/*
 *  The MIT License
 *
 *  Copyright (c) 2010-2011 tanjent <tanj...@gmail.com>, http://code.google.com/p/smhasher/
 *
 *  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.
 *
 */

#include "MurmurHash3.hpp"

#define _rotl(v, n)   (uint32_t((v) << ((n)&0x1F)) | uint32_t((v) >> (32 - ((n)&0x1F))))
#define _rotr(v, n)   (uint32_t((v) >> ((n)&0x1F)) | uint32_t((v) << (32 - ((n)&0x1F))))
#define _rotl64(v, n)   (uint64_t((v) << ((n)&0x3F)) | uint64_t((v) >> (64 - ((n)&0x3F))))
#define _rotr64(v, n)   (uint64_t((v) >> ((n)&0x3F)) | uint64_t((v) << (64 - ((n)&0x3F))))

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

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

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

// avalanches all bits to within 0.25% bias

inline uint32_t fmix32 (uint32_t h)
{
  h ^= h >> 16;
  h *= 0x85ebca6b;
  h ^= h >> 13;
  h *= 0xc2b2ae35;
  h ^= h >> 16;

  return h;
}

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

inline void bmix32 (uint32_t & h1, uint32_t & k1, uint32_t & c1,
		    uint32_t & c2)
{
  k1 *= c1;
  k1 = _rotl (k1, 11);
  k1 *= c2;
  h1 ^= k1;

  h1 = h1 * 3 + 0x52dce729;

  c1 = c1 * 5 + 0x7b7d159c;
  c2 = c2 * 5 + 0x6bce6396;
}

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

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 = 0x971e137b ^ seed;

  uint32_t c1 = (uint32_t) 0x95543787;
  uint32_t c2 = (uint32_t) 0x2ad7eb25;

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

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

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

    bmix32 (h1, k1, c1, c2);
  }

  //----------
  // 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];
    bmix32 (h1, k1, c1, c2);
  };

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

  h1 ^= len;

  h1 = fmix32 (h1);

  *(uint32_t *) out = h1;
}

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

inline void bmix32 (uint32_t & h1, uint32_t & h2, uint32_t & k1,
		    uint32_t & k2, uint32_t & c1, uint32_t & c2)
{
  k1 *= c1;
  k1 = _rotl (k1, 11);
  k1 *= c2;
  h1 ^= k1;
  h1 += h2;

  h2 = _rotl (h2, 17);

  k2 *= c2;
  k2 = _rotl (k2, 11);
  k2 *= c1;
  h2 ^= k2;
  h2 += h1;

  h1 = h1 * 3 + 0x52dce729;
  h2 = h2 * 3 + 0x38495ab5;

  c1 = c1 * 5 + 0x7b7d159c;
  c2 = c2 * 5 + 0x6bce6396;
}

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

void MurmurHash3_x86_64 (const void *key, const int len, const uint32_t seed,
			 void *out)
{
  const uint8_t *data = (const uint8_t *) key;
  const int nblocks = len / 8;

  uint32_t h1 = 0x8de1c3ac ^ seed;
  uint32_t h2 = 0xbab98226 ^ seed;

  uint32_t c1 = (uint32_t) 0x95543787;
  uint32_t c2 = (uint32_t) 0x2ad7eb25;

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

  const uint32_t *blocks = (const uint32_t *) (data + nblocks * 8);

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

    bmix32 (h1, h2, k1, k2, c1, c2);
  }

  //----------
  // tail

  const uint8_t *tail = (const uint8_t *) (data + nblocks * 8);

  uint32_t k1 = 0;
  uint32_t k2 = 0;

  switch (len & 7) {
  case 7:
    k2 ^= tail[6] << 16;
  case 6:
    k2 ^= tail[5] << 8;
  case 5:
    k2 ^= tail[4] << 0;
  case 4:
    k1 ^= tail[3] << 24;
  case 3:
    k1 ^= tail[2] << 16;
  case 2:
    k1 ^= tail[1] << 8;
  case 1:
    k1 ^= tail[0] << 0;
    bmix32 (h1, h2, k1, k2, c1, c2);
  };

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

  h2 ^= len;

  h1 += h2;
  h2 += h1;

  h1 = fmix32 (h1);
  h2 = fmix32 (h2);

  h1 += h2;
  h2 += h1;

  ((uint32_t *) out)[0] = h1;
  ((uint32_t *) out)[1] = h2;
}

//-----------------------------------------------------------------------------
// This mix is large enough that VC++ refuses to inline it unless we use
// __forceinline. It's also not all that fast due to register spillage.

