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//-----------------------------------------------------------------------------
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. The author hereby disclaims copyright to this source code.
// Note - The x86 and x64 versions do _not_ produce the same results, as the
// algorithms are optimized for their respective platforms. You can still
// compile and run any of them on any platform, but your performance with the
// non-native version will be less than optimal.
#include "murmur.h"
#define FORCE_INLINE inline static
FORCE_INLINE uint64_t rotl64(uint64_t x, int8_t r)
{
return (x << r) | (x >> (64 - r));
}
#define ROTL64(x, y) rotl64(x, y)
#define BIG_CONSTANT(x) (x##LLU)
#define getblock(x, i) (x[i])
//-----------------------------------------------------------------------------
// Finalization mix - force all bits of a hash block to avalanche
FORCE_INLINE uint64_t fmix64(uint64_t k)
{
k ^= k >> 33;
k *= BIG_CONSTANT(0xff51afd7ed558ccd);
k ^= k >> 33;
k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
k ^= k >> 33;
return k;
}
//-----------------------------------------------------------------------------
void MurmurHash3_x64_128(const void *key, const int len, const uint32_t seed, void *out)
{
const uint8_t *data = (const uint8_t *)key;
const int nblocks = len / 16;
uint64_t h1 = seed;
uint64_t h2 = seed;
uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
int i;
//----------
// body
const uint64_t *blocks = (const uint64_t *)(data);
for (i = 0; i < nblocks; i++)
{
uint64_t k1 = getblock(blocks, i * 2 + 0);
uint64_t k2 = getblock(blocks, i * 2 + 1);
k1 *= c1;
k1 = ROTL64(k1, 31);
k1 *= c2;
h1 ^= k1;
h1 = ROTL64(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729;
k2 *= c2;
k2 = ROTL64(k2, 33);
k2 *= c1;
h2 ^= k2;
h2 = 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 = 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 = ROTL64(k1, 31);
k1 *= c2;
h1 ^= k1;
}
//----------
// finalization
h1 ^= len;
h2 ^= len;
h1 += h2;
h2 += h1;
h1 = fmix64(h1);
h2 = fmix64(h2);
h1 += h2;
h2 += h1;
((uint64_t *)out)[0] = h1;
((uint64_t *)out)[1] = h2;
}
//-----------------------------------------------------------------------------
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