Split benchmark

regex_bench.rs

use criterion::{black_box, criterion_group, criterion_main, Criterion};
use regex::Regex;
use rand::{Rng, distributions::{Alphanumeric, Uniform}};

pub fn criterion_benchmark(c: &mut Criterion) {
    let reg = Regex::new(&regex::escape("\\")).unwrap();
    let mut group = c.benchmark_group("single character");
    let mut rng = rand::thread_rng();
    let base: usize = 2;
    for size in (0..30).step_by(10).map(|x| base.pow(x)) {
        let mut str = (&mut rng).sample_iter(&Alphanumeric).take(size).map(char::from).collect::<String>();
        if size > 1 {
            let replaces = randomly_replace_chars(&str, '\\', size/100);
        }
        group.bench_function(format!{"single char escaped {size}"}, |b| b.iter(|| str.split('\\').collect::<Vec<_>>()));
        group.bench_function(format!("single char escaped regex {size}"), |b| b.iter(|| reg.split(&str).collect::<Vec<_>>()));
    
    }
    group.finish();
}

fn randomly_replace_chars(input: &str, replacement: char, num_replacements: usize) -> String {
    let mut rng = rand::thread_rng();
    let mut chars: Vec<char> = input.chars().collect();
    let index_dist = Uniform::from(0..chars.len());

    for _ in 0..num_replacements {
        let index = rng.sample(index_dist);
        chars[index] = replacement;
    }

    chars.into_iter().collect()
}

criterion_group!(benches, criterion_benchmark);
criterion_main!{benches}