                 0, 0, 2, 2, 2, 2, 3, 3, 4, 0};
+  static const int masks[] = {0x00, 0x7f, 0x1f, 0x0f, 0x07};
+  static const uint32_t mins[] = {4194304, 0, 128, 2048, 65536};
+  static const int shiftc[] = {0, 18, 12, 6, 0};
+  static const int shifte[] = {0, 6, 4, 2, 0};
+
+  auto s = reinterpret_cast<const unsigned char*>(buf);
+  int len = lengths[s[0] >> 3];
+
+  // Compute the pointer to the next character early so that the next
+  // iteration can start working on the next character. Neither Clang
+  // nor GCC figure out this reordering on their own.
+  const char* next = buf + len + !len;
+
+  // Assume a four-byte character and load four bytes. Unused bits are
+  // shifted out.
+  *c = uint32_t(s[0] & masks[len]) << 18;
+  *c |= uint32_t(s[1] & 0x3f) << 12;
+  *c |= uint32_t(s[2] & 0x3f) << 6;
+  *c |= uint32_t(s[3] & 0x3f) << 0;
+  *c >>= shiftc[len];
+
+  // Accumulate the various error conditions.
+  *e = (*c < mins[len]) << 6;       // non-canonical encoding
+  *e |= ((*c >> 11) == 0x1b) << 7;  // surrogate half?
+  *e |= (*c > 0x10FFFF) << 8;       // out of range?
+  *e |= (s[1] & 0xc0) >> 2;
+  *e |= (s[2] & 0xc0) >> 4;
+  *e |= (s[3]) >> 6;
+  *e ^= 0x2a;  // top two bits of each tail byte correct?
+  *e >>= shifte[len];
+
+  return next;
+}
+}  // namespace detail
+
+template <> struct formatter<detail::bigint> {
+  format_parse_context::iterator parse(format_parse_context& ctx) {
+    return ctx.begin();
+  }
+
+  format_context::iterator format(const detail::bigint& n,
+                                  format_context& ctx) {
+    auto out = ctx.out();
+    bool first = true;
+    for (auto i = n.bigits_.size(); i > 0; --i) {
+      auto value = n.bigits_[i - 1u];
+      if (first) {
+        out = format_to(out, "{:x}", value);
+        first = false;
+        continue;
+      }
+      out = format_to(out, "{:08x}", value);
+    }
+    if (n.exp_ > 0)
+      out = format_to(out, "p{}", n.exp_ * detail::bigint::bigit_bits);
+    return out;
+  }
+};
+
+FMT_FUNC detail::utf8_to_utf16::utf8_to_utf16(string_view s) {
+  auto transcode = [this](const char* p) {
+    auto cp = uint32_t();
+    auto error = 0;
+    p = utf8_decode(p, &cp, &error);
+    if (error != 0) FMT_THROW(std::runtime_error("invalid utf8"));
+    if (cp <= 0xFFFF) {
+      buffer_.push_back(static_cast<wchar_t>(cp));
+    } else {
+      cp -= 0x10000;
+      buffer_.push_back(static_cast<wchar_t>(0xD800 + (cp >> 10)));
+      buffer_.push_back(static_cast<wchar_t>(0xDC00 + (cp & 0x3FF)));
+    }
+    return p;
+  };
+  auto p = s.data();
+  const size_t block_size = 4;  // utf8_decode always reads blocks of 4 chars.
+  if (s.size() >= block_size) {
+    for (auto end = p + s.size() - block_size + 1; p < end;) p = transcode(p);
+  }
+  if (auto num_chars_left = s.data() + s.size() - p) {
+    char buf[2 * block_size - 1] = {};
+    memcpy(buf, p, to_unsigned(num_chars_left));
+    p = buf;
+    do {
+      p = transcode(p);
+    } while (p - buf < num_chars_left);
+  }
+  buffer_.push_back(0);
+}
+
+FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
+                                  string_view message) FMT_NOEXCEPT {
+  FMT_TRY {
+    memory_buffer buf;
+    buf.resize(inline_buffer_size);
+    for (;;) {
+      char* system_message = &buf[0];
+      int result =
+          detail::safe_strerror(error_code, system_message, buf.size());
+      if (result == 0) {
+        format_to(std::back_inserter(out), "{}: {}", message, system_message);
+        return;
+      }
+      if (result != ERANGE)
+        break;  // Can't get error message, report error code instead.
+      buf.resize(buf.size() * 2);
+    }
+  }
+  FMT_CATCH(...) {}
+  format_error_code(out, error_code, message);
+}
+
+FMT_FUNC void detail::error_handler::on_error(const char* message) {
+  FMT_THROW(format_error(message));
+}
+
+FMT_FUNC void report_system_error(int error_code,
+                                  fmt::string_view message) FMT_NOEXCEPT {
+  report_error(format_system_error, error_code, message);
+}
+
+struct stringifier {
+  template <typename T> FMT_INLINE std::string operator()(T value) const {
+    return to_string(value);
+  }
+  std::string operator()(basic_format_arg<format_context>::handle h) const {
+    memory_buffer buf;
+    detail::buffer<char>& base = buf;
+    format_parse_context parse_ctx({});
+    format_context format_ctx(std::back_inserter(base), {}, {});
+    h.format(parse_ctx, format_ctx);
+    return to_string(buf);
+  }
+};
+
+FMT_FUNC std::string detail::vformat(string_view format_str, format_args args) {
+  if (format_str.size() == 2 && equal2(format_str.data(), "{}")) {
+    auto arg = args.get(0);
+    if (!arg) error_handler().on_error("argument not found");
+    return visit_format_arg(stringifier(), arg);
+  }
+  memory_buffer buffer;
+  detail::vformat_to(buffer, format_str, args);
+  return to_string(buffer);
+}
+
+FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) {
+  memory_buffer buffer;
+  detail::vformat_to(buffer, format_str,
+                     basic_format_args<buffer_context<char>>(args));
+#ifdef _WIN32
+  auto fd = _fileno(f);
+  if (_isatty(fd)) {
+    detail::utf8_to_utf16 u16(string_view(buffer.data(), buffer.size()));
+    auto written = DWORD();
+    if (!WriteConsoleW(reinterpret_cast<HANDLE>(_get_osfhandle(fd)),
+                       u16.c_str(), static_cast<DWORD>(u16.size()), &written,
+                       nullptr)) {
+      FMT_THROW(format_error("failed to write to console"));
+    }
+    return;
+  }
+#endif
+  detail::fwrite_fully(buffer.data(), 1, buffer.size(), f);
+}
+
+#ifdef _WIN32
+// Print assuming legacy (non-Unicode) encoding.
+FMT_FUNC void detail::vprint_mojibake(std::FILE* f, string_view format_str,
+                                      format_args args) {
+  memory_buffer buffer;
+  detail::vformat_to(buffer, format_str,
+                     basic_format_args<buffer_context<char>>(args));
+  fwrite_fully(buffer.data(), 1, buffer.size(), f);
+}
+#endif
+
+FMT_FUNC void vprint(string_view format_str, format_args args) {
+  vprint(stdout, format_str, args);
+}
+
+FMT_END_NAMESPACE
+
+#ifdef _MSC_VER
+#  pragma warning(pop)
+#endif
+
+#endif  // FMT_FORMAT_INL_H_

spdlog/fmt/bundled/locale.h

+// Formatting library for C++ - std::locale support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_LOCALE_H_
+#define FMT_LOCALE_H_
+
+#include <locale>
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+template <typename Char>
+typename buffer_context<Char>::iterator vformat_to(
+    const std::locale& loc, buffer<Char>& buf,
+    basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  using af = arg_formatter<typename buffer_context<Char>::iterator, Char>;
+  return vformat_to<af>(std::back_inserter(buf), to_string_view(format_str),
+                        args, detail::locale_ref(loc));
+}
+
+template <typename Char>
+std::basic_string<Char> vformat(
+    const std::locale& loc, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buffer;
+  detail::vformat_to(loc, buffer, format_str, args);
+  return fmt::to_string(buffer);
+}
+}  // namespace detail
+
+template <typename S, typename Char = char_t<S>>
+inline std::basic_string<Char> vformat(
+    const std::locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  return detail::vformat(loc, to_string_view(format_str), args);
+}
+
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline std::basic_string<Char> format(const std::locale& loc,
+                                      const S& format_str, Args&&... args) {
+  return detail::vformat(
+      loc, to_string_view(format_str),
+      detail::make_args_checked<Args...>(format_str, args...));
+}
+
+template <typename S, typename OutputIt, typename... Args,
+          typename Char = enable_if_t<
+              detail::is_output_iterator<OutputIt>::value, char_t<S>>>
+inline OutputIt vformat_to(
+    OutputIt out, const std::locale& loc, const S& format_str,
+    format_args_t<type_identity_t<OutputIt>, Char> args) {
+  using af = detail::arg_formatter<OutputIt, Char>;
+  return vformat_to<af>(out, to_string_view(format_str), args,
+                        detail::locale_ref(loc));
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&&
+                            detail::is_string<S>::value)>
+inline OutputIt format_to(OutputIt out, const std::locale& loc,
+                          const S& format_str, Args&&... args) {
+  detail::check_format_string<Args...>(format_str);
+  using context = format_context_t<OutputIt, char_t<S>>;
+  format_arg_store<context, Args...> as{args...};
+  return vformat_to(out, loc, to_string_view(format_str),
+                    basic_format_args<context>(as));
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_LOCALE_H_

spdlog/fmt/bundled/os.h

+// Formatting library for C++ - optional OS-specific functionality
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_OS_H_
+#define FMT_OS_H_
+
+#if defined(__MINGW32__) || defined(__CYGWIN__)
+// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
+#  undef __STRICT_ANSI__
+#endif
+
+#include <cerrno>
+#include <clocale>  // for locale_t
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>  // for strtod_l
+
+#if defined __APPLE__ || defined(__FreeBSD__)
+#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
+#endif
+
+#include "format.h"
+
+// UWP doesn't provide _pipe.
+#if FMT_HAS_INCLUDE("winapifamily.h")
+#  include <winapifamily.h>
+#endif
+#if FMT_HAS_INCLUDE("fcntl.h") && \
+    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#  include <fcntl.h>  // for O_RDONLY
+#  define FMT_USE_FCNTL 1
+#else
+#  define FMT_USE_FCNTL 0
+#endif
+
+#ifndef FMT_POSIX
+#  if defined(_WIN32) && !defined(__MINGW32__)
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX(call) _##call
+#  else
+#    define FMT_POSIX(call) call
+#  endif
+#endif
+
+// Calls to system functions are wrapped in FMT_SYSTEM for testability.
+#ifdef FMT_SYSTEM
+#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
+#else
+#  define FMT_SYSTEM(call) ::call
+#  ifdef _WIN32
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX_CALL(call) ::_##call
+#  else
+#    define FMT_POSIX_CALL(call) ::call
+#  endif
+#endif
+
+// Retries the expression while it evaluates to error_result and errno
+// equals to EINTR.
+#ifndef _WIN32
+#  define FMT_RETRY_VAL(result, expression, error_result) \
+    do {                                                  \
+      (result) = (expression);                            \
+    } while ((result) == (error_result) && errno == EINTR)
+#else
+#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+
+FMT_BEGIN_NAMESPACE
+
+/**
+  \rst
+  A reference to a null-terminated string. It can be constructed from a C
+  string or ``std::string``.
+
+  You can use one of the following type aliases for common character types:
+
+  +---------------+-----------------------------+
+  | Type          | Definition                  |
+  +===============+=============================+
+  | cstring_view  | basic_cstring_view<char>    |
+  +---------------+-----------------------------+
+  | wcstring_view | basic_cstring_view<wchar_t> |
+  +---------------+-----------------------------+
+
+  This class is most useful as a parameter type to allow passing
+  different types of strings to a function, for example::
+
+    template <typename... Args>
+    std::string format(cstring_view format_str, const Args & ... args);
+
+    format("{}", 42);
+    format(std::string("{}"), 42);
+  \endrst
+ */
+template <typename Char> class basic_cstring_view {
+ private:
+  const Char* data_;
+
+ public:
+  /** Constructs a string reference object from a C string. */
+  basic_cstring_view(const Char* s) : data_(s) {}
+
+  /**
+    \rst
+    Constructs a string reference from an ``std::string`` object.
+    \endrst
+   */
+  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
+
+  /** Returns the pointer to a C string. */
+  const Char* c_str() const { return data_; }
+};
+
+using cstring_view = basic_cstring_view<char>;
+using wcstring_view = basic_cstring_view<wchar_t>;
+
+// An error code.
+class error_code {
+ private:
+  int value_;
+
+ public:
+  explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
+
+  int get() const FMT_NOEXCEPT { return value_; }
+};
+
+#ifdef _WIN32
+namespace detail {
+// A converter from UTF-16 to UTF-8.
+// It is only provided for Windows since other systems support UTF-8 natively.
+class utf16_to_utf8 {
+ private:
+  memory_buffer buffer_;
+
+ public:
+  utf16_to_utf8() {}
+  FMT_API explicit utf16_to_utf8(wstring_view s);
+  operator string_view() const { return string_view(&buffer_[0], size()); }
+  size_t size() const { return buffer_.size() - 1; }
+  const char* c_str() const { return &buffer_[0]; }
+  std::string str() const { return std::string(&buffer_[0], size()); }
+
+  // Performs conversion returning a system error code instead of
+  // throwing exception on conversion error. This method may still throw
+  // in case of memory allocation error.
+  FMT_API int convert(wstring_view s);
+};
+
+FMT_API void format_windows_error(buffer<char>& out, int error_code,
+                                  string_view message) FMT_NOEXCEPT;
+}  // namespace detail
+
+/** A Windows error. */
+class windows_error : public system_error {
+ private:
+  FMT_API void init(int error_code, string_view format_str, format_args args);
+
+ public:
+  /**
+   \rst
+   Constructs a :class:`fmt::windows_error` object with the description
+   of the form
+
+   .. parsed-literal::
+     *<message>*: *<system-message>*
+
+   where *<message>* is the formatted message and *<system-message>* is the
+   system message corresponding to the error code.
+   *error_code* is a Windows error code as given by ``GetLastError``.
+   If *error_code* is not a valid error code such as -1, the system message
+   will look like "error -1".
+
+   **Example**::
+
+     // This throws a windows_error with the description
+     //   cannot open file 'madeup': The system cannot find the file specified.
+     // or similar (system message may vary).
+     const char *filename = "madeup";
+     LPOFSTRUCT of = LPOFSTRUCT();
+     HFILE file = OpenFile(filename, &of, OF_READ);
+     if (file == HFILE_ERROR) {
+       throw fmt::windows_error(GetLastError(),
+                                "cannot open file '{}'", filename);
+     }
+   \endrst
+  */
+  template <typename... Args>
+  windows_error(int error_code, string_view message, const Args&... args) {
+    init(error_code, message, make_format_args(args...));
+  }
+};
+
+// Reports a Windows error without throwing an exception.
+// Can be used to report errors from destructors.
+FMT_API void report_windows_error(int error_code,
+                                  string_view message) FMT_NOEXCEPT;
+#endif  // _WIN32
+
+// A buffered file.
+class buffered_file {
+ private:
+  FILE* file_;
+
+  friend class file;
+
+  explicit buffered_file(FILE* f) : file_(f) {}
+
+ public:
+  buffered_file(const buffered_file&) = delete;
+  void operator=(const buffered_file&) = delete;
+
+  // Constructs a buffered_file object which doesn't represent any file.
+  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~buffered_file() FMT_NOEXCEPT;
+
+ public:
+  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+    other.file_ = nullptr;
+  }
+
+  buffered_file& operator=(buffered_file&& other) {
+    close();
+    file_ = other.file_;
+    other.file_ = nullptr;
+    return *this;
+  }
+
+  // Opens a file.
+  FMT_API buffered_file(cstring_view filename, cstring_view mode);
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the pointer to a FILE object representing this file.
+  FILE* get() const FMT_NOEXCEPT { return file_; }
+
+  // We place parentheses around fileno to workaround a bug in some versions
+  // of MinGW that define fileno as a macro.
+  FMT_API int(fileno)() const;
+
+  void vprint(string_view format_str, format_args args) {
+    fmt::vprint(file_, format_str, args);
+  }
+
+  template <typename... Args>
+  inline void print(string_view format_str, const Args&... args) {
+    vprint(format_str, make_format_args(args...));
+  }
+};
+
+#if FMT_USE_FCNTL
+// A file. Closed file is represented by a file object with descriptor -1.
+// Methods that are not declared with FMT_NOEXCEPT may throw
+// fmt::system_error in case of failure. Note that some errors such as
+// closing the file multiple times will cause a crash on Windows rather
+// than an exception. You can get standard behavior by overriding the
+// invalid parameter handler with _set_invalid_parameter_handler.
+class file {
+ private:
+  int fd_;  // File descriptor.
+
+  // Constructs a file object with a given descriptor.
+  explicit file(int fd) : fd_(fd) {}
+
+ public:
+  // Possible values for the oflag argument to the constructor.
+  enum {
+    RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
+    WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
+    RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
+    CREATE = FMT_POSIX(O_CREAT)    // Create if the file doesn't exist.
+  };
+
+  // Constructs a file object which doesn't represent any file.
+  file() FMT_NOEXCEPT : fd_(-1) {}
+
+  // Opens a file and constructs a file object representing this file.
+  FMT_API file(cstring_view path, int oflag);
+
+ public:
+  file(const file&) = delete;
+  void operator=(const file&) = delete;
+
+  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
+
+  file& operator=(file&& other) FMT_NOEXCEPT {
+    close();
+    fd_ = other.fd_;
+    other.fd_ = -1;
+    return *this;
+  }
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~file() FMT_NOEXCEPT;
+
+  // Returns the file descriptor.
+  int descriptor() const FMT_NOEXCEPT { return fd_; }
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the file size. The size has signed type for consistency with
+  // stat::st_size.
+  FMT_API long long size() const;
+
+  // Attempts to read count bytes from the file into the specified buffer.
+  FMT_API size_t read(void* buffer, size_t count);
+
+  // Attempts to write count bytes from the specified buffer to the file.
+  FMT_API size_t write(const void* buffer, size_t count);
+
+  // Duplicates a file descriptor with the dup function and returns
+  // the duplicate as a file object.
+  FMT_API static file dup(int fd);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  FMT_API void dup2(int fd);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
+
+  // Creates a pipe setting up read_end and write_end file objects for reading
+  // and writing respectively.
+  FMT_API static void pipe(file& read_end, file& write_end);
+
+  // Creates a buffered_file object associated with this file and detaches
+  // this file object from the file.
+  FMT_API buffered_file fdopen(const char* mode);
+};
+
+// Returns the memory page size.
+long getpagesize();
+
+class direct_buffered_file;
+
+template <typename S, typename... Args>
+void print(direct_buffered_file& f, const S& format_str,
+           const Args&... args);
+
+// A buffered file with a direct buffer access and no synchronization.
+class direct_buffered_file {
+ private:
+  file file_;
+
+  enum { buffer_size = 4096 };
+  char buffer_[buffer_size];
+  int pos_;
+
+  void flush() {
+    if (pos_ == 0) return;
+    file_.write(buffer_, pos_);
+    pos_ = 0;
+  }
+
+  int free_capacity() const { return buffer_size - pos_; }
+
+ public:
+  direct_buffered_file(cstring_view path, int oflag)
+    : file_(path, oflag), pos_(0) {}
+
+  ~direct_buffered_file() {
+    flush();
+  }
+
+  void close() {
+    flush();
+    file_.close();
+  }
+
+  template <typename S, typename... Args>
+  friend void print(direct_buffered_file& f, const S& format_str,
+                    const Args&... args) {
+    // We could avoid double buffering.
+    auto buf = fmt::memory_buffer();
+    fmt::format_to(std::back_inserter(buf), format_str, args...);
+    auto remaining_pos = 0;
+    auto remaining_size = buf.size();
+    while (remaining_size > detail::to_unsigned(f.free_capacity())) {
+      auto size = f.free_capacity();
+      memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, size);
+      f.pos_ += size;
+      f.flush();
+      remaining_pos += size;
+      remaining_size -= size;
+    }
+    memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, remaining_size);
+    f.pos_ += static_cast<int>(remaining_size);
+  }
+};
+#endif  // FMT_USE_FCNTL
+
+#ifdef FMT_LOCALE
+// A "C" numeric locale.
+class locale {
+ private:
+#  ifdef _WIN32
+  using locale_t = _locale_t;
+
+  static void freelocale(locale_t loc) { _free_locale(loc); }
+
+  static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
+    return _strtod_l(nptr, endptr, loc);
+  }
+#  endif
+
+  locale_t locale_;
+
+ public:
+  using type = locale_t;
+  locale(const locale&) = delete;
+  void operator=(const locale&) = delete;
+
+  locale() {
+#  ifndef _WIN32
+    locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
+#  else
+    locale_ = _create_locale(LC_NUMERIC, "C");
+#  endif
+    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
+  }
+  ~locale() { freelocale(locale_); }
+
+  type get() const { return locale_; }
+
+  // Converts string to floating-point number and advances str past the end
+  // of the parsed input.
+  double strtod(const char*& str) const {
+    char* end = nullptr;
+    double result = strtod_l(str, &end, locale_);
+    str = end;
+    return result;
+  }
+};
+using Locale FMT_DEPRECATED_ALIAS = locale;
+#endif  // FMT_LOCALE
+FMT_END_NAMESPACE
+
+#endif  // FMT_OS_H_

spdlog/fmt/bundled/ostream.h

+// Formatting library for C++ - std::ostream support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_OSTREAM_H_
+#define FMT_OSTREAM_H_
+
+#include <ostream>
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+template <typename Char> class basic_printf_parse_context;
+template <typename OutputIt, typename Char> class basic_printf_context;
+
+namespace detail {
+
+template <class Char> class formatbuf : public std::basic_streambuf<Char> {
+ private:
+  using int_type = typename std::basic_streambuf<Char>::int_type;
+  using traits_type = typename std::basic_streambuf<Char>::traits_type;
+
+  buffer<Char>& buffer_;
+
+ public:
+  formatbuf(buffer<Char>& buf) : buffer_(buf) {}
+
+ protected:
+  // The put-area is actually always empty. This makes the implementation
+  // simpler and has the advantage that the streambuf and the buffer are always
+  // in sync and sputc never writes into uninitialized memory. The obvious
+  // disadvantage is that each call to sputc always results in a (virtual) call
+  // to overflow. There is no disadvantage here for sputn since this always
+  // results in a call to xsputn.
+
+  int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
+    if (!traits_type::eq_int_type(ch, traits_type::eof()))
+      buffer_.push_back(static_cast<Char>(ch));
+    return ch;
+  }
+
+  std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
+    buffer_.append(s, s + count);
+    return count;
+  }
+};
+
+template <typename Char> struct test_stream : std::basic_ostream<Char> {
+ private:
+  // Hide all operator<< from std::basic_ostream<Char>.
+  void_t<> operator<<(null<>);
+  void_t<> operator<<(const Char*);
+
+  template <typename T, FMT_ENABLE_IF(std::is_convertible<T, int>::value &&
+                                      !std::is_enum<T>::value)>
+  void_t<> operator<<(T);
+};
+
+// Checks if T has a user-defined operator<< (e.g. not a member of
+// std::ostream).
+template <typename T, typename Char> class is_streamable {
+ private:
+  template <typename U>
+  static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
+                                              << std::declval<U>()),
+                                     void_t<>>::value>
+  test(int);
+
+  template <typename> static std::false_type test(...);
+
+  using result = decltype(test<T>(0));
+
+ public:
+  static const bool value = result::value;
+};
+
+// Write the content of buf to os.
+template <typename Char>
+void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
+  const Char* buf_data = buf.data();
+  using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
+  unsigned_streamsize size = buf.size();
+  unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
+  do {
+    unsigned_streamsize n = size <= max_size ? size : max_size;
+    os.write(buf_data, static_cast<std::streamsize>(n));
+    buf_data += n;
+    size -= n;
+  } while (size != 0);
+}
+
+template <typename Char, typename T>
+void format_value(buffer<Char>& buf, const T& value,
+                  locale_ref loc = locale_ref()) {
+  formatbuf<Char> format_buf(buf);
+  std::basic_ostream<Char> output(&format_buf);
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
+  if (loc) output.imbue(loc.get<std::locale>());
+#endif
+  output << value;
+  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+  buf.resize(buf.size());
+}
+
+// Formats an object of type T that has an overloaded ostream operator<<.
+template <typename T, typename Char>
+struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
+    : private formatter<basic_string_view<Char>, Char> {
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    return formatter<basic_string_view<Char>, Char>::parse(ctx);
+  }
+  template <typename ParseCtx,
+            FMT_ENABLE_IF(std::is_same<
+                          ParseCtx, basic_printf_parse_context<Char>>::value)>
+  auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
+      -> OutputIt {
+    basic_memory_buffer<Char> buffer;
+    format_value(buffer, value, ctx.locale());
+    basic_string_view<Char> str(buffer.data(), buffer.size());
+    return formatter<basic_string_view<Char>, Char>::format(str, ctx);
+  }
+  template <typename OutputIt>
+  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
+      -> OutputIt {
+    basic_memory_buffer<Char> buffer;
+    format_value(buffer, value, ctx.locale());
+    return std::copy(buffer.begin(), buffer.end(), ctx.out());
+  }
+};
+}  // namespace detail
+
+template <typename Char>
+void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buffer;
+  detail::vformat_to(buffer, format_str, args);
+  detail::write_buffer(os, buffer);
+}
+
+/**
+  \rst
+  Prints formatted data to the stream *os*.
+
+  **Example**::
+
+    fmt::print(cerr, "Don't {}!", "panic");
+  \endrst
+ */
+template <typename S, typename... Args,
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
+void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
+  vprint(os, to_string_view(format_str),
+         detail::make_args_checked<Args...>(format_str, args...));
+}
+FMT_END_NAMESPACE
+
+#endif  // FMT_OSTREAM_H_

spdlog/fmt/bundled/posix.h

+#include "os.h"
+#warning "fmt/posix.h is deprecated; use fmt/os.h instead"

