2018-01-31 23:42:55 +00:00
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use core::num::Wrapping;
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2018-09-02 04:51:04 +00:00
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use core::ops::{Add, Mul, Shl, Shr, Sub};
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2017-01-22 08:45:35 +00:00
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macro_rules! wrapping_impl {
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($trait_name:ident, $method:ident, $t:ty) => {
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impl $trait_name for $t {
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#[inline]
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fn $method(&self, v: &Self) -> Self {
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<$t>::$method(*self, *v)
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}
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}
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};
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($trait_name:ident, $method:ident, $t:ty, $rhs:ty) => {
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impl $trait_name<$rhs> for $t {
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#[inline]
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fn $method(&self, v: &$rhs) -> Self {
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<$t>::$method(*self, *v)
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}
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}
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2018-07-13 00:09:22 +00:00
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};
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2017-01-22 08:45:35 +00:00
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}
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2017-01-26 20:12:27 +00:00
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/// Performs addition that wraps around on overflow.
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2018-07-13 00:09:22 +00:00
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pub trait WrappingAdd: Sized + Add<Self, Output = Self> {
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2017-01-22 08:45:35 +00:00
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/// Wrapping (modular) addition. Computes `self + other`, wrapping around at the boundary of
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/// the type.
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fn wrapping_add(&self, v: &Self) -> Self;
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}
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wrapping_impl!(WrappingAdd, wrapping_add, u8);
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wrapping_impl!(WrappingAdd, wrapping_add, u16);
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wrapping_impl!(WrappingAdd, wrapping_add, u32);
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wrapping_impl!(WrappingAdd, wrapping_add, u64);
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wrapping_impl!(WrappingAdd, wrapping_add, usize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingAdd, wrapping_add, u128);
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2017-01-22 08:45:35 +00:00
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wrapping_impl!(WrappingAdd, wrapping_add, i8);
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wrapping_impl!(WrappingAdd, wrapping_add, i16);
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wrapping_impl!(WrappingAdd, wrapping_add, i32);
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wrapping_impl!(WrappingAdd, wrapping_add, i64);
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wrapping_impl!(WrappingAdd, wrapping_add, isize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingAdd, wrapping_add, i128);
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2017-01-22 08:45:35 +00:00
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2017-01-26 20:12:27 +00:00
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/// Performs subtraction that wraps around on overflow.
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2018-07-13 00:09:22 +00:00
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pub trait WrappingSub: Sized + Sub<Self, Output = Self> {
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2017-01-22 08:45:35 +00:00
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/// Wrapping (modular) subtraction. Computes `self - other`, wrapping around at the boundary
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/// of the type.
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fn wrapping_sub(&self, v: &Self) -> Self;
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}
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wrapping_impl!(WrappingSub, wrapping_sub, u8);
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wrapping_impl!(WrappingSub, wrapping_sub, u16);
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wrapping_impl!(WrappingSub, wrapping_sub, u32);
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wrapping_impl!(WrappingSub, wrapping_sub, u64);
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wrapping_impl!(WrappingSub, wrapping_sub, usize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingSub, wrapping_sub, u128);
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2017-01-22 08:45:35 +00:00
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wrapping_impl!(WrappingSub, wrapping_sub, i8);
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wrapping_impl!(WrappingSub, wrapping_sub, i16);
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wrapping_impl!(WrappingSub, wrapping_sub, i32);
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wrapping_impl!(WrappingSub, wrapping_sub, i64);
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wrapping_impl!(WrappingSub, wrapping_sub, isize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingSub, wrapping_sub, i128);
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2017-01-22 08:45:35 +00:00
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2017-01-26 20:12:27 +00:00
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/// Performs multiplication that wraps around on overflow.
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2018-07-13 00:09:22 +00:00
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pub trait WrappingMul: Sized + Mul<Self, Output = Self> {
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2017-01-22 08:45:35 +00:00
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/// Wrapping (modular) multiplication. Computes `self * other`, wrapping around at the boundary
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/// of the type.
