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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 core::cmp::Ordering::*;
use malachite_base::num::arithmetic::traits::{NextPowerOf2, NextPowerOf2Assign, PowerOf2};
use malachite_base::num::conversion::traits::ExactFrom;
use malachite_base::num::logic::traits::SignificantBits;
impl NextPowerOf2 for Rational {
type Output = Self;
/// Finds the smallest power of 2 greater than or equal to a [`Rational`]. The [`Rational`] is
/// taken by value.
///
/// $f(x) = 2^{\lceil \log_2 x \rceil}$.
///
/// # 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()`.
///
/// # Panics
/// Panics if `self` is less than or equal to zero.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::NextPowerOf2;
/// use malachite_q::Rational;
///
/// assert_eq!(Rational::from(123).next_power_of_2(), 128);
/// assert_eq!(
/// Rational::from_signeds(1, 10).next_power_of_2().to_string(),
/// "1/8"
/// );
/// ```
#[inline]
fn next_power_of_2(self) -> Self {
assert!(self > 0);
let mut exponent = i64::exact_from(self.numerator.significant_bits())
- i64::exact_from(self.denominator.significant_bits());
match self.numerator.cmp_normalized(&self.denominator) {
Equal => return self,
Greater => exponent += 1,
_ => {}
}
Self::power_of_2(exponent)
}
}
impl NextPowerOf2 for &Rational {
type Output = Rational;
/// Finds the smallest power of 2 greater than or equal to a [`Rational`]. The [`Rational`] is
/// taken by reference.
///
/// $f(x) = 2^{\lceil \log_2 x \rceil}$.
///
/// # 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()`.
///
/// # Panics
/// Panics if `self` is less than or equal to zero.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::NextPowerOf2;
/// use malachite_q::Rational;
///
/// assert_eq!((&Rational::from(123)).next_power_of_2(), 128);
/// assert_eq!(
/// (&Rational::from_signeds(1, 10))
/// .next_power_of_2()
/// .to_string(),
/// "1/8"
/// );
/// ```
fn next_power_of_2(self) -> Rational {
assert!(*self > 0);
let mut exponent = i64::exact_from(self.numerator.significant_bits())
- i64::exact_from(self.denominator.significant_bits());
if self.numerator.cmp_normalized(&self.denominator) == Greater {
exponent += 1;
}
Rational::power_of_2(exponent)
}
}
impl NextPowerOf2Assign for Rational {
/// Finds the smallest power of 2 greater than or equal to a [`Rational`]. The [`Rational`] is
/// taken by reference.
///
/// $f(x) = 2^{\lceil \log_2 x \rceil}$.
///
/// # 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()`.
///
/// # Panics
/// Panics if `self` is less than or equal to zero.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::NextPowerOf2Assign;
/// use malachite_q::Rational;
///
/// let mut x = Rational::from(123);
/// x.next_power_of_2_assign();
/// assert_eq!(x, 128);
///
/// let mut x = Rational::from_signeds(1, 10);
/// x.next_power_of_2_assign();
/// assert_eq!(x.to_string(), "1/8");
/// ```
#[inline]
fn next_power_of_2_assign(&mut self) {
*self = (&*self).next_power_of_2();
}
}