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

/// Normalize arbitrary `RangeBounds` to a `Range`

pub(super) fn simplify_range(range: impl RangeBounds<usize>, len: usize) -> Range<usize> {

    let start = match range.start_bound() {

        Bound::Unbounded => 0,

        Bound::Included(&i) if i <= len => i,

        Bound::Excluded(&i) if i < len => i + 1,

        bound => panic!("range start {bound:?} should be <= length {len}"),

    };

    let end = match range.end_bound() {

        Bound::Unbounded => len,

        Bound::Excluded(&i) if i <= len => i,

        Bound::Included(&i) if i < len => i + 1,

        bound => panic!("range end {bound:?} should be <= length {len}"),

    };

    if start > end {

        panic!(

            "range start {:?} should be <= range end {:?}",

            range.start_bound(),

            range.end_bound()

        );

    }

    start..end

}

Unexecuted instantiation: rayon::math::simplify_range::<core::ops::range::RangeFull>

Unexecuted instantiation: rayon::math::simplify_range::<_>