hash.h

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/*
 * The following hash function is based on MurmurHash3, placed into the public
 * domain by Austin Appleby.  See https://github.com/aappleby/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 rz_out[2]);
void    hash_x64_128(const void *key, const int len, const uint32_t seed,
    uint64_t rz_out[2]);
void    hash(const void *key, size_t len, const uint32_t seed,
    size_t rz_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)
{
 
    /* Handle unaligned read. */
    if (unlikely((uintptr_t)p & (sizeof(uint32_t)-1)) != 0) {
        uint32_t ret;
 
        memcpy(&ret, (uint8_t *)(p + i), sizeof(uint32_t));
        return (ret);
    }
 
    return (p[i]);
}
 
JEMALLOC_INLINE uint64_t
hash_get_block_64(const uint64_t *p, int i)
{
 
    /* Handle unaligned read. */
    if (unlikely((uintptr_t)p & (sizeof(uint64_t)-1)) != 0) {
        uint64_t ret;
 
        memcpy(&ret, (uint8_t *)(p + i), sizeof(uint64_t));
        return (ret);
    }
 
    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 *= KQU(0xff51afd7ed558ccd);
    k ^= k >> 33;
    k *= KQU(0xc4ceb9fe1a85ec53);
    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);
}
 
RZ_UNUSED JEMALLOC_INLINE void
hash_x86_128(const void *key, const int len, uint32_t seed,
    uint64_t rz_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;
 
    rz_out[0] = (((uint64_t) h2) << 32) | h1;
    rz_out[1] = (((uint64_t) h4) << 32) | h3;
}
 
RZ_UNUSED JEMALLOC_INLINE void
hash_x64_128(const void *key, const int len, const uint32_t seed,
    uint64_t rz_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 = KQU(0x87c37b91114253d5);
    const uint64_t c2 = KQU(0x4cf5ad432745937f);
 
    /* 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;
 
    rz_out[0] = h1;
    rz_out[1] = h2;
}
 
/******************************************************************************/
/* API. */
JEMALLOC_INLINE void
hash(const void *key, size_t len, const uint32_t seed, size_t rz_hash[2])
{
 
    assert(len <= INT_MAX); /* Unfortunate implementation limitation. */
 
#if (LG_SIZEOF_PTR == 3 && !defined(JEMALLOC_BIG_ENDIAN))
    hash_x64_128(key, (int)len, seed, (uint64_t *)rz_hash);
#else
    {
        uint64_t hashes[2];
        hash_x86_128(key, (int)len, seed, hashes);
        rz_hash[0] = (size_t)hashes[0];
        rz_hash[1] = (size_t)hashes[1];
    }
#endif
}
#endif
 
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/