murmurhash2算法 和 DJB Hash算法是目前最流行的hash算法

murmurhash2算法 和 DJB Hash算法是目前最流行的hash算法

1.DJB HASH算法

1 2 3 4 5 6 7 8 9 10 11

/* the famous DJB Hash Function for strings */ unsigned int DJBHash(char *str) { unsigned int hash = 5381;   while (*str){ hash = ((hash << 5) + hash) + (*str++); /* times 33 */ } hash &= ~(1 << 31); /* strip the highest bit */ return hash; }

2.murmurhash2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

uint32_t murmur_hash2(char *data, size_t len) { uint32_t h, k;   h = 0 ^ len;   while (len >= 4) { k = data[0]; k |= data[1] << 8; k |= data[2] << 16; k |= data[3] << 24;   k *= 0x5bd1e995; k ^= k >> 24; k *= 0x5bd1e995;   h *= 0x5bd1e995; h ^= k;   data += 4; len -= 4; }   switch (len) { case 3: h ^= data[2] << 16; case 2: h ^= data[1] << 8; case 1: h ^= data[0]; h *= 0x5bd1e995; }   h ^= h >> 13; h *= 0x5bd1e995; h ^= h >> 15;   return h; }

 

 

 

 

http://daodaoliang.com/c-%E5%AD%A6%E4%B9%A0/2017/03/08/c-%E5%AD%A6%E4%B9%A0-2017-03-08-HashAlgorithm/