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// Copyright © 2026 Mikhail Hogrefe
//
// This file is part of Malachite.
//
// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
use crate::num::arithmetic::mul_add_mul::{
Wide, mul_add_mul_wide_signed, mul_add_mul_wide_unsigned,
};
use crate::num::arithmetic::traits::CheckedMulAddMul;
macro_rules! impl_checked_mul_add_mul_unsigned {
($t:ident) => {
impl CheckedMulAddMul for $t {
type Output = $t;
/// Adds the products of two pairs of numbers, returning `None` if the result cannot be
/// represented.
///
/// $$
/// f(x, y, z, w) = \\begin{cases}
/// xy + zw & \\text{if} \\quad xy + zw \\ \\text{is representable} \\\\
/// \\operatorname{None} & \\text{otherwise}
/// \\end{cases}
/// $$
///
/// The products are formed at double width, so a product that does not fit does not by
/// itself make the result unrepresentable.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::checked_mul_add_mul#checked_mul_add_mul).
#[inline]
fn checked_mul_add_mul(self, y: $t, z: $t, w: $t) -> Option<$t> {
match mul_add_mul_wide_unsigned(self, y, z, w, false) {
Wide::Fits(v) => Some(v),
_ => None,
}
}
}
};
}
apply_to_unsigneds!(impl_checked_mul_add_mul_unsigned);
macro_rules! impl_checked_mul_add_mul_signed {
($t:ident) => {
impl CheckedMulAddMul for $t {
type Output = $t;
/// Adds the products of two pairs of numbers, returning `None` if the result cannot be
/// represented.
///
/// $$
/// f(x, y, z, w) = \\begin{cases}
/// xy + zw & \\text{if} \\quad xy + zw \\ \\text{is representable} \\\\
/// \\operatorname{None} & \\text{otherwise}
/// \\end{cases}
/// $$
///
/// The products are formed at double width, so a product that does not fit does not by
/// itself make the result unrepresentable.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::checked_mul_add_mul#checked_mul_add_mul).
#[inline]
fn checked_mul_add_mul(self, y: $t, z: $t, w: $t) -> Option<$t> {
match mul_add_mul_wide_signed(self, y, z, w, false) {
Wide::Fits(v) => Some(v),
_ => None,
}
}
}
};
}
apply_to_signeds!(impl_checked_mul_add_mul_signed);