Comment by wowczarek

Bread and butter stuff. Pulling together all of the assorted algorithms and data structures I implemented in C over the years out of necessity - lists, trees, stacks, queues, hash tables, memory pools, etc. - aligning the APIs, cleaning up and merging into a library. It's a background project but super fun. This and several parsers - JSON, some config file formats, and parsers for some GPS / GNSS receiver data protocols. FSMs also always feel like nice, clean fun. And prematurely optimising every bit.