crypto_bigint/limb/
shl.rs

1//! Limb left bitshift
2
3use crate::Limb;
4use core::ops::{Shl, ShlAssign};
5use num_traits::WrappingShl;
6
7impl Limb {
8    /// Computes `self << shift`.
9    /// Panics if `shift` overflows `Limb::BITS`.
10    #[inline(always)]
11    pub const fn shl(self, shift: u32) -> Self {
12        Limb(self.0 << shift)
13    }
14
15    /// Computes `self << 1` and return the result and the carry (0 or 1).
16    #[inline(always)]
17    pub(crate) const fn shl1(self) -> (Self, Self) {
18        (Self(self.0 << 1), Self(self.0 >> Self::HI_BIT))
19    }
20}
21
22macro_rules! impl_shl {
23    ($($shift:ty),+) => {
24        $(
25            impl Shl<$shift> for Limb {
26                type Output = Limb;
27
28                #[inline]
29                fn shl(self, shift: $shift) -> Limb {
30                     Self::shl(self, u32::try_from(shift).expect("invalid shift"))
31                }
32            }
33
34            impl Shl<$shift> for &Limb {
35                type Output = Limb;
36
37                #[inline]
38                fn shl(self, shift: $shift) -> Limb {
39                   *self << shift
40                }
41            }
42
43            impl ShlAssign<$shift> for Limb {
44                #[inline]
45                fn shl_assign(&mut self, shift: $shift) {
46                    *self = *self << shift;
47                }
48            }
49        )+
50    };
51}
52
53impl_shl!(i32, u32, usize);
54
55impl WrappingShl for Limb {
56    #[inline]
57    fn wrapping_shl(&self, shift: u32) -> Limb {
58        Self(self.0.wrapping_shl(shift))
59    }
60}
61
62#[cfg(test)]
63mod tests {
64    use crate::Limb;
65
66    #[test]
67    fn shl1() {
68        assert_eq!(Limb(1) << 1, Limb(2));
69    }
70
71    #[test]
72    fn shl2() {
73        assert_eq!(Limb(1) << 2, Limb(4));
74    }
75
76    #[test]
77    fn shl_assign1() {
78        let mut l = Limb(1);
79        l <<= 1;
80        assert_eq!(l, Limb(2));
81    }
82
83    #[test]
84    fn shl_assign2() {
85        let mut l = Limb(1);
86        l <<= 2;
87        assert_eq!(l, Limb(4));
88    }
89}
crypto_bigint/limb/shl.rs

crypto_bigint/limb/
shl.rs
