this is a c3 port of the murmur hash 3 that i didnt end up using for a project but it felt a shame to just delete it so i put it here

murmur_hash3.c3

// This code has been ported from the original (https://github.com/aappleby/smhasher/) to c3

import ntypes;

//-----------------------------------------------------------------------------
// 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.


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

macro Un32 getblock32 ( Un32 * p, int i )
{
  return p[i];
}

macro Un64 getblock64 ( Un64 * p, int i )
{
  return p[i];
}

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

macro Un32 fmix32 ( Un32 h )
{
  h ^= h >> 16;
  h *= 0x85ebca6bu32;
  h ^= h >> 13;
  h *= 0xc2b2ae35u32;
  h ^= h >> 16;

  return h;
}

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

macro Un64 fmix64 ( Un64 k )
{
  k ^= k >> 33;
  k *= 0xff51afd7ed558ccdu64;
  k ^= k >> 33;
  k *= 0xc4ceb9fe1a85ec53u64;
  k ^= k >> 33;

  return k;
}

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

fn void murmurHash3_x86_32 ( void * key, int len,
                          Un32 seed, void * out )
{
  Un8 * data = (Un8*)key;
  int nblocks = len / 4;

  Un32 h1 = seed;

  Un32 c1 = 0xcc9e2d51u32;
  Un32 c2 = 0x1b873593u32;

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

  Un32 * blocks = (Un32 *)(data + nblocks*4);

  for(int i = -nblocks; i; i++)
  {
    Un32 k1 = getblock32(blocks,i);

    k1 *= c1;
    k1 = Un32.rotl(k1,15);
    k1 *= c2;
    
    h1 ^= k1;
    h1 = Un32.rotl(h1,13); 
    h1 = h1*5u32+0xe6546b64u32;
  }

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

  Un8 * tail = (Un8*)(data + nblocks*4);

  Un32 k1 = 0;

  switch(len & 3)
  {
  case 3: k1 ^= tail[2] << 16; nextcase;
  case 2: k1 ^= tail[1] << 8; nextcase;
  case 1: k1 ^= tail[0];
          k1 *= c1; k1 = Un32.rotl(k1,15); k1 *= c2; h1 ^= k1; //nextcase;
  };

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

  h1 ^= len;

  h1 = fmix32(h1);

  *(Un32*)out = h1;
} 

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

fn void murmurHash3_x86_128 ( void * key, int len,
                           Un32 seed, void * out )
{
  Un8 * data = (Un8*)key;
  int nblocks = len / 16;

  Un32 h1 = seed;
  Un32 h2 = seed;
  Un32 h3 = seed;
  Un32 h4 = seed;

  Un32 c1 = 0x239b961bu32;
  Un32 c2 = 0xab0e9789u32;
  Un32 c3 = 0x38b34ae5u32;
  Un32 c4 = 0xa1e38b93u32;

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

  Un32 * blocks = (Un32 *)(data + nblocks*16);

  for(int i = -nblocks; i; i++)
  {
    Un32 k1 = getblock32(blocks,i*4+0);
    Un32 k2 = getblock32(blocks,i*4+1);
    Un32 k3 = getblock32(blocks,i*4+2);
    Un32 k4 = getblock32(blocks,i*4+3);

    k1 *= c1; k1  = Un32.rotl(k1,15); k1 *= c2; h1 ^= k1;

    h1 = Un32.rotl(h1,19); h1 += h2; h1 = h1*5u32+0x561ccd1bu32;

    k2 *= c2; k2  = Un32.rotl(k2,16); k2 *= c3; h2 ^= k2;

    h2 = Un32.rotl(h2,17); h2 += h3; h2 = h2*5u32+0x0bcaa747u32;

    k3 *= c3; k3  = Un32.rotl(k3,17); k3 *= c4; h3 ^= k3;

    h3 = Un32.rotl(h3,15); h3 += h4; h3 = h3*5u32+0x96cd1c35u32;

    k4 *= c4; k4  = Un32.rotl(k4,18); k4 *= c1; h4 ^= k4;

    h4 = Un32.rotl(h4,13); h4 += h1; h4 = h4*5u32+0x32ac3b17u32;
  }

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

  Un8 * tail = (Un8*)(data + nblocks*16);