spdlog/fmt/bundled/printf.h

+// Formatting library for C++ - legacy printf implementation
+//
+// Copyright (c) 2012 - 2016, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_PRINTF_H_
+#define FMT_PRINTF_H_
+
+#include <algorithm>  // std::max
+#include <limits>     // std::numeric_limits
+
+#include "ostream.h"
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+// Checks if a value fits in int - used to avoid warnings about comparing
+// signed and unsigned integers.
+template <bool IsSigned> struct int_checker {
+  template <typename T> static bool fits_in_int(T value) {
+    unsigned max = max_value<int>();
+    return value <= max;
+  }
+  static bool fits_in_int(bool) { return true; }
+};
+
+template <> struct int_checker<true> {
+  template <typename T> static bool fits_in_int(T value) {
+    return value >= (std::numeric_limits<int>::min)() &&
+           value <= max_value<int>();
+  }
+  static bool fits_in_int(int) { return true; }
+};
+
+class printf_precision_handler {
+ public:
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  int operator()(T value) {
+    if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
+      FMT_THROW(format_error("number is too big"));
+    return (std::max)(static_cast<int>(value), 0);
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  int operator()(T) {
+    FMT_THROW(format_error("precision is not integer"));
+    return 0;
+  }
+};
+
+// An argument visitor that returns true iff arg is a zero integer.
+class is_zero_int {
+ public:
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  bool operator()(T value) {
+    return value == 0;
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  bool operator()(T) {
+    return false;
+  }
+};
+
+template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {};
+
+template <> struct make_unsigned_or_bool<bool> { using type = bool; };
+
+template <typename T, typename Context> class arg_converter {
+ private:
+  using char_type = typename Context::char_type;
+
+  basic_format_arg<Context>& arg_;
+  char_type type_;
+
+ public:
+  arg_converter(basic_format_arg<Context>& arg, char_type type)
+      : arg_(arg), type_(type) {}
+
+  void operator()(bool value) {
+    if (type_ != 's') operator()<bool>(value);
+  }
+
+  template <typename U, FMT_ENABLE_IF(std::is_integral<U>::value)>
+  void operator()(U value) {
+    bool is_signed = type_ == 'd' || type_ == 'i';
+    using target_type = conditional_t<std::is_same<T, void>::value, U, T>;
+    if (const_check(sizeof(target_type) <= sizeof(int))) {
+      // Extra casts are used to silence warnings.
+      if (is_signed) {
+        arg_ = detail::make_arg<Context>(
+            static_cast<int>(static_cast<target_type>(value)));
+      } else {
+        using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
+        arg_ = detail::make_arg<Context>(
+            static_cast<unsigned>(static_cast<unsigned_type>(value)));
+      }
+    } else {
+      if (is_signed) {
+        // glibc's printf doesn't sign extend arguments of smaller types:
+        //   std::printf("%lld", -42);  // prints "4294967254"
+        // but we don't have to do the same because it's a UB.
+        arg_ = detail::make_arg<Context>(static_cast<long long>(value));
+      } else {
+        arg_ = detail::make_arg<Context>(
+            static_cast<typename make_unsigned_or_bool<U>::type>(value));
+      }
+    }
+  }
+
+  template <typename U, FMT_ENABLE_IF(!std::is_integral<U>::value)>
+  void operator()(U) {}  // No conversion needed for non-integral types.
+};
+
+// Converts an integer argument to T for printf, if T is an integral type.
+// If T is void, the argument is converted to corresponding signed or unsigned
+// type depending on the type specifier: 'd' and 'i' - signed, other -
+// unsigned).
+template <typename T, typename Context, typename Char>
+void convert_arg(basic_format_arg<Context>& arg, Char type) {
+  visit_format_arg(arg_converter<T, Context>(arg, type), arg);
+}
+
+// Converts an integer argument to char for printf.
+template <typename Context> class char_converter {
+ private:
+  basic_format_arg<Context>& arg_;
+
+ public:
+  explicit char_converter(basic_format_arg<Context>& arg) : arg_(arg) {}
+
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  void operator()(T value) {
+    arg_ = detail::make_arg<Context>(
+        static_cast<typename Context::char_type>(value));
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  void operator()(T) {}  // No conversion needed for non-integral types.
+};
+
+// An argument visitor that return a pointer to a C string if argument is a
+// string or null otherwise.
+template <typename Char> struct get_cstring {
+  template <typename T> const Char* operator()(T) { return nullptr; }
+  const Char* operator()(const Char* s) { return s; }
+};
+
+// Checks if an argument is a valid printf width specifier and sets
+// left alignment if it is negative.
+template <typename Char> class printf_width_handler {
+ private:
+  using format_specs = basic_format_specs<Char>;
+
+  format_specs& specs_;
+
+ public:
+  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  unsigned operator()(T value) {
+    auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
+    if (detail::is_negative(value)) {
+      specs_.align = align::left;
+      width = 0 - width;
+    }
+    unsigned int_max = max_value<int>();
+    if (width > int_max) FMT_THROW(format_error("number is too big"));
+    return static_cast<unsigned>(width);
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  unsigned operator()(T) {
+    FMT_THROW(format_error("width is not integer"));
+    return 0;
+  }
+};
+
+template <typename Char, typename Context>
+void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
+             basic_format_args<Context> args) {
+  Context(std::back_inserter(buf), format, args).format();
+}
+}  // namespace detail
+
+// For printing into memory_buffer.
+template <typename Char, typename Context>
+FMT_DEPRECATED void printf(detail::buffer<Char>& buf,
+                           basic_string_view<Char> format,
+                           basic_format_args<Context> args) {
+  return detail::vprintf(buf, format, args);
+}
+using detail::vprintf;
+
+template <typename Char>
+class basic_printf_parse_context : public basic_format_parse_context<Char> {
+  using basic_format_parse_context<Char>::basic_format_parse_context;
+};
+template <typename OutputIt, typename Char> class basic_printf_context;
+
+/**
+  \rst
+  The ``printf`` argument formatter.
+  \endrst
+ */
+template <typename OutputIt, typename Char>
+class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
+ public:
+  using iterator = OutputIt;
+
+ private:
+  using char_type = Char;
+  using base = detail::arg_formatter_base<OutputIt, Char>;
+  using context_type = basic_printf_context<OutputIt, Char>;
+
+  context_type& context_;
+
+  void write_null_pointer(char) {
+    this->specs()->type = 0;
+    this->write("(nil)");
+  }
+
+  void write_null_pointer(wchar_t) {
+    this->specs()->type = 0;
+    this->write(L"(nil)");
+  }
+
+ public:
+  using format_specs = typename base::format_specs;
+
+  /**
+    \rst
+    Constructs an argument formatter object.
+    *buffer* is a reference to the output buffer and *specs* contains format
+    specifier information for standard argument types.
+    \endrst
+   */
+  printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
+      : base(iter, &specs, detail::locale_ref()), context_(ctx) {}
+
+  template <typename T, FMT_ENABLE_IF(fmt::detail::is_integral<T>::value)>
+  iterator operator()(T value) {
+    // MSVC2013 fails to compile separate overloads for bool and char_type so
+    // use std::is_same instead.
+    if (std::is_same<T, bool>::value) {
+      format_specs& fmt_specs = *this->specs();
+      if (fmt_specs.type != 's') return base::operator()(value ? 1 : 0);
+      fmt_specs.type = 0;
+      this->write(value != 0);
+    } else if (std::is_same<T, char_type>::value) {
+      format_specs& fmt_specs = *this->specs();
+      if (fmt_specs.type && fmt_specs.type != 'c')
+        return (*this)(static_cast<int>(value));
+      fmt_specs.sign = sign::none;
+      fmt_specs.alt = false;
+      fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
+      // align::numeric needs to be overwritten here since the '0' flag is
+      // ignored for non-numeric types
+      if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
+        fmt_specs.align = align::right;
+      return base::operator()(value);
+    } else {
+      return base::operator()(value);
+    }
+    return this->out();
+  }
+
+  template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+  iterator operator()(T value) {
+    return base::operator()(value);
+  }
+
+  /** Formats a null-terminated C string. */
+  iterator operator()(const char* value) {
+    if (value)
+      base::operator()(value);
+    else if (this->specs()->type == 'p')
+      write_null_pointer(char_type());
+    else
+      this->write("(null)");
+    return this->out();
+  }
+
+  /** Formats a null-terminated wide C string. */
+  iterator operator()(const wchar_t* value) {
+    if (value)
+      base::operator()(value);
+    else if (this->specs()->type == 'p')
+      write_null_pointer(char_type());
+    else
+      this->write(L"(null)");
+    return this->out();
+  }
+
+  iterator operator()(basic_string_view<char_type> value) {
+    return base::operator()(value);
+  }
+
+  iterator operator()(monostate value) { return base::operator()(value); }
+
+  /** Formats a pointer. */
+  iterator operator()(const void* value) {
+    if (value) return base::operator()(value);
+    this->specs()->type = 0;
+    write_null_pointer(char_type());
+    return this->out();
+  }
+
+  /** Formats an argument of a custom (user-defined) type. */
+  iterator operator()(typename basic_format_arg<context_type>::handle handle) {
+    handle.format(context_.parse_context(), context_);
+    return this->out();
+  }
+};
+
+template <typename T> struct printf_formatter {
+  printf_formatter() = delete;
+
+  template <typename ParseContext>
+  auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
+    detail::format_value(detail::get_container(ctx.out()), value);
+    return ctx.out();
+  }
+};
+
+/**
+ This template formats data and writes the output through an output iterator.
+ */
+template <typename OutputIt, typename Char> class basic_printf_context {
+ public:
+  /** The character type for the output. */
+  using char_type = Char;
+  using iterator = OutputIt;
+  using format_arg = basic_format_arg<basic_printf_context>;
+  using parse_context_type = basic_printf_parse_context<Char>;
+  template <typename T> using formatter_type = printf_formatter<T>;
+
+ private:
+  using format_specs = basic_format_specs<char_type>;
+
+  OutputIt out_;
+  basic_format_args<basic_printf_context> args_;
+  parse_context_type parse_ctx_;
+
+  static void parse_flags(format_specs& specs, const Char*& it,
+                          const Char* end);
+
+  // Returns the argument with specified index or, if arg_index is -1, the next
+  // argument.
+  format_arg get_arg(int arg_index = -1);
+
+  // Parses argument index, flags and width and returns the argument index.
+  int parse_header(const Char*& it, const Char* end, format_specs& specs);
+
+ public:
+  /**
+   \rst
+   Constructs a ``printf_context`` object. References to the arguments are
+   stored in the context object so make sure they have appropriate lifetimes.
+   \endrst
+   */
+  basic_printf_context(OutputIt out, basic_string_view<char_type> format_str,
+                       basic_format_args<basic_printf_context> args)
+      : out_(out), args_(args), parse_ctx_(format_str) {}
+
+  OutputIt out() { return out_; }
+  void advance_to(OutputIt it) { out_ = it; }
+
+  detail::locale_ref locale() { return {}; }
+
+  format_arg arg(int id) const { return args_.get(id); }
+
+  parse_context_type& parse_context() { return parse_ctx_; }
+
+  FMT_CONSTEXPR void on_error(const char* message) {
+    parse_ctx_.on_error(message);
+  }
+
+  /** Formats stored arguments and writes the output to the range. */
+  template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>>
+  OutputIt format();
+};
+
+template <typename OutputIt, typename Char>
+void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
+                                                       const Char*& it,
+                                                       const Char* end) {
+  for (; it != end; ++it) {
+    switch (*it) {
+    case '-':
+      specs.align = align::left;
+      break;
+    case '+':
+      specs.sign = sign::plus;
+      break;
+    case '0':
+      specs.fill[0] = '0';
+      break;
+    case ' ':
+      if (specs.sign != sign::plus) {
+        specs.sign = sign::space;
+      }
+      break;
+    case '#':
+      specs.alt = true;
+      break;
+    default:
+      return;
+    }
+  }
+}
+
+template <typename OutputIt, typename Char>
+typename basic_printf_context<OutputIt, Char>::format_arg
+basic_printf_context<OutputIt, Char>::get_arg(int arg_index) {
+  if (arg_index < 0)
+    arg_index = parse_ctx_.next_arg_id();
+  else
+    parse_ctx_.check_arg_id(--arg_index);
+  return detail::get_arg(*this, arg_index);
+}
+
+template <typename OutputIt, typename Char>
+int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
+                                                       const Char* end,
+                                                       format_specs& specs) {
+  int arg_index = -1;
+  char_type c = *it;
+  if (c >= '0' && c <= '9') {
+    // Parse an argument index (if followed by '$') or a width possibly
+    // preceded with '0' flag(s).
+    detail::error_handler eh;
+    int value = parse_nonnegative_int(it, end, eh);
+    if (it != end && *it == '$') {  // value is an argument index
+      ++it;
+      arg_index = value;
+    } else {
+      if (c == '0') specs.fill[0] = '0';
+      if (value != 0) {
+        // Nonzero value means that we parsed width and don't need to
+        // parse it or flags again, so return now.
+        specs.width = value;
+        return arg_index;
+      }
+    }
+  }
+  parse_flags(specs, it, end);
+  // Parse width.
+  if (it != end) {
+    if (*it >= '0' && *it <= '9') {
+      detail::error_handler eh;
+      specs.width = parse_nonnegative_int(it, end, eh);
+    } else if (*it == '*') {
+      ++it;
+      specs.width = static_cast<int>(visit_format_arg(
+          detail::printf_width_handler<char_type>(specs), get_arg()));
+    }
+  }
+  return arg_index;
+}
+
+template <typename OutputIt, typename Char>
+template <typename ArgFormatter>
+OutputIt basic_printf_context<OutputIt, Char>::format() {
+  auto out = this->out();
+  const Char* start = parse_ctx_.begin();
+  const Char* end = parse_ctx_.end();
+  auto it = start;
+  while (it != end) {
+    char_type c = *it++;
+    if (c != '%') continue;
+    if (it != end && *it == c) {
+      out = std::copy(start, it, out);
+      start = ++it;
+      continue;
+    }
+    out = std::copy(start, it - 1, out);
+
+    format_specs specs;
+    specs.align = align::right;
+
+    // Parse argument index, flags and width.
+    int arg_index = parse_header(it, end, specs);
+    if (arg_index == 0) on_error("argument not found");
+
+    // Parse precision.
+    if (it != end && *it == '.') {
+      ++it;
+      c = it != end ? *it : 0;
+      if ('0' <= c && c <= '9') {
+        detail::error_handler eh;
+        specs.precision = parse_nonnegative_int(it, end, eh);
+      } else if (c == '*') {
+        ++it;
+        specs.precision = static_cast<int>(
+            visit_format_arg(detail::printf_precision_handler(), get_arg()));
+      } else {
+        specs.precision = 0;
+      }
+    }
+
+    format_arg arg = get_arg(arg_index);
+    // For d, i, o, u, x, and X conversion specifiers, if a precision is
+    // specified, the '0' flag is ignored
+    if (specs.precision >= 0 && arg.is_integral())
+      specs.fill[0] =
+          ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
+    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
+      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+      auto str_end = str + specs.precision;
+      auto nul = std::find(str, str_end, Char());
+      arg = detail::make_arg<basic_printf_context>(basic_string_view<Char>(
+          str,
+          detail::to_unsigned(nul != str_end ? nul - str : specs.precision)));
+    }
+    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
+      specs.alt = false;
+    if (specs.fill[0] == '0') {
+      if (arg.is_arithmetic() && specs.align != align::left)
+        specs.align = align::numeric;
+      else
+        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types or if '-'
+                              // flag is also present.
+    }
+
+    // Parse length and convert the argument to the required type.
+    c = it != end ? *it++ : 0;
+    char_type t = it != end ? *it : 0;
+    using detail::convert_arg;
+    switch (c) {
+    case 'h':
+      if (t == 'h') {
+        ++it;
+        t = it != end ? *it : 0;
+        convert_arg<signed char>(arg, t);
+      } else {
+        convert_arg<short>(arg, t);
+      }
+      break;
+    case 'l':
+      if (t == 'l') {
+        ++it;
+        t = it != end ? *it : 0;
+        convert_arg<long long>(arg, t);
+      } else {
+        convert_arg<long>(arg, t);
+      }
+      break;
+    case 'j':
+      convert_arg<intmax_t>(arg, t);
+      break;
+    case 'z':
+      convert_arg<size_t>(arg, t);
+      break;
+    case 't':
+      convert_arg<std::ptrdiff_t>(arg, t);
+      break;
+    case 'L':
+      // printf produces garbage when 'L' is omitted for long double, no
+      // need to do the same.
+      break;
+    default:
+      --it;
+      convert_arg<void>(arg, c);
+    }
+
+    // Parse type.
+    if (it == end) FMT_THROW(format_error("invalid format string"));
+    specs.type = static_cast<char>(*it++);
+    if (arg.is_integral()) {
+      // Normalize type.
+      switch (specs.type) {
+      case 'i':
+      case 'u':
+        specs.type = 'd';
+        break;
+      case 'c':
+        visit_format_arg(detail::char_converter<basic_printf_context>(arg),
+                         arg);
+        break;
+      }
+    }
+
+    start = it;
+
+    // Format argument.
+    out = visit_format_arg(ArgFormatter(out, specs, *this), arg);
+  }
+  return std::copy(start, it, out);
+}
+
+template <typename Char>
+using basic_printf_context_t =
+    basic_printf_context<std::back_insert_iterator<detail::buffer<Char>>, Char>;
+
+using printf_context = basic_printf_context_t<char>;
+using wprintf_context = basic_printf_context_t<wchar_t>;
+
+using printf_args = basic_format_args<printf_context>;
+using wprintf_args = basic_format_args<wprintf_context>;
+
+/**
+  \rst
+  Constructs an `~fmt::format_arg_store` object that contains references to
+  arguments and can be implicitly converted to `~fmt::printf_args`.
+  \endrst
+ */
+template <typename... Args>
+inline format_arg_store<printf_context, Args...> make_printf_args(
+    const Args&... args) {
+  return {args...};
+}
+
+/**
+  \rst
+  Constructs an `~fmt::format_arg_store` object that contains references to
+  arguments and can be implicitly converted to `~fmt::wprintf_args`.
+  \endrst
+ */
+template <typename... Args>
+inline format_arg_store<wprintf_context, Args...> make_wprintf_args(
+    const Args&... args) {
+  return {args...};
+}
+
+template <typename S, typename Char = char_t<S>>
+inline std::basic_string<Char> vsprintf(
+    const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buffer;
+  vprintf(buffer, to_string_view(format), args);
+  return to_string(buffer);
+}
+
+/**
+  \rst
+  Formats arguments and returns the result as a string.
+
+  **Example**::
+
+    std::string message = fmt::sprintf("The answer is %d", 42);
+  \endrst
+*/
+template <typename S, typename... Args,
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
+inline std::basic_string<Char> sprintf(const S& format, const Args&... args) {
+  using context = basic_printf_context_t<Char>;
+  return vsprintf(to_string_view(format), make_format_args<context>(args...));
+}
+
+template <typename S, typename Char = char_t<S>>
+inline int vfprintf(
+    std::FILE* f, const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buffer;
+  vprintf(buffer, to_string_view(format), args);
+  size_t size = buffer.size();
+  return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
+             ? -1
+             : static_cast<int>(size);
+}
+
+/**
+  \rst
+  Prints formatted data to the file *f*.
+
+  **Example**::
+
+    fmt::fprintf(stderr, "Don't %s!", "panic");
+  \endrst
+ */
+template <typename S, typename... Args,
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
+inline int fprintf(std::FILE* f, const S& format, const Args&... args) {
+  using context = basic_printf_context_t<Char>;
+  return vfprintf(f, to_string_view(format),
+                  make_format_args<context>(args...));
+}
+
+template <typename S, typename Char = char_t<S>>
+inline int vprintf(
+    const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+  return vfprintf(stdout, to_string_view(format), args);
+}
+
+/**
+  \rst
+  Prints formatted data to ``stdout``.
+
+  **Example**::
+
+    fmt::printf("Elapsed time: %.2f seconds", 1.23);
+  \endrst
+ */
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
+inline int printf(const S& format_str, const Args&... args) {
+  using context = basic_printf_context_t<char_t<S>>;
+  return vprintf(to_string_view(format_str),
+                 make_format_args<context>(args...));
+}
+
+template <typename S, typename Char = char_t<S>>
+inline int vfprintf(
+    std::basic_ostream<Char>& os, const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
+  basic_memory_buffer<Char> buffer;
+  vprintf(buffer, to_string_view(format), args);
+  detail::write_buffer(os, buffer);
+  return static_cast<int>(buffer.size());
+}
+
+/** Formats arguments and writes the output to the range. */
+template <typename ArgFormatter, typename Char,
+          typename Context =
+              basic_printf_context<typename ArgFormatter::iterator, Char>>
+typename ArgFormatter::iterator vprintf(
+    detail::buffer<Char>& out, basic_string_view<Char> format_str,
+    basic_format_args<type_identity_t<Context>> args) {
+  typename ArgFormatter::iterator iter(out);
+  Context(iter, format_str, args).template format<ArgFormatter>();
+  return iter;
+}
+
+/**
+  \rst
+  Prints formatted data to the stream *os*.
+
+  **Example**::
+
+    fmt::fprintf(cerr, "Don't %s!", "panic");
+  \endrst
+ */
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline int fprintf(std::basic_ostream<Char>& os, const S& format_str,
+                   const Args&... args) {
+  using context = basic_printf_context_t<Char>;
+  return vfprintf(os, to_string_view(format_str),
+                  make_format_args<context>(args...));
+}
+FMT_END_NAMESPACE
+
+#endif  // FMT_PRINTF_H_

