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/*
* Hash function from http://www.azillionmonkeys.com/qed/hash.html
* Copyright (C) 2004-2008 by Paul Hsieh
*/
#include "lmo.h"
uint32_t sfh_hash(const char * data, int len)
{
uint32_t hash = len, tmp;
int rem;
if (len <= 0 || data == NULL) return 0;
rem = len & 3;
len >>= 2;
/* Main loop */
for (;len > 0; len--) {
hash += sfh_get16(data);
tmp = (sfh_get16(data+2) << 11) ^ hash;
hash = (hash << 16) ^ tmp;
data += 2*sizeof(uint16_t);
hash += hash >> 11;
}
/* Handle end cases */
switch (rem) {
case 3: hash += sfh_get16(data);
hash ^= hash << 16;
hash ^= data[sizeof(uint16_t)] << 18;
hash += hash >> 11;
break;
case 2: hash += sfh_get16(data);
hash ^= hash << 11;
hash += hash >> 17;
break;
case 1: hash += *data;
hash ^= hash << 10;
hash += hash >> 1;
}
/* Force "avalanching" of final 127 bits */
hash ^= hash << 3;
hash += hash >> 5;
hash ^= hash << 4;
hash += hash >> 17;
hash ^= hash << 25;
hash += hash >> 6;
return hash;
}
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