Buffer on depng_filter_XXX

[kanryu]

Hi,

I found your implementation looking for a simd implementation for PNG 's unfilter.

I am currently investigating the implementation of depng_filter_ref, but your implementation uint8_t * u = NULL; It seems to me that it is implementing read access to this.

This is obviously illegal access and should originally be separate from the destination buffer and the source buffer, but each SIMD function is not so assumed.

How did you think to create this programs?

[kobalicek]

Hello, it's true that the pointer can be still null when processing the first line and a real decoder should never allow dereferencing such pointer. However, the code in this repository should not be considered a "ready-to-use" implementation and should only serve as a playground of implementing and benchmarking my ideas.