Function histogram_parallel

src/histogram.rs:17–26

(bytes: &[u8])

}

fn histogram_parallel(bytes: &[u8]) -> [usize; 256] {
    // Summing multiple 32 bit histograms is faster than a 64 bit histogram.
    let mut total = [0; 256];
    for bytes in bytes.chunks(u32::MAX as usize) {
        for (i, &v) in histogram_parallel_u32(bytes).iter().enumerate() {
            total[i] += v as usize;
        }
    }
    total
}

// Based on https://github.com/facebook/zstd/blob/1518570c62b95136b6a69714012957cae5487a9a/lib/compress/hist.c#L66
fn histogram_parallel_u32(bytes: &[u8]) -> [u32; 256] {