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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::Float;
use crate::InnerFloat::{Finite, Zero};
use core::cmp::Ordering::*;
use malachite_base::num::arithmetic::traits::CheckedLogBase2;
use malachite_base::num::comparison::traits::EqAbs;
use malachite_base::num::conversion::traits::ExactFrom;
use malachite_base::num::logic::traits::SignificantBits;
use malachite_q::Rational;
impl EqAbs<Rational> for Float {
/// Determines whether the absolute value of a [`Float`] is equal to the absolute value of a
/// [`Rational`].
///
/// $\infty$, $-\infty$, and NaN are not equal to any [`Rational`]. Both the [`Float`] zero and
/// the [`Float`] negative zero are equal to the [`Rational`] zero.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `min(self.significant_bits(),
/// other.significant_bits())`.
///
/// # Examples
/// ```
/// use malachite_base::num::basic::traits::OneHalf;
/// use malachite_base::num::comparison::traits::EqAbs;
/// use malachite_float::Float;
/// use malachite_q::Rational;
///
/// assert!(Float::from(123).eq_abs(&Rational::from(123)));
/// assert!(Float::from(-123).eq_abs(&Rational::from(123)));
/// assert!(Float::ONE_HALF.eq_abs(&Rational::ONE_HALF));
/// assert!(Float::from(1.0f64 / 3.0).ne_abs(&Rational::from_unsigneds(1u8, 3)));
/// ```
#[inline]
fn eq_abs(&self, other: &Rational) -> bool {
match self {
float_either_zero!() => *other == 0u32,
Self(Finite {
exponent,
significand,
..
}) => {
*other != 0
&& if let Some(log_d) = other.denominator_ref().checked_log_base_2() {
let n = other.numerator_ref();
i64::from(*exponent)
== i64::exact_from(n.significant_bits()) - i64::exact_from(log_d)
&& significand.cmp_normalized(n) == Equal
} else {
false
}
}
_ => false,
}
}
}
impl EqAbs<Float> for Rational {
/// Determines whether the absolute value of a [`Rational`] is equal to the absolute value of a
/// [`Float`].
///
/// No [`Rational`] is equal to $\infty$, $-\infty$, or NaN. The [`Rational`] zero is equal to
/// both the [`Float`] zero and the [`Float`] negative zero.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `min(self.significant_bits(),
/// other.significant_bits())`.
///
/// # Examples
/// ```
/// use malachite_base::num::basic::traits::OneHalf;
/// use malachite_base::num::comparison::traits::EqAbs;
/// use malachite_float::Float;
/// use malachite_q::Rational;
///
/// assert!(Rational::from(123).eq_abs(&Float::from(123)));
/// assert!(Rational::from(-123).eq_abs(&Float::from(123)));
/// assert!(Rational::ONE_HALF.eq_abs(&Float::ONE_HALF));
/// assert!(Rational::from_unsigneds(1u8, 3).ne_abs(&Float::from(1.0f64 / 3.0)));
/// ```
#[inline]
fn eq_abs(&self, other: &Float) -> bool {
other.eq_abs(self)
}
}