This is great stuff, both the exposition and the work itself. It’s stories like these that keep me coming back to Lobsters.
But… I couldn’t help but wonder, why even parse in the first place? If you have control over whatever’s emitting those timestamps and don’t need to validate, why not just use a binary format directly? It would be nice to see that option at least mentioned in the writeup.
Note that BCD computation is a thing. It’s super easy to implement, it makes sense for financial applications and the overhead vs. binary computation isn’t always significant.
Rust version in https://lobste.rs/s/nskrrl/faster_integer_parsing_rust