Function dmHashBufferNoReverse64

engine/dlib/src/dlib/hash.cpp:254–304

Based on MurmurHash2A but endian neutral

// Based on MurmurHash2A but endian neutral
uint64_t dmHashBufferNoReverse64(const void * key, uint32_t len)
{
    const uint64_t m = 0xc6a4a7935bd1e995ULL;
    const int r = 47;
    uint64_t l = len;

    const unsigned char * data = (const unsigned char *)key;

    uint64_t h = /*seed*/ 0;

    while(len >= 8)
    {
        uint64_t k;

        k  = uint64_t(data[0]);
        k |= uint64_t(data[1]) << 8;
        k |= uint64_t(data[2]) << 16;
        k |= uint64_t(data[3]) << 24;
        k |= uint64_t(data[4]) << 32;
        k |= uint64_t(data[5]) << 40;
        k |= uint64_t(data[6]) << 48;
        k |= uint64_t(data[7]) << 56;

        mmix(h,k);

        data += 8;
        len -= 8;
    }

    uint64_t t = 0;

    switch(len)
    {
    case 7: t ^= uint64_t(data[6]) << 48;
    case 6: t ^= uint64_t(data[5]) << 40;
    case 5: t ^= uint64_t(data[4]) << 32;
    case 4: t ^= uint64_t(data[3]) << 24;
    case 3: t ^= uint64_t(data[2]) << 16;
    case 2: t ^= uint64_t(data[1]) << 8;
    case 1: t ^= uint64_t(data[0]);
    };

    mmix(h,t);
    mmix(h,l);

    h ^= h >> r;
    h *= m;
    h ^= h >> r;

    return h;
}

uint64_t dmHashBuffer64(const void * key, uint32_t len)
{