uint32.js

/**
	C-like unsigned 32 bits integers in Javascript
	Copyright (C) 2013, Pierre Curto
	MIT license
 */
;(function (root) {

	// Local cache for typical radices
	var radixPowerCache = {
		36: UINT32( Math.pow(36, 5) )
	,	16: UINT32( Math.pow(16, 7) )
	,	10: UINT32( Math.pow(10, 9) )
	,	2:  UINT32( Math.pow(2, 30) )
	}
	var radixCache = {
		36: UINT32(36)
	,	16: UINT32(16)
	,	10: UINT32(10)
	,	2:  UINT32(2)
	}

	/**
	 *	Represents an unsigned 32 bits integer
	 * @constructor
	 * @param {Number|String|Number} low bits     | integer as a string 		 | integer as a number
	 * @param {Number|Number|Undefined} high bits | radix (optional, default=10)
	 * @return 
	 */
	function UINT32 (l, h) {
		if ( !(this instanceof UINT32) )
			return new UINT32(l, h)

		this._low = 0
		this._high = 0
		this.remainder = null
		if (typeof h == 'undefined')
			return fromNumber.call(this, l)

		if (typeof l == 'string')
			return fromString.call(this, l, h)

		fromBits.call(this, l, h)
	}

	/**
	 * Set the current _UINT32_ object with its low and high bits
	 * @method fromBits
	 * @param {Number} low bits
	 * @param {Number} high bits
	 * @return ThisExpression
	 */
	function fromBits (l, h) {
		this._low = l | 0
		this._high = h | 0

		return this
	}
	UINT32.prototype.fromBits = fromBits

	/**
	 * Set the current _UINT32_ object from a number
	 * @method fromNumber
	 * @param {Number} number
	 * @return ThisExpression
	 */
	function fromNumber (value) {
		this._low = value & 0xFFFF
		this._high = value >>> 16

		return this
	}
	UINT32.prototype.fromNumber = fromNumber

	/**
	 * Set the current _UINT32_ object from a string
	 * @method fromString
	 * @param {String} integer as a string
	 * @param {Number} radix (optional, default=10)
	 * @return ThisExpression
	 */
	function fromString (s, radix) {
		var value = parseInt(s, radix || 10)

		this._low = value & 0xFFFF
		this._high = value >>> 16

		return this
	}
	UINT32.prototype.fromString = fromString

	/**
	 * Convert this _UINT32_ to a number
	 * @method toNumber
	 * @return {Number} the converted UINT32
	 */
	UINT32.prototype.toNumber = function () {
		return (this._high * 65536) + this._low
	}

	/**
	 * Convert this _UINT32_ to a string
	 * @method toString
	 * @param {Number} radix (optional, default=10)
	 * @return {String} the converted UINT32
	 */
	UINT32.prototype.toString = function (radix) {
		return this.toNumber().toString(radix || 10)
	}

	/**
	 * Add two _UINT32_. The current _UINT32_ stores the result
	 * @method add
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.add = function (other) {
		var a00 = this._low + other._low
		var a16 = a00 >>> 16

		a16 += this._high + other._high

		this._low = a00 & 0xFFFF
		this._high = a16 & 0xFFFF

		return this
	}

	/**
	 * Subtract two _UINT32_. The current _UINT32_ stores the result
	 * @method subtract
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.subtract = function (other) {
		//TODO inline
		return this.add( other.clone().negate() )
	}

	/**
	 * Multiply two _UINT32_. The current _UINT32_ stores the result
	 * @method multiply
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.multiply = function (other) {
		/*
			a = a00 + a16
			b = b00 + b16
			a*b = (a00 + a16)(b00 + b16)
				= a00b00 + a00b16 + a16b00 + a16b16

			a16b16 overflows the 32bits
		 */
		var a16 = this._high
		var a00 = this._low
		var b16 = other._high
		var b00 = other._low

/* Removed to increase speed under normal circumstances (i.e. not multiplying by 0 or 1)
		// this == 0 or other == 1: nothing to do
		if ((a00 == 0 && a16 == 0) || (b00 == 1 && b16 == 0)) return this

		// other == 0 or this == 1: this = other
		if ((b00 == 0 && b16 == 0) || (a00 == 1 && a16 == 0)) {
			this._low = other._low
			this._high = other._high
			return this
		}
*/

		var c16, c00
		c00 = a00 * b00
		c16 = c00 >>> 16

		c16 += a16 * b00
		c16 &= 0xFFFF		// Not required but improves performance
		c16 += a00 * b16

		this._low = c00 & 0xFFFF
		this._high = c16 & 0xFFFF

		return this
	}

	/**
	 * Divide two _UINT32_. The current _UINT32_ stores the result.
	 * The remainder is made available as the _remainder_ property on
	 * the _UINT32_ object. It can be null, meaning there are no remainder.
	 * @method div
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.div = function (other) {
		if ( (other._low == 0) && (other._high == 0) ) throw Error('division by zero')

		// other == 1
		if (other._high == 0 && other._low == 1) {
			this.remainder = new UINT32(0)
			return this
		}

		// other > this: 0
		if ( other.gt(this) ) {
			this.remainder = this.clone()
			this._low = 0
			this._high = 0
			return this
		}
		// other == this: 1
		if ( this.eq(other) ) {
			this.remainder = new UINT32(0)
			this._low = 1
			this._high = 0
			return this
		}

