malachite_base/num/arithmetic/
sign.rs

1// Copyright © 2025 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::num::arithmetic::traits::Sign;
10use core::cmp::Ordering::{self, *};
11
12macro_rules! impl_sign_primitive_int {
13    ($t:ident) => {
14        impl Sign for $t {
15            /// Compares a number to zero.
16            ///
17            /// Returns `Greater`, `Equal`, or `Less`, depending on whether the number is positive,
18            /// zero, or negative, respectively.
19            ///
20            /// # Worst-case complexity
21            /// Constant time and additional memory.
22            ///
23            /// # Examples
24            /// See [here](super::sign#sign).
25            #[inline]
26            fn sign(&self) -> Ordering {
27                self.cmp(&0)
28            }
29        }
30    };
31}
32apply_to_primitive_ints!(impl_sign_primitive_int);
33
34macro_rules! impl_sign_primitive_float {
35    ($t:ident) => {
36        impl Sign for $t {
37            /// Compares a number to zero.
38            ///
39            /// - Positive finite numbers, positive zero, and positive infinity have sign `Greater`.
40            /// - Negative finite numbers, negative zero, and negative infinity have sign `Less`.
41            /// - `NaN` has sign `Equal`.
42            ///
43            /// # Worst-case complexity
44            /// Constant time and additional memory.
45            ///
46            /// # Examples
47            /// See [here](super::sign#sign).
48            #[inline]
49            fn sign(&self) -> Ordering {
50                if self.is_nan() {
51                    Equal
52                } else if self.is_sign_positive() {
53                    Greater
54                } else {
55                    Less
56                }
57            }
58        }
59    };
60}
61apply_to_primitive_floats!(impl_sign_primitive_float);
malachite_base/num/arithmetic/sign.rs

malachite_base/num/arithmetic/
sign.rs
