malachite-base 0.9.1

A collection of utilities, including new arithmetic traits and iterators that generate all values of a type.
Documentation 
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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 std::cmp::Ordering;
use std::fmt::Debug;
use std::str::FromStr;

#[macro_export]
macro_rules! assert_panic {
    ($e: expr) => {
        let result = catch_unwind(|| $e);
        assert!(result.is_err());
    };
}

fn read_strings<T: FromStr>(strings: &[&str]) -> Vec<T>
where
    T::Err: Debug,
{
    strings.iter().map(|s| s.parse().unwrap()).collect()
}

fn test_helper_helper<
    T: Debug + FromStr,
    U: Debug + Eq,
    F: FnMut(usize, usize) -> U,
    G: FnMut(&T, &T) -> U,
>(
    strings: &[&str],
    mut compare_indices: F,
    mut compare_elements: G,
) where
    T::Err: Debug,
{
    let xs = read_strings::<T>(strings);
    let ys = read_strings::<T>(strings);
    for (i, x) in xs.iter().enumerate() {
        for (j, y) in ys.iter().enumerate() {
            assert_eq!(compare_indices(i, j), compare_elements(x, y));
        }
    }
}

pub fn test_eq_helper<T: Debug + Eq + FromStr>(strings: &[&str])
where
    T::Err: Debug,
{
    test_helper_helper(strings, |i, j| i == j, |x: &T, y: &T| x == y);
}

pub fn test_cmp_helper<T: Debug + FromStr + Ord>(strings: &[&str])
where
    T::Err: Debug,
{
    test_helper_helper::<T, _, _, _>(strings, |i, j| i.cmp(&j), Ord::cmp);
}

pub fn test_custom_cmp_helper<T: Debug + FromStr, F: FnMut(&T, &T) -> Ordering>(
    strings: &[&str],
    compare: F,
) where
    T::Err: Debug,
{
    test_helper_helper(strings, |i, j| i.cmp(&j), compare);
}

#[macro_export]
macro_rules! triple_significant_bits_fn {
    ($t:ident, $bucketing_function:ident) => {
        fn $bucketing_function(t: &($t, $t, $t)) -> usize {
            usize::exact_from(max!(
                t.0.significant_bits(),
                t.1.significant_bits(),
                t.2.significant_bits()
            ))
        }
    };
}

pub const TRIPLE_SIGNIFICANT_BITS_LABEL: &str =
    "max(a.significant_bits(), b.significant_bits(), c.significant_bits())";

pub fn rle_encode<I: Iterator>(xs: I) -> Vec<(I::Item, usize)>
where
    I::Item: Clone + Eq,
{
    let mut out = Vec::new();
    let mut previous: Option<I::Item> = None;
    let mut count = 0;
    for x in xs {
        if let Some(p) = previous.as_ref() {
            if x == *p {
                count += 1;
            } else {
                out.push((p.clone(), count));
                previous = Some(x.clone());
                count = 1;
            }
        } else {
            count = 1;
            previous = Some(x.clone());
        }
    }
    if let Some(p) = previous {
        out.push((p, count));
    }
    out
}

pub fn rle_decode<T: Clone>(ps: &[(T, usize)]) -> Vec<T> {
    let mut out = Vec::new();
    for (x, count) in ps {
        for _ in 0..*count {
            out.push(x.clone());
        }
    }
    out
}

pub fn test_double_ended_iterator_size_hint<I: Clone + DoubleEndedIterator>(
    mut xs: I,
    original_expected_size: usize,
) {
    let original_xs = xs.clone();
    let mut expected_size = original_expected_size;
    for _ in 0..10 {
        assert_eq!(xs.size_hint(), (expected_size, Some(expected_size)));
        if xs.next().is_none() {
            break;
        };
        expected_size -= 1;
    }
    let mut xs = original_xs;
    let mut expected_size = original_expected_size;
    for _ in 0..10 {
        assert_eq!(xs.size_hint(), (expected_size, Some(expected_size)));
        if xs.next_back().is_none() {
            break;
        };
        expected_size -= 1;
    }
}