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Diffstat (limited to 'third_party/rust/num-traits/src/ops/wrapping.rs')
| -rw-r--r-- | third_party/rust/num-traits/src/ops/wrapping.rs | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/third_party/rust/num-traits/src/ops/wrapping.rs b/third_party/rust/num-traits/src/ops/wrapping.rs new file mode 100644 index 0000000000..265b8f3bbc --- /dev/null +++ b/third_party/rust/num-traits/src/ops/wrapping.rs @@ -0,0 +1,337 @@ +use core::num::Wrapping; +use core::ops::{Add, Mul, Neg, Shl, Shr, Sub}; + +macro_rules! wrapping_impl { + ($trait_name:ident, $method:ident, $t:ty) => { + impl $trait_name for $t { + #[inline] + fn $method(&self, v: &Self) -> Self { + <$t>::$method(*self, *v) + } + } + }; + ($trait_name:ident, $method:ident, $t:ty, $rhs:ty) => { + impl $trait_name<$rhs> for $t { + #[inline] + fn $method(&self, v: &$rhs) -> Self { + <$t>::$method(*self, *v) + } + } + }; +} + +/// Performs addition that wraps around on overflow. +pub trait WrappingAdd: Sized + Add<Self, Output = Self> { + /// Wrapping (modular) addition. Computes `self + other`, wrapping around at the boundary of + /// the type. + fn wrapping_add(&self, v: &Self) -> Self; +} + +wrapping_impl!(WrappingAdd, wrapping_add, u8); +wrapping_impl!(WrappingAdd, wrapping_add, u16); +wrapping_impl!(WrappingAdd, wrapping_add, u32); +wrapping_impl!(WrappingAdd, wrapping_add, u64); +wrapping_impl!(WrappingAdd, wrapping_add, usize); +#[cfg(has_i128)] +wrapping_impl!(WrappingAdd, wrapping_add, u128); + +wrapping_impl!(WrappingAdd, wrapping_add, i8); +wrapping_impl!(WrappingAdd, wrapping_add, i16); +wrapping_impl!(WrappingAdd, wrapping_add, i32); +wrapping_impl!(WrappingAdd, wrapping_add, i64); +wrapping_impl!(WrappingAdd, wrapping_add, isize); +#[cfg(has_i128)] +wrapping_impl!(WrappingAdd, wrapping_add, i128); + +/// Performs subtraction that wraps around on overflow. +pub trait WrappingSub: Sized + Sub<Self, Output = Self> { + /// Wrapping (modular) subtraction. Computes `self - other`, wrapping around at the boundary + /// of the type. + fn wrapping_sub(&self, v: &Self) -> Self; +} + +wrapping_impl!(WrappingSub, wrapping_sub, u8); +wrapping_impl!(WrappingSub, wrapping_sub, u16); +wrapping_impl!(WrappingSub, wrapping_sub, u32); +wrapping_impl!(WrappingSub, wrapping_sub, u64); +wrapping_impl!(WrappingSub, wrapping_sub, usize); +#[cfg(has_i128)] +wrapping_impl!(WrappingSub, wrapping_sub, u128); + +wrapping_impl!(WrappingSub, wrapping_sub, i8); +wrapping_impl!(WrappingSub, wrapping_sub, i16); +wrapping_impl!(WrappingSub, wrapping_sub, i32); +wrapping_impl!(WrappingSub, wrapping_sub, i64); +wrapping_impl!(WrappingSub, wrapping_sub, isize); +#[cfg(has_i128)] +wrapping_impl!(WrappingSub, wrapping_sub, i128); + +/// Performs multiplication that wraps around on overflow. +pub trait WrappingMul: Sized + Mul<Self, Output = Self> { + /// Wrapping (modular) multiplication. Computes `self * other`, wrapping around at the boundary + /// of the type. + fn wrapping_mul(&self, v: &Self) -> Self; +} + +wrapping_impl!(WrappingMul, wrapping_mul, u8); +wrapping_impl!(WrappingMul, wrapping_mul, u16); +wrapping_impl!(WrappingMul, wrapping_mul, u32); +wrapping_impl!(WrappingMul, wrapping_mul, u64); +wrapping_impl!(WrappingMul, wrapping_mul, usize); +#[cfg(has_i128)] +wrapping_impl!(WrappingMul, wrapping_mul, u128); + +wrapping_impl!(WrappingMul, wrapping_mul, i8); +wrapping_impl!(WrappingMul, wrapping_mul, i16); +wrapping_impl!(WrappingMul, wrapping_mul, i32); +wrapping_impl!(WrappingMul, wrapping_mul, i64); +wrapping_impl!(WrappingMul, wrapping_mul, isize); +#[cfg(has_i128)] +wrapping_impl!