hash.h

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/*
 * The following hash function is based on MurmurHash3, placed into the public
 * domain by Austin Appleby. See http://code.google.com/p/smhasher/ for
 * details.
 */
/******************************************************************************/
#ifdef JEMALLOC_H_TYPES

#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS

#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS

#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES

#ifndef JEMALLOC_ENABLE_INLINE
uint32_t hash_x86_32(const void *key, int len, uint32_t seed);
void hash_x86_128(const void *key, const int len, uint32_t seed,
 uint64_t r_out[2]);
void hash_x64_128(const void *key, const int len, const uint32_t seed,
 uint64_t r_out[2]);
void hash(const void *key, size_t len, const uint32_t seed,
 size_t r_hash[2]);
#endif

#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_HASH_C_))
/******************************************************************************/
/* Internal implementation. */
JEMALLOC_INLINE uint32_t
hash_rotl_32(uint32_t x, int8_t r)
{

 return (x << r) | (x >> (32 - r));
}

JEMALLOC_INLINE uint64_t
hash_rotl_64(uint64_t x, int8_t r)
{
 return (x << r) | (x >> (64 - r));
}

JEMALLOC_INLINE uint32_t
hash_get_block_32(const uint32_t *p, int i)
{

 return (p[i]);
}

JEMALLOC_INLINE uint64_t
hash_get_block_64(const uint64_t *p, int i)
{

 return (p[i]);
}

JEMALLOC_INLINE uint32_t
hash_fmix_32(uint32_t h)
{

 h ^= h >> 16;
 h *= 0x85ebca6b;
 h ^= h >> 13;
 h *= 0xc2b2ae35;
 h ^= h >> 16;

 return (h);
}

JEMALLOC_INLINE uint64_t
hash_fmix_64(uint64_t k)
{

 k ^= k >> 33;
 k *= QU(0xff51afd7ed558ccdLLU);
 k ^= k >> 33;
 k *= QU(0xc4ceb9fe1a85ec53LLU);
 k ^= k >> 33;

 return (k);
}

JEMALLOC_INLINE uint32_t
hash_x86_32(const void *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);
 int i;

 for (i = -nblocks; i; i++) {
 uint32_t k1 = hash_get_block_32(blocks, i);

 k1 *= c1;
 k1 = hash_rotl_32(k1, 15);
 k1 *= c2;

 h1 ^= k1;
 h1 = hash_rotl_32(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 = hash_rotl_32(k1, 15);
 k1 *= c2; h1 ^= k1;
 }
 }

 /* finalization */
 h1 ^= len;

 h1 = hash_fmix_32(h1);

 return (h1);
}

UNUSED JEMALLOC_INLINE void
hash_x86_128(const void *key, const int len, uint32_t seed,
 uint64_t r_out[2])
{
 const uint8_t * data = (const uint8_t *) key;
 const int nblocks = len / 16;

 uint32_t h1 = seed;
 uint32_t h2 = seed;
 uint32_t h3 = seed;
 uint32_t h4 = seed;

 const uint32_t c1 = 0x239b961b;
 const uint32_t c2 = 0xab0e9789;
 const uint32_t c3 = 0x38b34ae5;
 const uint32_t c4 = 0xa1e38b93;

 /* body */
 {
 const uint32_t *blocks = (const uint32_t *) (data + nblocks*16);
 int i;

 for (i = -nblocks; i; i++) {
 uint32_t k1 = hash_get_block_32(blocks, i*4 + 0);
 uint32_t k2 = hash_get_block_32(blocks, i*4 + 1);
 uint32_t k3 = hash_get_block_32(blocks, i*4 + 2);
 uint32_t k4 = hash_get_block_32(blocks, i*4 + 3);

 k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;

 h1 = hash_rotl_32(h1, 19); h1 += h2;
 h1 = h1*5 + 0x561ccd1b;

 k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;