inline void bmix32 (uint32_t & h1, uint32_t & h2, uint32_t & h3,
		    uint32_t & h4, uint32_t & k1, uint32_t & k2,
		    uint32_t & k3, uint32_t & k4, uint32_t & c1,
		    uint32_t & c2)
{
  k1 *= c1;
  k1 = _rotl (k1, 11);
  k1 *= c2;
  h1 ^= k1;
  h1 += h2;
  h1 += h3;
  h1 += h4;

  h1 = _rotl (h1, 17);

  k2 *= c2;
  k2 = _rotl (k2, 11);
  k2 *= c1;
  h2 ^= k2;
  h2 += h1;

  h1 = h1 * 3 + 0x52dce729;
  h2 = h2 * 3 + 0x38495ab5;

  c1 = c1 * 5 + 0x7b7d159c;
  c2 = c2 * 5 + 0x6bce6396;

  k3 *= c1;
  k3 = _rotl (k3, 11);
  k3 *= c2;
  h3 ^= k3;
  h3 += h1;

  k4 *= c2;
  k4 = _rotl (k4, 11);
  k4 *= c1;
  h4 ^= k4;
  h4 += h1;

  h3 = h3 * 3 + 0x52dce729;
  h4 = h4 * 3 + 0x38495ab5;

  c1 = c1 * 5 + 0x7b7d159c;
  c2 = c2 * 5 + 0x6bce6396;
}

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

void MurmurHash3_x86_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;

  uint32_t h1 = 0x8de1c3ac ^ seed;
  uint32_t h2 = 0xbab98226 ^ seed;
  uint32_t h3 = 0xfcba5b2d ^ seed;
  uint32_t h4 = 0x32452e3e ^ seed;

  uint32_t c1 = (uint32_t) 0x95543787;
  uint32_t c2 = (uint32_t) 0x2ad7eb25;

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

  const uint32_t *blocks = (const uint32_t *) (data);

  for (int i = 0; i < nblocks; 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);

    bmix32 (h1, h2, h3, h4, k1, k2, k3, k4, c1, c2);
  }

  //----------
  // 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;
  case 12:
    k3 ^= tail[11] << 24;
  case 11:
    k3 ^= tail[10] << 16;
  case 10:
    k3 ^= tail[9] << 8;
  case 9:
    k3 ^= tail[8] << 0;
  case 8:
    k2 ^= tail[7] << 24;
  case 7:
    k2 ^= tail[6] << 16;
  case 6:
    k2 ^= tail[5] << 8;
  case 5:
    k2 ^= tail[4] << 0;
  case 4:
    k1 ^= tail[3] << 24;
  case 3:
    k1 ^= tail[2] << 16;
  case 2:
    k1 ^= tail[1] << 8;
  case 1:
    k1 ^= tail[0] << 0;
    bmix32 (h1, h2, h3, h4, k1, k2, k3, k4, c1, c2);
  };

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

  h4 ^= len;

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

  h1 = fmix32 (h1);
  h2 = fmix32 (h2);
  h3 = fmix32 (h3);
  h4 = fmix32 (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;
}

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

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

//----------
// Block mix - combine the key bits with the hash bits and scramble everything

inline void bmix64 (uint64_t & h1, uint64_t & h2, uint64_t & k1,
		    uint64_t & k2, uint64_t & c1, uint64_t & c2)
{
  k1 *= c1;
  k1 = _rotl64 (k1, 23);
  k1 *= c2;
  h1 ^= k1;
  h1 += h2;

  h2 = _rotl64 (h2, 41);

  k2 *= c2;
  k2 = _rotl64 (k2, 23);
  k2 *= c1;
  h2 ^= k2;
  h2 += h1;

  h1 = h1 * 3 + 0x52dce729;
  h2 = h2 * 3 + 0x38495ab5;

  c1 = c1 * 5 + 0x7b7d159c;
  c2 = c2 * 5 + 0x6bce6396;
}

//----------
// Finalization mix - avalanches all bits to within 0.05% bias

inline uint64_t fmix64 (uint64_t k)
{
  k ^= k >> 33;
  k *= 0xff51afd7ed558ccd;
  k ^= k >> 33;
  k *= 0xc4ceb9fe1a85ec53;
  k ^= k >> 33;

  return k;
}

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

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 = 0x9368e53c2f6af274 ^ seed;
  uint64_t h2 = 0x586dcd208f7cd3fd ^ seed;

  uint64_t c1 = 0x87c37b91114253d5;
  uint64_t c2 = 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);

    bmix64 (h1, h2, k1, k2, c1, c2);
  }

  //----------
  // 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;

  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;
    bmix64 (h1, h2, k1, k2, c1, c2);
  };

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

  h2 ^= len;

  h1 += h2;
  h2 += h1;

  h1 = fmix64 (h1);
  h2 = fmix64 (h2);

  h1 += h2;
  h2 += h1;

  ((uint64_t *) out)[0] = h1;
  ((uint64_t *) out)[1] = h2;
}

//-----------------------------------------------------------------------------
// If we need a smaller hash value, it's faster to just use a portion of the 
// 128-bit hash

void MurmurHash3_x64_32 (const void *key, int len, uint32_t seed, void *out)
{
  uint32_t temp[4];

  MurmurHash3_x64_128 (key, len, seed, temp);

  *(uint32_t *) out = temp[0];
}

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

void MurmurHash3_x64_64 (const void *key, int len, uint32_t seed, void *out)
{
  uint64_t temp[2];

  MurmurHash3_x64_128 (key, len, seed, temp);

  *(uint64_t *) out = temp[0];
}

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