Dqn/dqn_hash.cpp

248 lines
6.0 KiB
C++

// NOTE: [$FNV1] Dqn_FNV1A =========================================================================
// Default values recommended by: http://isthe.com/chongo/tech/comp/fnv/
DQN_API uint32_t Dqn_FNV1A32_Iterate(void const *bytes, Dqn_usize size, uint32_t hash)
{
auto buffer = DQN_CAST(uint8_t const *)bytes;
for (Dqn_usize i = 0; i < size; i++)
hash = (buffer[i] ^ hash) * 16777619 /*FNV Prime*/;
return hash;
}
DQN_API uint32_t Dqn_FNV1A32_Hash(void const *bytes, Dqn_usize size)
{
uint32_t result = Dqn_FNV1A32_Iterate(bytes, size, DQN_FNV1A32_SEED);
return result;
}
DQN_API uint64_t Dqn_FNV1A64_Iterate(void const *bytes, Dqn_usize size, uint64_t hash)
{
auto buffer = DQN_CAST(uint8_t const *)bytes;
for (Dqn_usize i = 0; i < size; i++)
hash = (buffer[i] ^ hash) * 1099511628211 /*FNV Prime*/;
return hash;
}
DQN_API uint64_t Dqn_FNV1A64_Hash(void const *bytes, Dqn_usize size)
{
uint64_t result = Dqn_FNV1A64_Iterate(bytes, size, DQN_FNV1A64_SEED);
return result;
}
// NOTE: [$MMUR] Dqn_MurmurHash3 ===================================================================
#if defined(DQN_COMPILER_W32_MSVC) || defined(DQN_COMPILER_W32_CLANG)
#define DQN_MMH3_ROTL32(x, y) _rotl(x, y)
#define DQN_MMH3_ROTL64(x, y) _rotl64(x, y)
#else
#define DQN_MMH3_ROTL32(x, y) ((x) << (y)) | ((x) >> (32 - (y)))
#define DQN_MMH3_ROTL64(x, y) ((x) << (y)) | ((x) >> (64 - (y)))
#endif
//-----------------------------------------------------------------------------
// Block read - if your platform needs to do endian-swapping or can only
// handle aligned reads, do the conversion here
DQN_FORCE_INLINE uint32_t Dqn_MurmurHash3_GetBlock32(uint32_t const *p, int i)
{
return p[i];
}
DQN_FORCE_INLINE uint64_t Dqn_MurmurHash3_GetBlock64(uint64_t const *p, int i)
{
return p[i];
}
//-----------------------------------------------------------------------------
// Finalization mix - force all bits of a hash block to avalanche
DQN_FORCE_INLINE uint32_t Dqn_MurmurHash3_FMix32(uint32_t h)
{
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
DQN_FORCE_INLINE uint64_t Dqn_MurmurHash3_FMix64(uint64_t k)
{
k ^= k >> 33;
k *= 0xff51afd7ed558ccd;
k ^= k >> 33;
k *= 0xc4ceb9fe1a85ec53;
k ^= k >> 33;
return k;
}
DQN_API uint32_t Dqn_MurmurHash3_x86U32(void const *key, int len, uint32_t seed)
{
const uint8_t *data = (const uint8_t *)key;
const int nblocks = len / 4;
uint32_t h1 = seed;
const uint32_t c1 = 0xcc9e2d51;
const uint32_t c2 = 0x1b873593;
//----------
// body
const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
for (int i = -nblocks; i; i++)
{
uint32_t k1 = Dqn_MurmurHash3_GetBlock32(blocks, i);
k1 *= c1;
k1 = DQN_MMH3_ROTL32(k1, 15);
k1 *= c2;
h1 ^= k1;
h1 = DQN_MMH3_ROTL32(h1, 13);
h1 = h1 * 5 + 0xe6546b64;
}
//----------
// tail
const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
uint32_t k1 = 0;
switch (len & 3)
{
case 3:
k1 ^= tail[2] << 16;
case 2:
k1 ^= tail[1] << 8;
case 1:
k1 ^= tail[0];
k1 *= c1;
k1 = DQN_MMH3_ROTL32(k1, 15);
k1 *= c2;
h1 ^= k1;
};
//----------
// finalization
h1 ^= len;
h1 = Dqn_MurmurHash3_FMix32(h1);
return h1;
}
DQN_API Dqn_MurmurHash3 Dqn_MurmurHash3_x64U128(void const *key, int len, uint32_t seed)
{
const uint8_t *data = (const uint8_t *)key;
const int nblocks = len / 16;
uint64_t h1 = seed;
uint64_t h2 = seed;
const uint64_t c1 = 0x87c37b91114253d5;
const uint64_t c2 = 0x4cf5ad432745937f;
//----------
// body
const uint64_t *blocks = (const uint64_t *)(data);
for (int i = 0; i < nblocks; i++)
{
uint64_t k1 = Dqn_MurmurHash3_GetBlock64(blocks, i * 2 + 0);
uint64_t k2 = Dqn_MurmurHash3_GetBlock64(blocks, i * 2 + 1);
k1 *= c1;
k1 = DQN_MMH3_ROTL64(k1, 31);
k1 *= c2;
h1 ^= k1;
h1 = DQN_MMH3_ROTL64(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729;
k2 *= c2;
k2 = DQN_MMH3_ROTL64(k2, 33);
k2 *= c1;
h2 ^= k2;
h2 = DQN_MMH3_ROTL64(h2, 31);
h2 += h1;
h2 = h2 * 5 + 0x38495ab5;
}
//----------
// tail
const uint8_t *tail = (const uint8_t *)(data + nblocks * 16);
uint64_t k1 = 0;
uint64_t k2 = 0;
switch (len & 15)
{
case 15:
k2 ^= ((uint64_t)tail[14]) << 48;
case 14:
k2 ^= ((uint64_t)tail[13]) << 40;
case 13:
k2 ^= ((uint64_t)tail[12]) << 32;
case 12:
k2 ^= ((uint64_t)tail[11]) << 24;
case 11:
k2 ^= ((uint64_t)tail[10]) << 16;
case 10:
k2 ^= ((uint64_t)tail[9]) << 8;
case 9:
k2 ^= ((uint64_t)tail[8]) << 0;
k2 *= c2;
k2 = DQN_MMH3_ROTL64(k2, 33);
k2 *= c1;
h2 ^= k2;
case 8:
k1 ^= ((uint64_t)tail[7]) << 56;
case 7:
k1 ^= ((uint64_t)tail[6]) << 48;
case 6:
k1 ^= ((uint64_t)tail[5]) << 40;
case 5:
k1 ^= ((uint64_t)tail[4]) << 32;
case 4:
k1 ^= ((uint64_t)tail[3]) << 24;
case 3:
k1 ^= ((uint64_t)tail[2]) << 16;
case 2:
k1 ^= ((uint64_t)tail[1]) << 8;
case 1:
k1 ^= ((uint64_t)tail[0]) << 0;
k1 *= c1;
k1 = DQN_MMH3_ROTL64(k1, 31);
k1 *= c2;
h1 ^= k1;
};
//----------
// finalization
h1 ^= len;
h2 ^= len;
h1 += h2;
h2 += h1;
h1 = Dqn_MurmurHash3_FMix64(h1);
h2 = Dqn_MurmurHash3_FMix64(h2);
h1 += h2;
h2 += h1;
Dqn_MurmurHash3 result = {};
result.e[0] = h1;
result.e[1] = h2;
return result;
}