Compression

Continuing my exploration of pair programming with AI agents, I grew pigzpp from a C++ gzip rewrite into a compression library for Python data prep, PNG, Docker layers, ZIP documents, Rust, and WebAssembly — then measured it against the tools people actually use.

I gave Claude Opus 4.6 and GPT 5.4 the same task: rewrite pigz (a parallel gzip tool) in modern C++23. After 70 minutes, one delivered a clean-room rewrite, the other a wrapper around the old code. Then I pushed the winner to beat pigz — and it did.