public static unsafe void Shuffle(int bytesOfType, Span <byte> source, Span <byte> destination)
{
fixed(byte *src = source, dest = destination)
{
ShuffleGeneric.shuffle_avx2(bytesOfType, 0, source.Length, src, dest);
}
}
/* Shuffle a block. This can never fail. */
private static unsafe void shuffle_avx2(int bytesoftype, int blocksize,
byte *_src, byte *_dest)
{
int vectorized_chunk_size = bytesoftype * sizeof(Vector256 <byte>);
/* If the block size is too small to be vectorized,
* use the generic implementation. */
if (blocksize < vectorized_chunk_size)
{
ShuffleGeneric.shuffle_avx2(bytesoftype, 0, blocksize, _src, _dest);
return;
}
/* If the blocksize is not a multiple of both the typesize and
* the vector size, round the blocksize down to the next value
* which is a multiple of both. The vectorized shuffle can be
* used for that portion of the data, and the naive implementation
* can be used for the remaining portion. */
int vectorizable_bytes = blocksize - (blocksize % vectorized_chunk_size);
int vectorizable_elements = vectorizable_bytes / bytesoftype;
int total_elements = blocksize / bytesoftype;
/* Optimized shuffle implementations */
switch (bytesoftype)
{
case 2:
shuffle2_avx2(_dest, _src, vectorizable_elements, total_elements);
break;
case 4:
shuffle4_avx2(_dest, _src, vectorizable_elements, total_elements);
break;
case 8:
shuffle8_avx2(_dest, _src, vectorizable_elements, total_elements);
break;
case 16:
shuffle16_avx2(_dest, _src, vectorizable_elements, total_elements);
break;
default:
/* For types larger than 16 bytes, use the AVX2 tiled shuffle. */
if (bytesoftype > (int)sizeof(Vector128 <byte>))
{
shuffle16_tiled_avx2(_dest, _src, vectorizable_elements, total_elements, bytesoftype);
}
else
{
/* Non-optimized shuffle */
ShuffleGeneric.shuffle_avx2(bytesoftype, 0, blocksize, _src, _dest);
/* The non-optimized function covers the whole buffer,
* so we're done processing here. */
return;
}
break;
}
/* If the buffer had any bytes at the end which couldn't be handled
* by the vectorized implementations, use the non-optimized version
* to finish them up. */
if (vectorizable_bytes < blocksize)
{
ShuffleGeneric.shuffle_avx2(bytesoftype, vectorizable_bytes, blocksize, _src, _dest);
}
}