malachite_float/comparison/
eq_abs_primitive_float.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, NaN, Zero};
11use core::cmp::Ordering::*;
12use malachite_base::num::basic::floats::PrimitiveFloat;
13use malachite_base::num::comparison::traits::EqAbs;
14use malachite_nz::natural::Natural;
15
16fn float_eq_abs_primitive_float<T: PrimitiveFloat>(x: &Float, y: &T) -> bool {
17    match x {
18        float_nan!() => false,
19        float_either_infinity!() => *y == T::INFINITY || *y == T::NEGATIVE_INFINITY,
20        float_either_zero!() => *y == T::ZERO,
21        Float(Finite {
22            exponent,
23            significand,
24            ..
25        }) => {
26            y.is_finite()
27                && *y != T::ZERO
28                && i64::from(*exponent - 1) == y.sci_exponent()
29                && significand.cmp_normalized(&Natural::from(y.integer_mantissa())) == Equal
30        }
31    }
32}
33
34macro_rules! impl_eq_abs_primitive_float {
35    ($t: ident) => {
36        impl EqAbs<$t> for Float {
37            /// Determines whether the absolute value of a [`Float`] is equal to the absolute value
38            /// of a primitive float.
39            ///
40            /// The [`Float`] $\infty$ is equal to the primitive float $\infty$, and the [`Float`]
41            /// $-\infty$ is equal to the primitive float $-\infty$. The [`Float`] NaN is not equal
42            /// to anything, not even the primitive float NaN. Every [`Float`] zero is equal to
43            /// every primitive float zero, regardless of sign.
44            ///
45            /// # Worst-case complexity
46            /// $T(n) = O(n)$
47            ///
48            /// $M(n) = O(1)$
49            ///
50            /// where $T$ is time, $M$ is additional memory, and $n$ is
51            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
52            ///
53            /// # Examples
54            /// See [here](super::eq_abs_primitive_float#eq_abs).
55            #[inline]
56            fn eq_abs(&self, other: &$t) -> bool {
57                float_eq_abs_primitive_float(self, other)
58            }
59        }
60
61        impl EqAbs<Float> for $t {
62            /// Determines whether a primitive float is equal to a [`Float`].
63            ///
64            /// The primitive float $\infty$ is equal to the [`Float`] $\infty$, and the primitive
65            /// float $-\infty$ is equal to the [`Float`] $-\infty$. The primitive float NaN is not
66            /// equal to anything, not even the [`Float`] NaN. Every primitive float zero is equal
67            /// to every [`Float`] zero, regardless of sign.
68            ///
69            /// # Worst-case complexity
70            /// $T(n) = O(n)$
71            ///
72            /// $M(n) = O(1)$
73            ///
74            /// where $T$ is time, $M$ is additional memory, and $n$ is
75            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
76            ///
77            /// # Examples
78            /// See [here](super::eq_abs_primitive_float#eq_abs).
79            #[inline]
80            fn eq_abs(&self, other: &Float) -> bool {
81                other.eq_abs(self)
82            }
83        }
84    };
85}
86apply_to_primitive_floats!(impl_eq_abs_primitive_float);
malachite_float/comparison/eq_abs_primitive_float.rs

malachite_float/comparison/
eq_abs_primitive_float.rs
