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author | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
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committer | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
commit | 1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch) | |
tree | 7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/num-traits/src/identities.rs | |
parent | 5ecd8cf2cba827454317368b68571df0d13d7842 (diff) | |
download | fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip |
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/num-traits/src/identities.rs')
-rw-r--r-- | vendor/num-traits/src/identities.rs | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/vendor/num-traits/src/identities.rs b/vendor/num-traits/src/identities.rs new file mode 100644 index 0000000..2486cb1 --- /dev/null +++ b/vendor/num-traits/src/identities.rs @@ -0,0 +1,202 @@ +use core::num::Wrapping; +use core::ops::{Add, Mul}; + +/// Defines an additive identity element for `Self`. +/// +/// # Laws +/// +/// ```text +/// a + 0 = a ∀ a ∈ Self +/// 0 + a = a ∀ a ∈ Self +/// ``` +pub trait Zero: Sized + Add<Self, Output = Self> { + /// Returns the additive identity element of `Self`, `0`. + /// # Purity + /// + /// This function should return the same result at all times regardless of + /// external mutable state, for example values stored in TLS or in + /// `static mut`s. + // This cannot be an associated constant, because of bignums. + fn zero() -> Self; + + /// Sets `self` to the additive identity element of `Self`, `0`. + fn set_zero(&mut self) { + *self = Zero::zero(); + } + + /// Returns `true` if `self` is equal to the additive identity. + fn is_zero(&self) -> bool; +} + +macro_rules! zero_impl { + ($t:ty, $v:expr) => { + impl Zero for $t { + #[inline] + fn zero() -> $t { + $v + } + #[inline] + fn is_zero(&self) -> bool { + *self == $v + } + } + }; +} + +zero_impl!(usize, 0); +zero_impl!(u8, 0); +zero_impl!(u16, 0); +zero_impl!(u32, 0); +zero_impl!(u64, 0); +zero_impl!(u128, 0); + +zero_impl!(isize, 0); +zero_impl!(i8, 0); +zero_impl!(i16, 0); +zero_impl!(i32, 0); +zero_impl!(i64, 0); +zero_impl!(i128, 0); + +zero_impl!(f32, 0.0); +zero_impl!(f64, 0.0); + +impl<T: Zero> Zero for Wrapping<T> +where + Wrapping<T>: Add<Output = Wrapping<T>>, +{ + fn is_zero(&self) -> bool { + self.0.is_zero() + } + + fn set_zero(&mut self) { + self.0.set_zero(); + } + + fn zero() -> Self { + Wrapping(T::zero()) + } +} + +/// Defines a multiplicative identity element for `Self`. +/// +/// # Laws +/// +/// ```text +/// a * 1 = a ∀ a ∈ Self +/// 1 * a = a ∀ a ∈ Self +/// ``` +pub trait One: Sized + Mul<Self, Output = Self> { + /// Returns the multiplicative identity element of `Self`, `1`. + /// + /// # Purity + /// + /// This function should return the same result at all times regardless of + /// external mutable state, for example values stored in TLS or in + /// `static mut`s. + // This cannot be an associated constant, because of bignums. + fn one() -> Self; + + /// Sets `self` to the multiplicative identity element of `Self`, `1`. + fn set_one(&mut self) { + *self = One::one(); + } + + /// Returns `true` if `self` is equal to the multiplicative identity. + /// + /// For performance reasons, it's best to implement this manually. + /// After a semver bump, this method will be required, and the + /// `where Self: PartialEq` bound will be removed. + #[inline] + fn is_one(&self) -> bool + where + Self: PartialEq, + { + *self == Self::one() + } +} + +macro_rules! one_impl { + ($t:ty, $v:expr) => { + impl One for $t { + #[inline] + fn one() -> $t { + $v + } + #[inline] + fn is_one(&self) -> bool { + *self == $v + } + } + }; +} + +one_impl!(usize, 1); +one_impl!(u8, 1); +one_impl!(u16, 1); +one_impl!(u32, 1); +one_impl!(u64, 1); +one_impl!(u128, 1); + +one_impl!(isize, 1); +one_impl!(i8, 1); +one_impl!(i16, 1); +one_impl!(i32, 1); +one_impl!(i64, 1); +one_impl!(i128, 1); + +one_impl!(f32, 1.0); +one_impl!(f64, 1.0); + +impl<T: One> One for Wrapping<T> +where + Wrapping<T>: Mul<Output = Wrapping<T>>, +{ + fn set_one(&mut self) { + self.0.set_one(); + } + + fn one() -> Self { + Wrapping(T::one()) + } +} + +// Some helper functions provided for backwards compatibility. + +/// Returns the additive identity, `0`. +#[inline(always)] +pub fn zero<T: Zero>() -> T { + Zero::zero() +} + +/// Returns the multiplicative identity, `1`. +#[inline(always)] +pub fn one<T: One>() -> T { + One::one() +} + +#[test] +fn wrapping_identities() { + macro_rules! test_wrapping_identities { + ($($t:ty)+) => { + $( + assert_eq!(zero::<$t>(), zero::<Wrapping<$t>>().0); + assert_eq!(one::<$t>(), one::<Wrapping<$t>>().0); + assert_eq!((0 as $t).is_zero(), Wrapping(0 as $t).is_zero()); + assert_eq!((1 as $t).is_zero(), Wrapping(1 as $t).is_zero()); + )+ + }; + } + + test_wrapping_identities!(isize i8 i16 i32 i64 usize u8 u16 u32 u64); +} + +#[test] +fn wrapping_is_zero() { + fn require_zero<T: Zero>(_: &T) {} + require_zero(&Wrapping(42)); +} +#[test] +fn wrapping_is_one() { + fn require_one<T: One>(_: &T) {} + require_one(&Wrapping(42)); +} |