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//! Extension traits for things either not implemented or not yet stable in the MSRV.
/// Marker trait for integer types.
pub(crate) trait Integer: Sized {
/// The maximum number of digits that this type can have.
const MAX_NUM_DIGITS: u8;
/// The zero value for this type.
const ZERO: Self;
/// Push a digit onto the end of this integer, assuming no overflow.
///
/// This is equivalent to `self * 10 + digit`.
fn push_digit(self, digit: u8) -> Self;
/// Push a digit onto the end of this integer, returning `None` on overflow.
///
/// This is equivalent to `self.checked_mul(10)?.checked_add(digit)`.
fn checked_push_digit(self, digit: u8) -> Option<Self>;
}
/// Parse the given types from bytes.
macro_rules! impl_parse_bytes {
($($t:ty)*) => ($(
impl Integer for $t {
const MAX_NUM_DIGITS: u8 = match Self::MAX.checked_ilog10() {
Some(digits) => digits as u8 + 1,
None => 1,
};
const ZERO: Self = 0;
#[allow(trivial_numeric_casts, reason = "macro-generated code")]
#[inline]
fn push_digit(self, digit: u8) -> Self {
self * 10 + digit as Self
}
#[allow(trivial_numeric_casts, reason = "macro-generated code")]
#[inline]
fn checked_push_digit(self, digit: u8) -> Option<Self> {
self.checked_mul(10)?.checked_add(digit as Self)
}
}
)*)
}
impl_parse_bytes! { u8 u16 u32 u128 }