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/** * @preserve * JS Implementation of incremental MurmurHash3 (r150) (as of May 10, 2013) * * @author <a href="mailto:jensyt@gmail.com">Jens Taylor</a> * @see http://github.com/homebrewing/brauhaus-diff * @author <a href="mailto:gary.court@gmail.com">Gary Court</a> * @see http://github.com/garycourt/murmurhash-js * @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a> * @see http://sites.google.com/site/murmurhash/ */ (function(){ var cache; // Call this function without `new` to use the cached object (good for // single-threaded environments), or with `new` to create a new object. // // @param {string} key A UTF-16 or ASCII string // @param {number} seed An optional positive integer // @return {object} A MurmurHash3 object for incremental hashing function MurmurHash3(key, seed) { var m = this instanceof MurmurHash3 ? this : cache; m.reset(seed) if (typeof key === 'string' && key.length > 0) { m.hash(key); } if (m !== this) { return m; } }; // Incrementally add a string to this hash // // @param {string} key A UTF-16 or ASCII string // @return {object} this MurmurHash3.prototype.hash = function(key) { var h1, k1, i, top, len; len = key.length; this.len += len; k1 = this.k1; i = 0; switch (this.rem) { case 0: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) : 0; case 1: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 8 : 0; case 2: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 16 : 0; case 3: k1 ^= len > i ? (key.charCodeAt(i) & 0xff) << 24 : 0; k1 ^= len > i ? (key.charCodeAt(i++) & 0xff00) >> 8 : 0; } this.rem = (len + this.rem) & 3; // & 3 is same as % 4 len -= this.rem; if (len > 0) { h1 = this.h1; while (1) { k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff; k1 = (k1 << 15) | (k1 >>> 17); k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff; h1 ^= k1; h1 = (h1 << 13) | (h1 >>> 19); h1 = (h1 * 5 + 0xe6546b64) & 0xffffffff; if (i >= len) { break; } k1 = ((key.charCodeAt(i++) & 0xffff)) ^ ((key.charCodeAt(i++) & 0xffff) << 8) ^ ((key.charCodeAt(i++) & 0xffff) << 16); top = key.charCodeAt(i++); k1 ^= ((top & 0xff) << 24) ^ ((top & 0xff00) >> 8); } k1 = 0; switch (this.rem) { case 3: k1 ^= (key.charCodeAt(i + 2) & 0xffff) << 16; case 2: k1 ^= (key.charCodeAt(i + 1) & 0xffff) << 8; case 1: k1 ^= (key.charCodeAt(i) & 0xffff); } this.h1 = h1; } this.k1 = k1; return this; }; // Get the result of this hash // // @return {number} The 32-bit hash MurmurHash3.prototype.result = function() { var k1, h1; k1 = this.k1; h1 = this.h1; if (k1 > 0) { k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff; k1 = (k1 << 15) | (k1 >>> 17); k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff; h1 ^= k1; } h1 ^= this.len; h1 ^= h1 >>> 16; h1 = (h1 * 0xca6b + (h1 & 0xffff) * 0x85eb0000) & 0xffffffff; h1 ^= h1 >>> 13; h1 = (h1 * 0xae35 + (h1 & 0xffff) * 0xc2b20000) & 0xffffffff; h1 ^= h1 >>> 16; return h1 >>> 0; }; // Reset the hash object for reuse // // @param {number} seed An optional positive integer MurmurHash3.prototype.reset = function(seed) { this.h1 = typeof seed === 'number' ? seed : 0; this.rem = this.k1 = this.len = 0; return this; }; // A cached object to use. This can be safely used if you're in a single- // threaded environment, otherwise you need to create new hashes to use. cache = new MurmurHash3(); if (typeof(module) != 'undefined') { module.exports = MurmurHash3; } else { this.MurmurHash3 = MurmurHash3; } }());