Update hash from MurmurHash2 to MurmurHash3.
Update hash from MurmurHash2 to MurmurHash3, primarily because the latter generates 128 bits in a single call for no extra cost, which simplifies integration with cuckoo hashing.
This commit is contained in:
Jason Evans
@@ -1,3 +1,8 @@
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/*
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* The following hash function is based on MurmurHash3, placed into the public
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* domain by Austin Appleby. See http://code.google.com/p/smhasher/ for
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* details.
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*/
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/******************************************************************************/
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#ifdef JEMALLOC_H_TYPES
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@@ -14,55 +19,311 @@
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#ifdef JEMALLOC_H_INLINES
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#ifndef JEMALLOC_ENABLE_INLINE
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uint64_t hash(const void *key, size_t len, uint64_t seed);
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void hash(const void *key, size_t len, const uint32_t seed,
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size_t r_hash[2]);
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#endif
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#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_HASH_C_))
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/*
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* The following hash function is based on MurmurHash64A(), placed into the
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* public domain by Austin Appleby. See http://murmurhash.googlepages.com/ for
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* details.
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*/
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JEMALLOC_INLINE uint64_t
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hash(const void *key, size_t len, uint64_t seed)
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/******************************************************************************/
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/* Internal implementation. */
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JEMALLOC_INLINE uint32_t
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hash_rotl_32(uint32_t x, int8_t r)
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{
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const uint64_t m = UINT64_C(0xc6a4a7935bd1e995);
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const int r = 47;
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uint64_t h = seed ^ (len * m);
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const uint64_t *data = (const uint64_t *)key;
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const uint64_t *end = data + (len/8);
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const unsigned char *data2;
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assert(((uintptr_t)key & 0x7) == 0);
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return (x << r) | (x >> (32 - r));
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}
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while(data != end) {
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uint64_t k = *data++;
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JEMALLOC_INLINE uint64_t
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hash_rotl_64(uint64_t x, int8_t r)
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{
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return (x << r) | (x >> (64 - r));
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}
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k *= m;
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k ^= k >> r;
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k *= m;
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JEMALLOC_INLINE uint32_t
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hash_get_block_32(const uint32_t *p, int i)
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{
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h ^= k;
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h *= m;
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return p[i];
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}
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JEMALLOC_INLINE uint64_t
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hash_get_block_64(const uint64_t *p, int i)
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{
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return p[i];
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}
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JEMALLOC_INLINE uint32_t
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hash_fmix_32(uint32_t h)
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{
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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JEMALLOC_INLINE uint64_t
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hash_fmix_64(uint64_t k)
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{
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k ^= k >> 33;
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k *= QU(0xff51afd7ed558ccdLLU);
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k ^= k >> 33;
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k *= QU(0xc4ceb9fe1a85ec53LLU);
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k ^= k >> 33;
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return k;
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}
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JEMALLOC_INLINE uint32_t
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hash_x86_32(const void *key, int len, uint32_t seed)
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{
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const uint8_t *data = (const uint8_t *) key;
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const int nblocks = len / 4;
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uint32_t h1 = seed;
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const uint32_t c1 = 0xcc9e2d51;
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const uint32_t c2 = 0x1b873593;
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/* body */
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{
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const uint32_t *blocks = (const uint32_t *) (data + nblocks*4);
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int i;
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for (i = -nblocks; i; i++) {
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uint32_t k1 = hash_get_block_32(blocks, i);
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k1 *= c1;
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k1 = hash_rotl_32(k1, 15);
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k1 *= c2;
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h1 ^= k1;
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h1 = hash_rotl_32(h1, 13);
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h1 = h1*5 + 0xe6546b64;
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}
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}
