malachite_float/comparison/
partial_cmp_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::{self, *};
12use malachite_base::num::basic::floats::PrimitiveFloat;
13use malachite_base::num::comparison::traits::PartialOrdAbs;
14use malachite_nz::natural::Natural;
15
16fn float_partial_cmp_abs_primitive_float<T: PrimitiveFloat>(x: &Float, y: &T) -> Option<Ordering> {
17    match (x, y) {
18        (float_nan!(), _) => None,
19        (_, y) if y.is_nan() => None,
20        (Float(Infinity { .. }), y) if !y.is_finite() => Some(Equal),
21        (Float(Infinity { .. }), _) => Some(Greater),
22        (_, y) if !y.is_finite() => Some(Less),
23        (float_either_zero!(), y) => Some(if *y == T::ZERO { Equal } else { Less }),
24        (_, y) if *y == T::ZERO => Some(Greater),
25        (
26            Float(Finite {
27                exponent: e_x,
28                significand: m_x,
29                ..
30            }),
31            y,
32        ) => Some(
33            (i64::from(*e_x) - 1)
34                .cmp(&y.sci_exponent())
35                .then_with(|| m_x.cmp_normalized(&Natural::from(y.integer_mantissa()))),
36        ),
37    }
38}
39
40macro_rules! impl_partial_cmp_abs_primitive_float {
41    ($t: ident) => {
42        impl PartialOrdAbs<$t> for Float {
43            /// Compares the absolute values of a [`Float`] and a primitive float.
44            ///
45            /// The [`Float`] NaN is not comparable to any primitive float, not even the primitive
46            /// float NaN. Every [`Float`] zero is equal to every primitive float zero, regardless
47            /// of sign.
48            ///
49            /// # Worst-case complexity
50            /// $T(n) = O(n)$
51            ///
52            /// $M(n) = O(1)$
53            ///
54            /// where $T$ is time, $M$ is additional memory, and $n$ is
55            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
56            ///
57            /// # Examples
58            /// See [here](super::partial_cmp_abs_primitive_float#partial_cmp_abs).
59            #[inline]
60            fn partial_cmp_abs(&self, other: &$t) -> Option<Ordering> {
61                float_partial_cmp_abs_primitive_float(self, other)
62            }
63        }
64
65        impl PartialOrdAbs<Float> for $t {
66            /// Compares the absolute values of a primitive float and a [`Float`].
67            ///
68            /// The primitive float NaN is not comparable to any primitive float, not even the
69            /// [`Float`] NaN. Every primitive float zero is equal to every [`Float`] zero,
70            /// regardless of sign.
71            ///
72            /// # Worst-case complexity
73            /// $T(n) = O(n)$
74            ///
75            /// $M(n) = O(1)$
76            ///
77            /// where $T$ is time, $M$ is additional memory, and $n$ is
78            /// `max(self.significant_bits(), other.sci_exponent().abs())`.
79            ///
80            /// # Examples
81            /// See [here](super::partial_cmp_primitive_float#partial_cmp_abs).
82            #[inline]
83            fn partial_cmp_abs(&self, other: &Float) -> Option<Ordering> {
84                other.partial_cmp_abs(self).map(Ordering::reverse)
85            }
86        }
87    };
88}
89apply_to_primitive_floats!(impl_partial_cmp_abs_primitive_float);
malachite_float/comparison/partial_cmp_abs_primitive_float.rs

malachite_float/comparison/
partial_cmp_abs_primitive_float.rs
