diff --git a/traits/src/lib.rs b/traits/src/lib.rs index 0aeb783..341d1f4 100644 --- a/traits/src/lib.rs +++ b/traits/src/lib.rs @@ -20,6 +20,7 @@ pub use bounds::Bounded; pub use float::{Float, FloatConst}; pub use identities::{Zero, One, zero, one}; pub use ops::checked::*; +pub use ops::wrapping::*; pub use ops::saturating::Saturating; pub use sign::{Signed, Unsigned, abs, abs_sub, signum}; pub use cast::*; diff --git a/traits/src/ops/mod.rs b/traits/src/ops/mod.rs index 2632a0f..ec9edeb 100644 --- a/traits/src/ops/mod.rs +++ b/traits/src/ops/mod.rs @@ -1,2 +1,3 @@ pub mod saturating; pub mod checked; +pub mod wrapping; diff --git a/traits/src/ops/wrapping.rs b/traits/src/ops/wrapping.rs new file mode 100644 index 0000000..40b266d --- /dev/null +++ b/traits/src/ops/wrapping.rs @@ -0,0 +1,88 @@ +use std::ops::{Add, Sub, Mul}; + +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 { + /// 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); + +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); + +/// Performs subtraction that wraps around on overflow. +pub trait WrappingSub: Sized + Sub { + /// 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); + +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); + +/// Performs multiplication that wraps around on overflow. +pub trait WrappingMul: Sized + Mul { + /// 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); + +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); + + +#[test] +fn test_wrapping_traits() { + fn wrapping_add(a: T, b: T) -> T { a.wrapping_add(&b) } + fn wrapping_sub(a: T, b: T) -> T { a.wrapping_sub(&b) } + fn wrapping_mul(a: T, b: T) -> T { a.wrapping_mul(&b) } + assert_eq!(wrapping_add(255, 1), 0u8); + assert_eq!(wrapping_sub(0, 1), 255u8); + assert_eq!(wrapping_mul(255, 2), 254u8); +}