spdlog/fmt/bundled/ranges.h

+// Formatting library for C++ - experimental range support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+//
+// Copyright (c) 2018 - present, Remotion (Igor Schulz)
+// All Rights Reserved
+// {fmt} support for ranges, containers and types tuple interface.
+
+#ifndef FMT_RANGES_H_
+#define FMT_RANGES_H_
+
+#include <initializer_list>
+#include <type_traits>
+
+#include "format.h"
+
+// output only up to N items from the range.
+#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
+#  define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
+#endif
+
+FMT_BEGIN_NAMESPACE
+
+template <typename Char> struct formatting_base {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+};
+
+template <typename Char, typename Enable = void>
+struct formatting_range : formatting_base<Char> {
+  static FMT_CONSTEXPR_DECL const size_t range_length_limit =
+      FMT_RANGE_OUTPUT_LENGTH_LIMIT;  // output only up to N items from the
+                                      // range.
+  Char prefix;
+  Char delimiter;
+  Char postfix;
+  formatting_range() : prefix('{'), delimiter(','), postfix('}') {}
+  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
+  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
+};
+
+template <typename Char, typename Enable = void>
+struct formatting_tuple : formatting_base<Char> {
+  Char prefix;
+  Char delimiter;
+  Char postfix;
+  formatting_tuple() : prefix('('), delimiter(','), postfix(')') {}
+  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
+  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
+};
+
+namespace detail {
+
+template <typename RangeT, typename OutputIterator>
+OutputIterator copy(const RangeT& range, OutputIterator out) {
+  for (auto it = range.begin(), end = range.end(); it != end; ++it)
+    *out++ = *it;
+  return out;
+}
+
+template <typename OutputIterator>
+OutputIterator copy(const char* str, OutputIterator out) {
+  while (*str) *out++ = *str++;
+  return out;
+}
+
+template <typename OutputIterator>
+OutputIterator copy(char ch, OutputIterator out) {
+  *out++ = ch;
+  return out;
+}
+
+/// Return true value if T has std::string interface, like std::string_view.
+template <typename T> class is_like_std_string {
+  template <typename U>
+  static auto check(U* p)
+      -> decltype((void)p->find('a'), p->length(), (void)p->data(), int());
+  template <typename> static void check(...);
+
+ public:
+  static FMT_CONSTEXPR_DECL const bool value =
+      is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename Char>
+struct is_like_std_string<fmt::basic_string_view<Char>> : std::true_type {};
+
+template <typename... Ts> struct conditional_helper {};
+
+template <typename T, typename _ = void> struct is_range_ : std::false_type {};
+
+#if !FMT_MSC_VER || FMT_MSC_VER > 1800
+template <typename T>
+struct is_range_<
+    T, conditional_t<false,
+                     conditional_helper<decltype(std::declval<T>().begin()),
+                                        decltype(std::declval<T>().end())>,
+                     void>> : std::true_type {};
+#endif
+
+/// tuple_size and tuple_element check.
+template <typename T> class is_tuple_like_ {
+  template <typename U>
+  static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
+  template <typename> static void check(...);
+
+ public:
+  static FMT_CONSTEXPR_DECL const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+// Check for integer_sequence
+#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
+template <typename T, T... N>
+using integer_sequence = std::integer_sequence<T, N...>;
+template <size_t... N> using index_sequence = std::index_sequence<N...>;
+template <size_t N> using make_index_sequence = std::make_index_sequence<N>;
+#else
+template <typename T, T... N> struct integer_sequence {
+  using value_type = T;
+
+  static FMT_CONSTEXPR size_t size() { return sizeof...(N); }
+};
+
+template <size_t... N> using index_sequence = integer_sequence<size_t, N...>;
+
+template <typename T, size_t N, T... Ns>
+struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
+template <typename T, T... Ns>
+struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
+
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
+#endif
+
+template <class Tuple, class F, size_t... Is>
+void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT {
+  using std::get;
+  // using free function get<I>(T) now.
+  const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
+  (void)_;  // blocks warnings
+}
+
+template <class T>
+FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes(
+    T const&) {
+  return {};
+}
+
+template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
+  const auto indexes = get_indexes(tup);
+  for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
+}
+
+template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
+                                      typename std::decay<Arg>::type>::value)>
+FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
+  return add_space ? " {}" : "{}";
+}
+
+template <typename Arg, FMT_ENABLE_IF(is_like_std_string<
+                                      typename std::decay<Arg>::type>::value)>
+FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
+  return add_space ? " \"{}\"" : "\"{}\"";
+}
+
+FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) {
+  return add_space ? " \"{}\"" : "\"{}\"";
+}
+FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) {
+  return add_space ? L" \"{}\"" : L"\"{}\"";
+}
+
+FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
+  return add_space ? " '{}'" : "'{}'";
+}
+FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
+  return add_space ? L" '{}'" : L"'{}'";
+}
+
+}  // namespace detail
+
+template <typename T> struct is_tuple_like {
+  static FMT_CONSTEXPR_DECL const bool value =
+      detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
+};
+
+template <typename TupleT, typename Char>
+struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
+ private:
+  // C++11 generic lambda for format()
+  template <typename FormatContext> struct format_each {
+    template <typename T> void operator()(const T& v) {
+      if (i > 0) {
+        if (formatting.add_prepostfix_space) {
+          *out++ = ' ';
+        }
+        out = detail::copy(formatting.delimiter, out);
+      }
+      out = format_to(out,
+                      detail::format_str_quoted(
+                          (formatting.add_delimiter_spaces && i > 0), v),
+                      v);
+      ++i;
+    }
+
+    formatting_tuple<Char>& formatting;
+    size_t& i;
+    typename std::add_lvalue_reference<decltype(
+        std::declval<FormatContext>().out())>::type out;
+  };
+
+ public:
+  formatting_tuple<Char> formatting;
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return formatting.parse(ctx);
+  }
+
+  template <typename FormatContext = format_context>
+  auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    size_t i = 0;
+    detail::copy(formatting.prefix, out);
+
+    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
+    if (formatting.add_prepostfix_space) {
+      *out++ = ' ';
+    }
+    detail::copy(formatting.postfix, out);
+
+    return ctx.out();
+  }
+};
+
+template <typename T, typename Char> struct is_range {
+  static FMT_CONSTEXPR_DECL const bool value =
+      detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
+      !std::is_convertible<T, std::basic_string<Char>>::value &&
+      !std::is_constructible<detail::std_string_view<Char>, T>::value;
+};
+
+template <typename RangeT, typename Char>
+struct formatter<RangeT, Char,
+                 enable_if_t<fmt::is_range<RangeT, Char>::value>> {
+  formatting_range<Char> formatting;
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return formatting.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  typename FormatContext::iterator format(const RangeT& values,
+                                          FormatContext& ctx) {
+    auto out = detail::copy(formatting.prefix, ctx.out());
+    size_t i = 0;
+    auto it = values.begin();
+    auto end = values.end();
+    for (; it != end; ++it) {
+      if (i > 0) {
+        if (formatting.add_prepostfix_space) *out++ = ' ';
+        out = detail::copy(formatting.delimiter, out);
+      }
+      out = format_to(out,
+                      detail::format_str_quoted(
+                          (formatting.add_delimiter_spaces && i > 0), *it),
+                      *it);
+      if (++i > formatting.range_length_limit) {
+        out = format_to(out, " ... <other elements>");
+        break;
+      }
+    }
+    if (formatting.add_prepostfix_space) *out++ = ' ';
+    return detail::copy(formatting.postfix, out);
+  }
+};
+
+template <typename Char, typename... T> struct tuple_arg_join : detail::view {
+  const std::tuple<T...>& tuple;
+  basic_string_view<Char> sep;
+
+  tuple_arg_join(const std::tuple<T...>& t, basic_string_view<Char> s)
+      : tuple{t}, sep{s} {}
+};
+
+template <typename Char, typename... T>
+struct formatter<tuple_arg_join<Char, T...>, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  typename FormatContext::iterator format(
+      const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
+    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
+  }
+
+ private:
+  template <typename FormatContext, size_t... N>
+  typename FormatContext::iterator format(
+      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
+      detail::index_sequence<N...>) {
+    return format_args(value, ctx, std::get<N>(value.tuple)...);
+  }
+
+  template <typename FormatContext>
+  typename FormatContext::iterator format_args(
+      const tuple_arg_join<Char, T...>&, FormatContext& ctx) {
+    // NOTE: for compilers that support C++17, this empty function instantiation
+    // can be replaced with a constexpr branch in the variadic overload.
+    return ctx.out();
+  }
+
+  template <typename FormatContext, typename Arg, typename... Args>
+  typename FormatContext::iterator format_args(
+      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
+      const Arg& arg, const Args&... args) {
+    using base = formatter<typename std::decay<Arg>::type, Char>;
+    auto out = ctx.out();
+    out = base{}.format(arg, ctx);
+    if (sizeof...(Args) > 0) {
+      out = std::copy(value.sep.begin(), value.sep.end(), out);
+      ctx.advance_to(out);
+      return format_args(value, ctx, args...);
+    }
+    return out;
+  }
+};
+
+/**
+  \rst
+  Returns an object that formats `tuple` with elements separated by `sep`.
+
+  **Example**::
+
+    std::tuple<int, char> t = {1, 'a'};
+    fmt::print("{}", fmt::join(t, ", "));
+    // Output: "1, a"
+  \endrst
+ */
+template <typename... T>
+FMT_CONSTEXPR tuple_arg_join<char, T...> join(const std::tuple<T...>& tuple,
+                                              string_view sep) {
+  return {tuple, sep};
+}
+
+template <typename... T>
+FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
+                                                 wstring_view sep) {
+  return {tuple, sep};
+}
+
+/**
+  \rst
+  Returns an object that formats `initializer_list` with elements separated by
+  `sep`.
+
+  **Example**::
+
+    fmt::print("{}", fmt::join({1, 2, 3}, ", "));
+    // Output: "1, 2, 3"
+  \endrst
+ */
+template <typename T>
+arg_join<const T*, const T*, char> join(std::initializer_list<T> list,
+                                        string_view sep) {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename T>
+arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list,
+                                           wstring_view sep) {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_RANGES_H_

spdlog/fmt/chrono.h

+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's chrono support
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#ifdef SPDLOG_HEADER_ONLY
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#endif
+#include <spdlog/fmt/bundled/chrono.h>
+#else
+#include <fmt/chrono.h>
+#endif

spdlog/fmt/fmt.h

+//
+// Copyright(c) 2016-2018 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+//
+// Include a bundled header-only copy of fmtlib or an external one.
+// By default spdlog include its own copy.
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#if !defined(SPDLOG_COMPILED_LIB) && !defined(FMT_HEADER_ONLY)
+#define FMT_HEADER_ONLY
+#endif
+#ifndef FMT_USE_WINDOWS_H
+#define FMT_USE_WINDOWS_H 0
+#endif
+// enable the 'n' flag in for backward compatibility with fmt 6.x
+#define FMT_DEPRECATED_N_SPECIFIER
+#include <spdlog/fmt/bundled/core.h>
+#include <spdlog/fmt/bundled/format.h>
+#else // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
+#include <fmt/core.h>
+#include <fmt/format.h>
+#endif
\ No newline at end of file

spdlog/fmt/ostr.h

+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ostream support
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#ifdef SPDLOG_HEADER_ONLY
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#endif
+#include <spdlog/fmt/bundled/ostream.h>
+#else
+#include <fmt/ostream.h>
+#endif

spdlog/formatter.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/details/log_msg.h>
+
+namespace spdlog {
+
+class formatter
+{
+public:
+    virtual ~formatter() = default;
+    virtual void format(const details::log_msg &msg, memory_buf_t &dest) = 0;
+    virtual std::unique_ptr<formatter> clone() const = 0;
+};
+} // namespace spdlog

spdlog/fwd.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+namespace spdlog {
+class logger;
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+} // namespace spdlog

spdlog/logger-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/logger.h>
+#endif
+
+#include <spdlog/sinks/sink.h>
+#include <spdlog/details/backtracer.h>
+#include <spdlog/pattern_formatter.h>
+
+#include <cstdio>
+
+namespace spdlog {
+
+// public methods
+SPDLOG_INLINE logger::logger(const logger &other)
+    : name_(other.name_)
+    , sinks_(other.sinks_)
+    , level_(other.level_.load(std::memory_order_relaxed))
+    , flush_level_(other.flush_level_.load(std::memory_order_relaxed))
+    , custom_err_handler_(other.custom_err_handler_)
+    , tracer_(other.tracer_)
+{}
+
+SPDLOG_INLINE logger::logger(logger &&other) SPDLOG_NOEXCEPT : name_(std::move(other.name_)),
+                                                               sinks_(std::move(other.sinks_)),
+                                                               level_(other.level_.load(std::memory_order_relaxed)),
+                                                               flush_level_(other.flush_level_.load(std::memory_order_relaxed)),
+                                                               custom_err_handler_(std::move(other.custom_err_handler_)),
+                                                               tracer_(std::move(other.tracer_))
+
+{}
+
+SPDLOG_INLINE logger &logger::operator=(logger other) SPDLOG_NOEXCEPT
+{
+    this->swap(other);
+    return *this;
+}
+
+SPDLOG_INLINE void logger::swap(spdlog::logger &other) SPDLOG_NOEXCEPT
+{
+    name_.swap(other.name_);
+    sinks_.swap(other.sinks_);
+
+    // swap level_
+    auto other_level = other.level_.load();
+    auto my_level = level_.exchange(other_level);
+    other.level_.store(my_level);
+
+    // swap flush level_
+    other_level = other.flush_level_.load();
+    my_level = flush_level_.exchange(other_level);
+    other.flush_level_.store(my_level);
+
+    custom_err_handler_.swap(other.custom_err_handler_);
+    std::swap(tracer_, other.tracer_);
+}
+
+SPDLOG_INLINE void swap(logger &a, logger &b)
+{
+    a.swap(b);
+}
+
+SPDLOG_INLINE void logger::set_level(level::level_enum log_level)
+{
+    level_.store(log_level);
+}
+
+SPDLOG_INLINE level::level_enum logger::level() const
+{
+    return static_cast<level::level_enum>(level_.load(std::memory_order_relaxed));
+}
+
+SPDLOG_INLINE const std::string &logger::name() const
+{
+    return name_;
+}
+
+// set formatting for the sinks in this logger.
+// each sink will get a separate instance of the formatter object.
+SPDLOG_INLINE void logger::set_formatter(std::unique_ptr<formatter> f)
+{
+    for (auto it = sinks_.begin(); it != sinks_.end(); ++it)
+    {
+        if (std::next(it) == sinks_.end())
+        {
+            // last element - we can be move it.
+            (*it)->set_formatter(std::move(f));
+            break; // to prevent clang-tidy warning
+        }
+        else
+        {
+            (*it)->set_formatter(f->clone());
+        }
+    }
+}
+
+SPDLOG_INLINE void logger::set_pattern(std::string pattern, pattern_time_type time_type)
+{
+    auto new_formatter = details::make_unique<pattern_formatter>(std::move(pattern), time_type);
+    set_formatter(std::move(new_formatter));
+}
+
+// create new backtrace sink and move to it all our child sinks
+SPDLOG_INLINE void logger::enable_backtrace(size_t n_messages)
+{
+    tracer_.enable(n_messages);
+}
+
+// restore orig sinks and level and delete the backtrace sink
+SPDLOG_INLINE void logger::disable_backtrace()
+{
+    tracer_.disable();
+}
+
+SPDLOG_INLINE void logger::dump_backtrace()
+{
+    dump_backtrace_();
+}
+
+// flush functions
+SPDLOG_INLINE void logger::flush()
+{
+    flush_();
+}
+
+SPDLOG_INLINE void logger::flush_on(level::level_enum log_level)
+{
+    flush_level_.store(log_level);
+}
+
+SPDLOG_INLINE level::level_enum logger::flush_level() const
+{
+    return static_cast<level::level_enum>(flush_level_.load(std::memory_order_relaxed));
+}
+
+// sinks
+SPDLOG_INLINE const std::vector<sink_ptr> &logger::sinks() const
+{
+    return sinks_;
+}
+
+SPDLOG_INLINE std::vector<sink_ptr> &logger::sinks()
+{
+    return sinks_;
+}
+
+// error handler
+SPDLOG_INLINE void logger::set_error_handler(err_handler handler)
+{
+    custom_err_handler_ = std::move(handler);
+}
+
+// create new logger with same sinks and configuration.
+SPDLOG_INLINE std::shared_ptr<logger> logger::clone(std::string logger_name)
+{
+    auto cloned = std::make_shared<logger>(*this);
+    cloned->name_ = std::move(logger_name);
+    return cloned;
+}
+
+// protected methods
+SPDLOG_INLINE void logger::log_it_(const spdlog::details::log_msg &log_msg, bool log_enabled, bool traceback_enabled)
+{
+    if (log_enabled)
+    {
+        sink_it_(log_msg);
+    }
+    if (traceback_enabled)
+    {
+        tracer_.push_back(log_msg);
+    }
+}
+
+SPDLOG_INLINE void logger::sink_it_(const details::log_msg &msg)
+{
+    for (auto &sink : sinks_)
+    {
+        if (sink->should_log(msg.level))
+        {
+            SPDLOG_TRY
+            {
+                sink->log(msg);
+            }
+            SPDLOG_LOGGER_CATCH()
+        }
+    }
+
+    if (should_flush_(msg))
+    {
+        flush_();
+    }
+}
+
+SPDLOG_INLINE void logger::flush_()
+{
+    for (auto &sink : sinks_)
+    {
+        SPDLOG_TRY
+        {
+            sink->flush();
+        }
+        SPDLOG_LOGGER_CATCH()
+    }
+}
+
+SPDLOG_INLINE void logger::dump_backtrace_()
+{
+    using details::log_msg;
+    if (tracer_.enabled())
+    {
+        sink_it_(log_msg{name(), level::info, "****************** Backtrace Start ******************"});
+        tracer_.foreach_pop([this](const log_msg &msg) { this->sink_it_(msg); });
+        sink_it_(log_msg{name(), level::info, "****************** Backtrace End ********************"});
+    }
+}
+
+SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg)
+{
+    auto flush_level = flush_level_.load(std::memory_order_relaxed);
+    return (msg.level >= flush_level) && (msg.level != level::off);
+}
+
+SPDLOG_INLINE void logger::err_handler_(const std::string &msg)
+{
+    if (custom_err_handler_)
+    {
+        custom_err_handler_(msg);
+    }
+    else
+    {
+        using std::chrono::system_clock;
+        static std::mutex mutex;
+        static std::chrono::system_clock::time_point last_report_time;
+        static size_t err_counter = 0;
+        std::lock_guard<std::mutex> lk{mutex};
+        auto now = system_clock::now();
+        err_counter++;
+        if (now - last_report_time < std::chrono::seconds(1))
+        {
+            return;
+        }
+        last_report_time = now;
+        auto tm_time = details::os::localtime(system_clock::to_time_t(now));
+        char date_buf[64];
+        std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
+#if defined(USING_R) && defined(R_R_H) // if in R environment
+        REprintf("[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
+#else
+        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
+#endif
+    }
+}
+} // namespace spdlog

spdlog/logger.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Thread safe logger (except for set_error_handler())
+// Has name, log level, vector of std::shared sink pointers and formatter
+// Upon each log write the logger:
+// 1. Checks if its log level is enough to log the message and if yes:
+// 2. Call the underlying sinks to do the job.
+// 3. Each sink use its own private copy of a formatter to format the message
+// and send to its destination.
+//
+// The use of private formatter per sink provides the opportunity to cache some
+// formatted data, and support for different format per sink.
+
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/details/backtracer.h>
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+#include <spdlog/details/os.h>
+#endif
+
+#include <vector>
+#ifndef SPDLOG_NO_EXCEPTIONS
+#define SPDLOG_LOGGER_CATCH()                                                                                                              \
+    catch (const std::exception &ex)                                                                                                       \
+    {                                                                                                                                      \
+        err_handler_(ex.what());                                                                                                           \
+    }                                                                                                                                      \
+    catch (...)                                                                                                                            \
+    {                                                                                                                                      \
+        err_handler_("Unknown exception in logger");                                                                                       \
+    }
+#else
+#define SPDLOG_LOGGER_CATCH()
+#endif
+
+namespace spdlog {
+
+class SPDLOG_API logger
+{
+public:
+    // Empty logger
+    explicit logger(std::string name)
+        : name_(std::move(name))
+        , sinks_()
+    {}
+
+    // Logger with range on sinks
+    template<typename It>
+    logger(std::string name, It begin, It end)
+        : name_(std::move(name))
+        , sinks_(begin, end)
+    {}
+
+    // Logger with single sink
+    logger(std::string name, sink_ptr single_sink)
+        : logger(std::move(name), {std::move(single_sink)})
+    {}
+
+    // Logger with sinks init list
+    logger(std::string name, sinks_init_list sinks)
+        : logger(std::move(name), sinks.begin(), sinks.end())
+    {}
+
+    virtual ~logger() = default;
+
+    logger(const logger &other);
+    logger(logger &&other) SPDLOG_NOEXCEPT;
+    logger &operator=(logger other) SPDLOG_NOEXCEPT;
+
+    void swap(spdlog::logger &other) SPDLOG_NOEXCEPT;
+
+    // FormatString is a type derived from fmt::compile_string
+    template<typename FormatString, typename std::enable_if<fmt::is_compile_string<FormatString>::value, int>::type = 0, typename... Args>
+    void log(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args&&...args)
+    {
+        log_(loc, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    // FormatString is NOT a type derived from fmt::compile_string but is a string_view_t or can be implicitly converted to one
+    template<typename... Args>
+    void log(source_loc loc, level::level_enum lvl, string_view_t fmt, Args&&...args)
+    {
+        log_(loc, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void log(level::level_enum lvl, const FormatString &fmt, Args&&...args)
+    {
+        log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void trace(const FormatString &fmt, Args&&...args)
+    {
+        log(level::trace, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void debug(const FormatString &fmt, Args&&...args)
+    {
+        log(level::debug, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void info(const FormatString &fmt, Args&&...args)
+    {
+        log(level::info, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void warn(const FormatString &fmt, Args&&...args)
+    {
+        log(level::warn, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void error(const FormatString &fmt, Args&&...args)
+    {
+        log(level::err, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename FormatString, typename... Args>
+    void critical(const FormatString &fmt, Args&&...args)
+    {
+        log(level::critical, fmt, std::forward<Args>(args)...);
+    }
+
+    template<typename T>
+    void log(level::level_enum lvl, const T &msg)
+    {
+        log(source_loc{}, lvl, msg);
+    }
+
+    // T can be statically converted to string_view and isn't a fmt::compile_string
+    template<class T, typename std::enable_if<
+                          std::is_convertible<const T &, spdlog::string_view_t>::value && !fmt::is_compile_string<T>::value, int>::type = 0>
+    void log(source_loc loc, level::level_enum lvl, const T &msg)
+    {
+        log(loc, lvl, string_view_t{msg});
+    }
+
+    void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, string_view_t msg)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+
+        details::log_msg log_msg(log_time, loc, name_, lvl, msg);
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(source_loc loc, level::level_enum lvl, string_view_t msg)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+
+        details::log_msg log_msg(loc, name_, lvl, msg);
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(level::level_enum lvl, string_view_t msg)
+    {
+        log(source_loc{}, lvl, msg);
+    }
+
+    // T cannot be statically converted to string_view or wstring_view
+    template<class T, typename std::enable_if<!std::is_convertible<const T &, spdlog::string_view_t>::value &&
+                                                  !is_convertible_to_wstring_view<const T &>::value,
+                          int>::type = 0>
+    void log(source_loc loc, level::level_enum lvl, const T &msg)
+    {
+        log(loc, lvl, "{}", msg);
+    }
+
+    template<typename T>
+    void trace(const T &msg)
+    {
+        log(level::trace, msg);
+    }
+
+    template<typename T>
+    void debug(const T &msg)
+    {
+        log(level::debug, msg);
+    }
+
+    template<typename T>
+    void info(const T &msg)
+    {
+        log(level::info, msg);
+    }
+
+    template<typename T>
+    void warn(const T &msg)
+    {
+        log(level::warn, msg);
+    }
+
+    template<typename T>
+    void error(const T &msg)
+    {
+        log(level::err, msg);
+    }
+
+    template<typename T>
+    void critical(const T &msg)
+    {
+        log(level::critical, msg);
+    }
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+#ifndef _WIN32
+#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+#else
+
+    template<typename... Args>
+    void log(source_loc loc, level::level_enum lvl, wstring_view_t fmt, Args&&...args)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+        SPDLOG_TRY
+        {
+            // format to wmemory_buffer and convert to utf8
+            fmt::wmemory_buffer wbuf;
+            fmt::format_to(wbuf, fmt, std::forward<Args>(args)...);
+
+            memory_buf_t buf;
+            details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH()
+    }
+
+    // T can be statically converted to wstring_view
+    template<class T, typename std::enable_if<is_convertible_to_wstring_view<const T &>::value, int>::type = 0>
+    void log(source_loc loc, level::level_enum lvl, const T &msg)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+
+        SPDLOG_TRY
+        {
+            memory_buf_t buf;
+            details::os::wstr_to_utf8buf(msg, buf);
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH()
+    }
+#endif // _WIN32
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+    // return true logging is enabled for the given level.
+    bool should_log(level::level_enum msg_level) const
+    {
+        return msg_level >= level_.load(std::memory_order_relaxed);
+    }
+
+    // return true if backtrace logging is enabled.
+    bool should_backtrace() const
+    {
+        return tracer_.enabled();
+    }
+
+    void set_level(level::level_enum log_level);
+
+    level::level_enum level() const;
+
+    const std::string &name() const;
+
+    // set formatting for the sinks in this logger.
+    // each sink will get a separate instance of the formatter object.
+    void set_formatter(std::unique_ptr<formatter> f);
+
+    void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
+
+    // backtrace support.
+    // efficiently store all debug/trace messages in a circular buffer until needed for debugging.
+    void enable_backtrace(size_t n_messages);
+    void disable_backtrace();
+    void dump_backtrace();
+
+    // flush functions
+    void flush();
+    void flush_on(level::level_enum log_level);
+    level::level_enum flush_level() const;
+
+    // sinks
+    const std::vector<sink_ptr> &sinks() const;
+
+    std::vector<sink_ptr> &sinks();
+
+    // error handler
+    void set_error_handler(err_handler);
+
+    // create new logger with same sinks and configuration.
+    virtual std::shared_ptr<logger> clone(std::string logger_name);
+
+protected:
+    std::string name_;
+    std::vector<sink_ptr> sinks_;
+    spdlog::level_t level_{level::info};
+    spdlog::level_t flush_level_{level::off};
+    err_handler custom_err_handler_{nullptr};
+    details::backtracer tracer_;
+
+    // common implementation for after templated public api has been resolved
+    template<typename FormatString, typename... Args>
+    void log_(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args&&...args)
+    {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled)
+        {
+            return;
+        }
+        SPDLOG_TRY
+        {
+            memory_buf_t buf;
+            fmt::format_to(buf, fmt, std::forward<Args>(args)...);
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH()
+    }
+
+    // log the given message (if the given log level is high enough),
+    // and save backtrace (if backtrace is enabled).
+    void log_it_(const details::log_msg &log_msg, bool log_enabled, bool traceback_enabled);
+    virtual void sink_it_(const details::log_msg &msg);
+    virtual void flush_();
+    void dump_backtrace_();
+    bool should_flush_(const details::log_msg &msg);
+
+    // handle errors during logging.
+    // default handler prints the error to stderr at max rate of 1 message/sec.
+    void err_handler_(const std::string &msg);
+};
+
+void swap(logger &a, logger &b);
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "logger-inl.h"
+#endif

