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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::comparison::traits::EqAbs;
use malachite_base::num::logic::traits::SignificantBits;
use malachite_nz::natural::Natural;
impl EqAbs<Natural> for Float {
/// Determines whether the absolute value of a [`Float`] is equal to a [`Natural`].
///
/// $\infty$, $-\infty$, and NaN are not equal to any [`Natural`]. Both the [`Float`] zero and
/// the [`Float`] negative zero are equal to the [`Natural`] 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::{One, OneHalf};
/// use malachite_base::num::comparison::traits::EqAbs;
/// use malachite_float::Float;
/// use malachite_nz::natural::Natural;
///
/// assert!(Float::from(123).eq_abs(&Natural::from(123u32)));
/// assert!(Float::ONE_HALF.ne_abs(&Natural::ONE));
/// ```
fn eq_abs(&self, other: &Natural) -> bool {
match self {
float_either_zero!() => *other == 0u32,
Self(Finite {
exponent,
significand,
..
}) => {
*other != 0u32
&& *exponent >= 0
&& other.significant_bits() == u64::from(exponent.unsigned_abs())
&& significand.cmp_normalized(other) == Equal
}
_ => false,
}
}
}
impl EqAbs<Float> for Natural {
/// Determines whether a [`Natural`] is equal to the absolute value of a [`Float`].
///
/// No [`Natural`] is equal to $\infty$, $-\infty$, or NaN. The [`Natural`] 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::{One, OneHalf};
/// use malachite_base::num::comparison::traits::EqAbs;
/// use malachite_float::Float;
/// use malachite_nz::natural::Natural;
///
/// assert!(Natural::from(123u32).eq_abs(&Float::from(123)));
/// assert!(Natural::ONE.ne_abs(&Float::ONE_HALF));
/// ```
#[inline]
fn eq_abs(&self, other: &Float) -> bool {
other.eq_abs(self)
}
}