(WrappingMul, wrapping_mul, i128); + +macro_rules! wrapping_unary_impl { + ($trait_name:ident, $method:ident, $t:ty) => { + impl $trait_name for $t { + #[inline] + fn $method(&self) -> $t { + <$t>::$method(*self) + } + } + }; +} + +/// Performs a negation that does not panic. +pub trait WrappingNeg: Sized { + /// Wrapping (modular) negation. Computes `-self`, + /// wrapping around at the boundary of the type. + /// + /// Since unsigned types do not have negative equivalents + /// all applications of this function will wrap (except for `-0`). + /// For values smaller than the corresponding signed type's maximum + /// the result is the same as casting the corresponding signed value. + /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where + /// `MAX` is the corresponding signed type's maximum. + /// + /// ``` + /// use num_traits::WrappingNeg; + /// + /// assert_eq!(100i8.wrapping_neg(), -100); + /// assert_eq!((-100i8).wrapping_neg(), 100); + /// assert_eq!((-128i8).wrapping_neg(), -128); // wrapped! + /// ``` + fn wrapping_neg(&self) -> Self; +} + +wrapping_unary_impl!(WrappingNeg, wrapping_neg, u8); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, u16); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, u32); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, u64); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, usize); +#[cfg(has_i128)] +wrapping_unary_impl!(WrappingNeg, wrapping_neg, u128); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, i8); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, i16); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, i32); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, i64); +wrapping_unary_impl!(WrappingNeg, wrapping_neg, isize); +#[cfg(has_i128)] +wrapping_unary_impl!(WrappingNeg, wrapping_neg, i128); + +macro_rules! wrapping_shift_impl { + ($trait_name:ident, $method:ident, $t:ty) => { + impl $trait_name for $t { + #[inline] + fn $method(&self, rhs: u32) -> $t { + <$t>::$method(*self, rhs) + } + } + }; +} + +/// Performs a left shift that does not panic. +pub trait WrappingShl: Sized + Shl<usize, Output = Self> { + /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, + /// where `mask` removes any high order bits of `rhs` that would + /// cause the shift to exceed the bitwidth of the type. + /// + /// ``` + /// use num_traits::WrappingShl; + /// + /// let x: u16 = 0x0001; + /// + /// assert_eq!(WrappingShl::wrapping_shl(&x, 0), 0x0001); + /// assert_eq!(WrappingShl::wrapping_shl(&x, 1), 0x0002); + /// assert_eq!(WrappingShl::wrapping_shl(&x, 15), 0x8000); + /// assert_eq!(WrappingShl::wrapping_shl(&x, 16), 0x0001); + /// ``` + fn wrapping_shl(&self, rhs: u32) -> Self; +} + +wrapping_shift_impl!(WrappingShl, wrapping_shl, u8); +wrapping_shift_impl!(WrappingShl, wrapping_shl, u16); +wrapping_shift_impl!(WrappingShl, wrapping_shl, u32); +wrapping_shift_impl!(WrappingShl, wrapping_shl, u64); +wrapping_shift_impl!(WrappingShl, wrapping_shl, usize); +#[cfg(has_i128)] +wrapping_shift_impl!(WrappingShl, wrapping_shl, u128); + +wrapping_shift_impl!(WrappingShl, wrapping_shl, i8); +wrapping_shift_impl!(WrappingShl, wrapping_shl, i16); +wrapping_shift_impl!(WrappingShl, wrapping_shl, i32); +wrapping_shift_impl!(WrappingShl, wrapping_shl, i64); +wrapping_shift_impl!(WrappingShl, wrapping_shl, isize); +#[cfg(has_i128)] +wrapping_shift_impl!(WrappingShl, wrapping_shl, i128); + +/// Performs a right shift that does not panic. +pub trait WrappingShr: Sized + Shr<usize, Output = Self> { + /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, + /// where `mask` removes any high order bits of `rhs` that would + /// cause the shift to exceed the bitwidth of the type. + /// + /// ``` + /// use num_traits::WrappingShr; + /// + /// let x: u16 = 0x8000; + /// + /// assert_eq!(WrappingShr::wrapping_shr(&x, 0), 0x8000); + /// assert_eq!(WrappingShr::wrapping_shr(&x, 1), 0x4000); + /// assert_eq!(WrappingShr::wrapping_shr(&x, 15), 0x0001); + /// assert_eq!(WrappingShr::wrapping_shr(&x, 16), 0x8000); + /// ``` + fn wrapping_shr(&self, rhs: u32) -> Self; +} + +wrapping_shift_impl!(WrappingShr, wrapping_shr, u8); +wrapping_shift_impl!