malachite_base/num/arithmetic/
checked_mul_add_mul.rs

1// Copyright © 2026 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::mul_add_mul::{
10    Wide, mul_add_mul_wide_signed, mul_add_mul_wide_unsigned,
11};
12use crate::num::arithmetic::traits::CheckedMulAddMul;
13
14macro_rules! impl_checked_mul_add_mul_unsigned {
15    ($t:ident) => {
16        impl CheckedMulAddMul for $t {
17            type Output = $t;
18
19            /// Adds the products of two pairs of numbers, returning `None` if the result cannot be
20            /// represented.
21            ///
22            /// $$
23            /// f(x, y, z, w) = \\begin{cases}
24            ///     xy + zw & \\text{if} \\quad xy + zw \\ \\text{is representable} \\\\
25            ///     \\operatorname{None} & \\text{otherwise}
26            /// \\end{cases}
27            /// $$
28            ///
29            /// The products are formed at double width, so a product that does not fit does not by
30            /// itself make the result unrepresentable.
31            ///
32            /// # Worst-case complexity
33            /// Constant time and additional memory.
34            ///
35            /// # Examples
36            /// See [here](super::checked_mul_add_mul#checked_mul_add_mul).
37            #[inline]
38            fn checked_mul_add_mul(self, y: $t, z: $t, w: $t) -> Option<$t> {
39                match mul_add_mul_wide_unsigned(self, y, z, w, false) {
40                    Wide::Fits(v) => Some(v),
41                    _ => None,
42                }
43            }
44        }
45    };
46}
47apply_to_unsigneds!(impl_checked_mul_add_mul_unsigned);
48
49macro_rules! impl_checked_mul_add_mul_signed {
50    ($t:ident) => {
51        impl CheckedMulAddMul for $t {
52            type Output = $t;
53
54            /// Adds the products of two pairs of numbers, returning `None` if the result cannot be
55            /// represented.
56            ///
57            /// $$
58            /// f(x, y, z, w) = \\begin{cases}
59            ///     xy + zw & \\text{if} \\quad xy + zw \\ \\text{is representable} \\\\
60            ///     \\operatorname{None} & \\text{otherwise}
61            /// \\end{cases}
62            /// $$
63            ///
64            /// The products are formed at double width, so a product that does not fit does not by
65            /// itself make the result unrepresentable.
66            ///
67            /// # Worst-case complexity
68            /// Constant time and additional memory.
69            ///
70            /// # Examples
71            /// See [here](super::checked_mul_add_mul#checked_mul_add_mul).
72            #[inline]
73            fn checked_mul_add_mul(self, y: $t, z: $t, w: $t) -> Option<$t> {
74                match mul_add_mul_wide_signed(self, y, z, w, false) {
75                    Wide::Fits(v) => Some(v),
76                    _ => None,
77                }
78            }
79        }
80    };
81}
82apply_to_signeds!(impl_checked_mul_add_mul_signed);
malachite_base/num/arithmetic/checked_mul_add_mul.rs

malachite_base/num/arithmetic/
checked_mul_add_mul.rs
