//-----------------------------------------------------------------------------
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. The author hereby disclaims copyright to this source code.

// Note - The x86 and x64 versions do _not_ produce the same results, as the
// algorithms are optimized for their respective platforms. You can still
// compile and run any of them on any platform, but your performance with the
// non-native version will be less than optimal.

#include "MurmurHash3.h"

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

// Microsoft Visual Studio

#if defined(_MSC_VER)

#define FORCE_INLINE	__forceinline

#include <cstdlib>

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

#define BIG_CONSTANT(x) (x)

// Other compilers

#else	// defined(_MSC_VER)

#define	FORCE_INLINE inline __attribute__((always_inline))

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

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 // !defined(_MSC_VER)

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

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

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

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

  return h;
}

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

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;
}

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