zstd VS LZFSE

zstd still doesn't have a seekable format as part of the official standard (I wish it did): https://github.com/facebook/zstd/issues/395#issuecomment-535...

Look at the pull request in that bug: https://github.com/facebook/zstd/pull/3165

zstd normally uses timespec_get() for measuring wall-clock time. But that's available only since C11. For older standards, it uses clock(), but that returns CPU time, which is wrong.

https://github.com/facebook/zstd/pull/3165

The thing I don't get about zstd is that their own github page shows lz4 is faster at both compression and decompression at the cost of some compression ratio: https://github.com/facebook/zstd

But most people I work with will pick zstd every time even in cases where decompression speed matters the most.

https://github.com/facebook/zstd/tree/dev/doc/educational_de... is a self-contained zstd decoder. I get a 64 KB dynamically linked executable after running "make" in that directory.

  $ size harness

> Yikes; half a meg of code!

It's plausible that the lib you checked is the output from the project's default build target (zstd), which "(...) uncludes dictionary builder, benchmark, and supports decompression of legacy zstd formats"

https://github.com/facebook/zstd/tree/dev/programs

The project also provides another build target, zstd-small, which is "CLI optimized for minimal size; no dictionary builder, no benchmark, and no support for legacy zstd formats"

Also, take a look at what exactly is bundled with the binary.

I'm not entirely correct, though. Because Unarchiver likely uses this compression algorithm by calling directly into the API. And there is an open-source implementation for it: lzfse/lzfse.