390 lines
8.8 KiB
JavaScript
390 lines
8.8 KiB
JavaScript
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/**
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xxHash implementation in pure Javascript
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Copyright (C) 2013, Pierre Curto
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MIT license
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*/
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var UINT32 = require('cuint').UINT32
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/*
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Merged this sequence of method calls as it speeds up
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the calculations by a factor of 2
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*/
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// this.v1.add( other.multiply(PRIME32_2) ).rotl(13).multiply(PRIME32_1);
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UINT32.prototype.xxh_update = function (low, high) {
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var b00 = PRIME32_2._low
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var b16 = PRIME32_2._high
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var c16, c00
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c00 = low * b00
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c16 = c00 >>> 16
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c16 += high * b00
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c16 &= 0xFFFF // Not required but improves performance
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c16 += low * b16
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var a00 = this._low + (c00 & 0xFFFF)
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var a16 = a00 >>> 16
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a16 += this._high + (c16 & 0xFFFF)
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var v = (a16 << 16) | (a00 & 0xFFFF)
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v = (v << 13) | (v >>> 19)
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a00 = v & 0xFFFF
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a16 = v >>> 16
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b00 = PRIME32_1._low
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b16 = PRIME32_1._high
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c00 = a00 * b00
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c16 = c00 >>> 16
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c16 += a16 * b00
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c16 &= 0xFFFF // Not required but improves performance
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c16 += a00 * b16
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this._low = c00 & 0xFFFF
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this._high = c16 & 0xFFFF
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}
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/*
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* Constants
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*/
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var PRIME32_1 = UINT32( '2654435761' )
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var PRIME32_2 = UINT32( '2246822519' )
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var PRIME32_3 = UINT32( '3266489917' )
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var PRIME32_4 = UINT32( '668265263' )
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var PRIME32_5 = UINT32( '374761393' )
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/**
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* Convert string to proper UTF-8 array
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* @param str Input string
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* @returns {Uint8Array} UTF8 array is returned as uint8 array
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*/
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function toUTF8Array (str) {
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var utf8 = []
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for (var i=0, n=str.length; i < n; i++) {
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var charcode = str.charCodeAt(i)
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if (charcode < 0x80) utf8.push(charcode)
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else if (charcode < 0x800) {
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utf8.push(0xc0 | (charcode >> 6),
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0x80 | (charcode & 0x3f))
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}
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else if (charcode < 0xd800 || charcode >= 0xe000) {
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utf8.push(0xe0 | (charcode >> 12),
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0x80 | ((charcode>>6) & 0x3f),
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0x80 | (charcode & 0x3f))
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}
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// surrogate pair
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else {
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i++;
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// UTF-16 encodes 0x10000-0x10FFFF by
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// subtracting 0x10000 and splitting the
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// 20 bits of 0x0-0xFFFFF into two halves
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charcode = 0x10000 + (((charcode & 0x3ff)<<10)
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| (str.charCodeAt(i) & 0x3ff))
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utf8.push(0xf0 | (charcode >>18),
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0x80 | ((charcode>>12) & 0x3f),
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0x80 | ((charcode>>6) & 0x3f),
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0x80 | (charcode & 0x3f))
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}
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}
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return new Uint8Array(utf8)
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}
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/**
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* XXH object used as a constructor or a function
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* @constructor
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* or
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* @param {Object|String} input data
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* @param {Number|UINT32} seed
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* @return ThisExpression
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* or
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* @return {UINT32} xxHash
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*/
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function XXH () {
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if (arguments.length == 2)
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return new XXH( arguments[1] ).update( arguments[0] ).digest()
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if (!(this instanceof XXH))
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return new XXH( arguments[0] )
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init.call(this, arguments[0])
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}
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/**
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* Initialize the XXH instance with the given seed
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* @method init
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* @param {Number|Object} seed as a number or an unsigned 32 bits integer
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* @return ThisExpression
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*/
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function init (seed) {
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this.seed = seed instanceof UINT32 ? seed.clone() : UINT32(seed)
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this.v1 = this.seed.clone().add(PRIME32_1).add(PRIME32_2)
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this.v2 = this.seed.clone().add(PRIME32_2)
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this.v3 = this.seed.clone()
