crypto_bigint/uint/
bit_xor.rs

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1//! [`UInt`] bitwise xor operations.
2
3use super::UInt;
4use crate::{Limb, Wrapping};
5use core::ops::{BitXor, BitXorAssign};
6use subtle::{Choice, CtOption};
7
8impl<const LIMBS: usize> UInt<LIMBS> {
9    /// Computes bitwise `a ^ b`.
10    #[inline(always)]
11    pub const fn bitxor(&self, rhs: &Self) -> Self {
12        let mut limbs = [Limb::ZERO; LIMBS];
13        let mut i = 0;
14
15        while i < LIMBS {
16            limbs[i] = self.limbs[i].bitxor(rhs.limbs[i]);
17            i += 1;
18        }
19
20        Self { limbs }
21    }
22
23    /// Perform wrapping bitwise `XOR``.
24    ///
25    /// There's no way wrapping could ever happen.
26    /// This function exists so that all operations are accounted for in the wrapping operations
27    pub const fn wrapping_xor(&self, rhs: &Self) -> Self {
28        self.bitxor(rhs)
29    }
30
31    /// Perform checked bitwise `XOR`, returning a [`CtOption`] which `is_some` always
32    pub fn checked_xor(&self, rhs: &Self) -> CtOption<Self> {
33        let result = self.bitxor(rhs);
34        CtOption::new(result, Choice::from(1))
35    }
36}
37
38impl<const LIMBS: usize> BitXor for UInt<LIMBS> {
39    type Output = Self;
40
41    fn bitxor(self, rhs: Self) -> UInt<LIMBS> {
42        self.bitxor(&rhs)
43    }
44}
45
46impl<const LIMBS: usize> BitXor<&UInt<LIMBS>> for UInt<LIMBS> {
47    type Output = UInt<LIMBS>;
48
49    fn bitxor(self, rhs: &UInt<LIMBS>) -> UInt<LIMBS> {
50        (&self).bitxor(rhs)
51    }
52}
53
54impl<const LIMBS: usize> BitXor<UInt<LIMBS>> for &UInt<LIMBS> {
55    type Output = UInt<LIMBS>;
56
57    fn bitxor(self, rhs: UInt<LIMBS>) -> UInt<LIMBS> {
58        self.bitxor(&rhs)
59    }
60}
61
62impl<const LIMBS: usize> BitXor<&UInt<LIMBS>> for &UInt<LIMBS> {
63    type Output = UInt<LIMBS>;
64
65    fn bitxor(self, rhs: &UInt<LIMBS>) -> UInt<LIMBS> {
66        self.bitxor(rhs)
67    }
68}
69
70impl<const LIMBS: usize> BitXorAssign for UInt<LIMBS> {
71    fn bitxor_assign(&mut self, other: Self) {
72        *self = *self ^ other;
73    }
74}
75
76impl<const LIMBS: usize> BitXorAssign<&UInt<LIMBS>> for UInt<LIMBS> {
77    fn bitxor_assign(&mut self, other: &Self) {
78        *self = *self ^ other;
79    }
80}
81
82impl<const LIMBS: usize> BitXor for Wrapping<UInt<LIMBS>> {
83    type Output = Self;
84
85    fn bitxor(self, rhs: Self) -> Wrapping<UInt<LIMBS>> {
86        Wrapping(self.0.bitxor(&rhs.0))
87    }
88}
89
90impl<const LIMBS: usize> BitXor<&Wrapping<UInt<LIMBS>>> for Wrapping<UInt<LIMBS>> {
91    type Output = Wrapping<UInt<LIMBS>>;
92
93    fn bitxor(self, rhs: &Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
94        Wrapping(self.0.bitxor(&rhs.0))
95    }
96}
97
98impl<const LIMBS: usize> BitXor<Wrapping<UInt<LIMBS>>> for &Wrapping<UInt<LIMBS>> {
99    type Output = Wrapping<UInt<LIMBS>>;
100
101    fn bitxor(self, rhs: Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
102        Wrapping(self.0.bitxor(&rhs.0))
103    }
104}
105
106impl<const LIMBS: usize> BitXor<&Wrapping<UInt<LIMBS>>> for &Wrapping<UInt<LIMBS>> {
107    type Output = Wrapping<UInt<LIMBS>>;
108
109    fn bitxor(self, rhs: &Wrapping<UInt<LIMBS>>) -> Wrapping<UInt<LIMBS>> {
110        Wrapping(self.0.bitxor(&rhs.0))
111    }
112}
113
114impl<const LIMBS: usize> BitXorAssign for Wrapping<UInt<LIMBS>> {
115    fn bitxor_assign(&mut self, other: Self) {
116        *self = *self ^ other;
117    }
118}
119
120impl<const LIMBS: usize> BitXorAssign<&Wrapping<UInt<LIMBS>>> for Wrapping<UInt<LIMBS>> {
121    fn bitxor_assign(&mut self, other: &Self) {
122        *self = *self ^ other;
123    }
124}
125
126#[cfg(test)]
127mod tests {
128    use crate::U128;
129
130    #[test]
131    fn checked_xor_ok() {
132        let result = U128::ZERO.checked_xor(&U128::ONE);
133        assert_eq!(result.unwrap(), U128::ONE);
134    }
135
136    #[test]
137    fn overlapping_xor_ok() {
138        let result = U128::ZERO.wrapping_xor(&U128::ONE);
139        assert_eq!(result, U128::ONE);
140    }
141}
crypto_bigint/uint/bit_xor.rs

crypto_bigint/uint/
bit_xor.rs
