原始版本的murmurhash2算法

来源：互联网发布：腾讯企业邮箱pop 端口编辑：程序博客网时间：2024/04/27 17:50

原始版本的murmurhash2算法（Google Code 的 Murmurhash 开源项目主页上的 Murmurhash2）

uint32_t MurmurHash2 ( const void * key, int len, uint32_t seed ){  // 'm' and 'r' are mixing constants generated offline.  // They're not really 'magic', they just happen to work well.  const uint32_t m = 0x5bd1e995;  const int r = 24;  // Initialize the hash to a 'random' value  uint32_t h = seed ^ len;  // Mix 4 bytes at a time into the hash  const unsigned char * data = (const unsigned char *)key;  while(len >= 4)  {    uint32_t k = *(uint32_t*)data;    k *= m;    k ^= k >> r;    k *= m;    h *= m;    h ^= k;    data += 4;    len -= 4;  }  // Handle the last few bytes of the input array  switch(len)  {  case 3: h ^= data[2] << 16;  case 2: h ^= data[1] << 8;  case 1: h ^= data[0];      h *= m;  };  // Do a few final mixes of the hash to ensure the last few  // bytes are well-incorporated.  h ^= h >> 13;  h *= m;  h ^= h >> 15;  return h;}

0 0