range-mutex 0.1.7

A `Mutex<[T]>`-like type, that allows locking different ranges separately.
Documentation 
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//! Copied from stdlib core/src/slice/index.rs

use std::ops::{Bound, Range, RangeBounds};

#[inline]
pub fn range(len: usize, range: impl RangeBounds<usize>) -> Range<usize> {
    let start: Bound<&usize> = range.start_bound();
    let start = match start {
        Bound::Included(&start) => start,
        Bound::Excluded(start) => start
            .checked_add(1)
            .unwrap_or_else(|| slice_start_index_overflow_fail()),
        Bound::Unbounded => 0,
    };

    let end: Bound<&usize> = range.end_bound();
    let end = match end {
        Bound::Included(end) => end
            .checked_add(1)
            .unwrap_or_else(|| slice_end_index_overflow_fail()),
        Bound::Excluded(&end) => end,
        Bound::Unbounded => len,
    };

    if start > end {
        slice_index_order_fail(start, end);
    }
    if end > len {
        slice_end_index_len_fail(end, len);
    }

    Range { start, end }
}

#[cold]
const fn slice_start_index_overflow_fail() -> ! {
    panic!("attempted to index slice from after maximum usize");
}

#[cold]
const fn slice_end_index_overflow_fail() -> ! {
    panic!("attempted to index slice up to maximum usize");
}

#[cold]
fn slice_index_order_fail(index: usize, end: usize) -> ! {
    panic!("slice index starts at {index} but ends at {end}");
}

#[cold]
fn slice_end_index_len_fail(index: usize, len: usize) -> ! {
    panic!("range end index {index} out of range for slice of length {len}");
}