  Un32 k1 = 0;
  Un32 k2 = 0;
  Un32 k3 = 0;
  Un32 k4 = 0;

  switch(len & 15)
  {
  case 15: k4 ^= tail[14] << 16; nextcase;
  case 14: k4 ^= tail[13] << 8; nextcase;
  case 13: k4 ^= tail[12] << 0;
           k4 *= c4; k4  = Un32.rotl(k4,18); k4 *= c1; h4 ^= k4; nextcase;

  case 12: k3 ^= tail[11] << 24; nextcase;
  case 11: k3 ^= tail[10] << 16; nextcase;
  case 10: k3 ^= tail[ 9] << 8; nextcase;
  case  9: k3 ^= tail[ 8] << 0;
           k3 *= c3; k3  = Un32.rotl(k3,17); k3 *= c4; h3 ^= k3; nextcase;

  case  8: k2 ^= tail[ 7] << 24; nextcase;
  case  7: k2 ^= tail[ 6] << 16; nextcase;
  case  6: k2 ^= tail[ 5] << 8; nextcase;
  case  5: k2 ^= tail[ 4] << 0;
           k2 *= c2; k2  = Un32.rotl(k2,16); k2 *= c3; h2 ^= k2; nextcase;

  case  4: k1 ^= tail[ 3] << 24; nextcase;
  case  3: k1 ^= tail[ 2] << 16; nextcase;
  case  2: k1 ^= tail[ 1] << 8; nextcase;
  case  1: k1 ^= tail[ 0] << 0;
           k1 *= c1; k1  = Un32.rotl(k1,15); k1 *= c2; h1 ^= k1; //nextcase;
  };

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

  h1 ^= len; h2 ^= len; h3 ^= len; 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;

  ((Un32*)out)[0] = h1;
  ((Un32*)out)[1] = h2;
  ((Un32*)out)[2] = h3;
  ((Un32*)out)[3] = h4;
}

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

fn void murmurHash3_x64_128 ( void * key, int len,
                           Un32 seed, void * out )
{
  Un8 * data = (Un8*)key;
  int nblocks = len / 16;

  Un64 h1 = seed;
  Un64 h2 = seed;

  Un64 c1 = 0x87c37b91114253d5u64;
  Un64 c2 = 0x4cf5ad432745937fu64;

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

  Un64 * blocks = (Un64 *)(data);

  for(int i = 0; i < nblocks; i++)
  {
    Un64 k1 = getblock64(blocks,i*2+0);
    Un64 k2 = getblock64(blocks,i*2+1);

    k1 *= c1; k1  = Un64.rotl(k1,31); k1 *= c2; h1 ^= k1;

    h1 = Un64.rotl(h1,27); h1 += h2; h1 = h1*5u32+0x52dce729u32;

    k2 *= c2; k2  = Un64.rotl(k2,33); k2 *= c1; h2 ^= k2;

    h2 = Un64.rotl(h2,31); h2 += h1; h2 = h2*5u32+0x38495ab5u32;
  }

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

  Un8 * tail = (Un8*)(data + nblocks*16);

  Un64 k1 = 0;
  Un64 k2 = 0;

  switch(len & 15)
  {
  case 15: k2 ^= ((Un64)tail[14]) << 48; nextcase;
  case 14: k2 ^= ((Un64)tail[13]) << 40; nextcase;
  case 13: k2 ^= ((Un64)tail[12]) << 32; nextcase;
  case 12: k2 ^= ((Un64)tail[11]) << 24; nextcase;
  case 11: k2 ^= ((Un64)tail[10]) << 16; nextcase;
  case 10: k2 ^= ((Un64)tail[ 9]) << 8; nextcase;
  case  9: k2 ^= ((Un64)tail[ 8]) << 0;
           k2 *= c2; k2  = Un64.rotl(k2,33); k2 *= c1; h2 ^= k2; nextcase;

  case  8: k1 ^= ((Un64)tail[ 7]) << 56; nextcase;
  case  7: k1 ^= ((Un64)tail[ 6]) << 48; nextcase;
  case  6: k1 ^= ((Un64)tail[ 5]) << 40; nextcase;
  case  5: k1 ^= ((Un64)tail[ 4]) << 32; nextcase;
  case  4: k1 ^= ((Un64)tail[ 3]) << 24; nextcase;
  case  3: k1 ^= ((Un64)tail[ 2]) << 16; nextcase;
  case  2: k1 ^= ((Un64)tail[ 1]) << 8; nextcase;
  case  1: k1 ^= ((Un64)tail[ 0]) << 0;
           k1 *= c1; k1  = Un64.rotl(k1,31); k1 *= c2; h1 ^= k1; //nextcase;
  };

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

  h1 ^= len; h2 ^= len;

  h1 += h2;
  h2 += h1;

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

  h1 += h2;
  h2 += h1;

  ((Un64*)out)[0] = h1;
  ((Un64*)out)[1] = h2;
}

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