https://github.com/cloudflare/zlib/blob/31043308c3d3edfb487d...
It's great material for anyone interested in these types of low level optimizations.
Do you know what the file extension inc stands for?
It's a fairly common extension for a file containing C implementation code (and not just headers) that is intended to be #included by some other file.
Edit:
Here's an example of a .inc file being used
Double Edit:
git log --all -p contrib/amd64/longest-match.inc
It was merged directly into deflate.c
https://github.com/cloudflare/zlib/blob/31043308c3d3edfb487d...
It's great material for anyone interested in these types of low level optimizations.