spdlog/pattern_formatter-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/pattern_formatter.h>
+#endif
+
+#include <spdlog/details/fmt_helper.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/details/os.h>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/formatter.h>
+
+#include <array>
+#include <chrono>
+#include <ctime>
+#include <cctype>
+#include <cstring>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <utility>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+
+///////////////////////////////////////////////////////////////////////
+// name & level pattern appender
+///////////////////////////////////////////////////////////////////////
+
+class scoped_padder
+{
+public:
+    scoped_padder(size_t wrapped_size, const padding_info &padinfo, memory_buf_t &dest)
+        : padinfo_(padinfo)
+        , dest_(dest)
+    {
+        remaining_pad_ = static_cast<long>(padinfo.width_) - static_cast<long>(wrapped_size);
+        if (remaining_pad_ <= 0)
+        {
+            return;
+        }
+
+        if (padinfo_.side_ == padding_info::pad_side::left)
+        {
+            pad_it(remaining_pad_);
+            remaining_pad_ = 0;
+        }
+        else if (padinfo_.side_ == padding_info::pad_side::center)
+        {
+            auto half_pad = remaining_pad_ / 2;
+            auto reminder = remaining_pad_ & 1;
+            pad_it(half_pad);
+            remaining_pad_ = half_pad + reminder; // for the right side
+        }
+    }
+
+    template<typename T>
+    static unsigned int count_digits(T n)
+    {
+        return fmt_helper::count_digits(n);
+    }
+
+    ~scoped_padder()
+    {
+        if (remaining_pad_ >= 0)
+        {
+            pad_it(remaining_pad_);
+        }
+        else if (padinfo_.truncate_)
+        {
+            long new_size = static_cast<long>(dest_.size()) + remaining_pad_;
+            dest_.resize(static_cast<size_t>(new_size));
+        }
+    }
+
+private:
+    void pad_it(long count)
+    {
+        fmt_helper::append_string_view(string_view_t(spaces_.data(), static_cast<size_t>(count)), dest_);
+    }
+
+    const padding_info &padinfo_;
+    memory_buf_t &dest_;
+    long remaining_pad_;
+    string_view_t spaces_{"                                                                ", 64};
+};
+
+struct null_scoped_padder
+{
+    null_scoped_padder(size_t /*wrapped_size*/, const padding_info & /*padinfo*/, memory_buf_t & /*dest*/) {}
+
+    template<typename T>
+    static unsigned int count_digits(T /* number */)
+    {
+        return 0;
+    }
+};
+
+template<typename ScopedPadder>
+class name_formatter final : public flag_formatter
+{
+public:
+    explicit name_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        ScopedPadder p(msg.logger_name.size(), padinfo_, dest);
+        fmt_helper::append_string_view(msg.logger_name, dest);
+    }
+};
+
+// log level appender
+template<typename ScopedPadder>
+class level_formatter final : public flag_formatter
+{
+public:
+    explicit level_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        string_view_t &level_name = level::to_string_view(msg.level);
+        ScopedPadder p(level_name.size(), padinfo_, dest);
+        fmt_helper::append_string_view(level_name, dest);
+    }
+};
+
+// short log level appender
+template<typename ScopedPadder>
+class short_level_formatter final : public flag_formatter
+{
+public:
+    explicit short_level_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        string_view_t level_name{level::to_short_c_str(msg.level)};
+        ScopedPadder p(level_name.size(), padinfo_, dest);
+        fmt_helper::append_string_view(level_name, dest);
+    }
+};
+
+///////////////////////////////////////////////////////////////////////
+// Date time pattern appenders
+///////////////////////////////////////////////////////////////////////
+
+static const char *ampm(const tm &t)
+{
+    return t.tm_hour >= 12 ? "PM" : "AM";
+}
+
+static int to12h(const tm &t)
+{
+    return t.tm_hour > 12 ? t.tm_hour - 12 : t.tm_hour;
+}
+
+// Abbreviated weekday name
+static std::array<const char *, 7> days{{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}};
+
+template<typename ScopedPadder>
+class a_formatter final : public flag_formatter
+{
+public:
+    explicit a_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        string_view_t field_value{days[static_cast<size_t>(tm_time.tm_wday)]};
+        ScopedPadder p(field_value.size(), padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Full weekday name
+static std::array<const char *, 7> full_days{{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}};
+
+template<typename ScopedPadder>
+class A_formatter : public flag_formatter
+{
+public:
+    explicit A_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        string_view_t field_value{full_days[static_cast<size_t>(tm_time.tm_wday)]};
+        ScopedPadder p(field_value.size(), padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Abbreviated month
+static const std::array<const char *, 12> months{{"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"}};
+
+template<typename ScopedPadder>
+class b_formatter final : public flag_formatter
+{
+public:
+    explicit b_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        string_view_t field_value{months[static_cast<size_t>(tm_time.tm_mon)]};
+        ScopedPadder p(field_value.size(), padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Full month name
+static const std::array<const char *, 12> full_months{
+    {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"}};
+
+template<typename ScopedPadder>
+class B_formatter final : public flag_formatter
+{
+public:
+    explicit B_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        string_view_t field_value{full_months[static_cast<size_t>(tm_time.tm_mon)]};
+        ScopedPadder p(field_value.size(), padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Date and time representation (Thu Aug 23 15:35:46 2014)
+template<typename ScopedPadder>
+class c_formatter final : public flag_formatter
+{
+public:
+    explicit c_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 24;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        fmt_helper::append_string_view(days[static_cast<size_t>(tm_time.tm_wday)], dest);
+        dest.push_back(' ');
+        fmt_helper::append_string_view(months[static_cast<size_t>(tm_time.tm_mon)], dest);
+        dest.push_back(' ');
+        fmt_helper::append_int(tm_time.tm_mday, dest);
+        dest.push_back(' ');
+        // time
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+        dest.push_back(' ');
+        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
+    }
+};
+
+// year - 2 digit
+template<typename ScopedPadder>
+class C_formatter final : public flag_formatter
+{
+public:
+    explicit C_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_year % 100, dest);
+    }
+};
+
+// Short MM/DD/YY date, equivalent to %m/%d/%y 08/23/01
+template<typename ScopedPadder>
+class D_formatter final : public flag_formatter
+{
+public:
+    explicit D_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 10;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
+        dest.push_back('/');
+        fmt_helper::pad2(tm_time.tm_mday, dest);
+        dest.push_back('/');
+        fmt_helper::pad2(tm_time.tm_year % 100, dest);
+    }
+};
+
+// year - 4 digit
+template<typename ScopedPadder>
+class Y_formatter final : public flag_formatter
+{
+public:
+    explicit Y_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 4;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
+    }
+};
+
+// month 1-12
+template<typename ScopedPadder>
+class m_formatter final : public flag_formatter
+{
+public:
+    explicit m_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
+    }
+};
+
+// day of month 1-31
+template<typename ScopedPadder>
+class d_formatter final : public flag_formatter
+{
+public:
+    explicit d_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_mday, dest);
+    }
+};
+
+// hours in 24 format 0-23
+template<typename ScopedPadder>
+class H_formatter final : public flag_formatter
+{
+public:
+    explicit H_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+    }
+};
+
+// hours in 12 format 1-12
+template<typename ScopedPadder>
+class I_formatter final : public flag_formatter
+{
+public:
+    explicit I_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(to12h(tm_time), dest);
+    }
+};
+
+// minutes 0-59
+template<typename ScopedPadder>
+class M_formatter final : public flag_formatter
+{
+public:
+    explicit M_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_min, dest);
+    }
+};
+
+// seconds 0-59
+template<typename ScopedPadder>
+class S_formatter final : public flag_formatter
+{
+public:
+    explicit S_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+    }
+};
+
+// milliseconds
+template<typename ScopedPadder>
+class e_formatter final : public flag_formatter
+{
+public:
+    explicit e_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        auto millis = fmt_helper::time_fraction<std::chrono::milliseconds>(msg.time);
+        const size_t field_size = 3;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
+    }
+};
+
+// microseconds
+template<typename ScopedPadder>
+class f_formatter final : public flag_formatter
+{
+public:
+    explicit f_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        auto micros = fmt_helper::time_fraction<std::chrono::microseconds>(msg.time);
+
+        const size_t field_size = 6;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad6(static_cast<size_t>(micros.count()), dest);
+    }
+};
+
+// nanoseconds
+template<typename ScopedPadder>
+class F_formatter final : public flag_formatter
+{
+public:
+    explicit F_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        auto ns = fmt_helper::time_fraction<std::chrono::nanoseconds>(msg.time);
+        const size_t field_size = 9;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::pad9(static_cast<size_t>(ns.count()), dest);
+    }
+};
+
+// seconds since epoch
+template<typename ScopedPadder>
+class E_formatter final : public flag_formatter
+{
+public:
+    explicit E_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        const size_t field_size = 10;
+        ScopedPadder p(field_size, padinfo_, dest);
+        auto duration = msg.time.time_since_epoch();
+        auto seconds = std::chrono::duration_cast<std::chrono::seconds>(duration).count();
+        fmt_helper::append_int(seconds, dest);
+    }
+};
+
+// AM/PM
+template<typename ScopedPadder>
+class p_formatter final : public flag_formatter
+{
+public:
+    explicit p_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 2;
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::append_string_view(ampm(tm_time), dest);
+    }
+};
+
+// 12 hour clock 02:55:02 pm
+template<typename ScopedPadder>
+class r_formatter final : public flag_formatter
+{
+public:
+    explicit r_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 11;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(to12h(tm_time), dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+        dest.push_back(' ');
+        fmt_helper::append_string_view(ampm(tm_time), dest);
+    }
+};
+
+// 24-hour HH:MM time, equivalent to %H:%M
+template<typename ScopedPadder>
+class R_formatter final : public flag_formatter
+{
+public:
+    explicit R_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 5;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+    }
+};
+
+// ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
+template<typename ScopedPadder>
+class T_formatter final : public flag_formatter
+{
+public:
+    explicit T_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 8;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+    }
+};
+
+// ISO 8601 offset from UTC in timezone (+-HH:MM)
+template<typename ScopedPadder>
+class z_formatter final : public flag_formatter
+{
+public:
+    explicit z_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    z_formatter() = default;
+    z_formatter(const z_formatter &) = delete;
+    z_formatter &operator=(const z_formatter &) = delete;
+
+    void format(const details::log_msg &msg, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        const size_t field_size = 6;
+        ScopedPadder p(field_size, padinfo_, dest);
+
+        auto total_minutes = get_cached_offset(msg, tm_time);
+        bool is_negative = total_minutes < 0;
+        if (is_negative)
+        {
+            total_minutes = -total_minutes;
+            dest.push_back('-');
+        }
+        else
+        {
+            dest.push_back('+');
+        }
+
+        fmt_helper::pad2(total_minutes / 60, dest); // hours
+        dest.push_back(':');
+        fmt_helper::pad2(total_minutes % 60, dest); // minutes
+    }
+
+private:
+    log_clock::time_point last_update_{std::chrono::seconds(0)};
+    int offset_minutes_{0};
+
+    int get_cached_offset(const log_msg &msg, const std::tm &tm_time)
+    {
+        // refresh every 10 seconds
+        if (msg.time - last_update_ >= std::chrono::seconds(10))
+        {
+            offset_minutes_ = os::utc_minutes_offset(tm_time);
+            last_update_ = msg.time;
+        }
+        return offset_minutes_;
+    }
+};
+
+// Thread id
+template<typename ScopedPadder>
+class t_formatter final : public flag_formatter
+{
+public:
+    explicit t_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        const auto field_size = ScopedPadder::count_digits(msg.thread_id);
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::append_int(msg.thread_id, dest);
+    }
+};
+
+// Current pid
+template<typename ScopedPadder>
+class pid_formatter final : public flag_formatter
+{
+public:
+    explicit pid_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &, const std::tm &, memory_buf_t &dest) override
+    {
+        const auto pid = static_cast<uint32_t>(details::os::pid());
+        auto field_size = ScopedPadder::count_digits(pid);
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::append_int(pid, dest);
+    }
+};
+
+template<typename ScopedPadder>
+class v_formatter final : public flag_formatter
+{
+public:
+    explicit v_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        ScopedPadder p(msg.payload.size(), padinfo_, dest);
+        fmt_helper::append_string_view(msg.payload, dest);
+    }
+};
+
+class ch_formatter final : public flag_formatter
+{
+public:
+    explicit ch_formatter(char ch)
+        : ch_(ch)
+    {}
+
+    void format(const details::log_msg &, const std::tm &, memory_buf_t &dest) override
+    {
+        dest.push_back(ch_);
+    }
+
+private:
+    char ch_;
+};
+
+// aggregate user chars to display as is
+class aggregate_formatter final : public flag_formatter
+{
+public:
+    aggregate_formatter() = default;
+
+    void add_ch(char ch)
+    {
+        str_ += ch;
+    }
+    void format(const details::log_msg &, const std::tm &, memory_buf_t &dest) override
+    {
+        fmt_helper::append_string_view(str_, dest);
+    }
+
+private:
+    std::string str_;
+};
+
+// mark the color range. expect it to be in the form of "%^colored text%$"
+class color_start_formatter final : public flag_formatter
+{
+public:
+    explicit color_start_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        msg.color_range_start = dest.size();
+    }
+};
+
+class color_stop_formatter final : public flag_formatter
+{
+public:
+    explicit color_stop_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        msg.color_range_end = dest.size();
+    }
+};
+
+// print source location
+template<typename ScopedPadder>
+class source_location_formatter final : public flag_formatter
+{
+public:
+    explicit source_location_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+
+        size_t text_size;
+        if (padinfo_.enabled())
+        {
+            // calc text size for padding based on "filename:line"
+            text_size = std::char_traits<char>::length(msg.source.filename) + ScopedPadder::count_digits(msg.source.line) + 1;
+        }
+        else
+        {
+            text_size = 0;
+        }
+
+        ScopedPadder p(text_size, padinfo_, dest);
+        fmt_helper::append_string_view(msg.source.filename, dest);
+        dest.push_back(':');
+        fmt_helper::append_int(msg.source.line, dest);
+    }
+};
+
+// print source filename
+template<typename ScopedPadder>
+class source_filename_formatter final : public flag_formatter
+{
+public:
+    explicit source_filename_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(msg.source.filename) : 0;
+        ScopedPadder p(text_size, padinfo_, dest);
+        fmt_helper::append_string_view(msg.source.filename, dest);
+    }
+};
+
+template<typename ScopedPadder>
+class short_filename_formatter final : public flag_formatter
+{
+public:
+    explicit short_filename_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    static const char *basename(const char *filename)
+    {
+        const char *rv = std::strrchr(filename, os::folder_sep);
+        return rv != nullptr ? rv + 1 : filename;
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        auto filename = basename(msg.source.filename);
+        size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(filename) : 0;
+        ScopedPadder p(text_size, padinfo_, dest);
+        fmt_helper::append_string_view(filename, dest);
+    }
+};
+
+template<typename ScopedPadder>
+class source_linenum_formatter final : public flag_formatter
+{
+public:
+    explicit source_linenum_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+
+        auto field_size = ScopedPadder::count_digits(msg.source.line);
+        ScopedPadder p(field_size, padinfo_, dest);
+        fmt_helper::append_int(msg.source.line, dest);
+    }
+};
+
+// print source funcname
+template<typename ScopedPadder>
+class source_funcname_formatter final : public flag_formatter
+{
+public:
+    explicit source_funcname_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(msg.source.funcname) : 0;
+        ScopedPadder p(text_size, padinfo_, dest);
+        fmt_helper::append_string_view(msg.source.funcname, dest);
+    }
+};
+
+// print elapsed time since last message
+template<typename ScopedPadder, typename Units>
+class elapsed_formatter final : public flag_formatter
+{
+public:
+    using DurationUnits = Units;
+
+    explicit elapsed_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+        , last_message_time_(log_clock::now())
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override
+    {
+        auto delta = (std::max)(msg.time - last_message_time_, log_clock::duration::zero());
+        auto delta_units = std::chrono::duration_cast<DurationUnits>(delta);
+        last_message_time_ = msg.time;
+        auto delta_count = static_cast<size_t>(delta_units.count());
+        auto n_digits = static_cast<size_t>(ScopedPadder::count_digits(delta_count));
+        ScopedPadder p(n_digits, padinfo_, dest);
+        fmt_helper::append_int(delta_count, dest);
+    }
+
+private:
+    log_clock::time_point last_message_time_;
+};
+
+// Full info formatter
+// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
+class full_formatter final : public flag_formatter
+{
+public:
+    explicit full_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {}
+
+    void format(const details::log_msg &msg, const std::tm &tm_time, memory_buf_t &dest) override
+    {
+        using std::chrono::duration_cast;
+        using std::chrono::milliseconds;
+        using std::chrono::seconds;
+
+        // cache the date/time part for the next second.
+        auto duration = msg.time.time_since_epoch();
+        auto secs = duration_cast<seconds>(duration);
+
+        if (cache_timestamp_ != secs || cached_datetime_.size() == 0)
+        {
+            cached_datetime_.clear();
+            cached_datetime_.push_back('[');
+            fmt_helper::append_int(tm_time.tm_year + 1900, cached_datetime_);
+            cached_datetime_.push_back('-');
+
+            fmt_helper::pad2(tm_time.tm_mon + 1, cached_datetime_);
+            cached_datetime_.push_back('-');
+
+            fmt_helper::pad2(tm_time.tm_mday, cached_datetime_);
+            cached_datetime_.push_back(' ');
+
+            fmt_helper::pad2(tm_time.tm_hour, cached_datetime_);
+            cached_datetime_.push_back(':');
+
+            fmt_helper::pad2(tm_time.tm_min, cached_datetime_);
+            cached_datetime_.push_back(':');
+
+            fmt_helper::pad2(tm_time.tm_sec, cached_datetime_);
+            cached_datetime_.push_back('.');
+
+            cache_timestamp_ = secs;
+        }
+        dest.append(cached_datetime_.begin(), cached_datetime_.end());
+
+        auto millis = fmt_helper::time_fraction<milliseconds>(msg.time);
+        fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
+        dest.push_back(']');
+        dest.push_back(' ');
+
+        // append logger name if exists
+        if (msg.logger_name.size() > 0)
+        {
+            dest.push_back('[');
+            fmt_helper::append_string_view(msg.logger_name, dest);
+            dest.push_back(']');
+            dest.push_back(' ');
+        }
+
+        dest.push_back('[');
+        // wrap the level name with color
+        msg.color_range_start = dest.size();
+        // fmt_helper::append_string_view(level::to_c_str(msg.level), dest);
+        fmt_helper::append_string_view(level::to_string_view(msg.level), dest);
+        msg.color_range_end = dest.size();
+        dest.push_back(']');
+        dest.push_back(' ');
+
+        // add source location if present
+        if (!msg.source.empty())
+        {
+            dest.push_back('[');
+            const char *filename = details::short_filename_formatter<details::null_scoped_padder>::basename(msg.source.filename);
+            fmt_helper::append_string_view(filename, dest);
+            dest.push_back(':');
+            fmt_helper::append_int(msg.source.line, dest);
+            dest.push_back(']');
+            dest.push_back(' ');
+        }
+        // fmt_helper::append_string_view(msg.msg(), dest);
+        fmt_helper::append_string_view(msg.payload, dest);
+    }
+
+private:
+    std::chrono::seconds cache_timestamp_{0};
+    memory_buf_t cached_datetime_;
+};
+
+} // namespace details
+
+SPDLOG_INLINE pattern_formatter::pattern_formatter(
+    std::string pattern, pattern_time_type time_type, std::string eol, custom_flags custom_user_flags)
+    : pattern_(std::move(pattern))
+    , eol_(std::move(eol))
+    , pattern_time_type_(time_type)
+    , last_log_secs_(0)
+    , custom_handlers_(std::move(custom_user_flags))
+{
+    std::memset(&cached_tm_, 0, sizeof(cached_tm_));
+    compile_pattern_(pattern_);
+}
+
+// use by default full formatter for if pattern is not given
+SPDLOG_INLINE pattern_formatter::pattern_formatter(pattern_time_type time_type, std::string eol)
+    : pattern_("%+")
+    , eol_(std::move(eol))
+    , pattern_time_type_(time_type)
+    , last_log_secs_(0)
+{
+    std::memset(&cached_tm_, 0, sizeof(cached_tm_));
+    formatters_.push_back(details::make_unique<details::full_formatter>(details::padding_info{}));
+}
+
+SPDLOG_INLINE std::unique_ptr<formatter> pattern_formatter::clone() const
+{
+    custom_flags cloned_custom_formatters;
+    for (auto &it : custom_handlers_)
+    {
+        cloned_custom_formatters[it.first] = it.second->clone();
+    }
+    return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_, std::move(cloned_custom_formatters));
+}
+
+SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory_buf_t &dest)
+{
+    auto secs = std::chrono::duration_cast<std::chrono::seconds>(msg.time.time_since_epoch());
+    if (secs != last_log_secs_)
+    {
+        cached_tm_ = get_time_(msg);
+        last_log_secs_ = secs;
+    }
+
+    for (auto &f : formatters_)
+    {
+        f->format(msg, cached_tm_, dest);
+    }
+    // write eol
+    details::fmt_helper::append_string_view(eol_, dest);
+}
+
+SPDLOG_INLINE void pattern_formatter::set_pattern(std::string pattern)
+{
+    pattern_ = std::move(pattern);
+    compile_pattern_(pattern_);
+}
+
+SPDLOG_INLINE std::tm pattern_formatter::get_time_(const details::log_msg &msg)
+{
+    if (pattern_time_type_ == pattern_time_type::local)
+    {
+        return details::os::localtime(log_clock::to_time_t(msg.time));
+    }
+    return details::os::gmtime(log_clock::to_time_t(msg.time));
+}
+
+template<typename Padder>
+SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_info padding)
+{
+    // process custom flags
+    auto it = custom_handlers_.find(flag);
+    if (it != custom_handlers_.end())
+    {
+        auto custom_handler = it->second->clone();
+        custom_handler->set_padding_info(padding);
+        formatters_.push_back(std::move(custom_handler));
+        return;
+    }
+
+    // process built-in flags
+    switch (flag)
+    {
+    case ('+'): // default formatter
+        formatters_.push_back(details::make_unique<details::full_formatter>(padding));
+        break;
+
+    case 'n': // logger name
+        formatters_.push_back(details::make_unique<details::name_formatter<Padder>>(padding));
+        break;
+
+    case 'l': // level
+        formatters_.push_back(details::make_unique<details::level_formatter<Padder>>(padding));
+        break;
+
+    case 'L': // short level
+        formatters_.push_back(details::make_unique<details::short_level_formatter<Padder>>(padding));
+        break;
+
+    case ('t'): // thread id
+        formatters_.push_back(details::make_unique<details::t_formatter<Padder>>(padding));
+        break;
+
+    case ('v'): // the message text
+        formatters_.push_back(details::make_unique<details::v_formatter<Padder>>(padding));
+        break;
+
+    case ('a'): // weekday
+        formatters_.push_back(details::make_unique<details::a_formatter<Padder>>(padding));
+        break;
+
+    case ('A'): // short weekday
+        formatters_.push_back(details::make_unique<details::A_formatter<Padder>>(padding));
+        break;
+
+    case ('b'):
+    case ('h'): // month
+        formatters_.push_back(details::make_unique<details::b_formatter<Padder>>(padding));
+        break;
+
+    case ('B'): // short month
+        formatters_.push_back(details::make_unique<details::B_formatter<Padder>>(padding));
+        break;
+
+    case ('c'): // datetime
+        formatters_.push_back(details::make_unique<details::c_formatter<Padder>>(padding));
+        break;
+
+    case ('C'): // year 2 digits
+        formatters_.push_back(details::make_unique<details::C_formatter<Padder>>(padding));
+        break;
+
+    case ('Y'): // year 4 digits
+        formatters_.push_back(details::make_unique<details::Y_formatter<Padder>>(padding));
+        break;
+
+    case ('D'):
+    case ('x'): // datetime MM/DD/YY
+        formatters_.push_back(details::make_unique<details::D_formatter<Padder>>(padding));
+        break;
+
+    case ('m'): // month 1-12
+        formatters_.push_back(details::make_unique<details::m_formatter<Padder>>(padding));
+        break;
+
+    case ('d'): // day of month 1-31
+        formatters_.push_back(details::make_unique<details::d_formatter<Padder>>(padding));
+        break;
+
+    case ('H'): // hours 24
+        formatters_.push_back(details::make_unique<details::H_formatter<Padder>>(padding));
+        break;
+
+    case ('I'): // hours 12
+        formatters_.push_back(details::make_unique<details::I_formatter<Padder>>(padding));
+        break;
+
+    case ('M'): // minutes
+        formatters_.push_back(details::make_unique<details::M_formatter<Padder>>(padding));
+        break;
+
+    case ('S'): // seconds
+        formatters_.push_back(details::make_unique<details::S_formatter<Padder>>(padding));
+        break;
+
+    case ('e'): // milliseconds
+        formatters_.push_back(details::make_unique<details::e_formatter<Padder>>(padding));
+        break;
+
+    case ('f'): // microseconds
+        formatters_.push_back(details::make_unique<details::f_formatter<Padder>>(padding));
+        break;
+
+    case ('F'): // nanoseconds
+        formatters_.push_back(details::make_unique<details::F_formatter<Padder>>(padding));
+        break;
+
+    case ('E'): // seconds since epoch
+        formatters_.push_back(details::make_unique<details::E_formatter<Padder>>(padding));
+        break;
+
+    case ('p'): // am/pm
+        formatters_.push_back(details::make_unique<details::p_formatter<Padder>>(padding));
+        break;
+
+    case ('r'): // 12 hour clock 02:55:02 pm
+        formatters_.push_back(details::make_unique<details::r_formatter<Padder>>(padding));
+        break;
+
+    case ('R'): // 24-hour HH:MM time
+        formatters_.push_back(details::make_unique<details::R_formatter<Padder>>(padding));
+        break;
+
+    case ('T'):
+    case ('X'): // ISO 8601 time format (HH:MM:SS)
+        formatters_.push_back(details::make_unique<details::T_formatter<Padder>>(padding));
+        break;
+
+    case ('z'): // timezone
+        formatters_.push_back(details::make_unique<details::z_formatter<Padder>>(padding));
+        break;
+
+    case ('P'): // pid
+        formatters_.push_back(details::make_unique<details::pid_formatter<Padder>>(padding));
+        break;
+
+    case ('^'): // color range start
+        formatters_.push_back(details::make_unique<details::color_start_formatter>(padding));
+        break;
+
+    case ('$'): // color range end
+        formatters_.push_back(details::make_unique<details::color_stop_formatter>(padding));
+        break;
+
+    case ('@'): // source location (filename:filenumber)
+        formatters_.push_back(details::make_unique<details::source_location_formatter<Padder>>(padding));
+        break;
+
+    case ('s'): // short source filename - without directory name
+        formatters_.push_back(details::make_unique<details::short_filename_formatter<Padder>>(padding));
+        break;
+
+    case ('g'): // full source filename
+        formatters_.push_back(details::make_unique<details::source_filename_formatter<Padder>>(padding));
+        break;
+
+    case ('#'): // source line number
+        formatters_.push_back(details::make_unique<details::source_linenum_formatter<Padder>>(padding));
+        break;
+
+    case ('!'): // source funcname
+        formatters_.push_back(details::make_unique<details::source_funcname_formatter<Padder>>(padding));
+        break;
+
+    case ('%'): // % char
+        formatters_.push_back(details::make_unique<details::ch_formatter>('%'));
+        break;
+
+    case ('u'): // elapsed time since last log message in nanos
+        formatters_.push_back(details::make_unique<details::elapsed_formatter<Padder, std::chrono::nanoseconds>>(padding));
+        break;
+
+    case ('i'): // elapsed time since last log message in micros
+        formatters_.push_back(details::make_unique<details::elapsed_formatter<Padder, std::chrono::microseconds>>(padding));
+        break;
+
+    case ('o'): // elapsed time since last log message in millis
+        formatters_.push_back(details::make_unique<details::elapsed_formatter<Padder, std::chrono::milliseconds>>(padding));
+        break;
+
+    case ('O'): // elapsed time since last log message in seconds
+        formatters_.push_back(details::make_unique<details::elapsed_formatter<Padder, std::chrono::seconds>>(padding));
+        break;
+
+    default: // Unknown flag appears as is
+        auto unknown_flag = details::make_unique<details::aggregate_formatter>();
+
+        if (!padding.truncate_)
+        {
+            unknown_flag->add_ch('%');
+            unknown_flag->add_ch(flag);
+            formatters_.push_back((std::move(unknown_flag)));
+        }
+        // fix issue #1617 (prev char was '!' and should have been treated as funcname flag instead of truncating flag)
+        // spdlog::set_pattern("[%10!] %v") => "[      main] some message"
+        // spdlog::set_pattern("[%3!!] %v") => "[mai] some message"
+        else
+        {
+            padding.truncate_ = false;
+            formatters_.push_back(details::make_unique<details::source_funcname_formatter<Padder>>(padding));
+            unknown_flag->add_ch(flag);
+            formatters_.push_back((std::move(unknown_flag)));
+        }
+
+        break;
+    }
+}
+
+// Extract given pad spec (e.g. %8X, %=8X, %-8!X, %8!X, %=8!X, %-8!X, %+8!X)
+// Advance the given it pass the end of the padding spec found (if any)
+// Return padding.
+SPDLOG_INLINE details::padding_info pattern_formatter::handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end)
+{
+    using details::padding_info;
+    using details::scoped_padder;
+    const size_t max_width = 64;
+    if (it == end)
+    {
+        return padding_info{};
+    }
+
+    padding_info::pad_side side;
+    switch (*it)
+    {
+    case '-':
+        side = padding_info::pad_side::right;
+        ++it;
+        break;
+    case '=':
+        side = padding_info::pad_side::center;
+        ++it;
+        break;
+    default:
+        side = details::padding_info::pad_side::left;
+        break;
+    }
+
+    if (it == end || !std::isdigit(static_cast<unsigned char>(*it)))
+    {
+        return padding_info{}; // no padding if no digit found here
+    }
+
+    auto width = static_cast<size_t>(*it) - '0';
+    for (++it; it != end && std::isdigit(static_cast<unsigned char>(*it)); ++it)
+    {
+        auto digit = static_cast<size_t>(*it) - '0';
+        width = width * 10 + digit;
+    }
+
+    // search for the optional truncate marker '!'
+    bool truncate;
+    if (it != end && *it == '!')
+    {
+        truncate = true;
+        ++it;
+    }
+    else
+    {
+        truncate = false;
+    }
+
+    return details::padding_info{std::min<size_t>(width, max_width), side, truncate};
+}
+
+SPDLOG_INLINE void pattern_formatter::compile_pattern_(const std::string &pattern)
+{
+    auto end = pattern.end();
+    std::unique_ptr<details::aggregate_formatter> user_chars;
+    formatters_.clear();
+    for (auto it = pattern.begin(); it != end; ++it)
+    {
+        if (*it == '%')
+        {
+            if (user_chars) // append user chars found so far
+            {
+                formatters_.push_back(std::move(user_chars));
+            }
+
+            auto padding = handle_padspec_(++it, end);
+
+            if (it != end)
+            {
+                if (padding.enabled())
+                {
+                    handle_flag_<details::scoped_padder>(*it, padding);
+                }
+                else
+                {
+                    handle_flag_<details::null_scoped_padder>(*it, padding);
+                }
+            }
+            else
+            {
+                break;
+            }
+        }
+        else // chars not following the % sign should be displayed as is
+        {
+            if (!user_chars)
+            {
+                user_chars = details::make_unique<details::aggregate_formatter>();
+            }
+            user_chars->add_ch(*it);
+        }
+    }
+    if (user_chars) // append raw chars found so far
+    {
+        formatters_.push_back(std::move(user_chars));
+    }
+}
+} // namespace spdlog

