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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::integer::Integer;
use malachite_base::num::arithmetic::traits::{DivExact, DivExactAssign};
impl DivExact<Self> for Integer {
type Output = Self;
/// Divides an [`Integer`] by another [`Integer`], taking both by value. The first [`Integer`]
/// must be exactly divisible by the second. If it isn't, this function may panic or return a
/// meaningless result.
///
/// $$
/// f(x, y) = \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `self / other` instead. If you're
/// unsure and you want to know, use `self.div_mod(other)` and check whether the remainder is
/// zero. If you want a function that panics if the division is not exact, use
/// `self.div_round(other, Exact)`.
///
/// # Worst-case complexity
/// $T(n) = O(n \log n \log \log n)$
///
/// $M(n) = O(n \log n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExact;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// assert_eq!(Integer::from(-56088).div_exact(Integer::from(456)), -123);
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// assert_eq!(
/// Integer::from_str("121932631112635269000000")
/// .unwrap()
/// .div_exact(Integer::from_str("-987654321000").unwrap()),
/// -123456789000i64
/// );
/// ```
#[inline]
fn div_exact(mut self, other: Self) -> Self {
self.div_exact_assign(other);
self
}
}
impl DivExact<&Self> for Integer {
type Output = Self;
/// Divides an [`Integer`] by another [`Integer`], taking the first by value and the second by
/// reference. The first [`Integer`] must be exactly divisible by the second. If it isn't, this
/// function may panic or return a meaningless result.
///
/// $$
/// f(x, y) = \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `self / &other` instead. If you're
/// unsure and you want to know, use `self.div_mod(&other)` and check whether the remainder is
/// zero. If you want a function that panics if the division is not exact, use
/// `self.div_round(&other, Exact)`.
///
/// # Worst-case complexity
/// $T(n) = O(n \log n \log \log n)$
///
/// $M(n) = O(n \log n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExact;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// assert_eq!(Integer::from(-56088).div_exact(&Integer::from(456)), -123);
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// assert_eq!(
/// Integer::from_str("121932631112635269000000")
/// .unwrap()
/// .div_exact(&Integer::from_str("-987654321000").unwrap()),
/// -123456789000i64
/// );
/// ```
#[inline]
fn div_exact(mut self, other: &Self) -> Self {
self.div_exact_assign(other);
self
}
}
impl DivExact<Integer> for &Integer {
type Output = Integer;
/// Divides an [`Integer`] by another [`Integer`], taking the first by reference and the second
/// by value. The first [`Integer`] must be exactly divisible by the second. If it isn't, this
/// function may panic or return a meaningless result.
///
/// $$
/// f(x, y) = \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `&self / other` instead. If you're
/// unsure and you want to know, use `self.div_mod(other)` and check whether the remainder is
/// zero. If you want a function that panics if the division is not exact, use
/// `(&self).div_round(other, Exact)`.
///
/// # Worst-case complexity
/// $T(n) = O(n \log n \log \log n)$
///
/// $M(n) = O(n \log n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExact;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// assert_eq!((&Integer::from(-56088)).div_exact(Integer::from(456)), -123);
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// assert_eq!(
/// (&Integer::from_str("121932631112635269000000").unwrap())
/// .div_exact(Integer::from_str("-987654321000").unwrap()),
/// -123456789000i64
/// );
/// ```
fn div_exact(self, other: Integer) -> Integer {
let q_abs = (&self.abs).div_exact(other.abs);
Integer {
sign: self.sign == other.sign || q_abs == 0,
abs: q_abs,
}
}
}
impl DivExact<&Integer> for &Integer {
type Output = Integer;
/// Divides an [`Integer`] by another [`Integer`], taking both by reference. The first
/// [`Integer`] must be exactly divisible by the second. If it isn't, this function may panic or
/// return a meaningless result.
///
/// $$
/// f(x, y) = \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `&self / &other` instead. If
/// you're unsure and you want to know, use `(&self).div_mod(&other)` and check whether the
/// remainder is zero. If you want a function that panics if the division is not exact, use
/// `(&self).div_round(&other, Exact)`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExact;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// assert_eq!(
/// (&Integer::from(-56088)).div_exact(&Integer::from(456)),
/// -123
/// );
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// assert_eq!(
/// (&Integer::from_str("121932631112635269000000").unwrap())
/// .div_exact(&Integer::from_str("-987654321000").unwrap()),
/// -123456789000i64
/// );
/// ```
fn div_exact(self, other: &Integer) -> Integer {
let q_abs = (&self.abs).div_exact(&other.abs);
Integer {
sign: self.sign == other.sign || q_abs == 0,
abs: q_abs,
}
}
}
impl DivExactAssign<Self> for Integer {
/// Divides an [`Integer`] by another [`Integer`] in place, taking the [`Integer`] on the
/// right-hand side by value. The first [`Integer`] must be exactly divisible by the second. If
/// it isn't, this function may panic or return a meaningless result.
///
/// $$
/// x \gets \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `self /= other` instead. If you're
/// unsure and you want to know, use `self.div_assign_mod(other)` and check whether the
/// remainder is zero. If you want a function that panics if the division is not exact, use
/// `self.div_round_assign(other, Exact)`.
///
/// # Worst-case complexity
/// $T(n) = O(n \log n \log \log n)$
///
/// $M(n) = O(n \log n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExactAssign;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// let mut x = Integer::from(-56088);
/// x.div_exact_assign(Integer::from(456));
/// assert_eq!(x, -123);
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// let mut x = Integer::from_str("121932631112635269000000").unwrap();
/// x.div_exact_assign(Integer::from_str("-987654321000").unwrap());
/// assert_eq!(x, -123456789000i64);
/// ```
fn div_exact_assign(&mut self, other: Self) {
self.abs.div_exact_assign(other.abs);
self.sign = self.sign == other.sign || self.abs == 0;
}
}
impl DivExactAssign<&Self> for Integer {
/// Divides an [`Integer`] by another [`Integer`] in place, taking the [`Integer`] on the
/// right-hand side by reference. The first [`Integer`] must be exactly divisible by the second.
/// If it isn't, this function may panic or return a meaningless result.
///
/// $$
/// x \gets \frac{x}{y}.
/// $$
///
/// If you are unsure whether the division will be exact, use `self /= &other` instead. If
/// you're unsure and you want to know, use `self.div_assign_mod(&other)` and check whether the
/// remainder is zero. If you want a function that panics if the division is not exact, use
/// `self.div_round_assign(&other, Exact)`.
///
/// # Worst-case complexity
/// $T(n) = O(n \log n \log \log n)$
///
/// $M(n) = O(n \log n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Panics
/// Panics if `other` is zero. May panic if `self` is not divisible by `other`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::DivExactAssign;
/// use malachite_nz::integer::Integer;
///
/// // -123 * 456 = -56088
/// let mut x = Integer::from(-56088);
/// x.div_exact_assign(&Integer::from(456));
/// assert_eq!(x, -123);
///
/// // -123456789000 * -987654321000 = 121932631112635269000000
/// let mut x = Integer::from_str("121932631112635269000000").unwrap();
/// x.div_exact_assign(&Integer::from_str("-987654321000").unwrap());
/// assert_eq!(x, -123456789000i64);
/// ```
fn div_exact_assign(&mut self, other: &Self) {
self.abs.div_exact_assign(&other.abs);
self.sign = self.sign == other.sign || self.abs == 0;
}
}