Oh nice, I did something similar recently (<a href="https://github.com/divyenduz/zoid-zip">https://github.com/divyenduz/zoid-zip</a>), mine is much lighter/smaller than yours. Instead of following a standard fully, I just use Huffman coding to make stuff smaller!
Related:<p><i>Decompressing a Gzip File by Hand</i> - <a href="https://news.ycombinator.com/item?id=29336271">https://news.ycombinator.com/item?id=29336271</a> - Nov 2021 (18 comments)