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use num_conv::prelude::*;
/// A trait that indicates the formatted width of the value can be determined.
///
/// Note that this should not be implemented for any signed integers. This forces the caller to
/// write the sign if desired.
pub(crate) trait DigitCount {
/// The number of digits in the stringified value.
fn num_digits(self) -> u8;
}
/// A macro to generate implementations of `DigitCount` for unsigned integers.
macro_rules! impl_digit_count {
($($t:ty),* $(,)?) => {
$(impl DigitCount for $t {
fn num_digits(self) -> u8 {
match self.checked_ilog10() {
Some(n) => n.truncate::<u8>() + 1,
None => 1,
}
}
})*
};
}
impl_digit_count!(u8, u16, u32);