Function next_hex

src/testdrive/src/format/bytes.rs:35–45

Retrieves the value of the next hexadecimal digit in `iter`, if the next byte is a valid hexadecimal digit.

(iter: &mut I)

/// Retrieves the value of the next hexadecimal digit in `iter`, if the next
/// byte is a valid hexadecimal digit.
fn next_hex<I>(iter: &mut I) -> Option<u8>
where
    I: Iterator<Item = u8>,
{
    iter.next().and_then(|c| match c {
        b'A'..=b'F' => Some(c - b'A' + 10),
        b'a'..=b'f' => Some(c - b'a' + 10),
        b'0'..=b'9' => Some(c - b'0'),
        _ => None,
    })
}