		// Shift the divisor left until it is higher than the dividend
		var _other = other.clone()
		var i = -1
		while ( !this.lt(_other) ) {
			// High bit can overflow the default 16bits
			// Its ok since we right shift after this loop
			// The overflown bit must be kept though
			_other.shiftLeft(1, true)
			i++
		}

		// Set the remainder
		this.remainder = this.clone()
		// Initialize the current result to 0
		this._low = 0
		this._high = 0
		for (; i >= 0; i--) {
			_other.shiftRight(1)
			// If shifted divisor is smaller than the dividend
			// then subtract it from the dividend
			if ( !this.remainder.lt(_other) ) {
				this.remainder.subtract(_other)
				// Update the current result
				if (i >= 16) {
					this._high |= 1 << (i - 16)
				} else {
					this._low |= 1 << i
				}
			}
		}

		return this
	}

	/**
	 * Negate the current _UINT32_
	 * @method negate
	 * @return ThisExpression
	 */
	UINT32.prototype.negate = function () {
		var v = ( ~this._low & 0xFFFF ) + 1
		this._low = v & 0xFFFF
		this._high = (~this._high + (v >>> 16)) & 0xFFFF

		return this
	}

	/**
	 * Equals
	 * @method eq
	 * @param {Object} other UINT32
	 * @return {Boolean}
	 */
	UINT32.prototype.equals = UINT32.prototype.eq = function (other) {
		return (this._low == other._low) && (this._high == other._high)
	}

	/**
	 * Greater than (strict)
	 * @method gt
	 * @param {Object} other UINT32
	 * @return {Boolean}
	 */
	UINT32.prototype.greaterThan = UINT32.prototype.gt = function (other) {
		if (this._high > other._high) return true
		if (this._high < other._high) return false
		return this._low > other._low
	}

	/**
	 * Less than (strict)
	 * @method lt
	 * @param {Object} other UINT32
	 * @return {Boolean}
	 */
	UINT32.prototype.lessThan = UINT32.prototype.lt = function (other) {
		if (this._high < other._high) return true
		if (this._high > other._high) return false
		return this._low < other._low
	}

	/**
	 * Bitwise OR
	 * @method or
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.or = function (other) {
		this._low |= other._low
		this._high |= other._high

		return this
	}

	/**
	 * Bitwise AND
	 * @method and
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.and = function (other) {
		this._low &= other._low
		this._high &= other._high

		return this
	}

	/**
	 * Bitwise NOT
	 * @method not
	 * @return ThisExpression
	 */
	UINT32.prototype.not = function() {
		this._low = ~this._low & 0xFFFF
		this._high = ~this._high & 0xFFFF

		return this
	}

	/**
	 * Bitwise XOR
	 * @method xor
	 * @param {Object} other UINT32
	 * @return ThisExpression
	 */
	UINT32.prototype.xor = function (other) {
		this._low ^= other._low
		this._high ^= other._high

		return this
	}

	/**
	 * Bitwise shift right
	 * @method shiftRight
	 * @param {Number} number of bits to shift
	 * @return ThisExpression
	 */
	UINT32.prototype.shiftRight = UINT32.prototype.shiftr = function (n) {
		if (n > 16) {
			this._low = this._high >> (n - 16)
			this._high = 0
		} else if (n == 16) {
			this._low = this._high
			this._high = 0
		} else {
			this._low = (this._low >> n) | ( (this._high << (16-n)) & 0xFFFF )
			this._high >>= n
		}

		return this
	}

	/**
	 * Bitwise shift left
	 * @method shiftLeft
	 * @param {Number} number of bits to shift
	 * @param {Boolean} allow overflow
	 * @return ThisExpression
	 */
	UINT32.prototype.shiftLeft = UINT32.prototype.shiftl = function (n, allowOverflow) {
		if (n > 16) {
			this._high = this._low << (n - 16)
			this._low = 0
			if (!allowOverflow) {
				this._high &= 0xFFFF
			}
		} else if (n == 16) {
			this._high = this._low
			this._low = 0
		} else {
			this._high = (this._high << n) | (this._low >> (16-n))
			this._low = (this._low << n) & 0xFFFF
			if (!allowOverflow) {
				// Overflow only allowed on the high bits...
				this._high &= 0xFFFF
			}
		}

		return this
	}

	/**
	 * Bitwise rotate left
	 * @method rotl
	 * @param {Number} number of bits to rotate
	 * @return ThisExpression
	 */
	UINT32.prototype.rotateLeft = UINT32.prototype.rotl = function (n) {
		var v = (this._high << 16) | this._low
		v = (v << n) | (v >>> (32 - n))
		this._low = v & 0xFFFF
		this._high = v >>> 16

		return this
	}

	/**
	 * Bitwise rotate right
	 * @method rotr
	 * @param {Number} number of bits to rotate
	 * @return ThisExpression
	 */
	UINT32.prototype.rotateRight = UINT32.prototype.rotr = function (n) {
		var v = (this._high << 16) | this._low
		v = (v >>> n) | (v << (32 - n))
		this._low = v & 0xFFFF
		this._high = v >>> 16

		return this
	}

	/**
	 * Clone the current _UINT32_
	 * @method clone
	 * @return {Object} cloned UINT32
	 */
	UINT32.prototype.clone = function () {
		return new UINT32(this._low, this._high)
	}

	if (typeof define != 'undefined' && define.amd) {
		// AMD / RequireJS
		define([], function () {
			return UINT32
		})
	} else if (typeof module != 'undefined' && module.exports) {
		// Node.js
		module.exports = UINT32
	} else {
		// Browser
		root['UINT32'] = UINT32
	}

})(this)