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this.v4 = this.seed.clone().subtract(PRIME32_1)
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this.total_len = 0
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this.memsize = 0
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this.memory = null
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return this
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}
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XXH.prototype.init = init
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/**
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* Add data to be computed for the XXH hash
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* @method update
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* @param {String|Buffer|ArrayBuffer} input as a string or nodejs Buffer or ArrayBuffer
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* @return ThisExpression
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*/
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XXH.prototype.update = function (input) {
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var isString = typeof input == 'string'
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var isArrayBuffer
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// Convert all strings to utf-8 first (issue #5)
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if (isString) {
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input = toUTF8Array(input)
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isString = false
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isArrayBuffer = true
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}
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if (typeof ArrayBuffer !== "undefined" && input instanceof ArrayBuffer)
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{
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isArrayBuffer = true
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input = new Uint8Array(input);
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}
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var p = 0
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var len = input.length
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var bEnd = p + len
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if (len == 0) return this
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this.total_len += len
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if (this.memsize == 0)
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{
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if (isString) {
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this.memory = ''
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} else if (isArrayBuffer) {
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this.memory = new Uint8Array(16)
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} else {
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this.memory = new Buffer(16)
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}
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}
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if (this.memsize + len < 16) // fill in tmp buffer
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{
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// XXH_memcpy(this.memory + this.memsize, input, len)
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if (isString) {
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this.memory += input
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} else if (isArrayBuffer) {
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this.memory.set( input.subarray(0, len), this.memsize )
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} else {
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input.copy( this.memory, this.memsize, 0, len )
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}
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this.memsize += len
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return this
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}
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if (this.memsize > 0) // some data left from previous update
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{
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// XXH_memcpy(this.memory + this.memsize, input, 16-this.memsize);
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if (isString) {
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this.memory += input.slice(0, 16 - this.memsize)
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} else if (isArrayBuffer) {
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this.memory.set( input.subarray(0, 16 - this.memsize), this.memsize )
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} else {
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input.copy( this.memory, this.memsize, 0, 16 - this.memsize )
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}
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var p32 = 0
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if (isString) {
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this.v1.xxh_update(
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(this.memory.charCodeAt(p32+1) << 8) | this.memory.charCodeAt(p32)
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, (this.memory.charCodeAt(p32+3) << 8) | this.memory.charCodeAt(p32+2)
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)
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p32 += 4
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this.v2.xxh_update(
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(this.memory.charCodeAt(p32+1) << 8) | this.memory.charCodeAt(p32)
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, (this.memory.charCodeAt(p32+3) << 8) | this.memory.charCodeAt(p32+2)
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)
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p32 += 4
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this.v3.xxh_update(
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(this.memory.charCodeAt(p32+1) << 8) | this.memory.charCodeAt(p32)
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, (this.memory.charCodeAt(p32+3) << 8) | this.memory.charCodeAt(p32+2)
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)
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p32 += 4
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this.v4.xxh_update(
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(this.memory.charCodeAt(p32+1) << 8) | this.memory.charCodeAt(p32)
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, (this.memory.charCodeAt(p32+3) << 8) | this.memory.charCodeAt(p32+2)
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)
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} else {
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this.v1.xxh_update(
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(this.memory[p32+1] << 8) | this.memory[p32]
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, (this.memory[p32+3] << 8) | this.memory[p32+2]
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)
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p32 += 4
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this.v2.xxh_update(
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(this.memory[p32+1] << 8) | this.memory[p32]
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, (this.memory[p32+3] << 8) | this.memory[p32+2]
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)
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p32 += 4
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this.v3.xxh_update(
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(this.memory[p32+1] << 8) | this.memory[p32]
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, (this.memory[p32+3] << 8) | this.memory[p32+2]
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)
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p32 += 4
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this.v4.xxh_update(
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(this.memory[p32+1] << 8) | this.memory[p32]
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, (this.memory[p32+3] << 8) | this.memory[p32+2]
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)
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}
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p += 16 - this.memsize
