malachite_float/comparison/
partial_eq_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_nz::natural::Natural;
14
15fn float_partial_eq_primitive_float<T: PrimitiveFloat>(x: &Float, y: &T) -> bool {
16    match x {
17        float_nan!() => false,
18        float_infinity!() => *y == T::INFINITY,
19        float_negative_infinity!() => *y == T::NEGATIVE_INFINITY,
20        float_either_zero!() => *y == T::ZERO,
21        Float(Finite {
22            sign,
23            exponent,
24            significand,
25            ..
26        }) => {
27            y.is_finite()
28                && *y != T::ZERO
29                && *sign == (*y > T::ZERO)
30                && i64::from(*exponent - 1) == y.sci_exponent()
31                && significand.cmp_normalized(&Natural::from(y.integer_mantissa())) == Equal
32        }
33    }
34}
35
36macro_rules! impl_partial_eq_primitive_float {
37    ($t: ident) => {
38        impl PartialEq<$t> for Float {
39            /// Determines whether a [`Float`] is equal to a primitive float.
40            ///
41            /// The [`Float`] $\infty$ is equal to the primitive float $\infty$, and the [`Float`]
42            /// $-\infty$ is equal to the primitive float $-\infty$. The [`Float`] NaN is not equal
43            /// to anything, not even the primitive float NaN. Every [`Float`] zero is equal to
44            /// every primitive float zero, regardless of sign.
45            ///
46            /// # Worst-case complexity
47            /// $T(n) = O(n)$
48            ///
49            /// $M(n) = O(1)$
50            ///
51            /// where $T$ is time, $M$ is additional memory, and $n$ is
52            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
53            ///
54            /// # Examples
55            /// See [here](super::partial_eq_primitive_float#partial_eq).
56            #[inline]
57            fn eq(&self, other: &$t) -> bool {
58                float_partial_eq_primitive_float(self, other)
59            }
60        }
61
62        impl PartialEq<Float> for $t {
63            /// Determines whether a primitive float is equal to a [`Float`].
64            ///
65            /// The primitive float $\infty$ is equal to the [`Float`] $\infty$, and the primitive
66            /// float $-\infty$ is equal to the [`Float`] $-\infty$. The primitive float NaN is not
67            /// equal to anything, not even the [`Float`] NaN. Every primitive float zero is equal
68            /// to every [`Float`] zero, regardless of sign.
69            ///
70            /// # Worst-case complexity
71            /// $T(n) = O(n)$
72            ///
73            /// $M(n) = O(1)$
74            ///
75            /// where $T$ is time, $M$ is additional memory, and $n$ is
76            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
77            ///
78            /// # Examples
79            /// See [here](super::partial_eq_primitive_float#partial_eq).
80            #[inline]
81            fn eq(&self, other: &Float) -> bool {
82                other == self
83            }
84        }
85    };
86}
87apply_to_primitive_floats!(impl_partial_eq_primitive_float);
malachite_float/comparison/partial_eq_primitive_float.rs

malachite_float/comparison/
partial_eq_primitive_float.rs
