libdeflate VS zlib-ng

zune-inflate is a port of libdeflate to safe Rust.

> The QOI benchmarks shows it only lagging a small bit behind PNG in compression ratio, while performing much faster (multiples) in both encoding and decoding.

Presumably that’s with stock libpng, which uses zlib. I wonder if anyone tried patching it to use the substantially faster (on x86) libdeflate[1] instead? It doesn’t do streaming, but you shouldn’t really need it for PNG textures.

[1] https://github.com/ebiggers/libdeflate

Eric biggers libdeflate https://github.com/ebiggers/libdeflate/blob/master/lib/deflate_decompress.c

Note that libdeflate has used essentially the same method since 2016 (https://github.com/ebiggers/libdeflate/blob/v0.4/lib/adler32...), though I recently switched it to use a slightly different method (https://github.com/ebiggers/libdeflate/blob/v1.12/lib/x86/ad...) that performs more consistently across different families of x86 CPUs.

Going away from Zlib proper but staying with its format, there’s libdeflate[1], an implementation that’s substantially faster on modern machines but can’t stream, and of course Zopfli[2], a glacially slow compressor that’s somewhat better (and occasionally much more so).

[1] https://github.com/ebiggers/libdeflate

[2] https://github.com/google/zopfli

Please note that allowing for 2% bigger resulting file could mean huge speedup in these circumstances even with the same compression routines, seeing these benchmarks of zlib and zlib-ng for different compression levels:

https://github.com/zlib-ng/zlib-ng/discussions/871

IMO the fair comparison of the real speed improvement brought by a new program is only between the almost identical resulting compressed sizes.

It is much faster than miniz_oxide and all other safe-Rust implementations, and consistently beats even Zlib. The performance is roughly on par with zlib-ng - sometimes faster, sometimes slower. It is not (yet) as fast as the original libdeflate in C.

Zlib-ng doesn't contain the same code, but it appears that their equivalent inflate() when used with their inflateGetHeader() implementation was affected by a similar problem: https://github.com/zlib-ng/zlib-ng/pull/1328

Also similarly, most client code will be unaffected because `state->head` will be NULL, because they (most client code) won't have used inflateGetHeader() at all.

I wonder if zlib-ng would make a difference, since it has a lot of optimizations for modern hardware.

https://github.com/zlib-ng/zlib-ng/discussions/871

zlib-ng also has adler32 implementations optimized for various architectures: https://github.com/zlib-ng/zlib-ng

Might be interesting to benchmark their implementation too to see how it compares.

zlib-ng: https://github.com/zlib-ng/zlib-ng/blob/develop/functable.c

(2) There are many packages that rely upon zlib and minizip and switching those underlying dependencies is easier said than done. We can't drop zlib completely and switch: "The idea of zlib-ng is not to replace zlib, but to co-exist as a drop-in replacement with a lower threshold for code change." - https://github.com/zlib-ng/zlib-ng

There are already active zlib forks (e.g. https://github.com/zlib-ng/zlib-ng), the problem is with having people move to them. It takes a lot of effort to move mindshare from the original version to a fork, there's some historical examples of it happening, but not a ton.