spdlog/pattern_formatter.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/details/os.h>
+#include <spdlog/formatter.h>
+
+#include <chrono>
+#include <ctime>
+#include <memory>
+
+#include <string>
+#include <vector>
+#include <unordered_map>
+
+namespace spdlog {
+namespace details {
+
+// padding information.
+struct padding_info
+{
+    enum class pad_side
+    {
+        left,
+        right,
+        center
+    };
+
+    padding_info() = default;
+    padding_info(size_t width, padding_info::pad_side side, bool truncate)
+        : width_(width)
+        , side_(side)
+        , truncate_(truncate)
+        , enabled_(true)
+    {}
+
+    bool enabled() const
+    {
+        return enabled_;
+    }
+    size_t width_ = 0;
+    pad_side side_ = pad_side::left;
+    bool truncate_ = false;
+    bool enabled_ = false;
+};
+
+class SPDLOG_API flag_formatter
+{
+public:
+    explicit flag_formatter(padding_info padinfo)
+        : padinfo_(padinfo)
+    {}
+    flag_formatter() = default;
+    virtual ~flag_formatter() = default;
+    virtual void format(const details::log_msg &msg, const std::tm &tm_time, memory_buf_t &dest) = 0;
+
+protected:
+    padding_info padinfo_;
+};
+
+} // namespace details
+
+class SPDLOG_API custom_flag_formatter : public details::flag_formatter
+{
+public:
+    virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;
+
+    void set_padding_info(details::padding_info padding)
+    {
+        flag_formatter::padinfo_ = padding;
+    }
+};
+
+class SPDLOG_API pattern_formatter final : public formatter
+{
+public:
+    using custom_flags = std::unordered_map<char, std::unique_ptr<custom_flag_formatter>>;
+
+    explicit pattern_formatter(std::string pattern, pattern_time_type time_type = pattern_time_type::local,
+        std::string eol = spdlog::details::os::default_eol, custom_flags custom_user_flags = custom_flags());
+
+    // use default pattern is not given
+    explicit pattern_formatter(pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol);
+
+    pattern_formatter(const pattern_formatter &other) = delete;
+    pattern_formatter &operator=(const pattern_formatter &other) = delete;
+
+    std::unique_ptr<formatter> clone() const override;
+    void format(const details::log_msg &msg, memory_buf_t &dest) override;
+
+    template<typename T, typename... Args>
+    pattern_formatter &add_flag(char flag, Args&&...args)
+    {
+        custom_handlers_[flag] = details::make_unique<T>(std::forward<Args>(args)...);
+        return *this;
+    }
+    void set_pattern(std::string pattern);
+
+private:
+    std::string pattern_;
+    std::string eol_;
+    pattern_time_type pattern_time_type_;
+    std::tm cached_tm_;
+    std::chrono::seconds last_log_secs_;
+    std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
+    custom_flags custom_handlers_;
+
+    std::tm get_time_(const details::log_msg &msg);
+    template<typename Padder>
+    void handle_flag_(char flag, details::padding_info padding);
+
+    // Extract given pad spec (e.g. %8X)
+    // Advance the given it pass the end of the padding spec found (if any)
+    // Return padding.
+    static details::padding_info handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end);
+
+    void compile_pattern_(const std::string &pattern);
+};
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "pattern_formatter-inl.h"
+#endif

spdlog/sinks/android_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifdef __ANDROID__
+
+#include <spdlog/details/fmt_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/os.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <android/log.h>
+#include <chrono>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#if !defined(SPDLOG_ANDROID_RETRIES)
+#define SPDLOG_ANDROID_RETRIES 2
+#endif
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Android sink (logging using __android_log_write)
+ */
+template<typename Mutex>
+class android_sink final : public base_sink<Mutex>
+{
+public:
+    explicit android_sink(std::string tag = "spdlog", bool use_raw_msg = false)
+        : tag_(std::move(tag))
+        , use_raw_msg_(use_raw_msg)
+    {}
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        const android_LogPriority priority = convert_to_android_(msg.level);
+        memory_buf_t formatted;
+        if (use_raw_msg_)
+        {
+            details::fmt_helper::append_string_view(msg.payload, formatted);
+        }
+        else
+        {
+            base_sink<Mutex>::formatter_->format(msg, formatted);
+        }
+        formatted.push_back('\0');
+        const char *msg_output = formatted.data();
+
+        // See system/core/liblog/logger_write.c for explanation of return value
+        int ret = __android_log_write(priority, tag_.c_str(), msg_output);
+        int retry_count = 0;
+        while ((ret == -11 /*EAGAIN*/) && (retry_count < SPDLOG_ANDROID_RETRIES))
+        {
+            details::os::sleep_for_millis(5);
+            ret = __android_log_write(priority, tag_.c_str(), msg_output);
+            retry_count++;
+        }
+
+        if (ret < 0)
+        {
+            throw_spdlog_ex("__android_log_write() failed", ret);
+        }
+    }
+
+    void flush_() override {}
+
+private:
+    static android_LogPriority convert_to_android_(spdlog::level::level_enum level)
+    {
+        switch (level)
+        {
+        case spdlog::level::trace:
+            return ANDROID_LOG_VERBOSE;
+        case spdlog::level::debug:
+            return ANDROID_LOG_DEBUG;
+        case spdlog::level::info:
+            return ANDROID_LOG_INFO;
+        case spdlog::level::warn:
+            return ANDROID_LOG_WARN;
+        case spdlog::level::err:
+            return ANDROID_LOG_ERROR;
+        case spdlog::level::critical:
+            return ANDROID_LOG_FATAL;
+        default:
+            return ANDROID_LOG_DEFAULT;
+        }
+    }
+
+    std::string tag_;
+    bool use_raw_msg_;
+};
+
+using android_sink_mt = android_sink<std::mutex>;
+using android_sink_st = android_sink<details::null_mutex>;
+} // namespace sinks
+
+// Create and register android syslog logger
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> android_logger_mt(const std::string &logger_name, const std::string &tag = "spdlog")
+{
+    return Factory::template create<sinks::android_sink_mt>(logger_name, tag);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> android_logger_st(const std::string &logger_name, const std::string &tag = "spdlog")
+{
+    return Factory::template create<sinks::android_sink_st>(logger_name, tag);
+}
+
+} // namespace spdlog
+
+#endif // __ANDROID__
\ No newline at end of file

spdlog/sinks/ansicolor_sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/ansicolor_sink.h>
+#endif
+
+#include <spdlog/pattern_formatter.h>
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace sinks {
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_sink<ConsoleMutex>::ansicolor_sink(FILE *target_file, color_mode mode)
+    : target_file_(target_file)
+    , mutex_(ConsoleMutex::mutex())
+    , formatter_(details::make_unique<spdlog::pattern_formatter>())
+
+{
+    set_color_mode(mode);
+    colors_[level::trace] = to_string_(white);
+    colors_[level::debug] = to_string_(cyan);
+    colors_[level::info] = to_string_(green);
+    colors_[level::warn] = to_string_(yellow_bold);
+    colors_[level::err] = to_string_(red_bold);
+    colors_[level::critical] = to_string_(bold_on_red);
+    colors_[level::off] = to_string_(reset);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color(level::level_enum color_level, string_view_t color)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    colors_[color_level] = to_string_(color);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::log(const details::log_msg &msg)
+{
+    // Wrap the originally formatted message in color codes.
+    // If color is not supported in the terminal, log as is instead.
+    std::lock_guard<mutex_t> lock(mutex_);
+    msg.color_range_start = 0;
+    msg.color_range_end = 0;
+    memory_buf_t formatted;
+    formatter_->format(msg, formatted);
+    if (should_do_colors_ && msg.color_range_end > msg.color_range_start)
+    {
+        // before color range
+        print_range_(formatted, 0, msg.color_range_start);
+        // in color range
+        print_ccode_(colors_[msg.level]);
+        print_range_(formatted, msg.color_range_start, msg.color_range_end);
+        print_ccode_(reset);
+        // after color range
+        print_range_(formatted, msg.color_range_end, formatted.size());
+    }
+    else // no color
+    {
+        print_range_(formatted, 0, formatted.size());
+    }
+    fflush(target_file_);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::flush()
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    fflush(target_file_);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_pattern(const std::string &pattern)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::unique_ptr<spdlog::formatter>(new pattern_formatter(pattern));
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::move(sink_formatter);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE bool ansicolor_sink<ConsoleMutex>::should_color()
+{
+    return should_do_colors_;
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode(color_mode mode)
+{
+    switch (mode)
+    {
+    case color_mode::always:
+        should_do_colors_ = true;
+        return;
+    case color_mode::automatic:
+        should_do_colors_ = details::os::in_terminal(target_file_) && details::os::is_color_terminal();
+        return;
+    case color_mode::never:
+        should_do_colors_ = false;
+        return;
+    }
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_ccode_(const string_view_t &color_code)
+{
+    fwrite(color_code.data(), sizeof(char), color_code.size(), target_file_);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_range_(const memory_buf_t &formatted, size_t start, size_t end)
+{
+    fwrite(formatted.data() + start, sizeof(char), end - start, target_file_);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE std::string ansicolor_sink<ConsoleMutex>::to_string_(const string_view_t &sv)
+{
+    return std::string(sv.data(), sv.size());
+}
+
+// ansicolor_stdout_sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_stdout_sink<ConsoleMutex>::ansicolor_stdout_sink(color_mode mode)
+    : ansicolor_sink<ConsoleMutex>(stdout, mode)
+{}
+
+// ansicolor_stderr_sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_stderr_sink<ConsoleMutex>::ansicolor_stderr_sink(color_mode mode)
+    : ansicolor_sink<ConsoleMutex>(stderr, mode)
+{}
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/ansicolor_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/console_globals.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/sink.h>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <array>
+
+namespace spdlog {
+namespace sinks {
+
+/**
+ * This sink prefixes the output with an ANSI escape sequence color code
+ * depending on the severity
+ * of the message.
+ * If no color terminal detected, omit the escape codes.
+ */
+
+template<typename ConsoleMutex>
+class ansicolor_sink : public sink
+{
+public:
+    using mutex_t = typename ConsoleMutex::mutex_t;
+    ansicolor_sink(FILE *target_file, color_mode mode);
+    ~ansicolor_sink() override = default;
+
+    ansicolor_sink(const ansicolor_sink &other) = delete;
+    ansicolor_sink(ansicolor_sink &&other) = delete;
+
+    ansicolor_sink &operator=(const ansicolor_sink &other) = delete;
+    ansicolor_sink &operator=(ansicolor_sink &&other) = delete;
+
+    void set_color(level::level_enum color_level, string_view_t color);
+    void set_color_mode(color_mode mode);
+    bool should_color();
+
+    void log(const details::log_msg &msg) override;
+    void flush() override;
+    void set_pattern(const std::string &pattern) final;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
+
+    // Formatting codes
+    const string_view_t reset = "\033[m";
+    const string_view_t bold = "\033[1m";
+    const string_view_t dark = "\033[2m";
+    const string_view_t underline = "\033[4m";
+    const string_view_t blink = "\033[5m";
+    const string_view_t reverse = "\033[7m";
+    const string_view_t concealed = "\033[8m";
+    const string_view_t clear_line = "\033[K";
+
+    // Foreground colors
+    const string_view_t black = "\033[30m";
+    const string_view_t red = "\033[31m";
+    const string_view_t green = "\033[32m";
+    const string_view_t yellow = "\033[33m";
+    const string_view_t blue = "\033[34m";
+    const string_view_t magenta = "\033[35m";
+    const string_view_t cyan = "\033[36m";
+    const string_view_t white = "\033[37m";
+
+    /// Background colors
+    const string_view_t on_black = "\033[40m";
+    const string_view_t on_red = "\033[41m";
+    const string_view_t on_green = "\033[42m";
+    const string_view_t on_yellow = "\033[43m";
+    const string_view_t on_blue = "\033[44m";
+    const string_view_t on_magenta = "\033[45m";
+    const string_view_t on_cyan = "\033[46m";
+    const string_view_t on_white = "\033[47m";
+
+    /// Bold colors
+    const string_view_t yellow_bold = "\033[33m\033[1m";
+    const string_view_t red_bold = "\033[31m\033[1m";
+    const string_view_t bold_on_red = "\033[1m\033[41m";
+
+private:
+    FILE *target_file_;
+    mutex_t &mutex_;
+    bool should_do_colors_;
+    std::unique_ptr<spdlog::formatter> formatter_;
+    std::array<std::string, level::n_levels> colors_;
+    void print_ccode_(const string_view_t &color_code);
+    void print_range_(const memory_buf_t &formatted, size_t start, size_t end);
+    static std::string to_string_(const string_view_t &sv);
+};
+
+template<typename ConsoleMutex>
+class ansicolor_stdout_sink : public ansicolor_sink<ConsoleMutex>
+{
+public:
+    explicit ansicolor_stdout_sink(color_mode mode = color_mode::automatic);
+};
+
+template<typename ConsoleMutex>
+class ansicolor_stderr_sink : public ansicolor_sink<ConsoleMutex>
+{
+public:
+    explicit ansicolor_stderr_sink(color_mode mode = color_mode::automatic);
+};
+
+using ansicolor_stdout_sink_mt = ansicolor_stdout_sink<details::console_mutex>;
+using ansicolor_stdout_sink_st = ansicolor_stdout_sink<details::console_nullmutex>;
+
+using ansicolor_stderr_sink_mt = ansicolor_stderr_sink<details::console_mutex>;
+using ansicolor_stderr_sink_st = ansicolor_stderr_sink<details::console_nullmutex>;
+
+} // namespace sinks
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "ansicolor_sink-inl.h"
+#endif

spdlog/sinks/base_sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/base_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/pattern_formatter.h>
+
+#include <memory>
+
+template<typename Mutex>
+SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::base_sink()
+    : formatter_{details::make_unique<spdlog::pattern_formatter>()}
+{}
+
+template<typename Mutex>
+SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::base_sink(std::unique_ptr<spdlog::formatter> formatter)
+    : formatter_{std::move(formatter)}
+{}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::log(const details::log_msg &msg)
+{
+    std::lock_guard<Mutex> lock(mutex_);
+    sink_it_(msg);
+}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::flush()
+{
+    std::lock_guard<Mutex> lock(mutex_);
+    flush_();
+}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_pattern(const std::string &pattern)
+{
+    std::lock_guard<Mutex> lock(mutex_);
+    set_pattern_(pattern);
+}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter)
+{
+    std::lock_guard<Mutex> lock(mutex_);
+    set_formatter_(std::move(sink_formatter));
+}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_pattern_(const std::string &pattern)
+{
+    set_formatter_(details::make_unique<spdlog::pattern_formatter>(pattern));
+}
+
+template<typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter)
+{
+    formatter_ = std::move(sink_formatter);
+}

spdlog/sinks/base_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+//
+// base sink templated over a mutex (either dummy or real)
+// concrete implementation should override the sink_it_() and flush_()  methods.
+// locking is taken care of in this class - no locking needed by the
+// implementers..
+//
+
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/sinks/sink.h>
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class base_sink : public sink
+{
+public:
+    base_sink();
+    explicit base_sink(std::unique_ptr<spdlog::formatter> formatter);
+    ~base_sink() override = default;
+
+    base_sink(const base_sink &) = delete;
+    base_sink(base_sink &&) = delete;
+
+    base_sink &operator=(const base_sink &) = delete;
+    base_sink &operator=(base_sink &&) = delete;
+
+    void log(const details::log_msg &msg) final;
+    void flush() final;
+    void set_pattern(const std::string &pattern) final;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) final;
+
+protected:
+    // sink formatter
+    std::unique_ptr<spdlog::formatter> formatter_;
+    Mutex mutex_;
+
+    virtual void sink_it_(const details::log_msg &msg) = 0;
+    virtual void flush_() = 0;
+    virtual void set_pattern_(const std::string &pattern);
+    virtual void set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter);
+};
+} // namespace sinks
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "base_sink-inl.h"
+#endif

spdlog/sinks/basic_file_sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/basic_file_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace sinks {
+
+template<typename Mutex>
+SPDLOG_INLINE basic_file_sink<Mutex>::basic_file_sink(const filename_t &filename, bool truncate)
+{
+    file_helper_.open(filename, truncate);
+}
+
+template<typename Mutex>
+SPDLOG_INLINE const filename_t &basic_file_sink<Mutex>::filename() const
+{
+    return file_helper_.filename();
+}
+
+template<typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::sink_it_(const details::log_msg &msg)
+{
+    memory_buf_t formatted;
+    base_sink<Mutex>::formatter_->format(msg, formatted);
+    file_helper_.write(formatted);
+}
+
+template<typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::flush_()
+{
+    file_helper_.flush();
+}
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/basic_file_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Trivial file sink with single file as target
+ */
+template<typename Mutex>
+class basic_file_sink final : public base_sink<Mutex>
+{
+public:
+    explicit basic_file_sink(const filename_t &filename, bool truncate = false);
+    const filename_t &filename() const;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+
+private:
+    details::file_helper file_helper_;
+};
+
+using basic_file_sink_mt = basic_file_sink<std::mutex>;
+using basic_file_sink_st = basic_file_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate = false)
+{
+    return Factory::template create<sinks::basic_file_sink_mt>(logger_name, filename, truncate);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate = false)
+{
+    return Factory::template create<sinks::basic_file_sink_st>(logger_name, filename, truncate);
+}
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "basic_file_sink-inl.h"
+#endif
\ No newline at end of file

spdlog/sinks/daily_file_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/circular_q.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <chrono>
+#include <cstdio>
+#include <ctime>
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Generator of daily log file names in format basename.YYYY-MM-DD.ext
+ */
+struct daily_filename_calculator
+{
+    // Create filename for the form basename.YYYY-MM-DD
+    static filename_t calc_filename(const filename_t &filename, const tm &now_tm)
+    {
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
+        return fmt::format(
+            SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday, ext);
+    }
+};
+
+/*
+ * Rotating file sink based on date.
+ * If truncate != false , the created file will be truncated.
+ * If max_files > 0, retain only the last max_files and delete previous.
+ */
+template<typename Mutex, typename FileNameCalc = daily_filename_calculator>
+class daily_file_sink final : public base_sink<Mutex>
+{
+public:
+    // create daily file sink which rotates on given time
+    daily_file_sink(filename_t base_filename, int rotation_hour, int rotation_minute, bool truncate = false, uint16_t max_files = 0)
+        : base_filename_(std::move(base_filename))
+        , rotation_h_(rotation_hour)
+        , rotation_m_(rotation_minute)
+        , truncate_(truncate)
+        , max_files_(max_files)
+        , filenames_q_()
+    {
+        if (rotation_hour < 0 || rotation_hour > 23 || rotation_minute < 0 || rotation_minute > 59)
+        {
+            throw_spdlog_ex("daily_file_sink: Invalid rotation time in ctor");
+        }
+
+        auto now = log_clock::now();
+        auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
+        file_helper_.open(filename, truncate_);
+        rotation_tp_ = next_rotation_tp_();
+
+        if (max_files_ > 0)
+        {
+            init_filenames_q_();
+        }
+    }
+
+    filename_t filename()
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        return file_helper_.filename();
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        auto time = msg.time;
+        bool should_rotate = time >= rotation_tp_;
+        if (should_rotate)
+        {
+            auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(time));
+            file_helper_.open(filename, truncate_);
+            rotation_tp_ = next_rotation_tp_();
+        }
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        file_helper_.write(formatted);
+
+        // Do the cleaning only at the end because it might throw on failure.
+        if (should_rotate && max_files_ > 0)
+        {
+            delete_old_();
+        }
+    }
+
+    void flush_() override
+    {
+        file_helper_.flush();
+    }
+
+private:
+    void init_filenames_q_()
+    {
+        using details::os::path_exists;
+
+        filenames_q_ = details::circular_q<filename_t>(static_cast<size_t>(max_files_));
+        std::vector<filename_t> filenames;
+        auto now = log_clock::now();
+        while (filenames.size() < max_files_)
+        {
+            auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
+            if (!path_exists(filename))
+            {
+                break;
+            }
+            filenames.emplace_back(filename);
+            now -= std::chrono::hours(24);
+        }
+        for (auto iter = filenames.rbegin(); iter != filenames.rend(); ++iter)
+        {
+            filenames_q_.push_back(std::move(*iter));
+        }
+    }
+
+    tm now_tm(log_clock::time_point tp)
+    {
+        time_t tnow = log_clock::to_time_t(tp);
+        return spdlog::details::os::localtime(tnow);
+    }
+
+    log_clock::time_point next_rotation_tp_()
+    {
+        auto now = log_clock::now();
+        tm date = now_tm(now);
+        date.tm_hour = rotation_h_;
+        date.tm_min = rotation_m_;
+        date.tm_sec = 0;
+        auto rotation_time = log_clock::from_time_t(std::mktime(&date));
+        if (rotation_time > now)
+        {
+            return rotation_time;
+        }
+        return {rotation_time + std::chrono::hours(24)};
+    }
+
+    // Delete the file N rotations ago.
+    // Throw spdlog_ex on failure to delete the old file.
+    void delete_old_()
+    {
+        using details::os::filename_to_str;
+        using details::os::remove_if_exists;
+
+        filename_t current_file = file_helper_.filename();
+        if (filenames_q_.full())
+        {
+            auto old_filename = std::move(filenames_q_.front());
+            filenames_q_.pop_front();
+            bool ok = remove_if_exists(old_filename) == 0;
+            if (!ok)
+            {
+                filenames_q_.push_back(std::move(current_file));
+                throw_spdlog_ex("Failed removing daily file " + filename_to_str(old_filename), errno);
+            }
+        }
+        filenames_q_.push_back(std::move(current_file));
+    }
+
+    filename_t base_filename_;
+    int rotation_h_;
+    int rotation_m_;
+    log_clock::time_point rotation_tp_;
+    details::file_helper file_helper_;
+    bool truncate_;
+    uint16_t max_files_;
+    details::circular_q<filename_t> filenames_q_;
+};
+
+using daily_file_sink_mt = daily_file_sink<std::mutex>;
+using daily_file_sink_st = daily_file_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> daily_logger_mt(
+    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+{
+    return Factory::template create<sinks::daily_file_sink_mt>(logger_name, filename, hour, minute, truncate, max_files);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> daily_logger_st(
+    const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0, bool truncate = false, uint16_t max_files = 0)
+{
+    return Factory::template create<sinks::daily_file_sink_st>(logger_name, filename, hour, minute, truncate, max_files);
+}
+} // namespace spdlog