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fn wrapping_mul(&self, v: &Self) -> Self;
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}
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wrapping_impl!(WrappingMul, wrapping_mul, u8);
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wrapping_impl!(WrappingMul, wrapping_mul, u16);
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wrapping_impl!(WrappingMul, wrapping_mul, u32);
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wrapping_impl!(WrappingMul, wrapping_mul, u64);
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wrapping_impl!(WrappingMul, wrapping_mul, usize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingMul, wrapping_mul, u128);
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2017-01-22 08:45:35 +00:00
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wrapping_impl!(WrappingMul, wrapping_mul, i8);
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wrapping_impl!(WrappingMul, wrapping_mul, i16);
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wrapping_impl!(WrappingMul, wrapping_mul, i32);
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wrapping_impl!(WrappingMul, wrapping_mul, i64);
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wrapping_impl!(WrappingMul, wrapping_mul, isize);
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2018-05-11 22:50:48 +00:00
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#[cfg(has_i128)]
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2018-04-09 09:11:05 +00:00
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wrapping_impl!(WrappingMul, wrapping_mul, i128);
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2017-02-04 09:42:12 +00:00
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2018-09-02 04:51:04 +00:00
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macro_rules! wrapping_shift_impl {
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($trait_name:ident, $method:ident, $t:ty) => {
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impl $trait_name for $t {
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#[inline]
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fn $method(&self, rhs: u32) -> $t {
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<$t>::$method(*self, rhs)
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}
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}
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};
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}
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/// Performs a left shift that does not panic.
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pub trait WrappingShl: Sized + Shl<usize, Output = Self> {
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/// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
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/// where `mask` removes any high order bits of `rhs` that would
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/// cause the shift to exceed the bitwidth of the type.
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///
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/// ```
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/// use num_traits::WrappingShl;
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///
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/// let x: u16 = 0x0001;
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///
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/// assert_eq!(WrappingShl::wrapping_shl(&x, 0), 0x0001);
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/// assert_eq!(WrappingShl::wrapping_shl(&x, 1), 0x0002);
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/// assert_eq!(WrappingShl::wrapping_shl(&x, 15), 0x8000);
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/// assert_eq!(WrappingShl::wrapping_shl(&x, 16), 0x0001);
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/// ```
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fn wrapping_shl(&self, rhs: u32) -> Self;
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}
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wrapping_shift_impl!(WrappingShl, wrapping_shl, u8);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, u16);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, u32);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, u64);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, usize);
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#[cfg(has_i128)]
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wrapping_shift_impl!(WrappingShl, wrapping_shl, u128);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, i8);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, i16);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, i32);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, i64);
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wrapping_shift_impl!(WrappingShl, wrapping_shl, isize);
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#[cfg(has_i128)]
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wrapping_shift_impl!(WrappingShl, wrapping_shl, i128);
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/// Performs a right shift that does not panic.
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pub trait WrappingShr: Sized + Shr<usize, Output = Self> {
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/// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
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/// where `mask` removes any high order bits of `rhs` that would
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/// cause the shift to exceed the bitwidth of the type.
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///
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/// ```
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/// use num_traits::WrappingShr;
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///
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/// let x: u16 = 0x8000;
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///
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/// assert_eq!(WrappingShr::wrapping_shr(&x, 0), 0x8000);
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/// assert_eq!(WrappingShr::wrapping_shr(&x, 1), 0x4000);
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/// assert_eq!(WrappingShr::wrapping_shr(&x, 15), 0x0001);
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/// assert_eq!(WrappingShr::wrapping_shr(&x, 16), 0x8000);
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/// ```
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fn wrapping_shr(&self, rhs: u32) -> Self;
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}
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wrapping_shift_impl!(WrappingShr, wrapping_shr, u8);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, u16);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, u32);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, u64);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, usize);
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#[cfg(has_i128)]
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wrapping_shift_impl!(WrappingShr, wrapping_shr, u128);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, i8);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, i16);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, i32);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, i64);
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wrapping_shift_impl!(WrappingShr, wrapping_shr, isize);
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#[cfg(has_i128)]
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wrapping_shift_impl!(WrappingShr, wrapping_shr, i128);
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2017-04-29 06:29:02 +00:00
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// Well this is a bit funny, but all the more appropriate.
