Porting is generally very easy.

* If you already have the compression algorithm tagged, through a file extension, or a field, then you can use that to dispatch to the right decompression algorithm.

* Zlib, gzip, xz, zstd, ... all have headers. If you are using zlib, and switching to zstd, you simply have to check the first 4 bytes for the zstd header using ZSTD_isFrame() [0], or attempting to decompress with zstd and if it fails fall back to the previous decompression algorithm.

* The zstd CLI can decompress both zstd and zlib/gzip if compiled with zlib support.

* Zstd provides a wrapper around the zlib API so you could transparently switch to zstd. [1]

[0] https://github.com/facebook/zstd/blob/dev/lib/zstd.h#L1409 [1] https://github.com/facebook/zstd/tree/dev/zlibWrapper