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data2 = (const unsigned char *)data;
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switch(len & 7) {
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case 7: h ^= ((uint64_t)(data2[6])) << 48;
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case 6: h ^= ((uint64_t)(data2[5])) << 40;
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case 5: h ^= ((uint64_t)(data2[4])) << 32;
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case 4: h ^= ((uint64_t)(data2[3])) << 24;
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case 3: h ^= ((uint64_t)(data2[2])) << 16;
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case 2: h ^= ((uint64_t)(data2[1])) << 8;
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case 1: h ^= ((uint64_t)(data2[0]));
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h *= m;
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/* tail */
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{
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const uint8_t *tail = (const uint8_t *) (data + nblocks*4);
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uint32_t k1 = 0;
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switch (len & 3) {
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case 3: k1 ^= tail[2] << 16;
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case 2: k1 ^= tail[1] << 8;
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case 1: k1 ^= tail[0]; k1 *= c1; k1 = hash_rotl_32(k1, 15);
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k1 *= c2; h1 ^= k1;
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}
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}
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h ^= h >> r;
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h *= m;
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h ^= h >> r;
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/* finalization */
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h1 ^= len;
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return (h);
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h1 = hash_fmix_32(h1);
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return h1;
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}
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UNUSED JEMALLOC_INLINE void
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hash_x86_128(const void *key, const int len, uint32_t seed,
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uint64_t r_out[2])
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{
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const uint8_t * data = (const uint8_t *) key;
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const int nblocks = len / 16;
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uint32_t h1 = seed;
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uint32_t h2 = seed;
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uint32_t h3 = seed;
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uint32_t h4 = seed;
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const uint32_t c1 = 0x239b961b;
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const uint32_t c2 = 0xab0e9789;
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const uint32_t c3 = 0x38b34ae5;
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const uint32_t c4 = 0xa1e38b93;
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/* body */
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{
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const uint32_t *blocks = (const uint32_t *) (data + nblocks*16);
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int i;
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for (i = -nblocks; i; i++) {
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uint32_t k1 = hash_get_block_32(blocks, i*4 + 0);
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uint32_t k2 = hash_get_block_32(blocks, i*4 + 1);
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uint32_t k3 = hash_get_block_32(blocks, i*4 + 2);
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uint32_t k4 = hash_get_block_32(blocks, i*4 + 3);
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k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
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h1 = hash_rotl_32(h1, 19); h1 += h2;
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h1 = h1*5 + 0x561ccd1b;
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k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;
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h2 = hash_rotl_32(h2, 17); h2 += h3;
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h2 = h2*5 + 0x0bcaa747;
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k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
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h3 = hash_rotl_32(h3, 15); h3 += h4;
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h3 = h3*5 + 0x96cd1c35;
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k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;
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h4 = hash_rotl_32(h4, 13); h4 += h1;
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h4 = h4*5 + 0x32ac3b17;
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}
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}
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/* tail */
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{
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const uint8_t *tail = (const uint8_t *) (data + nblocks*16);
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uint32_t k1 = 0;
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uint32_t k2 = 0;
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uint32_t k3 = 0;
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uint32_t k4 = 0;
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switch (len & 15) {
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case 15: k4 ^= tail[14] << 16;
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case 14: k4 ^= tail[13] << 8;
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case 13: k4 ^= tail[12] << 0;
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k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;
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case 12: k3 ^= tail[11] << 24;
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case 11: k3 ^= tail[10] << 16;
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case 10: k3 ^= tail[ 9] << 8;
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case 9: k3 ^= tail[ 8] << 0;
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k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
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case 8: k2 ^= tail[ 7] << 24;
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case 7: k2 ^= tail[ 6] << 16;
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case 6: k2 ^= tail[ 5] << 8;
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case 5: k2 ^= tail[ 4] << 0;
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k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;
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case 4: k1 ^= tail[ 3] << 24;
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case 3: k1 ^= tail[ 2] << 16;
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case 2: k1 ^= tail[ 1] << 8;
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case 1: k1 ^= tail[ 0] << 0;
