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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/num-traits/src/identities.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-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.rs202
1 files changed, 202 insertions, 0 deletions
diff --git a/vendor/num-traits/src/identities.rs b/vendor/num-traits/src/identities.rs
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+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));
+}