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//! [`UInt`] bitwise xor operations.
use super::UInt;
use crate::{Limb, Wrapping};
use core::ops::{BitXor, BitXorAssign};
use subtle::{Choice, CtOption};
impl<const LIMBS: usize> UInt<LIMBS> {
/// Computes bitwise `a ^ b`.
#[inline(always)]
pub const fn bitxor(&self, rhs: &Self) -> Self {
let mut limbs = [Limb::ZERO; LIMBS];
let mut i = 0;
while i < LIMBS {
limbs[i] = self.limbs[i].bitxor(rhs.limbs[i]);
i += 1;
}
Self { limbs }
}
/// Perform wrapping bitwise `XOR``.
///
/// There's no way wrapping could ever happen.
/// This function exists so that all operations are accounted for in the wrapping operations
pub const fn wrapping_xor(&self, rhs: &Self) -> Self {
self.bitxor(rhs)
}
/// Perform checked bitwise `XOR`, returning a [`CtOption`] which `is_some` always
pub fn checked_xor(&self, rhs: &Self) -> CtOption<Self> {
let result = self.bitxor(rhs);
CtOption::new(result, Choice::from(1))
}
}
impl<const LIMBS: usize> BitXor for UInt<LIMBS> {
type Output = Self;
fn bitxor(self, rhs: Self) -> UInt<LIMBS> {
self.bitxor(&rhs)
}
}
impl<const LIMBS: usize> BitXor<&UInt<LIMBS>> for UInt<LIMBS> {
type Output = UInt<LIMBS>;
fn bitxor(self, rhs: &UInt<LIMBS>) -> UInt<LIMBS> {
(&self).bitxor(rhs)
}
}
impl<const LIMBS: usize> BitXor<UInt<LIMBS>> for &UInt<LIMBS> {
type Output = UInt<LIMBS>;
fn bitxor(self, rhs: UInt<LIMBS>) -> UInt<LIMBS> {
self.bitxor(&rhs)
}
}
impl<const LIMBS: usize> BitXor<&UInt<LIMBS>> for &UInt<LIMBS> {
type Output = UInt<LIMBS>;
fn bitxor(self, rhs: &UInt<LIMBS>) -> UInt<LIMBS> {
self.bitxor(rhs)
}
}
impl<const LIMBS: usize> BitXorAssign for UInt<LIMBS> {
fn bitxor_assign(&mut self, other: Self) {
*self = *self ^ other;
}
}
impl<const LIMBS: usize> BitXorAssign<&UInt<LIMBS>> for UInt<LIMBS> {
fn bitxor_assign(&mut self, other: &Self) {
*self = *self ^ other;
}
}
impl<const LIMBS: usize> BitXor for Wrapping<UInt<LIMBS>> {
type Output = Self;
fn bitxor(self, rhs: Self) -> Wrapping<UInt<LIMBS>> {
Wrapping(self.0.bitxor(&rhs.0))
}
}
impl<const LIMBS: usize> BitXor<&Wrapping<UInt<LIMBS>>> for Wrapping<UInt<LIMBS>> {
type Output = Wrapping<UInt<LIMBS>>;
fn bitxor(self, rhs: &Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
Wrapping(self.0.bitxor(&rhs.0))
}
}
impl<const LIMBS: usize> BitXor<Wrapping<UInt<LIMBS>>> for &Wrapping<UInt<LIMBS>> {
type Output = Wrapping<UInt<LIMBS>>;
fn bitxor(self, rhs: Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
Wrapping(self.0.bitxor(&rhs.0))
}
}
impl<const LIMBS: usize> BitXor<&Wrapping<UInt<LIMBS>>> for &Wrapping<UInt<LIMBS>> {
type Output = Wrapping<UInt<LIMBS>>;
fn bitxor(self, rhs: &Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
Wrapping(self.0.bitxor(&rhs.0))
}
}
impl<const LIMBS: usize> BitXorAssign for Wrapping<UInt<LIMBS>> {
fn bitxor_assign(&mut self, other: Self) {
*self = *self ^ other;
}
}
impl<const LIMBS: usize> BitXorAssign<&Wrapping<UInt<LIMBS>>> for Wrapping<UInt<LIMBS>> {
fn bitxor_assign(&mut self, other: &Self) {
*self = *self ^ other;
}
}
#[cfg(test)]
mod tests {
use crate::U128;
#[test]
fn checked_xor_ok() {
let result = U128::ZERO.checked_xor(&U128::ONE);
assert_eq!(result.unwrap(), U128::ONE);
}
#[test]
fn overlapping_xor_ok() {
let result = U128::ZERO.wrapping_xor(&U128::ONE);
assert_eq!(result, U128::ONE);
}
}
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