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// Copyright © 2024 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::natural::InnerNatural::Small;
use crate::natural::Natural;
use crate::platform::Limb;
use malachite_base::num::basic::traits::Zero;
use malachite_base::num::conversion::traits::{ConvertibleFrom, SaturatingFrom, VecFromOtherType};
impl Natural {
/// Converts a [`Limb`](crate#limbs) to a [`Natural`].
///
/// This function is const, so it may be used to define constants.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_nz::natural::Natural;
///
/// const TEN: Natural = Natural::const_from(10);
/// assert_eq!(TEN, 10);
/// ```
pub const fn const_from(x: Limb) -> Natural {
Natural(Small(x))
}
}
macro_rules! impl_from_limb {
($t: ident) => {
impl From<$t> for Natural {
/// Converts a [`Limb`](crate#limbs) to a [`Natural`].
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#from).
#[inline]
fn from(u: $t) -> Natural {
Natural(Small(u))
}
}
};
}
macro_rules! impl_from_smaller_than_limb {
($t: ident) => {
impl From<$t> for Natural {
/// Converts an unsigned primitive integer to a [`Natural`], where the integer's width
/// is smaller than a [`Limb`](crate#limbs)'s.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#from).
#[inline]
fn from(u: $t) -> Natural {
Natural(Small(Limb::from(u)))
}
}
};
}
macro_rules! impl_from_larger_than_limb_or_usize {
($t: ident) => {
impl From<$t> for Natural {
/// Converts an unsigned primitive integer to a [`Natural`], where the integer's width
/// is larger than a [`Limb`](crate#limbs)'s.
///
/// This implementation is general enough to also work for [`usize`], regardless of
/// whether it is equal in width to [`Limb`](crate#limbs).
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#from).
#[inline]
fn from(u: $t) -> Natural {
Natural::from_owned_limbs_asc(Limb::vec_from_other_type(u))
}
}
};
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct NaturalFromSignedError;
macro_rules! impl_signed {
($t: ident) => {
impl TryFrom<$t> for Natural {
type Error = NaturalFromSignedError;
/// Converts a signed primitive integer to a [`Natural`]. If the integer is negative, an
/// error is returned.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#try_from).
#[inline]
fn try_from(i: $t) -> Result<Natural, Self::Error> {
if i >= 0 {
Ok(Natural::from(i.unsigned_abs()))
} else {
Err(NaturalFromSignedError)
}
}
}
impl ConvertibleFrom<$t> for Natural {
/// Determines whether a signed primitive integer can be converted to a [`Natural`].
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#convertible_from).
#[inline]
fn convertible_from(i: $t) -> bool {
i >= 0
}
}
impl SaturatingFrom<$t> for Natural {
/// Converts a signed primitive primitive integer to a [`Natural`]. If the integer is
/// negative, 0 is returned.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_int#saturating_from).
#[inline]
fn saturating_from(i: $t) -> Natural {
if i >= 0 {
Natural::from(i.unsigned_abs())
} else {
Natural::ZERO
}
}
}
};
}
impl_from_smaller_than_limb!(u8);
impl_from_smaller_than_limb!(u16);
#[cfg(feature = "32_bit_limbs")]
impl_from_limb!(u32);
#[cfg(not(feature = "32_bit_limbs"))]
impl_from_smaller_than_limb!(u32);
#[cfg(feature = "32_bit_limbs")]
impl_from_larger_than_limb_or_usize!(u64);
#[cfg(not(feature = "32_bit_limbs"))]
impl_from_limb!(u64);
impl_from_larger_than_limb_or_usize!(u128);
impl_from_larger_than_limb_or_usize!(usize);
apply_to_signeds!(impl_signed);