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2018-07-13 00:09:22 +00:00
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impl<T: WrappingAdd> WrappingAdd for Wrapping<T>
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where
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Wrapping<T>: Add<Output = Wrapping<T>>,
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{
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2017-04-29 06:29:02 +00:00
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fn wrapping_add(&self, v: &Self) -> Self {
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Wrapping(self.0.wrapping_add(&v.0))
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}
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}
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2018-07-13 00:09:22 +00:00
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impl<T: WrappingSub> WrappingSub for Wrapping<T>
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where
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Wrapping<T>: Sub<Output = Wrapping<T>>,
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{
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2017-04-29 06:29:02 +00:00
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fn wrapping_sub(&self, v: &Self) -> Self {
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Wrapping(self.0.wrapping_sub(&v.0))
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}
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}
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2018-07-13 00:09:22 +00:00
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impl<T: WrappingMul> WrappingMul for Wrapping<T>
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where
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Wrapping<T>: Mul<Output = Wrapping<T>>,
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{
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2017-04-29 06:29:02 +00:00
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fn wrapping_mul(&self, v: &Self) -> Self {
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Wrapping(self.0.wrapping_mul(&v.0))
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}
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}
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2018-09-02 04:51:04 +00:00
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impl<T: WrappingShl> WrappingShl for Wrapping<T>
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where
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Wrapping<T>: Shl<usize, Output = Wrapping<T>>,
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{
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fn wrapping_shl(&self, rhs: u32) -> Self {
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Wrapping(self.0.wrapping_shl(rhs))
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}
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}
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impl<T: WrappingShr> WrappingShr for Wrapping<T>
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where
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Wrapping<T>: Shr<usize, Output = Wrapping<T>>,
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{
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fn wrapping_shr(&self, rhs: u32) -> Self {
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Wrapping(self.0.wrapping_shr(rhs))
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}
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}
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2017-04-29 06:29:02 +00:00
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2017-02-04 09:42:12 +00:00
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#[test]
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fn test_wrapping_traits() {
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2018-07-13 00:09:22 +00:00
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fn wrapping_add<T: WrappingAdd>(a: T, b: T) -> T {
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a.wrapping_add(&b)
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}
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fn wrapping_sub<T: WrappingSub>(a: T, b: T) -> T {
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a.wrapping_sub(&b)
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}
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fn wrapping_mul<T: WrappingMul>(a: T, b: T) -> T {
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a.wrapping_mul(&b)
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}
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2018-09-02 04:51:04 +00:00
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fn wrapping_shl<T: WrappingShl>(a: T, b: u32) -> T {
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a.wrapping_shl(b)
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}
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fn wrapping_shr<T: WrappingShr>(a: T, b: u32) -> T {
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a.wrapping_shr(b)
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}
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2017-02-04 09:42:12 +00:00
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assert_eq!(wrapping_add(255, 1), 0u8);
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assert_eq!(wrapping_sub(0, 1), 255u8);
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assert_eq!(wrapping_mul(255, 2), 254u8);
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2018-09-02 04:51:04 +00:00
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assert_eq!(wrapping_shl(255, 8), 255u8);
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assert_eq!(wrapping_shr(255, 8), 255u8);
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2017-04-30 08:17:06 +00:00
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assert_eq!(wrapping_add(255, 1), (Wrapping(255u8) + Wrapping(1u8)).0);
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assert_eq!(wrapping_sub(0, 1), (Wrapping(0u8) - Wrapping(1u8)).0);
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assert_eq!(wrapping_mul(255, 2), (Wrapping(255u8) * Wrapping(2u8)).0);
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2018-09-02 04:51:04 +00:00
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assert_eq!(wrapping_shl(255, 8), (Wrapping(255u8) << 8).0);
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assert_eq!(wrapping_shr(255, 8), (Wrapping(255u8) >> 8).0);
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2017-02-04 09:42:12 +00:00
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}
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2017-05-01 11:42:30 +00:00
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#[test]
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fn wrapping_is_wrappingadd() {
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fn require_wrappingadd<T: WrappingAdd>(_: &T) {}
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require_wrappingadd(&Wrapping(42));
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}
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#[test]
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fn wrapping_is_wrappingsub() {
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fn require_wrappingsub<T: WrappingSub>(_: &T) {}
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require_wrappingsub(&Wrapping(42));
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}
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#[test]
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fn wrapping_is_wrappingmul() {
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fn require_wrappingmul<T: WrappingMul>(_: &T) {}
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require_wrappingmul(&Wrapping(42));
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}
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2018-09-02 04:51:04 +00:00
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#[test]
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fn wrapping_is_wrappingshl() {
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fn require_wrappingshl<T: WrappingShl>(_: &T) {}
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require_wrappingshl(&Wrapping(42));
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}
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#[test]
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fn wrapping_is_wrappingshr() {
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fn require_wrappingshr<T: WrappingShr>(_: &T) {}
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require_wrappingshr(&Wrapping(42));
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}
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