crypto_bigint/uint/boxed/
bit_xor.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
//! [`BoxedUint`] bitwise XOR operations.

use super::BoxedUint;
use crate::Wrapping;
use core::ops::{BitXor, BitXorAssign};
use subtle::{Choice, CtOption};

impl BoxedUint {
    /// Computes bitwise `a ^ b`.
    #[inline(always)]
    pub fn bitxor(&self, rhs: &Self) -> Self {
        Self::map_limbs(self, rhs, |a, b| a.bitxor(b))
    }

    /// 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 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 BitXor for BoxedUint {
    type Output = Self;

    fn bitxor(self, rhs: Self) -> BoxedUint {
        self.bitxor(&rhs)
    }
}

impl BitXor<&BoxedUint> for BoxedUint {
    type Output = BoxedUint;

    fn bitxor(self, rhs: &BoxedUint) -> BoxedUint {
        Self::bitxor(&self, rhs)
    }
}

impl BitXor<BoxedUint> for &BoxedUint {
    type Output = BoxedUint;

    fn bitxor(self, rhs: BoxedUint) -> BoxedUint {
        self.bitxor(&rhs)
    }
}

impl BitXor<&BoxedUint> for &BoxedUint {
    type Output = BoxedUint;

    fn bitxor(self, rhs: &BoxedUint) -> BoxedUint {
        self.bitxor(rhs)
    }
}

impl BitXorAssign for BoxedUint {
    fn bitxor_assign(&mut self, other: Self) {
        *self = Self::bitxor(self, &other);
    }
}

impl BitXorAssign<&BoxedUint> for BoxedUint {
    fn bitxor_assign(&mut self, other: &Self) {
        *self = Self::bitxor(self, other);
    }
}

impl BitXor for Wrapping<BoxedUint> {
    type Output = Self;

    fn bitxor(self, rhs: Self) -> Wrapping<BoxedUint> {
        Wrapping(self.0.bitxor(&rhs.0))
    }
}

impl BitXor<&Wrapping<BoxedUint>> for Wrapping<BoxedUint> {
    type Output = Wrapping<BoxedUint>;

    fn bitxor(self, rhs: &Wrapping<BoxedUint>) -> Wrapping<BoxedUint> {
        Wrapping(self.0.bitxor(&rhs.0))
    }
}

impl BitXor<Wrapping<BoxedUint>> for &Wrapping<BoxedUint> {
    type Output = Wrapping<BoxedUint>;

    fn bitxor(self, rhs: Wrapping<BoxedUint>) -> Wrapping<BoxedUint> {
        Wrapping(BoxedUint::bitxor(&self.0, &rhs.0))
    }
}

impl BitXor<&Wrapping<BoxedUint>> for &Wrapping<BoxedUint> {
    type Output = Wrapping<BoxedUint>;

    fn bitxor(self, rhs: &Wrapping<BoxedUint>) -> Wrapping<BoxedUint> {
        Wrapping(BoxedUint::bitxor(&self.0, &rhs.0))
    }
}

impl BitXorAssign for Wrapping<BoxedUint> {
    fn bitxor_assign(&mut self, other: Self) {
        *self = Wrapping(BoxedUint::bitxor(&self.0, &other.0));
    }
}

impl BitXorAssign<&Wrapping<BoxedUint>> for Wrapping<BoxedUint> {
    fn bitxor_assign(&mut self, other: &Self) {
        *self = Wrapping(BoxedUint::bitxor(&self.0, &other.0));
    }
}

#[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);
    }
}