buffer.js
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var inherits = require('inherits');
var Reporter = require('../base').Reporter;
var Buffer = require('buffer').Buffer;
function DecoderBuffer(base, options) {
Reporter.call(this, options);
if (!Buffer.isBuffer(base)) {
this.error('Input not Buffer');
return;
}
this.base = base;
this.offset = 0;
this.length = base.length;
}
inherits(DecoderBuffer, Reporter);
exports.DecoderBuffer = DecoderBuffer;
DecoderBuffer.prototype.save = function save() {
return { offset: this.offset, reporter: Reporter.prototype.save.call(this) };
};
DecoderBuffer.prototype.restore = function restore(save) {
// Return skipped data
var res = new DecoderBuffer(this.base);
res.offset = save.offset;
res.length = this.offset;
this.offset = save.offset;
Reporter.prototype.restore.call(this, save.reporter);
return res;
};
DecoderBuffer.prototype.isEmpty = function isEmpty() {
return this.offset === this.length;
};
DecoderBuffer.prototype.readUInt8 = function readUInt8(fail) {
if (this.offset + 1 <= this.length)
return this.base.readUInt8(this.offset++, true);
else
return this.error(fail || 'DecoderBuffer overrun');
}
DecoderBuffer.prototype.skip = function skip(bytes, fail) {
if (!(this.offset + bytes <= this.length))
return this.error(fail || 'DecoderBuffer overrun');
var res = new DecoderBuffer(this.base);
// Share reporter state
res._reporterState = this._reporterState;
res.offset = this.offset;
res.length = this.offset + bytes;
this.offset += bytes;
return res;
}
DecoderBuffer.prototype.raw = function raw(save) {
return this.base.slice(save ? save.offset : this.offset, this.length);
}
function EncoderBuffer(value, reporter) {
if (Array.isArray(value)) {
this.length = 0;
this.value = value.map(function(item) {
if (!(item instanceof EncoderBuffer))
item = new EncoderBuffer(item, reporter);
this.length += item.length;
return item;
}, this);
} else if (typeof value === 'number') {
if (!(0 <= value && value <= 0xff))
return reporter.error('non-byte EncoderBuffer value');
this.value = value;
this.length = 1;
} else if (typeof value === 'string') {
this.value = value;
this.length = Buffer.byteLength(value);
} else if (Buffer.isBuffer(value)) {
this.value = value;
this.length = value.length;
} else {
return reporter.error('Unsupported type: ' + typeof value);
}
}
exports.EncoderBuffer = EncoderBuffer;
EncoderBuffer.prototype.join = function join(out, offset) {
if (!out)
out = new Buffer(this.length);
if (!offset)
offset = 0;
if (this.length === 0)
return out;
if (Array.isArray(this.value)) {
this.value.forEach(function(item) {
item.join(out, offset);
offset += item.length;
});
} else {
if (typeof this.value === 'number')
out[offset] = this.value;
else if (typeof this.value === 'string')
out.write(this.value, offset);
else if (Buffer.isBuffer(this.value))
this.value.copy(out, offset);
offset += this.length;
}
return out;
};