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k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
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}
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}
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/* finalization */
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h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;
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h1 += h2; h1 += h3; h1 += h4;
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h2 += h1; h3 += h1; h4 += h1;
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h1 = hash_fmix_32(h1);
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h2 = hash_fmix_32(h2);
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h3 = hash_fmix_32(h3);
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h4 = hash_fmix_32(h4);
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h1 += h2; h1 += h3; h1 += h4;
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h2 += h1; h3 += h1; h4 += h1;
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r_out[0] = (((uint64_t) h2) << 32) | h1;
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r_out[1] = (((uint64_t) h4) << 32) | h3;
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}
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UNUSED JEMALLOC_INLINE void
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hash_x64_128(const void *key, const int len, const uint32_t seed,
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uint64_t r_out[2])
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{
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const uint8_t *data = (const uint8_t *) key;
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const int nblocks = len / 16;
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uint64_t h1 = seed;
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uint64_t h2 = seed;
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const uint64_t c1 = QU(0x87c37b91114253d5LLU);
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const uint64_t c2 = QU(0x4cf5ad432745937fLLU);
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/* body */
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{
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const uint64_t *blocks = (const uint64_t *) (data);
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int i;
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for (i = 0; i < nblocks; i++) {
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uint64_t k1 = hash_get_block_64(blocks, i*2 + 0);
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uint64_t k2 = hash_get_block_64(blocks, i*2 + 1);
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k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
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h1 = hash_rotl_64(h1, 27); h1 += h2;
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h1 = h1*5 + 0x52dce729;
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k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;
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h2 = hash_rotl_64(h2, 31); h2 += h1;
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h2 = h2*5 + 0x38495ab5;
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}
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}
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/* tail */
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{
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const uint8_t *tail = (const uint8_t*)(data + nblocks*16);
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uint64_t k1 = 0;
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uint64_t k2 = 0;
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switch (len & 15) {
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case 15: k2 ^= ((uint64_t)(tail[14])) << 48;
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case 14: k2 ^= ((uint64_t)(tail[13])) << 40;
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case 13: k2 ^= ((uint64_t)(tail[12])) << 32;
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case 12: k2 ^= ((uint64_t)(tail[11])) << 24;
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case 11: k2 ^= ((uint64_t)(tail[10])) << 16;
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case 10: k2 ^= ((uint64_t)(tail[ 9])) << 8;
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case 9: k2 ^= ((uint64_t)(tail[ 8])) << 0;
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k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;
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case 8: k1 ^= ((uint64_t)(tail[ 7])) << 56;
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case 7: k1 ^= ((uint64_t)(tail[ 6])) << 48;
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case 6: k1 ^= ((uint64_t)(tail[ 5])) << 40;
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case 5: k1 ^= ((uint64_t)(tail[ 4])) << 32;
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case 4: k1 ^= ((uint64_t)(tail[ 3])) << 24;
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case 3: k1 ^= ((uint64_t)(tail[ 2])) << 16;
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case 2: k1 ^= ((uint64_t)(tail[ 1])) << 8;
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case 1: k1 ^= ((uint64_t)(tail[ 0])) << 0;
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k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
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}
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}
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/* finalization */
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h1 ^= len; h2 ^= len;
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h1 += h2;
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h2 += h1;
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h1 = hash_fmix_64(h1);
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h2 = hash_fmix_64(h2);
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h1 += h2;
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h2 += h1;
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r_out[0] = h1;
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r_out[1] = h2;
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}
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/******************************************************************************/
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/* API. */
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JEMALLOC_INLINE void
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hash(const void *key, size_t len, const uint32_t seed, size_t r_hash[2])
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{
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#if (LG_SIZEOF_PTR == 3)
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hash_x64_128(key, len, seed, (uint64_t *)r_hash);
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#else
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uint64_t hashes[2];
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hash_x86_128(key, len, seed, hashes);
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r_hash[0] = (size_t)hashes[0];
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r_hash[1] = (size_t)hashes[1];
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#endif
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}
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#endif
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