rippled/modules/beast_basics/math/beast_MurmurHash.cpp

//------------------------------------------------------------------------------
/*
    This file is part of Beast: https://github.com/vinniefalco/Beast
    Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>

    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.

    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

// http://code.google.com/p/smhasher/

namespace Murmur
{

//-----------------------------------------------------------------------------
// Platform-specific functions and macros

// Microsoft Visual Studio

#if BEAST_MSVC

#define ROTL32(x,y)     _rotl(x,y)
#define ROTL64(x,y)     _rotl64(x,y)

#define BIG_CONSTANT(x) (x)

// Other compilers

#else

static inline uint32_t rotl32 ( uint32_t x, int8_t r )
{
    return (x << r) | (x >> (32 - r));
}

static inline uint64_t rotl64 ( uint64_t x, int8_t r )
{
    return (x << r) | (x >> (64 - r));
}

#define ROTL32(x,y)     rotl32(x,y)
#define ROTL64(x,y)     rotl64(x,y)

#define BIG_CONSTANT(x) (x##LLU)

#endif

//-----------------------------------------------------------------------------
// Block read - if your platform needs to do endian-swapping or can only
// handle aligned reads, do the conversion here

static forcedinline uint32_t getblock ( const uint32_t* p, int i )
{
    return p[i];
}

static forcedinline uint64_t getblock ( const uint64_t* p, int i )
{
    return p[i];
}

//-----------------------------------------------------------------------------
// Finalization mix - force all bits of a hash block to avalanche

static forcedinline uint32_t fmix ( uint32_t h )
{
    h ^= h >> 16;
    h *= 0x85ebca6b;
    h ^= h >> 13;
    h *= 0xc2b2ae35;
    h ^= h >> 16;

    return h;
}

//----------

static forcedinline uint64_t fmix ( uint64_t k )
{
    k ^= k >> 33;
    k *= BIG_CONSTANT (0xff51afd7ed558ccd);
    k ^= k >> 33;
    k *= BIG_CONSTANT (0xc4ceb9fe1a85ec53);
    k ^= k >> 33;

    return k;
}

//-----------------------------------------------------------------------------

void MurmurHash3_x86_32 ( const void* key, int len,
                          uint32_t seed, void* out )
{
    const uint8_t* data = (const uint8_t*)key;
    const int nblocks = len / 4;

    uint32_t h1 = seed;

    uint32_t c1 = 0xcc9e2d51;
    uint32_t c2 = 0x1b873593;

    //----------
    // body

    const uint32_t* blocks = (const uint32_t*) (data + nblocks * 4);

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

        k1 *= c1;
        k1 = ROTL32 (k1, 15);
        k1 *= c2;

        h1 ^= k1;
        h1 = ROTL32 (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 = ROTL32 (k1, 15);
        k1 *= c2;
        h1 ^= k1;
    };

    //----------
    // finalization

    h1 ^= len;

    h1 = fmix (h1);

    * (uint32_t*)out = h1;
}

//-----------------------------------------------------------------------------

void MurmurHash3_x86_128 ( const void* key, const int len,
                           uint32_t seed, void* out )
{
    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;

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

    //----------
    // body

    const uint32_t* blocks = (const uint32_t*) (data + nblocks * 16);

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

        k1 *= c1;
        k1  = ROTL32 (k1, 15);
        k1 *= c2;
        h1 ^= k1;

        h1 = ROTL32 (h1, 19);
        h1 += h2;
        h1 = h1 * 5 + 0x561ccd1b;

        k2 *= c2;
        k2  = ROTL32 (k2, 16);
        k2 *= c3;
        h2 ^= k2;

        h2 = ROTL32 (h2, 17);
        h2 += h3;
        h2 = h2 * 5 + 0x0bcaa747;

        k3 *= c3;
        k3  = ROTL32 (k3, 17);
        k3 *= c4;
        h3 ^= k3;

        h3 = ROTL32 (h3, 15);
        h3 += h4;
        h3 = h3 * 5 + 0x96cd1c35;

        k4 *= c4;
        k4  = ROTL32 (k4, 18);
        k4 *= c1;
        h4 ^= k4;

        h4 = ROTL32 (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  = ROTL32 (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  = ROTL32 (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  = ROTL32 (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  = ROTL32 (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 = fmix (h1);

    h2 = fmix (h2);

    h3 = fmix (h3);

    h4 = fmix (h4);

    h1 += h2;

    h1 += h3;

    h1 += h4;

    h2 += h1;

    h3 += h1;

    h4 += h1;

    ((uint32_t*)out)[0] = h1;

    ((uint32_t*)out)[1] = h2;

    ((uint32_t*)out)[2] = h3;

    ((uint32_t*)out)[3] = h4;
}

//-----------------------------------------------------------------------------

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);

    //----------
    // body

    const uint64_t* blocks = (const uint64_t*) (data);

    for (int 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 = fmix (h1);

    h2 = fmix (h2);

    h1 += h2;

    h2 += h1;

    ((uint64_t*)out)[0] = h1;

    ((uint64_t*)out)[1] = h2;
}

}