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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::Rational;
use malachite_base::num::arithmetic::traits::{CanonicalizeUnit, CanonicalizeUnitAssign};
use malachite_base::num::basic::traits::{One, Zero};
impl CanonicalizeUnit for Rational {
type Output = Self;
/// Brings a [`Rational`] into canonical unit form, taking it by value.
///
/// The rationals form a field, so every nonzero [`Rational`] is a unit and its canonical
/// associate is 1. Zero is its own canonical associate.
///
/// $$
/// f(x) = \begin{cases}
/// 0 & \text{if} \quad x = 0, \\
/// 1 & \text{otherwise}.
/// \end{cases}
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnit;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_q::Rational;
///
/// assert_eq!(Rational::from_signeds(-22, 7).canonicalize_unit(), 1);
/// assert_eq!(Rational::from_signeds(22, 7).canonicalize_unit(), 1);
/// assert_eq!(Rational::ZERO.canonicalize_unit(), 0);
/// ```
#[inline]
fn canonicalize_unit(mut self) -> Self {
self.canonicalize_unit_assign();
self
}
}
impl CanonicalizeUnit for &Rational {
type Output = Rational;
/// Brings a [`Rational`] into canonical unit form, taking it by reference.
///
/// The rationals form a field, so every nonzero [`Rational`] is a unit and its canonical
/// associate is 1. Zero is its own canonical associate.
///
/// $$
/// f(x) = \begin{cases}
/// 0 & \text{if} \quad x = 0, \\
/// 1 & \text{otherwise}.
/// \end{cases}
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnit;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_q::Rational;
///
/// assert_eq!((&Rational::from_signeds(-22, 7)).canonicalize_unit(), 1);
/// assert_eq!((&Rational::from_signeds(22, 7)).canonicalize_unit(), 1);
/// assert_eq!((&Rational::ZERO).canonicalize_unit(), 0);
/// ```
#[inline]
fn canonicalize_unit(self) -> Rational {
if *self == 0u32 {
Rational::ZERO
} else {
Rational::ONE
}
}
}
impl CanonicalizeUnitAssign for Rational {
/// Replaces a [`Rational`] with its canonical unit form.
///
/// The rationals form a field, so every nonzero [`Rational`] is a unit and its canonical
/// associate is 1. Zero is its own canonical associate.
///
/// $$
/// f(x) = \begin{cases}
/// 0 & \text{if} \quad x = 0, \\
/// 1 & \text{otherwise}.
/// \end{cases}
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnitAssign;
/// use malachite_q::Rational;
///
/// let mut x = Rational::from_signeds(-22, 7);
/// x.canonicalize_unit_assign();
/// assert_eq!(x, 1);
/// ```
#[inline]
fn canonicalize_unit_assign(&mut self) {
if *self != 0u32 {
*self = Self::ONE;
}
}
}