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// Copyright © 2024 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::integer::Integer;
use core::ops::Neg;
use malachite_base::num::arithmetic::traits::NegAssign;
use malachite_base::num::basic::traits::Zero;
use malachite_base::num::logic::traits::NotAssign;
impl Neg for Integer {
type Output = Integer;
/// Negates an [`Integer`], taking it by value.
///
/// $$
/// f(x) = -x.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!(-Integer::ZERO, 0);
/// assert_eq!(-Integer::from(123), -123);
/// assert_eq!(-Integer::from(-123), 123);
/// ```
fn neg(mut self) -> Integer {
if self.abs != 0 {
self.sign.not_assign();
}
self
}
}
impl<'a> Neg for &'a Integer {
type Output = Integer;
/// Negates an [`Integer`], taking it by reference.
///
/// $$
/// f(x) = -x.
/// $$
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!(-&Integer::ZERO, 0);
/// assert_eq!(-&Integer::from(123), -123);
/// assert_eq!(-&Integer::from(-123), 123);
/// ```
fn neg(self) -> Integer {
if self.abs == 0 {
Integer::ZERO
} else {
Integer {
sign: !self.sign,
abs: self.abs.clone(),
}
}
}
}
impl NegAssign for Integer {
/// Negates an [`Integer`] in place.
///
/// $$
/// x \gets -x.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::NegAssign;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// let mut x = Integer::ZERO;
/// x.neg_assign();
/// assert_eq!(x, 0);
///
/// let mut x = Integer::from(123);
/// x.neg_assign();
/// assert_eq!(x, -123);
///
/// let mut x = Integer::from(-123);
/// x.neg_assign();
/// assert_eq!(x, 123);
/// ```
fn neg_assign(&mut self) {
if self.abs != 0 {
self.sign.not_assign();
}
}
}