crypto_bigint/uint/
bit_and.rs

1//! [`Uint`] bitwise and operations.
2
3use super::Uint;
4use crate::{Limb, Wrapping};
5use core::ops::{BitAnd, BitAndAssign};
6use subtle::{Choice, CtOption};
7
8impl<const LIMBS: usize> Uint<LIMBS> {
9    /// Computes bitwise `a & b`.
10    #[inline(always)]
11    pub const fn bitand(&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].bitand(rhs.limbs[i]);
17            i += 1;
18        }
19
20        Self { limbs }
21    }
22
23    /// Perform wrapping bitwise `AND`.
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_and(&self, rhs: &Self) -> Self {
28        self.bitand(rhs)
29    }
30
31    /// Perform checked bitwise `AND`, returning a [`CtOption`] which `is_some` always
32    pub fn checked_and(&self, rhs: &Self) -> CtOption<Self> {
33        let result = self.bitand(rhs);
34        CtOption::new(result, Choice::from(1))
35    }
36}
37
38impl<const LIMBS: usize> BitAnd for Uint<LIMBS> {
39    type Output = Self;
40
41    fn bitand(self, rhs: Self) -> Uint<LIMBS> {
42        self.bitand(&rhs)
43    }
44}
45
46impl<const LIMBS: usize> BitAnd<&Uint<LIMBS>> for Uint<LIMBS> {
47    type Output = Uint<LIMBS>;
48
49    #[allow(clippy::needless_borrow)]
50    fn bitand(self, rhs: &Uint<LIMBS>) -> Uint<LIMBS> {
51        (&self).bitand(rhs)
52    }
53}
54
55impl<const LIMBS: usize> BitAnd<Uint<LIMBS>> for &Uint<LIMBS> {
56    type Output = Uint<LIMBS>;
57
58    fn bitand(self, rhs: Uint<LIMBS>) -> Uint<LIMBS> {
59        self.bitand(&rhs)
60    }
61}
62
63impl<const LIMBS: usize> BitAnd<&Uint<LIMBS>> for &Uint<LIMBS> {
64    type Output = Uint<LIMBS>;
65
66    fn bitand(self, rhs: &Uint<LIMBS>) -> Uint<LIMBS> {
67        self.bitand(rhs)
68    }
69}
70
71impl<const LIMBS: usize> BitAndAssign for Uint<LIMBS> {
72    #[allow(clippy::assign_op_pattern)]
73    fn bitand_assign(&mut self, other: Self) {
74        *self = *self & other;
75    }
76}
77
78impl<const LIMBS: usize> BitAndAssign<&Uint<LIMBS>> for Uint<LIMBS> {
79    #[allow(clippy::assign_op_pattern)]
80    fn bitand_assign(&mut self, other: &Self) {
81        *self = *self & other;
82    }
83}
84
85impl<const LIMBS: usize> BitAnd for Wrapping<Uint<LIMBS>> {
86    type Output = Self;
87
88    fn bitand(self, rhs: Self) -> Wrapping<Uint<LIMBS>> {
89        Wrapping(self.0.bitand(&rhs.0))
90    }
91}
92
93impl<const LIMBS: usize> BitAnd<&Wrapping<Uint<LIMBS>>> for Wrapping<Uint<LIMBS>> {
94    type Output = Wrapping<Uint<LIMBS>>;
95
96    fn bitand(self, rhs: &Wrapping<Uint<LIMBS>>) -> Wrapping<Uint<LIMBS>> {
97        Wrapping(self.0.bitand(&rhs.0))
98    }
99}
100
101impl<const LIMBS: usize> BitAnd<Wrapping<Uint<LIMBS>>> for &Wrapping<Uint<LIMBS>> {
102    type Output = Wrapping<Uint<LIMBS>>;
103
104    fn bitand(self, rhs: Wrapping<Uint<LIMBS>>) -> Wrapping<Uint<LIMBS>> {
105        Wrapping(self.0.bitand(&rhs.0))
106    }
107}
108
109impl<const LIMBS: usize> BitAnd<&Wrapping<Uint<LIMBS>>> for &Wrapping<Uint<LIMBS>> {
110    type Output = Wrapping<Uint<LIMBS>>;
111
112    fn bitand(self, rhs: &Wrapping<Uint<LIMBS>>) -> Wrapping<Uint<LIMBS>> {
113        Wrapping(self.0.bitand(&rhs.0))
114    }
115}
116
117impl<const LIMBS: usize> BitAndAssign for Wrapping<Uint<LIMBS>> {
118    #[allow(clippy::assign_op_pattern)]
119    fn bitand_assign(&mut self, other: Self) {
120        *self = *self & other;
121    }
122}
123
124impl<const LIMBS: usize> BitAndAssign<&Wrapping<Uint<LIMBS>>> for Wrapping<Uint<LIMBS>> {
125    #[allow(clippy::assign_op_pattern)]
126    fn bitand_assign(&mut self, other: &Self) {
127        *self = *self & other;
128    }
129}
130
131#[cfg(test)]
132mod tests {
133    use crate::U128;
134
135    #[test]
136    fn checked_and_ok() {
137        let result = U128::ZERO.checked_and(&U128::ONE);
138        assert_eq!(result.unwrap(), U128::ZERO);
139    }
140
141    #[test]
142    fn overlapping_and_ok() {
143        let result = U128::MAX.wrapping_and(&U128::ONE);
144        assert_eq!(result, U128::ONE);
145    }
146}
crypto_bigint/uint/bit_and.rs

crypto_bigint/uint/
bit_and.rs
