od: fix parsing of hex input ending with E

[TheDcoder]

This should fix #4981.

This is my first contribution in Rust and I just started learning it today, so pardon me if I missed something, do let me know and I will fix it promptly!

Special thanks to @tertsdiepraam for finding the bug before I even started learning Rust, thus saving me a bunch of time 😄

[sylvestre]

cool, could you please add a test in tests/by-util/test_od.rs ?

[TheDcoder]

@sylvestre Ah, I haven't gotten far enough in "the book" to do that yet. Though I did take a look if I can just modify some existing test, but there doesn't seem to be (I might be wrong).

It's worth noting that hex input ending with B didn't have this bug since the initial implementation (459db47) because it already had the safeguard which I added to E.

So IMHO writing a new test is out of scope for both this PR and my technical knowledge in rust 😅

Also I did add a simple assertion to check if 0XE == 14 😄

Let me know what you think, if a new test is needed then I will need more time to study the book and implement it.

[sylvestre]

Adding a test should be trivial
Just copy another example from here:
https:/uutils/coreutils/blob/main/tests/by-util/test_od.rs

[sylvestre]

@TheDcoder https://www.phoronix.com/forums/forum/phoronix/latest-phoronix-articles/1398170-uutils-0-0-20-improves-gnu-coreutils-compatibility-for-this-rust-written-replacement/page7
Happy to read this ;)

[TheDcoder]

@sylvestre Thank you so much once again! Crazy how small things like this end up making such a big difference :)

I'm working on my first rust project right now (it's empty since I haven't committed any code).

[sylvestre]

we have plenty of other good first bugs here if you want

[TheDcoder]

I'm still not proficient, so I'm working on my own project to learn the ropes. Will definitely look into fixing some bugs here after that!