32bit / 64bit well hash functions

// Robert Jenkins' 32bit hash function unsigned __int32 hash(unsigned __int32 key) { key += (key<<12); key ^= (key>>22); key += (key<<4); key ^= (key>>9); key += (key<<10); key ^= (key>>2); key += (key<<7); key ^= (key>>12); return key; } // Thomas Wang's hash function unsigned __int32 hash32(unsigned __int32 key) { key = ~key + (key << 15); // key = (key << 15) - key - 1 key ^= (key >> 12); key += (key << 2); key ^= (key >> 4); key += (key << 3) + (key << 11); // key = key * 2057 key ^= (key >> 16); return key; } unsigned __int64 hash64(unsigned __int64 key) { key = ~key + (key << 21); // key = (key << 21) - key - 1 key ^= (key >> 24); key += (key << 3) + (key << 8); // key = key * 265 key ^= (key >> 14); key += (key << 2) + (key << 4); // key = key * 21 key ^= (key >> 28); key += (key << 31); return key; } unsigned __int32 hash6432(unsigned __int64 key) { key = ~key + (key << 18); // key = (key << 18) - key - 1 key ^= (key >> 31); key += (key << 2) + (key << 4); // key = key * 21 key ^= (key >> 11); key += (key << 6); key ^= (key >> 22); return (unsigned __int32)key; }