This is just a small collection of memcpy/memmove "versions" to "swap", "rotate", "flip" buffers etc. This was "yoinked" out of my personal game-engine and was mostly used for image-manipulation. Some functions are optimized, some are not, some might not even do what they claim to do :)
All functions come in one memcpy_ and one memmove_ flavour where the cpy-one expects non-aliasing buffers.