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
use ff::Field;
use std::ops::BitXor;
#[derive(Debug, PartialEq, Eq)]
pub enum Sgn0Result {
NonNegative,
Negative,
}
impl BitXor for Sgn0Result {
type Output = Self;
fn bitxor(self, rhs: Self) -> Self {
if self == rhs {
Sgn0Result::NonNegative
} else {
Sgn0Result::Negative
}
}
}
pub trait Signum0: Field {
fn sgn0(&self) -> Sgn0Result;
fn negate_if(&mut self, sgn: Sgn0Result) {
if sgn == Sgn0Result::Negative {
self.negate();
}
}
}
#[test]
#[allow(clippy::eq_op)]
fn test_sgn0result_xor() {
assert_eq!(
Sgn0Result::Negative ^ Sgn0Result::Negative,
Sgn0Result::NonNegative
);
assert_eq!(
Sgn0Result::Negative ^ Sgn0Result::NonNegative,
Sgn0Result::Negative
);
assert_eq!(
Sgn0Result::NonNegative ^ Sgn0Result::Negative,
Sgn0Result::Negative
);
assert_eq!(
Sgn0Result::NonNegative ^ Sgn0Result::NonNegative,
Sgn0Result::NonNegative
);
}