Added traits for wrapping arithmetics.

Added `Wrapping` traits for the most common operations. Similar to the already present `Checked` traits.

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::*;

traits/src/ops/mod.rs

@@ -1,2 +1,3 @@
 pub mod saturating;
 pub mod checked;
+pub mod wrapping;

traits/src/ops/wrapping.rs

@@ -0,0 +1,153 @@
+use std::ops::{Add, Sub, Mul, Div, Shl, Shr};
+
+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 wrapps 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);
+
+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 wrapps 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);
+
+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 wrapps 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);
+
+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);
+
+/// Performs division that wrapps around on overflow.
+pub trait WrappingDiv: Sized + Div<Self, Output=Self> {
+    /// Wrapping (modular) division. Computes `self / other`, wrapping around at the boundary of
+    /// the type.
+    ///
+    /// The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type
+    /// (where `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a
+    /// positive value that is too large to represent in the type. In such a case, this function
+    /// returns `MIN` itself.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if rhs is 0.
+    fn wrapping_div(&self, v: &Self) -> Self;
+}
+
+wrapping_impl!(WrappingDiv, wrapping_div, u8);
+wrapping_impl!(WrappingDiv, wrapping_div, u16);
+wrapping_impl!(WrappingDiv, wrapping_div, u32);
+wrapping_impl!(WrappingDiv, wrapping_div, u64);
+wrapping_impl!(WrappingDiv, wrapping_div, usize);
+
+wrapping_impl!(WrappingDiv, wrapping_div, i8);
+wrapping_impl!(WrappingDiv, wrapping_div, i16);
+wrapping_impl!(WrappingDiv, wrapping_div, i32);
+wrapping_impl!(WrappingDiv, wrapping_div, i64);
+wrapping_impl!(WrappingDiv, wrapping_div, isize);
+
+/// Performs bitwise shift left that wrapps around on overflow.
+pub trait WrappingShl<RHS>: Sized + Shl<RHS, 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.
+    ///
+    /// Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is
+    /// restricted to the range of the type, rather than the bits shifted out of the LHS being
+    /// returned to the other end. The primitive integer types all implement a `rotate_left`
+    /// function, which may be what you want instead.
+    fn wrapping_shl(&self, v: &RHS) -> Self;
+}
+
+wrapping_impl!(WrappingShl, wrapping_shl, u8, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, u16, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, u32, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, u64, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, usize, u32);
+
+wrapping_impl!(WrappingShl, wrapping_shl, i8, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, i16, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, i32, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, i64, u32);
+wrapping_impl!(WrappingShl, wrapping_shl, isize, u32);
+
+/// Performs bitwise shift right that wrapps around on overflow.
+pub trait WrappingShr<RHS>: Sized + Shr<RHS, 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.
+    ///
+    /// Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is
+    /// restricted to the range of the type, rather than the bits shifted out of the LHS being
+    /// returned to the other end. The primitive integer types all implement a `rotate_right`
+    /// function, which may be what you want instead.
+    fn wrapping_shr(&self, v: &RHS) -> Self;
+}
+
+wrapping_impl!(WrappingShr, wrapping_shr, u8, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, u16, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, u32, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, u64, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, usize, u32);
+
+wrapping_impl!(WrappingShr, wrapping_shr, i8, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, i16, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, i32, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, i64, u32);
+wrapping_impl!(WrappingShr, wrapping_shr, isize, u32);