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1e3186c Jan 29, 2011
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/**
* JS Implementation of MurmurHash2
*
* @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/
*
* @param {string} str ASCII only
* @param {number} seed Positive integer only
* @return {number} 32-bit positive integer hash
*/
function murmurhash2_32_gc(str, seed) {
var
l = str.length,
h = seed ^ l,
i = 0,
k;
while (l >= 4) {
k =
((str.charCodeAt(i) & 0xff)) |
((str.charCodeAt(++i) & 0xff) << 8) |
((str.charCodeAt(++i) & 0xff) << 16) |
((str.charCodeAt(++i) & 0xff) << 24);
k = (((k & 0xffff) * 0x5bd1e995) + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16));
k ^= k >>> 24;
k = (((k & 0xffff) * 0x5bd1e995) + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16));
h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16)) ^ k;
l -= 4;
++i;
}
switch (l) {
case 3: h ^= (str.charCodeAt(i + 2) & 0xff) << 16;
case 2: h ^= (str.charCodeAt(i + 1) & 0xff) << 8;
case 1: h ^= (str.charCodeAt(i) & 0xff);
h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16));
}
h ^= h >>> 13;
h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16));
h ^= h >>> 15;
return h >>> 0;
}