crypto_bigint/
wrapping.rs

Help
1//! Wrapping arithmetic.
2
3use crate::Zero;
4use core::fmt;
5use subtle::{Choice, ConditionallySelectable, ConstantTimeEq};
6
7#[cfg(feature = "serde")]
8use serdect::serde::{Deserialize, Deserializer, Serialize, Serializer};
9
10/// Provides intentionally-wrapped arithmetic on `T`.
11///
12/// This is analogous to [`core::num::Wrapping`] but allows this crate to
13/// define trait impls for this type.
14#[derive(Copy, Clone, Debug, Default, Eq, PartialEq, PartialOrd, Ord)]
15pub struct Wrapping<T>(pub T);
16
17impl<T: Zero> Zero for Wrapping<T> {
18    const ZERO: Self = Self(T::ZERO);
19}
20
21impl<T: fmt::Display> fmt::Display for Wrapping<T> {
22    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
23        self.0.fmt(f)
24    }
25}
26
27impl<T: fmt::Binary> fmt::Binary for Wrapping<T> {
28    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
29        self.0.fmt(f)
30    }
31}
32
33impl<T: fmt::Octal> fmt::Octal for Wrapping<T> {
34    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
35        self.0.fmt(f)
36    }
37}
38
39impl<T: fmt::LowerHex> fmt::LowerHex for Wrapping<T> {
40    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
41        self.0.fmt(f)
42    }
43}
44
45impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> {
46    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
47        self.0.fmt(f)
48    }
49}
50
51impl<T: ConditionallySelectable> ConditionallySelectable for Wrapping<T> {
52    fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
53        Wrapping(T::conditional_select(&a.0, &b.0, choice))
54    }
55}
56
57impl<T: ConstantTimeEq> ConstantTimeEq for Wrapping<T> {
58    fn ct_eq(&self, other: &Self) -> Choice {
59        self.0.ct_eq(&other.0)
60    }
61}
62
63#[cfg(feature = "serde")]
64#[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
65impl<'de, T: Deserialize<'de>> Deserialize<'de> for Wrapping<T> {
66    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
67    where
68        D: Deserializer<'de>,
69    {
70        Ok(Self(T::deserialize(deserializer)?))
71    }
72}
73
74#[cfg(feature = "serde")]
75#[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
76impl<'de, T: Serialize> Serialize for Wrapping<T> {
77    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
78    where
79        S: Serializer,
80    {
81        self.0.serialize(serializer)
82    }
83}
84
85#[cfg(all(test, feature = "serde"))]
86mod tests {
87    use crate::{Wrapping, U64};
88
89    #[test]
90    fn serde() {
91        const TEST: Wrapping<U64> = Wrapping(U64::from_u64(0x0011223344556677));
92
93        let serialized = bincode::serialize(&TEST).unwrap();
94        let deserialized: Wrapping<U64> = bincode::deserialize(&serialized).unwrap();
95
96        assert_eq!(TEST, deserialized);
97    }
98
99    #[test]
100    fn serde_owned() {
101        const TEST: Wrapping<U64> = Wrapping(U64::from_u64(0x0011223344556677));
102
103        let serialized = bincode::serialize(&TEST).unwrap();
104        let deserialized: Wrapping<U64> = bincode::deserialize_from(serialized.as_slice()).unwrap();
105
106        assert_eq!(TEST, deserialized);
107    }
108}
crypto_bigint/wrapping.rs

crypto_bigint/
wrapping.rs
