hash_test.rs

// cargo add sha2 and plotters

use sha2::Digest;

use plotters::prelude::*;
const OUT_FILE_NAME: &'static str = "output-test.png";

fn main() {
    // same for Sha512
    let mut bins_a = vec!(0; 256);
    let mut bins_b = vec!(0; 256);
    let mut max = 0;
    for i in 0..0xFFFF
    {
        let mut hasher = sha2::Sha512::new();
        hasher.update((i as u16).to_le_bytes());
        let result = hasher.finalize()[..].to_vec();
        let a = result[0];
        
        let mut hasher = sha2::Sha512::new();
        hasher.update([a]);
        let result = hasher.finalize()[..].to_vec();
        let b = result[1];
        
        bins_a[a as usize] += 1;
        bins_b[b as usize] += 1;
        max = std::cmp::max(bins_a[a as usize], max);
        max = std::cmp::max(bins_b[b as usize], max);
    }
    
    println!("{:?}", bins_a);
    println!("{:?}", bins_b);
    
    
    let root = BitMapBackend::new(OUT_FILE_NAME, (1280, 720)).into_drawing_area();

    root.fill(&WHITE).unwrap();

    let mut chart = ChartBuilder::on(&root)
        .set_label_area_size(LabelAreaPosition::Left, 40)
        .set_label_area_size(LabelAreaPosition::Bottom, 40)
        .build_cartesian_2d(0u32..256u32, (0u32..max).into_segmented())
        .unwrap();
    
    chart
        .configure_mesh()
        .bold_line_style(&WHITE.mix(0.3))
        .y_desc("Count")
        .x_desc("Bucket")
        .axis_desc_style(("sans-serif", 15))
        .draw().unwrap();

    chart.draw_series(bins_a.iter().enumerate().map(|(i, n)| {
        let i = i as u32;
        let mut bar = Rectangle::new([(i, SegmentValue::Exact(0)), (i+1, SegmentValue::Exact(*n as u32))], RED.mix(0.5).filled());
        bar.set_margin(0, 0, 5, 5);
        bar
    })).unwrap();

    chart.draw_series(bins_b.iter().enumerate().map(|(i, n)| {
        let i = i as u32;
        let mut bar = Rectangle::new([(i, SegmentValue::Exact(0)), (i+1, SegmentValue::Exact(*n as u32))], BLUE.mix(0.5).filled());
        bar.set_margin(0, 0, 5, 5);
        bar
    })).unwrap();

    root.present().unwrap();
}