spdlog/sinks/dist_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "base_sink.h"
+#include <spdlog/details/log_msg.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/pattern_formatter.h>
+
+#include <algorithm>
+#include <memory>
+#include <mutex>
+#include <vector>
+
+// Distribution sink (mux). Stores a vector of sinks which get called when log
+// is called
+
+namespace spdlog {
+namespace sinks {
+
+template<typename Mutex>
+class dist_sink : public base_sink<Mutex>
+{
+public:
+    dist_sink() = default;
+    explicit dist_sink(std::vector<std::shared_ptr<sink>> sinks)
+        : sinks_(sinks)
+    {}
+
+    dist_sink(const dist_sink &) = delete;
+    dist_sink &operator=(const dist_sink &) = delete;
+
+    void add_sink(std::shared_ptr<sink> sink)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        sinks_.push_back(sink);
+    }
+
+    void remove_sink(std::shared_ptr<sink> sink)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        sinks_.erase(std::remove(sinks_.begin(), sinks_.end(), sink), sinks_.end());
+    }
+
+    void set_sinks(std::vector<std::shared_ptr<sink>> sinks)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        sinks_ = std::move(sinks);
+    }
+
+    std::vector<std::shared_ptr<sink>> &sinks()
+    {
+        return sinks_;
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        for (auto &sink : sinks_)
+        {
+            if (sink->should_log(msg.level))
+            {
+                sink->log(msg);
+            }
+        }
+    }
+
+    void flush_() override
+    {
+        for (auto &sink : sinks_)
+        {
+            sink->flush();
+        }
+    }
+
+    void set_pattern_(const std::string &pattern) override
+    {
+        set_formatter_(details::make_unique<spdlog::pattern_formatter>(pattern));
+    }
+
+    void set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter) override
+    {
+        base_sink<Mutex>::formatter_ = std::move(sink_formatter);
+        for (auto &sink : sinks_)
+        {
+            sink->set_formatter(base_sink<Mutex>::formatter_->clone());
+        }
+    }
+    std::vector<std::shared_ptr<sink>> sinks_;
+};
+
+using dist_sink_mt = dist_sink<std::mutex>;
+using dist_sink_st = dist_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/dup_filter_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "dist_sink.h"
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/log_msg.h>
+
+#include <mutex>
+#include <string>
+#include <chrono>
+
+// Duplicate message removal sink.
+// Skip the message if previous one is identical and less than "max_skip_duration" have passed
+//
+// Example:
+//
+//     #include <spdlog/sinks/dup_filter_sink.h>
+//
+//     int main() {
+//         auto dup_filter = std::make_shared<dup_filter_sink_st>(std::chrono::seconds(5));
+//         dup_filter->add_sink(std::make_shared<stdout_color_sink_mt>());
+//         spdlog::logger l("logger", dup_filter);
+//         l.info("Hello");
+//         l.info("Hello");
+//         l.info("Hello");
+//         l.info("Different Hello");
+//     }
+//
+// Will produce:
+//       [2019-06-25 17:50:56.511] [logger] [info] Hello
+//       [2019-06-25 17:50:56.512] [logger] [info] Skipped 3 duplicate messages..
+//       [2019-06-25 17:50:56.512] [logger] [info] Different Hello
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class dup_filter_sink : public dist_sink<Mutex>
+{
+public:
+    template<class Rep, class Period>
+    explicit dup_filter_sink(std::chrono::duration<Rep, Period> max_skip_duration)
+        : max_skip_duration_{max_skip_duration}
+    {}
+
+protected:
+    std::chrono::microseconds max_skip_duration_;
+    log_clock::time_point last_msg_time_;
+    std::string last_msg_payload_;
+    size_t skip_counter_ = 0;
+
+    void sink_it_(const details::log_msg &msg) override
+    {
+        bool filtered = filter_(msg);
+        if (!filtered)
+        {
+            skip_counter_ += 1;
+            return;
+        }
+
+        // log the "skipped.." message
+        if (skip_counter_ > 0)
+        {
+            memory_buf_t buf;
+            fmt::format_to(buf, "Skipped {} duplicate messages..", skip_counter_);
+            details::log_msg skipped_msg{msg.logger_name, level::info, string_view_t{buf.data(), buf.size()}};
+            dist_sink<Mutex>::sink_it_(skipped_msg);
+        }
+
+        // log current message
+        dist_sink<Mutex>::sink_it_(msg);
+        last_msg_time_ = msg.time;
+        skip_counter_ = 0;
+        last_msg_payload_.assign(msg.payload.data(), msg.payload.data() + msg.payload.size());
+    }
+
+    // return whether the log msg should be displayed (true) or skipped (false)
+    bool filter_(const details::log_msg &msg)
+    {
+        auto filter_duration = msg.time - last_msg_time_;
+        return (filter_duration > max_skip_duration_) || (msg.payload != last_msg_payload_);
+    }
+};
+
+using dup_filter_sink_mt = dup_filter_sink<std::mutex>;
+using dup_filter_sink_st = dup_filter_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/msvc_sink.h

+// Copyright(c) 2016 Alexander Dalshov.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#if defined(_WIN32)
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+
+#include <mutex>
+#include <string>
+
+
+// Avoid including windows.h (https://stackoverflow.com/a/30741042)
+extern "C" __declspec(dllimport) void __stdcall OutputDebugStringA(const char *lpOutputString);
+
+namespace spdlog {
+namespace sinks {
+/*
+ * MSVC sink (logging using OutputDebugStringA)
+ */
+template<typename Mutex>
+class msvc_sink : public base_sink<Mutex>
+{
+public:
+    msvc_sink() = default;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        OutputDebugStringA(fmt::to_string(formatted).c_str());
+    }
+
+    void flush_() override {}
+};
+
+using msvc_sink_mt = msvc_sink<std::mutex>;
+using msvc_sink_st = msvc_sink<details::null_mutex>;
+
+using windebug_sink_mt = msvc_sink_mt;
+using windebug_sink_st = msvc_sink_st;
+
+} // namespace sinks
+} // namespace spdlog
+
+#endif

spdlog/sinks/null_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <mutex>
+
+namespace spdlog {
+namespace sinks {
+
+template<typename Mutex>
+class null_sink : public base_sink<Mutex>
+{
+protected:
+    void sink_it_(const details::log_msg &) override {}
+    void flush_() override {}
+};
+
+using null_sink_mt = null_sink<details::null_mutex>;
+using null_sink_st = null_sink<details::null_mutex>;
+
+} // namespace sinks
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> null_logger_mt(const std::string &logger_name)
+{
+    auto null_logger = Factory::template create<sinks::null_sink_mt>(logger_name);
+    null_logger->set_level(level::off);
+    return null_logger;
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> null_logger_st(const std::string &logger_name)
+{
+    auto null_logger = Factory::template create<sinks::null_sink_st>(logger_name);
+    null_logger->set_level(level::off);
+    return null_logger;
+}
+
+} // namespace spdlog

spdlog/sinks/ostream_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+
+#include <mutex>
+#include <ostream>
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class ostream_sink final : public base_sink<Mutex>
+{
+public:
+    explicit ostream_sink(std::ostream &os, bool force_flush = false)
+        : ostream_(os)
+        , force_flush_(force_flush)
+    {}
+    ostream_sink(const ostream_sink &) = delete;
+    ostream_sink &operator=(const ostream_sink &) = delete;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        ostream_.write(formatted.data(), static_cast<std::streamsize>(formatted.size()));
+        if (force_flush_)
+        {
+            ostream_.flush();
+        }
+    }
+
+    void flush_() override
+    {
+        ostream_.flush();
+    }
+
+    std::ostream &ostream_;
+    bool force_flush_;
+};
+
+using ostream_sink_mt = ostream_sink<std::mutex>;
+using ostream_sink_st = ostream_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/ringbuffer_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "spdlog/sinks/base_sink.h"
+#include "spdlog/details/circular_q.h"
+#include "spdlog/details/log_msg_buffer.h"
+#include "spdlog/details/null_mutex.h"
+
+#include <mutex>
+#include <string>
+#include <vector>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Ring buffer sink
+ */
+template<typename Mutex>
+class ringbuffer_sink final : public base_sink<Mutex>
+{
+public:
+    explicit ringbuffer_sink(size_t n_items)
+        : q_{n_items}
+    {}
+
+    std::vector<details::log_msg_buffer> last_raw(size_t lim = 0)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        auto items_available = q_.size();
+        auto n_items = lim > 0 ? (std::min)(lim, items_available) : items_available;
+        std::vector<details::log_msg_buffer> ret;
+        ret.reserve(n_items);
+        for (size_t i = (items_available - n_items); i < items_available; i++)
+        {
+            ret.push_back(q_.at(i));
+        }
+        return ret;
+    }
+
+    std::vector<std::string> last_formatted(size_t lim = 0)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        auto items_available = q_.size();
+        auto n_items = lim > 0 ? (std::min)(lim, items_available) : items_available;
+        std::vector<std::string> ret;
+        ret.reserve(n_items);
+        for (size_t i = (items_available - n_items); i < items_available; i++)
+        {
+            memory_buf_t formatted;
+            base_sink<Mutex>::formatter_->format(q_.at(i), formatted);
+            ret.push_back(fmt::to_string(formatted));
+        }
+        return ret;
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        q_.push_back(details::log_msg_buffer{msg});
+    }
+    void flush_() override {}
+
+private:
+    details::circular_q<details::log_msg_buffer> q_;
+};
+
+using ringbuffer_sink_mt = ringbuffer_sink<std::mutex>;
+using ringbuffer_sink_st = ringbuffer_sink<details::null_mutex>;
+
+} // namespace sinks
+
+} // namespace spdlog

spdlog/sinks/rotating_file_sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/rotating_file_sink.h>
+#endif
+
+#include <spdlog/common.h>
+
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/fmt/fmt.h>
+
+#include <cerrno>
+#include <chrono>
+#include <ctime>
+#include <mutex>
+#include <string>
+#include <tuple>
+
+namespace spdlog {
+namespace sinks {
+
+template<typename Mutex>
+SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
+    filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open)
+    : base_filename_(std::move(base_filename))
+    , max_size_(max_size)
+    , max_files_(max_files)
+{
+    file_helper_.open(calc_filename(base_filename_, 0));
+    current_size_ = file_helper_.size(); // expensive. called only once
+    if (rotate_on_open && current_size_ > 0)
+    {
+        rotate_();
+    }
+}
+
+// calc filename according to index and file extension if exists.
+// e.g. calc_filename("logs/mylog.txt, 3) => "logs/mylog.3.txt".
+template<typename Mutex>
+SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename_t &filename, std::size_t index)
+{
+    if (index == 0u)
+    {
+        return filename;
+    }
+
+    filename_t basename, ext;
+    std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
+    return fmt::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+}
+
+template<typename Mutex>
+SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::filename()
+{
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    return file_helper_.filename();
+}
+
+template<typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::sink_it_(const details::log_msg &msg)
+{
+    memory_buf_t formatted;
+    base_sink<Mutex>::formatter_->format(msg, formatted);
+    current_size_ += formatted.size();
+    if (current_size_ > max_size_)
+    {
+        rotate_();
+        current_size_ = formatted.size();
+    }
+    file_helper_.write(formatted);
+}
+
+template<typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::flush_()
+{
+    file_helper_.flush();
+}
+
+// Rotate files:
+// log.txt -> log.1.txt
+// log.1.txt -> log.2.txt
+// log.2.txt -> log.3.txt
+// log.3.txt -> delete
+template<typename Mutex>
+SPDLOG_INLINE void rotating_file_sink<Mutex>::rotate_()
+{
+    using details::os::filename_to_str;
+    using details::os::path_exists;
+    file_helper_.close();
+    for (auto i = max_files_; i > 0; --i)
+    {
+        filename_t src = calc_filename(base_filename_, i - 1);
+        if (!path_exists(src))
+        {
+            continue;
+        }
+        filename_t target = calc_filename(base_filename_, i);
+
+        if (!rename_file_(src, target))
+        {
+            // if failed try again after a small delay.
+            // this is a workaround to a windows issue, where very high rotation
+            // rates can cause the rename to fail with permission denied (because of antivirus?).
+            details::os::sleep_for_millis(100);
+            if (!rename_file_(src, target))
+            {
+                file_helper_.reopen(true); // truncate the log file anyway to prevent it to grow beyond its limit!
+                current_size_ = 0;
+                throw_spdlog_ex("rotating_file_sink: failed renaming " + filename_to_str(src) + " to " + filename_to_str(target), errno);
+            }
+        }
+    }
+    file_helper_.reopen(true);
+}
+
+// delete the target if exists, and rename the src file  to target
+// return true on success, false otherwise.
+template<typename Mutex>
+SPDLOG_INLINE bool rotating_file_sink<Mutex>::rename_file_(const filename_t &src_filename, const filename_t &target_filename)
+{
+    // try to delete the target file in case it already exists.
+    (void)details::os::remove(target_filename);
+    return details::os::rename(src_filename, target_filename) == 0;
+}
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/rotating_file_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <chrono>
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+
+//
+// Rotating file sink based on size
+//
+template<typename Mutex>
+class rotating_file_sink final : public base_sink<Mutex>
+{
+public:
+    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open = false);
+    static filename_t calc_filename(const filename_t &filename, std::size_t index);
+    filename_t filename();
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+
+private:
+    // Rotate files:
+    // log.txt -> log.1.txt
+    // log.1.txt -> log.2.txt
+    // log.2.txt -> log.3.txt
+    // log.3.txt -> delete
+    void rotate_();
+
+    // delete the target if exists, and rename the src file  to target
+    // return true on success, false otherwise.
+    bool rename_file_(const filename_t &src_filename, const filename_t &target_filename);
+
+    filename_t base_filename_;
+    std::size_t max_size_;
+    std::size_t max_files_;
+    std::size_t current_size_;
+    details::file_helper file_helper_;
+};
+
+using rotating_file_sink_mt = rotating_file_sink<std::mutex>;
+using rotating_file_sink_st = rotating_file_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> rotating_logger_mt(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files, bool rotate_on_open = false)
+{
+    return Factory::template create<sinks::rotating_file_sink_mt>(logger_name, filename, max_file_size, max_files, rotate_on_open);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> rotating_logger_st(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files, bool rotate_on_open = false)
+{
+    return Factory::template create<sinks::rotating_file_sink_st>(logger_name, filename, max_file_size, max_files, rotate_on_open);
+}
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "rotating_file_sink-inl.h"
+#endif

spdlog/sinks/sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/sink.h>
+#endif
+
+#include <spdlog/common.h>
+
+SPDLOG_INLINE bool spdlog::sinks::sink::should_log(spdlog::level::level_enum msg_level) const
+{
+    return msg_level >= level_.load(std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE void spdlog::sinks::sink::set_level(level::level_enum log_level)
+{
+    level_.store(log_level, std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE spdlog::level::level_enum spdlog::sinks::sink::level() const
+{
+    return static_cast<spdlog::level::level_enum>(level_.load(std::memory_order_relaxed));
+}

spdlog/sinks/sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg.h>
+#include <spdlog/formatter.h>
+
+namespace spdlog {
+
+namespace sinks {
+class SPDLOG_API sink
+{
+public:
+    virtual ~sink() = default;
+    virtual void log(const details::log_msg &msg) = 0;
+    virtual void flush() = 0;
+    virtual void set_pattern(const std::string &pattern) = 0;
+    virtual void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) = 0;
+
+    void set_level(level::level_enum log_level);
+    level::level_enum level() const;
+    bool should_log(level::level_enum msg_level) const;
+
+protected:
+    // sink log level - default is all
+    level_t level_{level::trace};
+};
+
+} // namespace sinks
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "sink-inl.h"
+#endif

spdlog/sinks/stdout_color_sinks-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/stdout_color_sinks.h>
+#endif
+
+#include <spdlog/logger.h>
+#include <spdlog/common.h>
+
+namespace spdlog {
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stdout_color_mt(const std::string &logger_name, color_mode mode)
+{
+    return Factory::template create<sinks::stdout_color_sink_mt>(logger_name, mode);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stdout_color_st(const std::string &logger_name, color_mode mode)
+{
+    return Factory::template create<sinks::stdout_color_sink_st>(logger_name, mode);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stderr_color_mt(const std::string &logger_name, color_mode mode)
+{
+    return Factory::template create<sinks::stderr_color_sink_mt>(logger_name, mode);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stderr_color_st(const std::string &logger_name, color_mode mode)
+{
+    return Factory::template create<sinks::stderr_color_sink_st>(logger_name, mode);
+}
+} // namespace spdlog
\ No newline at end of file

spdlog/sinks/stdout_color_sinks.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifdef _WIN32
+#include <spdlog/sinks/wincolor_sink.h>
+#else
+#include <spdlog/sinks/ansicolor_sink.h>
+#endif
+
+#include <spdlog/details/synchronous_factory.h>
+
+namespace spdlog {
+namespace sinks {
+#ifdef _WIN32
+using stdout_color_sink_mt = wincolor_stdout_sink_mt;
+using stdout_color_sink_st = wincolor_stdout_sink_st;
+using stderr_color_sink_mt = wincolor_stderr_sink_mt;
+using stderr_color_sink_st = wincolor_stderr_sink_st;
+#else
+using stdout_color_sink_mt = ansicolor_stdout_sink_mt;
+using stdout_color_sink_st = ansicolor_stdout_sink_st;
+using stderr_color_sink_mt = ansicolor_stderr_sink_mt;
+using stderr_color_sink_st = ansicolor_stderr_sink_st;
+#endif
+} // namespace sinks
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stdout_color_mt(const std::string &logger_name, color_mode mode = color_mode::automatic);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stdout_color_st(const std::string &logger_name, color_mode mode = color_mode::automatic);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stderr_color_mt(const std::string &logger_name, color_mode mode = color_mode::automatic);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stderr_color_st(const std::string &logger_name, color_mode mode = color_mode::automatic);
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "stdout_color_sinks-inl.h"
+#endif

spdlog/sinks/stdout_sinks-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/stdout_sinks.h>
+#endif
+
+#include <spdlog/details/console_globals.h>
+#include <spdlog/pattern_formatter.h>
+#include <memory>
+
+#ifdef _WIN32
+// under windows using fwrite to non-binary stream results in \r\r\n (see issue #1675)
+// so instead we use ::FileWrite
+#include <spdlog/details/windows_include.h>
+#include <fileapi.h> // WriteFile (..)
+#include <io.h>      // _get_osfhandle(..)
+#include <stdio.h>   // _fileno(..)
+#endif               // WIN32
+
+namespace spdlog {
+
+namespace sinks {
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE stdout_sink_base<ConsoleMutex>::stdout_sink_base(FILE *file)
+    : mutex_(ConsoleMutex::mutex())
+    , file_(file)
+    , formatter_(details::make_unique<spdlog::pattern_formatter>())
+{
+#ifdef _WIN32
+    // get windows handle from the FILE* object
+    handle_ = (HANDLE)::_get_osfhandle(::_fileno(file_));
+    if (handle_ == INVALID_HANDLE_VALUE)
+    {
+        throw_spdlog_ex("spdlog::stdout_sink_base: _get_osfhandle() failed", errno);
+    }
+#endif // WIN32
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::log(const details::log_msg &msg)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    memory_buf_t formatted;
+    formatter_->format(msg, formatted);
+#ifdef _WIN32
+    ::fflush(file_); // flush in case there is somthing in this file_ already
+    auto size = static_cast<DWORD>(formatted.size());
+    DWORD bytes_written = 0;
+    bool ok = ::WriteFile(handle_, formatted.data(), size, &bytes_written, nullptr) != 0;
+    if (!ok)
+    {
+        throw_spdlog_ex("stdout_sink_base: WriteFile() failed. GetLastError(): " + std::to_string(::GetLastError()));
+    }
+#else
+    ::fwrite(formatted.data(), sizeof(char), formatted.size(), file_);
+    ::fflush(file_); // flush every line to terminal
+#endif // WIN32    
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::flush()
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    fflush(file_);
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::set_pattern(const std::string &pattern)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::unique_ptr<spdlog::formatter>(new pattern_formatter(pattern));
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::move(sink_formatter);
+}
+
+// stdout sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE stdout_sink<ConsoleMutex>::stdout_sink()
+    : stdout_sink_base<ConsoleMutex>(stdout)
+{}
+
+// stderr sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE stderr_sink<ConsoleMutex>::stderr_sink()
+    : stdout_sink_base<ConsoleMutex>(stderr)
+{}
+
+} // namespace sinks
+
+// factory methods
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stdout_logger_mt(const std::string &logger_name)
+{
+    return Factory::template create<sinks::stdout_sink_mt>(logger_name);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stdout_logger_st(const std::string &logger_name)
+{
+    return Factory::template create<sinks::stdout_sink_st>(logger_name);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stderr_logger_mt(const std::string &logger_name)
+{
+    return Factory::template create<sinks::stderr_sink_mt>(logger_name);
+}
+
+template<typename Factory>
+SPDLOG_INLINE std::shared_ptr<logger> stderr_logger_st(const std::string &logger_name)
+{
+    return Factory::template create<sinks::stderr_sink_st>(logger_name);
+}
+} // namespace spdlog

spdlog/sinks/stdout_sinks.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/console_globals.h>
+#include <spdlog/details/synchronous_factory.h>
+#include <spdlog/sinks/sink.h>
+#include <cstdio>
+
+#ifdef _WIN32
+#include <spdlog/details/windows_include.h>
+#endif
+
+namespace spdlog {
+
+namespace sinks {
+
+template<typename ConsoleMutex>
+class stdout_sink_base : public sink
+{
+public:
+    using mutex_t = typename ConsoleMutex::mutex_t;
+    explicit stdout_sink_base(FILE *file);
+    ~stdout_sink_base() override = default;
+
+    stdout_sink_base(const stdout_sink_base &other) = delete;
+    stdout_sink_base(stdout_sink_base &&other) = delete;
+
+    stdout_sink_base &operator=(const stdout_sink_base &other) = delete;
+    stdout_sink_base &operator=(stdout_sink_base &&other) = delete;
+
+    void log(const details::log_msg &msg) override;
+    void flush() override;
+    void set_pattern(const std::string &pattern) override;
+
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
+
+protected:
+    mutex_t &mutex_;
+    FILE *file_;
+    std::unique_ptr<spdlog::formatter> formatter_;
+#ifdef _WIN32
+    HANDLE handle_;    
+#endif // WIN32
+};
+
+template<typename ConsoleMutex>
+class stdout_sink : public stdout_sink_base<ConsoleMutex>
+{
+public:
+    stdout_sink();
+};
+
+template<typename ConsoleMutex>
+class stderr_sink : public stdout_sink_base<ConsoleMutex>
+{
+public:
+    stderr_sink();
+};
+
+using stdout_sink_mt = stdout_sink<details::console_mutex>;
+using stdout_sink_st = stdout_sink<details::console_nullmutex>;
+
+using stderr_sink_mt = stderr_sink<details::console_mutex>;
+using stderr_sink_st = stderr_sink<details::console_nullmutex>;
+
+} // namespace sinks
+
+// factory methods
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stdout_logger_mt(const std::string &logger_name);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stdout_logger_st(const std::string &logger_name);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stderr_logger_mt(const std::string &logger_name);
+
+template<typename Factory = spdlog::synchronous_factory>
+std::shared_ptr<logger> stderr_logger_st(const std::string &logger_name);
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "stdout_sinks-inl.h"
+#endif

spdlog/sinks/syslog_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <array>
+#include <string>
+#include <syslog.h>
+
+namespace spdlog {
+namespace sinks {
+/**
+ * Sink that write to syslog using the `syscall()` library call.
+ */
+template<typename Mutex>
+class syslog_sink : public base_sink<Mutex>
+{
+
+public:
+    syslog_sink(std::string ident, int syslog_option, int syslog_facility, bool enable_formatting)
+        : enable_formatting_{enable_formatting}
+        , syslog_levels_{{/* spdlog::level::trace      */ LOG_DEBUG,
+              /* spdlog::level::debug      */ LOG_DEBUG,
+              /* spdlog::level::info       */ LOG_INFO,
+              /* spdlog::level::warn       */ LOG_WARNING,
+              /* spdlog::level::err        */ LOG_ERR,
+              /* spdlog::level::critical   */ LOG_CRIT,
+              /* spdlog::level::off        */ LOG_INFO}}
+        , ident_{std::move(ident)}
+    {
+        // set ident to be program name if empty
+        ::openlog(ident_.empty() ? nullptr : ident_.c_str(), syslog_option, syslog_facility);
+    }
+
+    ~syslog_sink() override
+    {
+        ::closelog();
+    }
+
+    syslog_sink(const syslog_sink &) = delete;
+    syslog_sink &operator=(const syslog_sink &) = delete;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        string_view_t payload;
+        memory_buf_t formatted;
+        if (enable_formatting_)
+        {
+            base_sink<Mutex>::formatter_->format(msg, formatted);
+            payload = string_view_t(formatted.data(), formatted.size());
+        }
+        else
+        {
+            payload = msg.payload;
+        }
+
+        size_t length = payload.size();
+        // limit to max int
+        if (length > static_cast<size_t>(std::numeric_limits<int>::max()))
+        {
+            length = static_cast<size_t>(std::numeric_limits<int>::max());
+        }
+
+        ::syslog(syslog_prio_from_level(msg), "%.*s", static_cast<int>(length), payload.data());
+    }
+
+    void flush_() override {}
+    bool enable_formatting_ = false;
+
+private:
+    using levels_array = std::array<int, 7>;
+    levels_array syslog_levels_;
+    // must store the ident because the man says openlog might use the pointer as
+    // is and not a string copy
+    const std::string ident_;
+
+    //
+    // Simply maps spdlog's log level to syslog priority level.
+    //
+    int syslog_prio_from_level(const details::log_msg &msg) const
+    {
+        return syslog_levels_.at(static_cast<levels_array::size_type>(msg.level));
+    }
+};
+
+using syslog_sink_mt = syslog_sink<std::mutex>;
+using syslog_sink_st = syslog_sink<details::null_mutex>;
+} // namespace sinks
+
+// Create and register a syslog logger
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> syslog_logger_mt(const std::string &logger_name, const std::string &syslog_ident = "", int syslog_option = 0,
+    int syslog_facility = LOG_USER, bool enable_formatting = false)
+{
+    return Factory::template create<sinks::syslog_sink_mt>(logger_name, syslog_ident, syslog_option, syslog_facility, enable_formatting);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> syslog_logger_st(const std::string &logger_name, const std::string &syslog_ident = "", int syslog_option = 0,
+    int syslog_facility = LOG_USER, bool enable_formatting = false)
+{
+    return Factory::template create<sinks::syslog_sink_st>(logger_name, syslog_ident, syslog_option, syslog_facility, enable_formatting);
+}
+} // namespace spdlog

