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use crate::natural::Natural;
use malachite_base::num::conversion::traits::{CheckedFrom, IntegerMantissaAndExponent};
use malachite_base::num::logic::traits::SignificantBits;
use std::cmp::Ordering;
macro_rules! impl_float {
($t: ident) => {
impl PartialEq<$t> for Natural {
/// Determines whether a [`Natural`] is equal to a primitive float.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Examples
/// See [here](super::partial_eq_primitive_float#partial_eq).
fn eq(&self, other: &$t) -> bool {
if !other.is_finite() {
false
} else if *other == 0.0 {
*self == 0u32
} else if *other < 1.0 || *self == 0u32 {
false
} else {
let (m, e) = other.integer_mantissa_and_exponent();
if let Some(e) = u64::checked_from(e) {
self.significant_bits() == m.significant_bits() + e
&& self.cmp_normalized(&Natural::from(m)) == Ordering::Equal
} else {
false
}
}
}
}
impl PartialEq<Natural> for $t {
/// Determines whether a primitive float is equal to a [`Natural`].
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `other.significant_bits()`.
///
/// # Examples
/// See [here](super::partial_eq_primitive_float#partial_eq).
#[inline]
fn eq(&self, other: &Natural) -> bool {
other == self
}
}
};
}
apply_to_primitive_floats!(impl_float);