uint64_t ccSpaceCurveMap3D21Bits64( uint64_t *point )
{
  int bit, rotation;
  uint64_t curveindex, pointindex, indexpart;
  uint64_t addmask, addbits;
  pointindex = point[2] ^ ( point[2] >> 1 );
  pointindex <<= 21;
  pointindex |= point[1] ^ ( point[1] >> 1 );
  pointindex <<= 21;
  pointindex |= point[0] ^ ( point[0] >> 1 );
  rotation = 0;
  addmask = 0;
  curveindex = 0;
  bit = 20;
  do
  {
    indexpart = pointindex >> bit;
    addmask ^= ( indexpart & 0x1 ) | ( ( indexpart >> 20 ) & 0x2 ) | ( ( indexpart >> 40 ) & 0x4 );
    addbits = ( ( addmask >> rotation ) | ( addmask << ( 3 - rotation ) ) ) & 0x7;
    curveindex = ( curveindex << 3 ) | addbits;
    addmask = 1 << rotation;
    rotation = ( 0x641289 >> ( ( ( addbits & 0x3 ) << 1 ) | ( rotation << 3 ) ) ) & 0x3;
  } while( --bit >= 0 );
  curveindex ^= (uint64_t)0x924924924924924;
  for( bit = 1 ; bit < 63 ; bit <<= 1 )
    curveindex ^= curveindex >> bit;
  return curveindex;
}