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this.memsize = 0
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if (isString) this.memory = ''
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}
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if (p <= bEnd - 16)
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{
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var limit = bEnd - 16
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do
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{
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if (isString) {
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this.v1.xxh_update(
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(input.charCodeAt(p+1) << 8) | input.charCodeAt(p)
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, (input.charCodeAt(p+3) << 8) | input.charCodeAt(p+2)
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)
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p += 4
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this.v2.xxh_update(
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(input.charCodeAt(p+1) << 8) | input.charCodeAt(p)
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, (input.charCodeAt(p+3) << 8) | input.charCodeAt(p+2)
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)
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p += 4
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this.v3.xxh_update(
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(input.charCodeAt(p+1) << 8) | input.charCodeAt(p)
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, (input.charCodeAt(p+3) << 8) | input.charCodeAt(p+2)
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)
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p += 4
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this.v4.xxh_update(
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(input.charCodeAt(p+1) << 8) | input.charCodeAt(p)
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, (input.charCodeAt(p+3) << 8) | input.charCodeAt(p+2)
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)
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} else {
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this.v1.xxh_update(
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(input[p+1] << 8) | input[p]
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, (input[p+3] << 8) | input[p+2]
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)
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p += 4
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this.v2.xxh_update(
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(input[p+1] << 8) | input[p]
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, (input[p+3] << 8) | input[p+2]
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)
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p += 4
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this.v3.xxh_update(
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(input[p+1] << 8) | input[p]
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, (input[p+3] << 8) | input[p+2]
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)
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p += 4
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this.v4.xxh_update(
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(input[p+1] << 8) | input[p]
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, (input[p+3] << 8) | input[p+2]
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)
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}
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p += 4
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} while (p <= limit)
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}
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if (p < bEnd)
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{
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// XXH_memcpy(this.memory, p, bEnd-p);
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if (isString) {
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this.memory += input.slice(p)
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} else if (isArrayBuffer) {
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this.memory.set( input.subarray(p, bEnd), this.memsize )
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} else {
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input.copy( this.memory, this.memsize, p, bEnd )
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}
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this.memsize = bEnd - p
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}
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return this
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}
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/**
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* Finalize the XXH computation. The XXH instance is ready for reuse for the given seed
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* @method digest
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* @return {UINT32} xxHash
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*/
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XXH.prototype.digest = function () {
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var input = this.memory
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var isString = typeof input == 'string'
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var p = 0
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var bEnd = this.memsize
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var h32, h
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var u = new UINT32
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if (this.total_len >= 16)
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{
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h32 = this.v1.rotl(1).add( this.v2.rotl(7).add( this.v3.rotl(12).add( this.v4.rotl(18) ) ) )
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}
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else
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{
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h32 = this.seed.clone().add( PRIME32_5 )
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}
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h32.add( u.fromNumber(this.total_len) )
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while (p <= bEnd - 4)
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{
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if (isString) {
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u.fromBits(
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(input.charCodeAt(p+1) << 8) | input.charCodeAt(p)
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, (input.charCodeAt(p+3) << 8) | input.charCodeAt(p+2)
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)
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} else {
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u.fromBits(
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(input[p+1] << 8) | input[p]
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, (input[p+3] << 8) | input[p+2]
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)
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}
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h32
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.add( u.multiply(PRIME32_3) )
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.rotl(17)
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.multiply( PRIME32_4 )
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p += 4
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}
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while (p < bEnd)
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{
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u.fromBits( isString ? input.charCodeAt(p++) : input[p++], 0 )
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h32
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.add( u.multiply(PRIME32_5) )
|
||
|
|
.rotl(11)
|
||
|
|
.multiply(PRIME32_1)
|
||
|
|
}
|
||
|
|
|
||
|
|
h = h32.clone().shiftRight(15)
|
||
|
|
h32.xor(h).multiply(PRIME32_2)
|
||
|
|
|
||
|
|
h = h32.clone().shiftRight(13)
|
||
|
|
h32.xor(h).multiply(PRIME32_3)
|
||
|
|
|
||
|
|
h = h32.clone().shiftRight(16)
|
||
|
|
h32.xor(h)
|
||
|
|
|
||
|
|
// Reset the state
|
||
|
|
this.init( this.seed )
|
||
|
|
|
||
|
|
return h32
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports = XXH
|