diff --git a/src/murmur/murmur.c b/src/murmur/murmur.c new file mode 100644 index 00000000..be8f4675 --- /dev/null +++ b/src/murmur/murmur.c @@ -0,0 +1,118 @@ +//----------------------------------------------------------------------------- +// 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; +} \ No newline at end of file diff --git a/src/murmur/murmur.h b/src/murmur/murmur.h new file mode 100644 index 00000000..33900679 --- /dev/null +++ b/src/murmur/murmur.h @@ -0,0 +1,12 @@ +//----------------------------------------------------------------------------- +// MurmurHash3 was written by Austin Appleby, and is placed in the public +// domain. The author hereby disclaims copyright to this source code. + +#ifndef _MURMURHASH3_H_ +#define _MURMURHASH3_H_ + +#include + +void MurmurHash3_x64_128 ( const void * key, int len, uint32_t seed, void * out ); + +#endif // _MURMURHASH3_H_ \ No newline at end of file