//! Helpers to convert and add digits from characters.
// Convert u8 to digit.
#[inline]
pub(crate) fn to_digit(c: u8) -> Option<u32> {
(c as char).to_digit(10)
}
// Add digit to mantissa.
#[inline]
pub(crate) fn add_digit(value: u64, digit: u32) -> Option<u64> {
return value
.checked_mul(10)?
.checked_add(digit as u64)
}