spdlog/sinks/systemd_sink.h

+// Copyright(c) 2019 ZVYAGIN.Alexander@gmail.com
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <array>
+#ifndef SD_JOURNAL_SUPPRESS_LOCATION
+#define SD_JOURNAL_SUPPRESS_LOCATION
+#endif
+#include <systemd/sd-journal.h>
+
+namespace spdlog {
+namespace sinks {
+
+/**
+ * Sink that write to systemd journal using the `sd_journal_send()` library call.
+ *
+ * Locking is not needed, as `sd_journal_send()` itself is thread-safe.
+ */
+template<typename Mutex>
+class systemd_sink : public base_sink<Mutex>
+{
+public:
+    //
+    systemd_sink()
+        : syslog_levels_{{/* spdlog::level::trace      */ LOG_DEBUG,
+              /* spdlog::level::debug      */ LOG_DEBUG,
+              /* spdlog::level::info       */ LOG_INFO,
+              /* spdlog::level::warn       */ LOG_WARNING,
+              /* spdlog::level::err        */ LOG_ERR,
+              /* spdlog::level::critical   */ LOG_CRIT,
+              /* spdlog::level::off        */ LOG_INFO}}
+    {}
+
+    ~systemd_sink() override {}
+
+    systemd_sink(const systemd_sink &) = delete;
+    systemd_sink &operator=(const systemd_sink &) = delete;
+
+protected:
+    using levels_array = std::array<int, 7>;
+    levels_array syslog_levels_;
+
+    void sink_it_(const details::log_msg &msg) override
+    {
+        int err;
+
+        size_t length = msg.payload.size();
+        // limit to max int
+        if (length > static_cast<size_t>(std::numeric_limits<int>::max()))
+        {
+            length = static_cast<size_t>(std::numeric_limits<int>::max());
+        }
+
+        // Do not send source location if not available
+        if (msg.source.empty())
+        {
+            // Note: function call inside '()' to avoid macro expansion
+            err = (sd_journal_send)("MESSAGE=%.*s", static_cast<int>(length), msg.payload.data(), "PRIORITY=%d", syslog_level(msg.level),
+                "SYSLOG_IDENTIFIER=%.*s", static_cast<int>(msg.logger_name.size()), msg.logger_name.data(), nullptr);
+        }
+        else
+        {
+            err = (sd_journal_send)("MESSAGE=%.*s", static_cast<int>(length), msg.payload.data(), "PRIORITY=%d", syslog_level(msg.level),
+                "SYSLOG_IDENTIFIER=%.*s", static_cast<int>(msg.logger_name.size()), msg.logger_name.data(), "CODE_FILE=%s",
+                msg.source.filename, "CODE_LINE=%d", msg.source.line, "CODE_FUNC=%s", msg.source.funcname, nullptr);
+        }
+
+        if (err)
+        {
+            throw_spdlog_ex("Failed writing to systemd", errno);
+        }
+    }
+
+    int syslog_level(level::level_enum l)
+    {
+        return syslog_levels_.at(static_cast<levels_array::size_type>(l));
+    }
+
+    void flush_() override {}
+};
+
+using systemd_sink_mt = systemd_sink<std::mutex>;
+using systemd_sink_st = systemd_sink<details::null_mutex>;
+} // namespace sinks
+
+// Create and register a syslog logger
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> systemd_logger_mt(const std::string &logger_name)
+{
+    return Factory::template create<sinks::systemd_sink_mt>(logger_name);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> systemd_logger_st(const std::string &logger_name)
+{
+    return Factory::template create<sinks::systemd_sink_st>(logger_name);
+}
+} // namespace spdlog

spdlog/sinks/tcp_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/null_mutex.h>
+#ifdef _WIN32
+#include <spdlog/details/tcp_client-windows.h>
+#else
+#include <spdlog/details/tcp_client.h>
+#endif
+
+#include <mutex>
+#include <string>
+#include <chrono>
+#include <functional>
+
+#pragma once
+
+// Simple tcp client sink
+// Connects to remote address and send the formatted log.
+// Will attempt to reconnect if connection drops.
+// If more complicated behaviour is needed (i.e get responses), you can inherit it and override the sink_it_ method.
+
+namespace spdlog {
+namespace sinks {
+
+struct tcp_sink_config
+{
+    std::string server_host;
+    int server_port;
+    bool lazy_connect = false; // if true connect on first log call instead of on construction
+
+    tcp_sink_config(std::string host, int port)
+        : server_host{std::move(host)}
+        , server_port{port}
+    {}
+};
+
+template<typename Mutex>
+class tcp_sink : public spdlog::sinks::base_sink<Mutex>
+{
+public:
+    // connect to tcp host/port or throw if failed
+    // host can be hostname or ip address
+
+    explicit tcp_sink(tcp_sink_config sink_config)
+        : config_{std::move(sink_config)}
+    {
+        if (!config_.lazy_connect)
+        {
+            this->client_.connect(config_.server_host, config_.server_port);
+        }
+    }
+
+    ~tcp_sink() override = default;
+
+protected:
+    void sink_it_(const spdlog::details::log_msg &msg) override
+    {
+        spdlog::memory_buf_t formatted;
+        spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
+        if (!client_.is_connected())
+        {
+            client_.connect(config_.server_host, config_.server_port);
+        }
+        client_.send(formatted.data(), formatted.size());
+    }
+
+    void flush_() override {}
+    tcp_sink_config config_;
+    details::tcp_client client_;
+};
+
+using tcp_sink_mt = tcp_sink<std::mutex>;
+using tcp_sink_st = tcp_sink<spdlog::details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/win_eventlog_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+// Writing to Windows Event Log requires the registry entries below to be present, with the following modifications:
+// 1. <log_name>    should be replaced with your log name (e.g. your application name)
+// 2. <source_name> should be replaced with the specific source name and the key should be duplicated for
+//                  each source used in the application
+//
+// Since typically modifications of this kind require elevation, it's better to do it as a part of setup procedure.
+// The snippet below uses mscoree.dll as the message file as it exists on most of the Windows systems anyway and
+// happens to contain the needed resource.
+//
+// You can also specify a custom message file if needed.
+// Please refer to Event Log functions descriptions in MSDN for more details on custom message files.
+
+/*---------------------------------------------------------------------------------------
+
+Windows Registry Editor Version 5.00
+
+[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\<log_name>]
+
+[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\<log_name>\<source_name>]
+"TypesSupported"=dword:00000007
+"EventMessageFile"=hex(2):25,00,73,00,79,00,73,00,74,00,65,00,6d,00,72,00,6f,\
+  00,6f,00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,\
+  5c,00,6d,00,73,00,63,00,6f,00,72,00,65,00,65,00,2e,00,64,00,6c,00,6c,00,00,\
+  00
+
+-----------------------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/base_sink.h>
+
+#include <spdlog/details/windows_include.h>
+#include <winbase.h>
+
+#include <mutex>
+#include <string>
+#include <vector>
+
+namespace spdlog {
+namespace sinks {
+
+namespace win_eventlog {
+
+namespace internal {
+
+/** Windows error */
+struct win32_error : public spdlog_ex
+{
+    /** Formats an error report line: "user-message: error-code (system message)" */
+    static std::string format(std::string const &user_message, DWORD error_code = GetLastError())
+    {
+        std::string system_message;
+
+        LPSTR format_message_result{};
+        auto format_message_succeeded =
+            ::FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
+                error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&format_message_result, 0, nullptr);
+
+        if (format_message_succeeded && format_message_result)
+        {
+            system_message = fmt::format(" ({})", format_message_result);
+        }
+
+        if (format_message_result)
+        {
+            LocalFree((HLOCAL)format_message_result);
+        }
+
+        return fmt::format("{}: {}{}", user_message, error_code, system_message);
+    }
+
+    explicit win32_error(std::string const &func_name, DWORD error = GetLastError())
+        : spdlog_ex(format(func_name, error))
+    {}
+};
+
+/** Wrapper for security identifiers (SID) on Windows */
+struct sid_t
+{
+    std::vector<char> buffer_;
+
+public:
+    sid_t() {}
+
+    /** creates a wrapped SID copy */
+    static sid_t duplicate_sid(PSID psid)
+    {
+        if (!::IsValidSid(psid))
+        {
+            throw_spdlog_ex("sid_t::sid_t(): invalid SID received");
+        }
+
+        auto const sid_length{::GetLengthSid(psid)};
+
+        sid_t result;
+        result.buffer_.resize(sid_length);
+        if (!::CopySid(sid_length, (PSID)result.as_sid(), psid))
+        {
+            SPDLOG_THROW(win32_error("CopySid"));
+        }
+
+        return result;
+    }
+
+    /** Retrieves pointer to the internal buffer contents as SID* */
+    SID *as_sid() const
+    {
+        return buffer_.empty() ? nullptr : (SID *)buffer_.data();
+    }
+
+    /** Get SID for the current user */
+    static sid_t get_current_user_sid()
+    {
+        /* create and init RAII holder for process token */
+        struct process_token_t
+        {
+            HANDLE token_handle_ = INVALID_HANDLE_VALUE;
+            explicit process_token_t(HANDLE process)
+            {
+                if (!::OpenProcessToken(process, TOKEN_QUERY, &token_handle_))
+                {
+                    SPDLOG_THROW(win32_error("OpenProcessToken"));
+                }
+            }
+
+            ~process_token_t()
+            {
+                ::CloseHandle(token_handle_);
+            }
+
+        } current_process_token(::GetCurrentProcess()); // GetCurrentProcess returns pseudohandle, no leak here!
+
+        // Get the required size, this is expected to fail with ERROR_INSUFFICIENT_BUFFER and return the token size
+        DWORD tusize = 0;
+        if (::GetTokenInformation(current_process_token.token_handle_, TokenUser, NULL, 0, &tusize))
+        {
+            SPDLOG_THROW(win32_error("GetTokenInformation should fail"));
+        }
+
+        // get user token
+        std::vector<unsigned char> buffer(static_cast<size_t>(tusize));
+        if (!::GetTokenInformation(current_process_token.token_handle_, TokenUser, (LPVOID)buffer.data(), tusize, &tusize))
+        {
+            SPDLOG_THROW(win32_error("GetTokenInformation"));
+        }
+
+        // create a wrapper of the SID data as stored in the user token
+        return sid_t::duplicate_sid(((TOKEN_USER *)buffer.data())->User.Sid);
+    }
+};
+
+struct eventlog
+{
+    static WORD get_event_type(details::log_msg const &msg)
+    {
+        switch (msg.level)
+        {
+        case level::trace:
+        case level::debug:
+            return EVENTLOG_SUCCESS;
+
+        case level::info:
+            return EVENTLOG_INFORMATION_TYPE;
+
+        case level::warn:
+            return EVENTLOG_WARNING_TYPE;
+
+        case level::err:
+        case level::critical:
+        case level::off:
+            return EVENTLOG_ERROR_TYPE;
+
+        default:
+            return EVENTLOG_INFORMATION_TYPE;
+        }
+    }
+
+    static WORD get_event_category(details::log_msg const &msg)
+    {
+        return (WORD)msg.level;
+    }
+};
+
+} // namespace internal
+
+/*
+ * Windows Event Log sink
+ */
+template<typename Mutex>
+class win_eventlog_sink : public base_sink<Mutex>
+{
+private:
+    HANDLE hEventLog_{NULL};
+    internal::sid_t current_user_sid_;
+    std::string source_;
+    WORD event_id_;
+
+    HANDLE event_log_handle()
+    {
+        if (!hEventLog_)
+        {
+            hEventLog_ = ::RegisterEventSource(nullptr, source_.c_str());
+            if (!hEventLog_ || hEventLog_ == (HANDLE)ERROR_ACCESS_DENIED)
+            {
+                SPDLOG_THROW(internal::win32_error("RegisterEventSource"));
+            }
+        }
+
+        return hEventLog_;
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        using namespace internal;
+
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        formatted.push_back('\0');
+        LPCSTR lp_str = static_cast<LPCSTR>(formatted.data());
+
+        auto succeeded = ::ReportEvent(event_log_handle(), eventlog::get_event_type(msg), eventlog::get_event_category(msg), event_id_,
+            current_user_sid_.as_sid(), 1, 0, &lp_str, nullptr);
+
+        if (!succeeded)
+        {
+            SPDLOG_THROW(win32_error("ReportEvent"));
+        }
+    }
+
+    void flush_() override {}
+
+public:
+    win_eventlog_sink(std::string const &source, WORD event_id = 1000 /* according to mscoree.dll */)
+        : source_(source)
+        , event_id_(event_id)
+    {
+        try
+        {
+            current_user_sid_ = internal::sid_t::get_current_user_sid();
+        }
+        catch (...)
+        {
+            // get_current_user_sid() is unlikely to fail and if it does, we can still proceed without
+            // current_user_sid but in the event log the record will have no user name
+        }
+    }
+
+    ~win_eventlog_sink()
+    {
+        if (hEventLog_)
+            DeregisterEventSource(hEventLog_);
+    }
+};
+
+} // namespace win_eventlog
+
+using win_eventlog_sink_mt = win_eventlog::win_eventlog_sink<std::mutex>;
+using win_eventlog_sink_st = win_eventlog::win_eventlog_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/wincolor_sink-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/sinks/wincolor_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/pattern_formatter.h>
+
+namespace spdlog {
+namespace sinks {
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE wincolor_sink<ConsoleMutex>::wincolor_sink(HANDLE out_handle, color_mode mode)
+    : out_handle_(out_handle)
+    , mutex_(ConsoleMutex::mutex())
+    , formatter_(details::make_unique<spdlog::pattern_formatter>())
+{
+    // check if out_handle is points to the actual console.
+    // ::GetConsoleMode() should return 0 if it is redirected or not valid console handle.
+    DWORD console_mode;
+    in_console_ = ::GetConsoleMode(out_handle, &console_mode) != 0;
+
+    set_color_mode(mode);
+    colors_[level::trace] = WHITE;
+    colors_[level::debug] = CYAN;
+    colors_[level::info] = GREEN;
+    colors_[level::warn] = YELLOW | BOLD;
+    colors_[level::err] = RED | BOLD;                         // red bold
+    colors_[level::critical] = BACKGROUND_RED | WHITE | BOLD; // white bold on red background
+    colors_[level::off] = 0;
+}
+
+template<typename ConsoleMutex>
+SPDLOG_INLINE wincolor_sink<ConsoleMutex>::~wincolor_sink()
+{
+    this->flush();
+}
+
+// change the color for the given level
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::set_color(level::level_enum level, WORD color)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    colors_[level] = color;
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::log(const details::log_msg &msg)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    msg.color_range_start = 0;
+    msg.color_range_end = 0;
+    memory_buf_t formatted;
+    formatter_->format(msg, formatted);
+    if (!in_console_)
+    {
+        write_to_file_(formatted);
+        return;
+    }
+    if (should_do_colors_ && msg.color_range_end > msg.color_range_start)
+    {
+        // before color range
+        print_range_(formatted, 0, msg.color_range_start);
+
+        // in color range
+        auto orig_attribs = set_foreground_color_(colors_[msg.level]);
+        print_range_(formatted, msg.color_range_start, msg.color_range_end);
+        // reset to orig colors
+        ::SetConsoleTextAttribute(out_handle_, orig_attribs);
+        print_range_(formatted, msg.color_range_end, formatted.size());
+    }
+    else // print without colors if color range is invalid (or color is disabled)
+    {
+        print_range_(formatted, 0, formatted.size());
+    }
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::flush()
+{
+    // windows console always flushed?
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::set_pattern(const std::string &pattern)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::unique_ptr<spdlog::formatter>(new pattern_formatter(pattern));
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter)
+{
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::move(sink_formatter);
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::set_color_mode(color_mode mode)
+{
+    switch (mode)
+    {
+    case color_mode::always:
+    case color_mode::automatic:
+        should_do_colors_ = true;
+        break;
+    case color_mode::never:
+        should_do_colors_ = false;
+        break;
+    default:
+        should_do_colors_ = true;
+    }
+}
+
+// set foreground color and return the orig console attributes (for resetting later)
+template<typename ConsoleMutex>
+WORD SPDLOG_INLINE wincolor_sink<ConsoleMutex>::set_foreground_color_(WORD attribs)
+{
+    CONSOLE_SCREEN_BUFFER_INFO orig_buffer_info;
+    ::GetConsoleScreenBufferInfo(out_handle_, &orig_buffer_info);
+    WORD back_color = orig_buffer_info.wAttributes;
+    // retrieve the current background color
+    back_color &= static_cast<WORD>(~(FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE | FOREGROUND_INTENSITY));
+    // keep the background color unchanged
+    ::SetConsoleTextAttribute(out_handle_, attribs | back_color);
+    return orig_buffer_info.wAttributes; // return orig attribs
+}
+
+// print a range of formatted message to console
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::print_range_(const memory_buf_t &formatted, size_t start, size_t end)
+{
+    auto size = static_cast<DWORD>(end - start);
+    ::WriteConsoleA(out_handle_, formatted.data() + start, size, nullptr, nullptr);
+}
+
+template<typename ConsoleMutex>
+void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::write_to_file_(const memory_buf_t &formatted)
+{
+    if (out_handle_ == nullptr) // no console and no file redirect
+    {
+        return;
+    }
+    auto size = static_cast<DWORD>(formatted.size());
+    DWORD bytes_written = 0;
+    bool ok = ::WriteFile(out_handle_, formatted.data(), size, &bytes_written, nullptr) != 0;
+    if (!ok)
+    {
+        throw_spdlog_ex("wincolor_sink: ::WriteFile() failed. GetLastError(): " + std::to_string(::GetLastError()));
+    }
+}
+
+// wincolor_stdout_sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE wincolor_stdout_sink<ConsoleMutex>::wincolor_stdout_sink(color_mode mode)
+    : wincolor_sink<ConsoleMutex>(::GetStdHandle(STD_OUTPUT_HANDLE), mode)
+{}
+
+// wincolor_stderr_sink
+template<typename ConsoleMutex>
+SPDLOG_INLINE wincolor_stderr_sink<ConsoleMutex>::wincolor_stderr_sink(color_mode mode)
+    : wincolor_sink<ConsoleMutex>(::GetStdHandle(STD_ERROR_HANDLE), mode)
+{}
+
+} // namespace sinks
+} // namespace spdlog

spdlog/sinks/wincolor_sink.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/console_globals.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/sink.h>
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include <array>
+
+#include <spdlog/details/windows_include.h>
+#include <wincon.h>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Windows color console sink. Uses WriteConsoleA to write to the console with
+ * colors
+ */
+template<typename ConsoleMutex>
+class wincolor_sink : public sink
+{
+public:
+    const WORD BOLD = FOREGROUND_INTENSITY;
+    const WORD RED = FOREGROUND_RED;
+    const WORD GREEN = FOREGROUND_GREEN;
+    const WORD CYAN = FOREGROUND_GREEN | FOREGROUND_BLUE;
+    const WORD WHITE = FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
+    const WORD YELLOW = FOREGROUND_RED | FOREGROUND_GREEN;
+
+    wincolor_sink(HANDLE out_handle, color_mode mode);
+    ~wincolor_sink() override;
+
+    wincolor_sink(const wincolor_sink &other) = delete;
+    wincolor_sink &operator=(const wincolor_sink &other) = delete;
+
+    // change the color for the given level
+    void set_color(level::level_enum level, WORD color);
+    void log(const details::log_msg &msg) final override;
+    void flush() final override;
+    void set_pattern(const std::string &pattern) override final;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override final;
+    void set_color_mode(color_mode mode);
+
+protected:
+    using mutex_t = typename ConsoleMutex::mutex_t;
+    HANDLE out_handle_;
+    mutex_t &mutex_;
+    bool in_console_;
+    bool should_do_colors_;
+    std::unique_ptr<spdlog::formatter> formatter_;
+    std::array<WORD, level::n_levels> colors_;
+
+    // set foreground color and return the orig console attributes (for resetting later)
+    WORD set_foreground_color_(WORD attribs);
+
+    // print a range of formatted message to console
+    void print_range_(const memory_buf_t &formatted, size_t start, size_t end);
+
+    // in case we are redirected to file (not in console mode)
+    void write_to_file_(const memory_buf_t &formatted);
+};
+
+template<typename ConsoleMutex>
+class wincolor_stdout_sink : public wincolor_sink<ConsoleMutex>
+{
+public:
+    explicit wincolor_stdout_sink(color_mode mode = color_mode::automatic);
+};
+
+template<typename ConsoleMutex>
+class wincolor_stderr_sink : public wincolor_sink<ConsoleMutex>
+{
+public:
+    explicit wincolor_stderr_sink(color_mode mode = color_mode::automatic);
+};
+
+using wincolor_stdout_sink_mt = wincolor_stdout_sink<details::console_mutex>;
+using wincolor_stdout_sink_st = wincolor_stdout_sink<details::console_nullmutex>;
+
+using wincolor_stderr_sink_mt = wincolor_stderr_sink<details::console_mutex>;
+using wincolor_stderr_sink_st = wincolor_stderr_sink<details::console_nullmutex>;
+
+} // namespace sinks
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "wincolor_sink-inl.h"
+#endif

spdlog/spdlog-inl.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include <spdlog/spdlog.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/pattern_formatter.h>
+
+namespace spdlog {
+
+SPDLOG_INLINE void initialize_logger(std::shared_ptr<logger> logger)
+{
+    details::registry::instance().initialize_logger(std::move(logger));
+}
+
+SPDLOG_INLINE std::shared_ptr<logger> get(const std::string &name)
+{
+    return details::registry::instance().get(name);
+}
+
+SPDLOG_INLINE void set_formatter(std::unique_ptr<spdlog::formatter> formatter)
+{
+    details::registry::instance().set_formatter(std::move(formatter));
+}
+
+SPDLOG_INLINE void set_pattern(std::string pattern, pattern_time_type time_type)
+{
+    set_formatter(std::unique_ptr<spdlog::formatter>(new pattern_formatter(std::move(pattern), time_type)));
+}
+
+SPDLOG_INLINE void enable_backtrace(size_t n_messages)
+{
+    details::registry::instance().enable_backtrace(n_messages);
+}
+
+SPDLOG_INLINE void disable_backtrace()
+{
+    details::registry::instance().disable_backtrace();
+}
+
+SPDLOG_INLINE void dump_backtrace()
+{
+    default_logger_raw()->dump_backtrace();
+}
+
+SPDLOG_INLINE level::level_enum get_level()
+{
+    return default_logger_raw()->level();
+}
+
+SPDLOG_INLINE bool should_log(level::level_enum log_level)
+{
+    return default_logger_raw()->should_log(log_level);
+}
+
+SPDLOG_INLINE void set_level(level::level_enum log_level)
+{
+    details::registry::instance().set_level(log_level);
+}
+
+SPDLOG_INLINE void flush_on(level::level_enum log_level)
+{
+    details::registry::instance().flush_on(log_level);
+}
+
+SPDLOG_INLINE void flush_every(std::chrono::seconds interval)
+{
+    details::registry::instance().flush_every(interval);
+}
+
+SPDLOG_INLINE void set_error_handler(void (*handler)(const std::string &msg))
+{
+    details::registry::instance().set_error_handler(handler);
+}
+
+SPDLOG_INLINE void register_logger(std::shared_ptr<logger> logger)
+{
+    details::registry::instance().register_logger(std::move(logger));
+}
+
+SPDLOG_INLINE void apply_all(const std::function<void(std::shared_ptr<logger>)> &fun)
+{
+    details::registry::instance().apply_all(fun);
+}
+
+SPDLOG_INLINE void drop(const std::string &name)
+{
+    details::registry::instance().drop(name);
+}
+
+SPDLOG_INLINE void drop_all()
+{
+    details::registry::instance().drop_all();
+}
+
+SPDLOG_INLINE void shutdown()
+{
+    details::registry::instance().shutdown();
+}
+
+SPDLOG_INLINE void set_automatic_registration(bool automatic_registration)
+{
+    details::registry::instance().set_automatic_registration(automatic_registration);
+}
+
+SPDLOG_INLINE std::shared_ptr<spdlog::logger> default_logger()
+{
+    return details::registry::instance().default_logger();
+}
+
+SPDLOG_INLINE spdlog::logger *default_logger_raw()
+{
+    return details::registry::instance().get_default_raw();
+}
+
+SPDLOG_INLINE void set_default_logger(std::shared_ptr<spdlog::logger> default_logger)
+{
+    details::registry::instance().set_default_logger(std::move(default_logger));
+}
+
+} // namespace spdlog

