#include "ucore_hash.h"

// 'm' and 'r' are mixing constants generated offline.
// They're not really 'magic', they just happen to work well.
#define m  0x5bd1e995
#define r  24

uint32_t 
uc_murmurmash2(const void *key, int len, uint32_t seed )
{


    // 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;
}