rippled/modules/beast_basics/math/beast_MurmurHash.cpp

/*============================================================================*/
/*
  VFLib: https://github.com/vinniefalco/VFLib

  Copyright (C) 2008 by Vinnie Falco <vinnie.falco@gmail.com>

  This library contains portions of other open source products covered by
  separate licenses. Please see the corresponding source files for specific
  terms.

  VFLib is provided under the terms of The MIT License (MIT):

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  IN THE SOFTWARE.
*/
/*============================================================================*/

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

//#include "modules/beast_core/system/beast_TargetPlatform.h"

namespace Murmur
{

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

// Microsoft Visual Studio

#if BEAST_MSVC

#define FORCE_INLINE    __forceinline

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

#define BIG_CONSTANT(x) (x)

// Other compilers

#else

#define FORCE_INLINE __attribute__((always_inline))

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

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

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

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

    return h;
}

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

static FORCE_INLINE 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;
}

}