malachite_float/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::Float;
10use crate::InnerFloat::{Finite, Infinity, Zero};
11use core::cmp::Ordering::{self, *};
12use malachite_base::num::arithmetic::traits::Sign;
13
14impl Sign for Float {
15    /// Returns the sign of a [`Float`].
16    ///
17    /// Returns `Greater` if the sign is positive and `Less` if the sign is negative. Never returns
18    /// `Equal`. $\infty$ and positive zero have a positive sign, and $-\infty$ and negative zero
19    /// have a negative sign.
20    ///
21    /// # Worst-case complexity
22    /// Constant time and additional memory.
23    ///
24    /// # Panics
25    /// Panics if `self` is NaN.
26    ///
27    /// # Examples
28    /// ```
29    /// use malachite_base::num::arithmetic::traits::Sign;
30    /// use malachite_base::num::basic::traits::{
31    ///     Infinity, NegativeInfinity, NegativeOne, NegativeZero, One, Zero,
32    /// };
33    /// use malachite_float::Float;
34    /// use std::cmp::Ordering::*;
35    ///
36    /// assert_eq!(Float::INFINITY.sign(), Greater);
37    /// assert_eq!(Float::NEGATIVE_INFINITY.sign(), Less);
38    /// assert_eq!(Float::ZERO.sign(), Greater);
39    /// assert_eq!(Float::NEGATIVE_ZERO.sign(), Less);
40    /// assert_eq!(Float::ONE.sign(), Greater);
41    /// assert_eq!(Float::NEGATIVE_ONE.sign(), Less);
42    /// ```
43    fn sign(&self) -> Ordering {
44        if let Float(Infinity { sign } | Zero { sign } | Finite { sign, .. }) = self {
45            if *sign { Greater } else { Less }
46        } else {
47            panic!()
48        }
49    }
50}
malachite_float/arithmetic/sign.rs

malachite_float/arithmetic/
sign.rs