spdlog/spdlog.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+// spdlog main header file.
+// see example.cpp for usage example
+
+#ifndef SPDLOG_H
+#define SPDLOG_H
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/registry.h>
+#include <spdlog/logger.h>
+#include <spdlog/version.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+
+namespace spdlog {
+
+using default_factory = synchronous_factory;
+
+// Create and register a logger with a templated sink type
+// The logger's level, formatter and flush level will be set according the
+// global settings.
+//
+// Example:
+//   spdlog::create<daily_file_sink_st>("logger_name", "dailylog_filename", 11, 59);
+template<typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create(std::string logger_name, SinkArgs &&...sink_args)
+{
+    return default_factory::create<Sink>(std::move(logger_name), std::forward<SinkArgs>(sink_args)...);
+}
+
+// Initialize and register a logger,
+// formatter and flush level will be set according the global settings.
+//
+// Useful for initializing manually created loggers with the global settings.
+//
+// Example:
+//   auto mylogger = std::make_shared<spdlog::logger>("mylogger", ...);
+//   spdlog::initialize_logger(mylogger);
+SPDLOG_API void initialize_logger(std::shared_ptr<logger> logger);
+
+// Return an existing logger or nullptr if a logger with such name doesn't
+// exist.
+// example: spdlog::get("my_logger")->info("hello {}", "world");
+SPDLOG_API std::shared_ptr<logger> get(const std::string &name);
+
+// Set global formatter. Each sink in each logger will get a clone of this object
+SPDLOG_API void set_formatter(std::unique_ptr<spdlog::formatter> formatter);
+
+// Set global format string.
+// example: spdlog::set_pattern("%Y-%m-%d %H:%M:%S.%e %l : %v");
+SPDLOG_API void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
+
+// enable global backtrace support
+SPDLOG_API void enable_backtrace(size_t n_messages);
+
+// disable global backtrace support
+SPDLOG_API void disable_backtrace();
+
+// call dump backtrace on default logger
+SPDLOG_API void dump_backtrace();
+
+// Get global logging level
+SPDLOG_API level::level_enum get_level();
+
+// Set global logging level
+SPDLOG_API void set_level(level::level_enum log_level);
+
+// Determine whether the default logger should log messages with a certain level
+SPDLOG_API bool should_log(level::level_enum lvl);
+
+// Set global flush level
+SPDLOG_API void flush_on(level::level_enum log_level);
+
+// Start/Restart a periodic flusher thread
+// Warning: Use only if all your loggers are thread safe!
+SPDLOG_API void flush_every(std::chrono::seconds interval);
+
+// Set global error handler
+SPDLOG_API void set_error_handler(void (*handler)(const std::string &msg));
+
+// Register the given logger with the given name
+SPDLOG_API void register_logger(std::shared_ptr<logger> logger);
+
+// Apply a user defined function on all registered loggers
+// Example:
+// spdlog::apply_all([&](std::shared_ptr<spdlog::logger> l) {l->flush();});
+SPDLOG_API void apply_all(const std::function<void(std::shared_ptr<logger>)> &fun);
+
+// Drop the reference to the given logger
+SPDLOG_API void drop(const std::string &name);
+
+// Drop all references from the registry
+SPDLOG_API void drop_all();
+
+// stop any running threads started by spdlog and clean registry loggers
+SPDLOG_API void shutdown();
+
+// Automatic registration of loggers when using spdlog::create() or spdlog::create_async
+SPDLOG_API void set_automatic_registration(bool automatic_registration);
+
+// API for using default logger (stdout_color_mt),
+// e.g: spdlog::info("Message {}", 1);
+//
+// The default logger object can be accessed using the spdlog::default_logger():
+// For example, to add another sink to it:
+// spdlog::default_logger()->sinks().push_back(some_sink);
+//
+// The default logger can replaced using spdlog::set_default_logger(new_logger).
+// For example, to replace it with a file logger.
+//
+// IMPORTANT:
+// The default API is thread safe (for _mt loggers), but:
+// set_default_logger() *should not* be used concurrently with the default API.
+// e.g do not call set_default_logger() from one thread while calling spdlog::info() from another.
+
+SPDLOG_API std::shared_ptr<spdlog::logger> default_logger();
+
+SPDLOG_API spdlog::logger *default_logger_raw();
+
+SPDLOG_API void set_default_logger(std::shared_ptr<spdlog::logger> default_logger);
+
+template<typename FormatString, typename... Args>
+inline void log(source_loc source, level::level_enum lvl, const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->log(source, lvl, fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void log(level::level_enum lvl, const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void trace(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->trace(fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void debug(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->debug(fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void info(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->info(fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void warn(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->warn(fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void error(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->error(fmt, std::forward<Args>(args)...);
+}
+
+template<typename FormatString, typename... Args>
+inline void critical(const FormatString &fmt, Args&&...args)
+{
+    default_logger_raw()->critical(fmt, std::forward<Args>(args)...);
+}
+
+template<typename T>
+inline void log(source_loc source, level::level_enum lvl, const T &msg)
+{
+    default_logger_raw()->log(source, lvl, msg);
+}
+
+template<typename T>
+inline void log(level::level_enum lvl, const T &msg)
+{
+    default_logger_raw()->log(lvl, msg);
+}
+
+template<typename T>
+inline void trace(const T &msg)
+{
+    default_logger_raw()->trace(msg);
+}
+
+template<typename T>
+inline void debug(const T &msg)
+{
+    default_logger_raw()->debug(msg);
+}
+
+template<typename T>
+inline void info(const T &msg)
+{
+    default_logger_raw()->info(msg);
+}
+
+template<typename T>
+inline void warn(const T &msg)
+{
+    default_logger_raw()->warn(msg);
+}
+
+template<typename T>
+inline void error(const T &msg)
+{
+    default_logger_raw()->error(msg);
+}
+
+template<typename T>
+inline void critical(const T &msg)
+{
+    default_logger_raw()->critical(msg);
+}
+
+} // namespace spdlog
+
+//
+// enable/disable log calls at compile time according to global level.
+//
+// define SPDLOG_ACTIVE_LEVEL to one of those (before including spdlog.h):
+// SPDLOG_LEVEL_TRACE,
+// SPDLOG_LEVEL_DEBUG,
+// SPDLOG_LEVEL_INFO,
+// SPDLOG_LEVEL_WARN,
+// SPDLOG_LEVEL_ERROR,
+// SPDLOG_LEVEL_CRITICAL,
+// SPDLOG_LEVEL_OFF
+//
+
+#define SPDLOG_LOGGER_CALL(logger, level, ...) (logger)->log(spdlog::source_loc{__FILE__, __LINE__, SPDLOG_FUNCTION}, level, __VA_ARGS__)
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_TRACE
+#define SPDLOG_LOGGER_TRACE(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::trace, __VA_ARGS__)
+#define SPDLOG_TRACE(...) SPDLOG_LOGGER_TRACE(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_TRACE(logger, ...) (void)0
+#define SPDLOG_TRACE(...) (void)0
+#endif
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_DEBUG
+#define SPDLOG_LOGGER_DEBUG(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::debug, __VA_ARGS__)
+#define SPDLOG_DEBUG(...) SPDLOG_LOGGER_DEBUG(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_DEBUG(logger, ...) (void)0
+#define SPDLOG_DEBUG(...) (void)0
+#endif
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_INFO
+#define SPDLOG_LOGGER_INFO(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::info, __VA_ARGS__)
+#define SPDLOG_INFO(...) SPDLOG_LOGGER_INFO(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_INFO(logger, ...) (void)0
+#define SPDLOG_INFO(...) (void)0
+#endif
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_WARN
+#define SPDLOG_LOGGER_WARN(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::warn, __VA_ARGS__)
+#define SPDLOG_WARN(...) SPDLOG_LOGGER_WARN(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_WARN(logger, ...) (void)0
+#define SPDLOG_WARN(...) (void)0
+#endif
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_ERROR
+#define SPDLOG_LOGGER_ERROR(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::err, __VA_ARGS__)
+#define SPDLOG_ERROR(...) SPDLOG_LOGGER_ERROR(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_ERROR(logger, ...) (void)0
+#define SPDLOG_ERROR(...) (void)0
+#endif
+
+#if SPDLOG_ACTIVE_LEVEL <= SPDLOG_LEVEL_CRITICAL
+#define SPDLOG_LOGGER_CRITICAL(logger, ...) SPDLOG_LOGGER_CALL(logger, spdlog::level::critical, __VA_ARGS__)
+#define SPDLOG_CRITICAL(...) SPDLOG_LOGGER_CRITICAL(spdlog::default_logger_raw(), __VA_ARGS__)
+#else
+#define SPDLOG_LOGGER_CRITICAL(logger, ...) (void)0
+#define SPDLOG_CRITICAL(...) (void)0
+#endif
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "spdlog-inl.h"
+#endif
+
+#endif // SPDLOG_H

spdlog/spdlogwarp.hh

+/*
+ *
+ *  Created on: 2020-12-13
+ *      Author: liuhang
+ */
+#ifndef _SLOG_WARPPER_HH_
+#define _SLOG_WARPPER_HH_
+#include <stdio.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <spdlog/spdlog.h>
+#include <spdlog/logger.h>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/sinks/rotating_file_sink.h>
+#include <spdlog/sinks/stdout_color_sinks.h>
+#include <map>
+#include <atomic>
+
+#define LOG_SIZE (1024*1024*10)
+class SLog {
+public:
+  static void init(const std::string& logdir, const std::string& appname) ;
+  static std::shared_ptr<spdlog::logger> global(){
+    while (m_state)
+      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    return m_globalLog;
+  }
+  static inline bool has_inited(){return m_inited;};
+
+  static std::shared_ptr<spdlog::logger> get(const std::string &name);
+  static std::shared_ptr<spdlog::logger> get_trace(const std::string &name);
+
+  template <typename... Args>
+  static void write(const std::string &name, std::string text, Args &&... args)
+  {
+    transto(text);
+    get(name)->info(text, std::forward<Args>(args)...);
+  }
+
+  template <typename... Args>
+  static void trace(const std::string &name, const std::string &text, Args&&...args)
+  {
+    get_trace(name)->trace(text, std::forward<Args>(args)...);
+  }
+
+  static void dump_trace();
+
+  static void transto(std::string &x);
+  static void cleanup();
+private:
+  static void monitor_thread();
+  static void makesure_dir(const std::string &path);
+  static std::string getymd();
+
+  static std::shared_ptr<spdlog::logger> m_globalLog;
+  static std::map<std::string, std::shared_ptr<spdlog::logger>> m_trace;
+  static std::map<std::string, std::shared_ptr<spdlog::logger>> m_loggers;
+  static std::string m_logdir;
+  static std::string m_appname;
+  static std::string m_lastymd;
+  static std::atomic<int> m_state;
+  static bool m_inited;
+  static std::mutex m_lock;
+
+};
+
+
+//template <typename T, typename... Args>
+//inline void cslog(const T &x, Args&&...args) throw()
+template <typename... Args>
+inline void cslog(std::string x, Args&&...args) throw()
+{
+  for (std::size_t i = 0; i < x.length() - 1; i++)
+  {
+    if (x[i] == '%' && x[i + 1] != '%' && x[std::max((int)i - 1, 0)] != '\\')
+    {
+      x[i] = '{';
+      x[i+1] = '}';
+    }
+  }
+
+  SLog::global()->info(x, std::forward<Args>(args)...);
+}
+void cslog(const char *text) ;
+
+#endif

spdlog/stopwatch.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/fmt/fmt.h>
+
+// Stopwatch support for spdlog  (using std::chrono::steady_clock).
+// Displays elapsed seconds since construction as double.
+//
+// Usage:
+//
+// spdlog::stopwatch sw;
+// ...
+// spdlog::debug("Elapsed: {} seconds", sw);    =>  "Elapsed 0.005116733 seconds"
+// spdlog::info("Elapsed: {:.6} seconds", sw);  =>  "Elapsed 0.005163 seconds"
+//
+//
+// If other units are needed (e.g. millis instead of double), include "fmt/chrono.h" and use "duration_cast<..>(sw.elapsed())":
+//
+// #include <spdlog/fmt/chrono.h>
+//..
+// using std::chrono::duration_cast;
+// using std::chrono::milliseconds;
+// spdlog::info("Elapsed {}", duration_cast<milliseconds>(sw.elapsed())); => "Elapsed 5ms"
+
+namespace spdlog {
+class stopwatch
+{
+    using clock = std::chrono::steady_clock;
+    std::chrono::time_point<clock> start_tp_;
+
+public:
+    stopwatch()
+        : start_tp_{clock::now()}
+    {}
+
+    std::chrono::duration<double> elapsed() const
+    {
+        return std::chrono::duration<double>(clock::now() - start_tp_);
+    }
+
+    void reset()
+    {
+        start_tp_ = clock ::now();
+    }
+};
+} // namespace spdlog
+
+// Support for fmt formatting  (e.g. "{:012.9}" or just "{}")
+namespace fmt {
+template<>
+struct formatter<spdlog::stopwatch> : formatter<double>
+{
+    template<typename FormatContext>
+    auto format(const spdlog::stopwatch &sw, FormatContext &ctx) -> decltype(ctx.out())
+    {
+        return formatter<double>::format(sw.elapsed().count(), ctx);
+    }
+};
+} // namespace fmt

spdlog/tweakme.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// Edit this file to squeeze more performance, and to customize supported
+// features
+//
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Under Linux, the much faster CLOCK_REALTIME_COARSE clock can be used.
+// This clock is less accurate - can be off by dozens of millis - depending on
+// the kernel HZ.
+// Uncomment to use it instead of the regular clock.
+//
+// #define SPDLOG_CLOCK_COARSE
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment if thread id logging is not needed (i.e. no %t in the log pattern).
+// This will prevent spdlog from querying the thread id on each log call.
+//
+// WARNING: If the log pattern contains thread id (i.e, %t) while this flag is
+// on, zero will be logged as thread id.
+//
+// #define SPDLOG_NO_THREAD_ID
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to prevent spdlog from using thread local storage.
+//
+// WARNING: if your program forks, UNCOMMENT this flag to prevent undefined
+// thread ids in the children logs.
+//
+// #define SPDLOG_NO_TLS
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to avoid spdlog's usage of atomic log levels
+// Use only if your code never modifies a logger's log levels concurrently by
+// different threads.
+//
+// #define SPDLOG_NO_ATOMIC_LEVELS
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable usage of wchar_t for file names on Windows.
+//
+// #define SPDLOG_WCHAR_FILENAMES
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to override default eol ("\n" or "\r\n" under Linux/Windows)
+//
+// #define SPDLOG_EOL ";-)\n"
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to use your own copy of the fmt library instead of spdlog's copy.
+// In this case spdlog will try to include <fmt/format.h> so set your -I flag
+// accordingly.
+//
+// #define SPDLOG_FMT_EXTERNAL
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable wchar_t support (convert to utf8)
+//
+// #define SPDLOG_WCHAR_TO_UTF8_SUPPORT
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to prevent child processes from inheriting log file descriptors
+//
+// #define SPDLOG_PREVENT_CHILD_FD
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to customize level names (e.g. "MT TRACE")
+//
+// #define SPDLOG_LEVEL_NAMES { "MY TRACE", "MY DEBUG", "MY INFO", "MY WARNING",
+// "MY ERROR", "MY CRITICAL", "OFF" }
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to customize short level names (e.g. "MT")
+// These can be longer than one character.
+//
+// #define SPDLOG_SHORT_LEVEL_NAMES { "T", "D", "I", "W", "E", "C", "O" }
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to disable default logger creation.
+// This might save some (very) small initialization time if no default logger is needed.
+//
+// #define SPDLOG_DISABLE_DEFAULT_LOGGER
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment and set to compile time level with zero cost (default is INFO).
+// Macros like SPDLOG_DEBUG(..), SPDLOG_INFO(..)  will expand to empty statements if not enabled
+//
+// #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment (and change if desired) macro to use for function names.
+// This is compiler dependent.
+// __PRETTY_FUNCTION__ might be nicer in clang/gcc, and __FUNCTION__ in msvc.
+// Defaults to __FUNCTION__ (should work on all compilers) if not defined.
+//
+// #define SPDLOG_FUNCTION __PRETTY_FUNCTION__
+///////////////////////////////////////////////////////////////////////////////

spdlog/version.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#define SPDLOG_VER_MAJOR 1
+#define SPDLOG_VER_MINOR 8
+#define SPDLOG_VER_PATCH 1
+
+#define SPDLOG_VERSION (SPDLOG_VER_MAJOR * 10000 + SPDLOG_VER_MINOR * 100 + SPDLOG_VER_PATCH)

spdlog_sample.cpp

+#include "spdlog/spdlogwarp.hh"
+#include <thread>
+#include <iostream>
+#include "spdlog/fmt/fmt.h"
+#include "spdlog/fmt/bin_to_hex.h"
+
+
+void thd()
+{
+  // trace日志会缓存在内存
+  while (1) {
+    auto tr = SLog::get_trace("trace1");
+    tr->trace("1");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("2");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("3");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("4");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("5");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("6");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    tr->trace("7");
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+  }
+}
+
+void thd2()
+{
+  while (1) {
+    auto tr = SLog::get("log2");
+    tr->error("th2 1");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->error("th2 2");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->info("th2 3");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->info("th2 4");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->info("th2 5");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->info("th2 6");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    tr->info("th2 7");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+}
+
+void thd3()
+{
+  while (1) {
+    SLog::get("log2")->info("th3 1");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    SLog::get("log2")->info("th3 2");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    SLog::get("log2")->info("th3 3");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+}
+
+void thd4()
+{
+  while (1) {
+    SLog::global()->info("th4 1");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    SLog::global()->info("th4 2");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    SLog::global()->info("th4 3");
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+}
+
+int main()
+{
+  //初始化前确认是否已经初始化过了。避免主程序已经初始化过了。子模块建议使用专属日志
+  if (!SLog::has_inited()) {
+    SLog::init("./", "sample");
+  }
+  // 公共日志
+  SLog::global()->info("I'm global {} {}", 1, "string");
+
+  // 此函数是为了方便替换原有代码中的printf
+  cslog("I'm global log too %d %s", 1, "string");
+
+  // 专属日志
+  SLog::get("subject")->error("I'm {}", "subject");
+  auto sublog = SLog::get("subject");
+  sublog->error("I'm {}", "subject");
+
+
+  SLog::get("./2222/subject")->error("I'm {}", "2222");
+
+  // 带行号文件名
+  SPDLOG_LOGGER_INFO(sublog, "with line filename");
+
+  // 额外赠送功能，string的format，fmtlib库
+  std::string fmtstr;
+  fmt::format(fmtstr, "format {} {} {}", 2, 2.9, "string");
+  std::cout << fmtstr;
+
+
+  unsigned char buffer[1024];
+  //memset(buffer, 1024, 0);
+
+  // 打印二进制数据
+  sublog->info("binary: {}", spdlog::to_hex(std::begin(buffer), std::begin(buffer)+1024));
+
+  SLog::cleanup();
+
+  SLog::get("subject")->error("after drop 1");
+  SLog::global()->info("after drop global");
+
+  //return 0;
+
+  auto th = std::thread(thd);
+  th.detach();
+  auto th2 = std::thread(thd2);
+  th2.detach();
+  auto th3 = std::thread(thd3);
+  th3.detach();
+  auto th4 = std::thread(thd4);
+  th4.detach();
+
+  SLog::global()->info("输入dump回车，将trace日志打印到文件中");
+  while (1) {
+    std::string input;
+    std::cin >> input;
+    if (input == "dump") {
+        SLog::dump_trace();
+    }
+  }
+}

spdlogwarp.cpp

+/*
+ *
+ *  Created on: 2020-12-13
+ *      Author: liuhang
+ */
+
+//fmtlib https://fmt.dev/latest/api.html#format-api
+
+#include "spdlog/spdlogwarp.hh"
+#include <stdarg.h>
+#include <iostream>
+#include <sstream>
+#include <chrono>
+#include <mutex>
+#include "spdlog/fmt/fmt.h"
+
+
+#define _SPD_FORMAT_ "%Y-%m-%d %H:%M:%S.%e%z|%l|[%s:%#:%t] %v"
+#define _SPD_FORMAT_2 "%Y-%m-%d %H:%M:%S.%e%z|{}|{}|%l|[%s:%#:%t] %v"
+std::shared_ptr<spdlog::logger> SLog::m_globalLog;
+std::map<std::string, std::shared_ptr<spdlog::logger>> SLog::m_trace;
+std::map<std::string, std::shared_ptr<spdlog::logger>> SLog::m_loggers;
+std::string SLog::m_logdir;
+std::string SLog::m_appname;
+std::string SLog::m_lastymd = "";
+std::atomic<int> SLog::m_state(0);
+bool SLog::m_inited = false;
+std::mutex SLog::m_lock;
+
+void cslog(const char *text)
+{
+  SLog::global()->info(text);
+}
+
+std::string SLog::getymd()
+{
+  std::chrono::system_clock::time_point now = std::chrono::system_clock::now();
+  time_t tt = std::chrono::system_clock::to_time_t(now);
+  tm utc_tm = *gmtime(&tt);
+  tm local_tm = *localtime(&tt);
+  return fmt::format("{:04}-{:02}-{:02}-{:02}", 1900+local_tm.tm_year, local_tm.tm_mon + 1, local_tm.tm_mday, local_tm.tm_min);
+}
+
+
+static std::string get_before_ymd(int days)
+{
+  std::chrono::duration<int, std::ratio<60 * 60 * 24>> nday(7);
+  std::chrono::system_clock::time_point before =
+      std::chrono::system_clock::now() - nday;
+
+  time_t tt = std::chrono::system_clock::to_time_t(before);
+  tm utc_tm = *gmtime(&tt);
+  tm local_tm = *localtime(&tt);
+  return fmt::format("{:04}-{:02}-{:02}-{:02}", 1900+local_tm.tm_year, local_tm.tm_mon + 1, local_tm.tm_mday, local_tm.tm_min);
+}
+static std::string getext(const std::string &appname)
+{
+  if(appname.find(".log") == std::string::npos && appname.find(".txt") == std::string::npos)
+    return ".log";
+  else
+    return "";
+}
+
+void SLog::makesure_dir(const std::string &path)
+{
+  std::string dirstr = path;
+  DIR *dirptr = opendir(dirstr.c_str());
+  if (dirptr == NULL) {
+    int ret = mkdir(dirstr.c_str(), (S_IRWXU | S_IRWXG | S_IRWXO));
+    if (ret == 0) {
+    } else {
+    }
+  }
+  else
+  {
+    closedir(dirptr);
+  }
+}
+
+void SLog::monitor_thread() {
+  while (1) {
+    std::string curymd = getymd();
+    if (curymd != m_lastymd) {
+      m_state = 1;
+      printf("spdlog::drop_all() ymd:%s, m_lastymd:%s", curymd.c_str(), m_lastymd.c_str());
+      m_lastymd = curymd;
+      spdlog::drop_all();
+      m_loggers.clear();
+      m_trace.clear();
+
+      auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+      console_sink->set_level(spdlog::level::debug);
+      std::string logname = m_logdir + "/" + getymd() + "/" + m_appname + getext(m_appname);
+      auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(logname, LOG_SIZE, 100);
+      file_sink->set_level(spdlog::level::debug);
+
+      auto globallog = std::shared_ptr<spdlog::logger>(new spdlog::logger(m_appname, {console_sink, file_sink}));
+      m_globalLog.swap(globallog);
+      m_globalLog->set_level(spdlog::level::debug);
+      spdlog::set_pattern(_SPD_FORMAT_);
+      m_globalLog->set_pattern(fmt::format(_SPD_FORMAT_2, m_appname, "global"));
+      m_globalLog->info("rebuild spdlog success");
+      set_default_logger(m_globalLog);
+
+      m_state = 0;
+    }
+    std::this_thread::sleep_for(std::chrono::seconds(5));
+  }
+}
+
+void SLog::init(const std::string &logdir, const std::string &appname)
+{
+  m_logdir = logdir;
+  m_state = 0;
+  m_appname = appname;
+  makesure_dir(logdir);
+  makesure_dir(logdir + "/" + getymd());
+  m_lastymd = getymd();
+  std::thread th = std::thread(monitor_thread);
+  th.detach();
+  auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+  console_sink->set_level(spdlog::level::debug);
+  std::string logname = logdir + "/" + getymd() + "/" + appname + getext(appname);
+  auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(logname, LOG_SIZE, 100);
+  file_sink->set_level(spdlog::level::debug);
+  m_globalLog = std::shared_ptr<spdlog::logger>(new spdlog::logger(appname, {console_sink, file_sink}));
+  m_globalLog->set_level(spdlog::level::debug);
+  spdlog::set_pattern(_SPD_FORMAT_);
+  m_globalLog->set_pattern(fmt::format(_SPD_FORMAT_2, appname, "global"));
+  m_globalLog->info("init spdlog success");
+  set_default_logger(m_globalLog);
+  spdlog::flush_every(std::chrono::seconds(1));
+  m_inited = true;
+}
+
+std::shared_ptr<spdlog::logger> SLog::get(const std::string &name)
+{
+  while(m_state)
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  std::shared_ptr<spdlog::logger> _logger;
+  std::lock_guard<std::mutex> autolock(m_lock);
+  auto iter = m_loggers.find(name);
+  if (iter == m_loggers.end())
+  {
+    auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+    console_sink->set_level(spdlog::level::debug);
+    makesure_dir(m_logdir + "/" + getymd());
+    std::string logname = m_logdir + "/" + getymd() + "/" + name + getext(name);
+    auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(logname, LOG_SIZE, 300);
+    file_sink->set_level(spdlog::level::debug);
+    _logger = std::shared_ptr<spdlog::logger>(new spdlog::logger(name, {console_sink, file_sink}));
+    _logger->set_pattern(fmt::format(_SPD_FORMAT_2, m_appname, name));
+    spdlog::register_logger(_logger);
+    m_loggers[name] = _logger;
+  }
+  else
+  {
+    _logger = iter->second;
+  }
+  return _logger;
+}
+
+std::shared_ptr<spdlog::logger> SLog::get_trace(const std::string &name)
+{
+  while(m_state)
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  std::shared_ptr<spdlog::logger> _logger;
+  auto iter = m_trace.find(name);
+  if (iter == m_trace.end())
+  {
+    auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+    // console_sink->set_level(spdlog::level::debug);
+    makesure_dir(m_logdir + "/" + getymd());
+    std::string logname = m_logdir + "/" + getymd() + "/" + name + getext(name);
+    auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(logname, LOG_SIZE, 100);
+    // file_sink->set_level(spdlog::level::debug);
+    _logger = std::shared_ptr<spdlog::logger>(new spdlog::logger(name, {console_sink, file_sink}));
+    _logger->set_pattern(fmt::format(_SPD_FORMAT_2, m_appname, name));
+    _logger->enable_backtrace(512);
+    m_trace[name] = _logger;
+    m_globalLog->info("add new trace name:{}", name);
+  }
+  else
+  {
+    _logger = iter->second;
+  }
+  return _logger;
+}
+void SLog::dump_trace()
+{
+  m_globalLog->info("dump_trace, m_trace.size() == {}", m_trace.size());
+  for (auto iter = m_trace.begin(); iter != m_trace.end(); iter++)
+  {
+    m_globalLog->info("dump trace name:{}", iter->first);
+    auto _logger = iter->second;
+    _logger->dump_backtrace();
+  }
+}
+
+void SLog::transto(std::string &x)
+{
+  for (std::size_t i = 0; i < x.length() - 1; i++)
+  {
+    if (x[i] == '%' && x[i + 1] != '%' && x[std::max((int)i - 1, 0)] != '\\')
+    {
+      x[i] = '{';
+      x[i + 1] = '}';
+    }
+  }
+}
+
+void SLog::cleanup()
+{
+  spdlog::drop_all();
+  m_loggers.clear();
+}