(WrappingShr, wrapping_shr, u16); +wrapping_shift_impl!(WrappingShr, wrapping_shr, u32); +wrapping_shift_impl!(WrappingShr, wrapping_shr, u64); +wrapping_shift_impl!(WrappingShr, wrapping_shr, usize); +#[cfg(has_i128)] +wrapping_shift_impl!(WrappingShr, wrapping_shr, u128); + +wrapping_shift_impl!(WrappingShr, wrapping_shr, i8); +wrapping_shift_impl!(WrappingShr, wrapping_shr, i16); +wrapping_shift_impl!(WrappingShr, wrapping_shr, i32); +wrapping_shift_impl!(WrappingShr, wrapping_shr, i64); +wrapping_shift_impl!(WrappingShr, wrapping_shr, isize); +#[cfg(has_i128)] +wrapping_shift_impl!(WrappingShr, wrapping_shr, i128); + +// Well this is a bit funny, but all the more appropriate. +impl<T: WrappingAdd> WrappingAdd for Wrapping<T> +where + Wrapping<T>: Add<Output = Wrapping<T>>, +{ + fn wrapping_add(&self, v: &Self) -> Self { + Wrapping(self.0.wrapping_add(&v.0)) + } +} +impl<T: WrappingSub> WrappingSub for Wrapping<T> +where + Wrapping<T>: Sub<Output = Wrapping<T>>, +{ + fn wrapping_sub(&self, v: &Self) -> Self { + Wrapping(self.0.wrapping_sub(&v.0)) + } +} +impl<T: WrappingMul> WrappingMul for Wrapping<T> +where + Wrapping<T>: Mul<Output = Wrapping<T>>, +{ + fn wrapping_mul(&self, v: &Self) -> Self { + Wrapping(self.0.wrapping_mul(&v.0)) + } +} +impl<T: WrappingNeg> WrappingNeg for Wrapping<T> +where + Wrapping<T>: Neg<Output = Wrapping<T>>, +{ + fn wrapping_neg(&self) -> Self { + Wrapping(self.0.wrapping_neg()) + } +} +impl<T: WrappingShl> WrappingShl for Wrapping<T> +where + Wrapping<T>: Shl<usize, Output = Wrapping<T>>, +{ + fn wrapping_shl(&self, rhs: u32) -> Self { + Wrapping(self.0.wrapping_shl(rhs)) + } +} +impl<T: WrappingShr> WrappingShr for Wrapping<T> +where + Wrapping<T>: Shr<usize, Output = Wrapping<T>>, +{ + fn wrapping_shr(&self, rhs: u32) -> Self { + Wrapping(self.0.wrapping_shr(rhs)) + } +} + +#[test] +fn test_wrapping_traits() { + fn wrapping_add<T: WrappingAdd>(a: T, b: T) -> T { + a.wrapping_add(&b) + } + fn wrapping_sub<T: WrappingSub>(a: T, b: T) -> T { + a.wrapping_sub(&b) + } + fn wrapping_mul<T: WrappingMul>(a: T, b: T) -> T { + a.wrapping_mul(&b) + } + fn wrapping_neg<T: WrappingNeg>(a: T) -> T { + a.wrapping_neg() + } + fn wrapping_shl<T: WrappingShl>(a: T, b: u32) -> T { + a.wrapping_shl(b) + } + fn wrapping_shr<T: WrappingShr>(a: T, b: u32) -> T { + a.wrapping_shr(b) + } + assert_eq!(wrapping_add(255, 1), 0u8); + assert_eq!(wrapping_sub(0, 1), 255u8); + assert_eq!(wrapping_mul(255, 2), 254u8); + assert_eq!(wrapping_neg(255), 1u8); + assert_eq!(wrapping_shl(255, 8), 255u8); + assert_eq!(wrapping_shr(255, 8), 255u8); + assert_eq!(wrapping_add(255, 1), (Wrapping(255u8) + Wrapping(1u8)).0); + assert_eq!(wrapping_sub(0, 1), (Wrapping(0u8) - Wrapping(1u8)).0); + assert_eq!(wrapping_mul(255, 2), (Wrapping(255u8) * Wrapping(2u8)).0); + // TODO: Test for Wrapping::Neg. Not possible yet since core::ops::Neg was + // only added to core::num::Wrapping<_> in Rust 1.10. + assert_eq!(wrapping_shl(255, 8), (Wrapping(255u8) << 8).0); + assert_eq!(wrapping_shr(255, 8), (Wrapping(255u8) >> 8).0); +} + +#[test] +fn wrapping_is_wrappingadd() { + fn require_wrappingadd<T: WrappingAdd>(_: &T) {} + require_wrappingadd(&Wrapping(42)); +} + +#[test] +fn wrapping_is_wrappingsub() { + fn require_wrappingsub<T: WrappingSub>(_: &T) {} + require_wrappingsub(&Wrapping(42)); +} + +#[test] +fn wrapping_is_wrappingmul() { + fn require_wrappingmul<T: WrappingMul>(_: &T) {} + require_wrappingmul(&Wrapping(42)); +} + +// TODO: Test for Wrapping::Neg. Not possible yet since core::ops::Neg was +// only added to core::num::Wrapping<_> in Rust 1.10. + +#[test] +fn wrapping_is_wrappingshl() { + fn require_wrappingshl<T: WrappingShl>(_: &T) {} + require_wrappingshl(&Wrapping(42)); +} + +#[test] +fn wrapping_is_wrappingshr() { + fn require_wrappingshr<T: WrappingShr>(_: &T) {} + require_wrappingshr(&Wrapping(42)); +} |