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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,84 @@ | ||
| macro_rules! impl_non_max_fmt { | ||
| (($($trait:ident),+) for $ty:ident) => { | ||
| $( | ||
| impl std::fmt::$trait for $ty { | ||
| #[inline] | ||
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { | ||
| self.get().fmt(f) | ||
| } | ||
| } | ||
| )+ | ||
| } | ||
| } | ||
|
|
||
| macro_rules! impl_non_max { | ||
| ($nonmax:ident, $nonzero:ty, $repr:ty, $test:ident) => { | ||
| #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)] | ||
| pub struct $nonmax($nonzero); | ||
|
|
||
| impl $nonmax { | ||
| /// Creates a non-max if `n` is not the maximum value. | ||
| #[inline] | ||
| #[allow(clippy::manual_map)] | ||
| pub const fn new(n: $repr) -> Option<Self> { | ||
| if let Some(n) = <$nonzero>::new(!n) { | ||
| Some(Self(n)) | ||
| } else { | ||
| None | ||
| } | ||
| } | ||
|
|
||
| /// Creates a non-max without checking the value. | ||
| /// | ||
| /// # Safety | ||
| /// `n` must not be equal to T::MAX. | ||
| #[inline] | ||
| pub const unsafe fn new_unchecked(n: $repr) -> Self { | ||
| Self(<$nonzero>::new_unchecked(!n)) | ||
| } | ||
|
|
||
| /// Returns the value as a primitive type. | ||
| /// | ||
| /// # Note | ||
| /// This function is not free. Consider storing the result | ||
| /// into a variable instead of calling `get()` multiple times. | ||
| #[inline] | ||
| pub const fn get(self) -> $repr { | ||
| !self.0.get() | ||
| } | ||
| } | ||
|
|
||
| impl_non_max_fmt! { | ||
| (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $nonmax | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod $test { | ||
| use super::*; | ||
|
|
||
| #[test] | ||
| fn test() { | ||
| assert!($nonmax::new(<$repr>::MAX).is_none()); | ||
| assert_eq!($nonmax::new(0).unwrap().get(), 0); | ||
| assert_eq!($nonmax::new(1).unwrap().get(), 1); | ||
|
|
||
| // SAFE: `0` != <$repr>::MAX | ||
| unsafe { | ||
| assert_eq!($nonmax::new_unchecked(0).get(), 0); | ||
| } | ||
|
|
||
| assert_eq!( | ||
| std::mem::size_of::<$nonmax>(), | ||
| std::mem::size_of::<Option<$nonmax>>() | ||
| ); | ||
| } | ||
| } | ||
| }; | ||
| } | ||
|
|
||
| impl_non_max!( | ||
| NonMaxUsize, | ||
| std::num::NonZeroUsize, | ||
| usize, | ||
| non_max_usize_test | ||
| ); |