I can confirm that the code looks totally different. Anyway there's no reason someone writing a libc would waste their time with pieces of code from other prove

I can confirm that the code looks totally different. Anyway there's no reason someone writing a libc would waste their time with pieces of code from other provenance. It takes less time to write a minimalist printf than trying to adapt an existing one to your exact needs, types, validity domains etc, and it'll be easier to extend yours that someone else's. You can write it however you want, it will always end up with a loop around a switch/case :-)