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,
    })
}
/// Retrieves the value of the next hexadecimal digit in `iter`, if the next
/// byte is a valid hexadecimal digit.
Retrieves the value of the next hexadecimal digit in `iter`, if the next
byte is a valid hexadecimal digit.
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,
    })
}
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 , } ) }
Retrieves the value of the next hexadecimal digit in `iter`, if the next
byte is a valid hexadecimal digit.
Retrieves the value of the next hexadecimal digit in ` iter ` if the next byte is a valid hexadecimal digit .
iter
&mut I
iter
&mut I