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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 malachite_base::num::conversion::traits::ConvertibleFrom;
use malachite_q::gaussian_rational::GaussianRational;
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct FloatFromGaussianRationalError;
impl TryFrom<GaussianRational> for Float {
type Error = FloatFromGaussianRationalError;
/// Converts a [`GaussianRational`] to a [`Float`], taking the [`GaussianRational`] by value. If
/// the [`GaussianRational`] is not real or is not exactly representable as a dyadic rational,
/// an error is returned.
///
/// If the [`GaussianRational`] is nonzero, the precision of the [`Float`] is the minimum
/// possible precision to represent it exactly.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `x.real.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_float::Float;
/// use malachite_float::float::conversion::from_gaussian_rational::*;
/// use malachite_q::gaussian_rational::GaussianRational;
/// use std::str::FromStr;
///
/// let x = GaussianRational::from_str("5/2").unwrap();
/// assert_eq!(Float::try_from(x).unwrap().to_string(), "2.5");
///
/// let x = GaussianRational::from_str("1/3").unwrap();
/// assert_eq!(Float::try_from(x), Err(FloatFromGaussianRationalError));
///
/// let x = GaussianRational::from_str("2-3i").unwrap();
/// assert_eq!(Float::try_from(x), Err(FloatFromGaussianRationalError));
/// ```
fn try_from(x: GaussianRational) -> Result<Self, Self::Error> {
if x.imaginary == 0u32 {
Self::try_from(x.real).map_err(|_| FloatFromGaussianRationalError)
} else {
Err(FloatFromGaussianRationalError)
}
}
}
impl TryFrom<&GaussianRational> for Float {
type Error = FloatFromGaussianRationalError;
/// Converts a [`GaussianRational`] to a [`Float`], taking the [`GaussianRational`] by
/// reference. If the [`GaussianRational`] is not real or is not exactly representable as a
/// dyadic rational, an error is returned.
///
/// If the [`GaussianRational`] is nonzero, the precision of the [`Float`] is the minimum
/// possible precision to represent it exactly.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `x.real.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_float::Float;
/// use malachite_float::float::conversion::from_gaussian_rational::*;
/// use malachite_q::gaussian_rational::GaussianRational;
/// use std::str::FromStr;
///
/// let x = GaussianRational::from_str("5/2").unwrap();
/// assert_eq!(Float::try_from(&x).unwrap().to_string(), "2.5");
///
/// let x = GaussianRational::from_str("1/3").unwrap();
/// assert_eq!(Float::try_from(&x), Err(FloatFromGaussianRationalError));
///
/// let x = GaussianRational::from_str("2-3i").unwrap();
/// assert_eq!(Float::try_from(&x), Err(FloatFromGaussianRationalError));
/// ```
fn try_from(x: &GaussianRational) -> Result<Self, Self::Error> {
if x.imaginary == 0u32 {
Self::try_from(&x.real).map_err(|_| FloatFromGaussianRationalError)
} else {
Err(FloatFromGaussianRationalError)
}
}
}
impl ConvertibleFrom<&GaussianRational> for Float {
/// Determines whether a [`GaussianRational`] can be converted to a [`Float`] (that is, whether
/// it is real or is not exactly representable as a dyadic rational), taking the
/// [`GaussianRational`] by reference.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `x.real.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_base::num::conversion::traits::ConvertibleFrom;
/// use malachite_float::Float;
/// use malachite_q::gaussian_rational::GaussianRational;
/// use std::str::FromStr;
///
/// let x = GaussianRational::from_str("5/2").unwrap();
/// assert_eq!(Float::convertible_from(&x), true);
///
/// let x = GaussianRational::from_str("1/3").unwrap();
/// assert_eq!(Float::convertible_from(&x), false);
///
/// let x = GaussianRational::from_str("2-3i").unwrap();
/// assert_eq!(Float::convertible_from(&x), false);
/// ```
#[inline]
fn convertible_from(x: &GaussianRational) -> bool {
x.imaginary == 0u32 && Self::convertible_from(&x.real)
}
}