pub const fn hex_digit(byte: u8) -> Option<u8>Expand description
The value of one ASCII hexadecimal digit, either case, and None for any
other byte.
A caller that wants the permissive reading — a bad digit counts as zero —
spells it as hex_digit(b).unwrap_or(0), so the permissiveness is visible
at the one place it is meant.
use pdfrum_common::hex_digit;
assert_eq!(hex_digit(b'7'), Some(7));
assert_eq!(hex_digit(b'a'), Some(10));
assert_eq!(hex_digit(b'F'), Some(15));
assert_eq!(hex_digit(b'g'), None);
assert_eq!(hex_digit(b' '), None);