 h2 = hash_rotl_32(h2, 17); h2 += h3;
 h2 = h2*5 + 0x0bcaa747;

 k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;

 h3 = hash_rotl_32(h3, 15); h3 += h4;
 h3 = h3*5 + 0x96cd1c35;

 k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;

 h4 = hash_rotl_32(h4, 13); h4 += h1;
 h4 = h4*5 + 0x32ac3b17;
 }
 }

 /* tail */
 {
 const uint8_t *tail = (const uint8_t *) (data + nblocks*16);
 uint32_t k1 = 0;
 uint32_t k2 = 0;
 uint32_t k3 = 0;
 uint32_t k4 = 0;

 switch (len & 15) {
 case 15: k4 ^= tail[14] << 16;
 case 14: k4 ^= tail[13] << 8;
 case 13: k4 ^= tail[12] << 0;
 k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;

 case 12: k3 ^= tail[11] << 24;
 case 11: k3 ^= tail[10] << 16;
 case 10: k3 ^= tail[ 9] << 8;
 case 9: k3 ^= tail[ 8] << 0;
 k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;

 case 8: k2 ^= tail[ 7] << 24;
 case 7: k2 ^= tail[ 6] << 16;
 case 6: k2 ^= tail[ 5] << 8;
 case 5: k2 ^= tail[ 4] << 0;
 k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;

 case 4: k1 ^= tail[ 3] << 24;
 case 3: k1 ^= tail[ 2] << 16;
 case 2: k1 ^= tail[ 1] << 8;
 case 1: k1 ^= tail[ 0] << 0;
 k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
 }
 }

 /* finalization */
 h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;

 h1 += h2; h1 += h3; h1 += h4;
 h2 += h1; h3 += h1; h4 += h1;

 h1 = hash_fmix_32(h1);
 h2 = hash_fmix_32(h2);
 h3 = hash_fmix_32(h3);
 h4 = hash_fmix_32(h4);

 h1 += h2; h1 += h3; h1 += h4;
 h2 += h1; h3 += h1; h4 += h1;

 r_out[0] = (((uint64_t) h2) << 32) | h1;
 r_out[1] = (((uint64_t) h4) << 32) | h3;
}

UNUSED JEMALLOC_INLINE void
hash_x64_128(const void *key, const int len, const uint32_t seed,
 uint64_t r_out[2])
{
 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 = QU(0x87c37b91114253d5LLU);
 const uint64_t c2 = QU(0x4cf5ad432745937fLLU);

 /* body */
 {
 const uint64_t *blocks = (const uint64_t *) (data);
 int i;

 for (i = 0; i < nblocks; i++) {
 uint64_t k1 = hash_get_block_64(blocks, i*2 + 0);
 uint64_t k2 = hash_get_block_64(blocks, i*2 + 1);

 k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;

 h1 = hash_rotl_64(h1, 27); h1 += h2;
 h1 = h1*5 + 0x52dce729;

 k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;

 h2 = hash_rotl_64(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 = hash_rotl_64(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 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
 }
 }

 /* finalization */
 h1 ^= len; h2 ^= len;

 h1 += h2;
 h2 += h1;

 h1 = hash_fmix_64(h1);
 h2 = hash_fmix_64(h2);

 h1 += h2;
 h2 += h1;

 r_out[0] = h1;
 r_out[1] = h2;
}

/******************************************************************************/
/* API. */
JEMALLOC_INLINE void
hash(const void *key, size_t len, const uint32_t seed, size_t r_hash[2])
{
#if (LG_SIZEOF_PTR == 3 && !defined(JEMALLOC_BIG_ENDIAN))
 hash_x64_128(key, len, seed, (uint64_t *)r_hash);
#else
 uint64_t hashes[2];
 hash_x86_128(key, len, seed, hashes);
 r_hash[0] = (size_t)hashes[0];
 r_hash[1] = (size_t)hashes[1];
#endif
}
#endif

#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/