Function check_histogram

src/pack.rs:231–239

Returns `Ok(histogram)` if buckets after `OUT` are 0.

(
        histogram: [usize; IN],
    )

    /// Returns `Ok(histogram)` if buckets after `OUT` are 0.
    fn check_histogram<const IN: usize, const OUT: usize>(
        histogram: [usize; IN],
    ) -> Result<[usize; OUT]> {
        let (histogram, remaining) = histogram.split_at(OUT);
        if remaining.iter().copied().sum::<usize>() != 0 {
            return invalid_packing();
        }
        Ok(*<&[usize; OUT]>::try_from(histogram).unwrap())
    }

    let p = Packing::new(N.saturating_sub(1) as u8);
    if p == Packing::_256 {