1 | //! Returns a number that represents the sign of `self`. |
2 | |
3 | use super::F32; |
4 | |
5 | impl F32 { |
6 | /// Returns a number that represents the sign of `self`. |
7 | /// |
8 | /// * `1.0` if the number is positive, `+0.0` or `INFINITY` |
9 | /// * `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY` |
10 | /// * `NAN` if the number is `NAN` |
11 | pub fn signum(self) -> Self { |
12 | if self.is_nan() { |
13 | Self::NAN |
14 | } else { |
15 | F32(1.0).copysign(self) |
16 | } |
17 | } |
18 | } |
19 | |
20 | #[cfg (test)] |
21 | mod tests { |
22 | use super::F32; |
23 | |
24 | #[test ] |
25 | fn sanity_check() { |
26 | assert_eq!(F32::INFINITY.signum(), F32(1.0)); |
27 | assert_eq!(F32(0.0).signum(), F32(1.0)); |
28 | assert_eq!(F32(1.0).signum(), F32(1.0)); |
29 | assert_eq!(F32::NEG_INFINITY.signum(), F32(-1.0)); |
30 | assert_eq!(F32(-0.0).signum(), F32(-1.0)); |
31 | assert_eq!(F32(-1.0).signum(), F32(-1.0)); |
32 | } |
33 | } |
34 | |