notes/school/intro-crypto/uebung/01/u01/src/main.rs

extern crate countmap;

use countmap::CountMap;
use std::{
    collections::HashMap,
    fs::File,
    io::{BufRead, BufReader},
    path::Path,
};

fn count() {
    let args: Vec<_> = std::env::args().collect();
    let file = &args[1];
    let mut map: CountMap<char, u32> = CountMap::new();
    let read = BufReader::new(File::open(file).unwrap());
    for line in read.lines() {
        if let Ok(line) = line {
            line.chars().filter(|c| c.is_alphabetic()).for_each(|c| {
                map.insert_or_increment(c);
            });
        }
    }
    let sum: u32 = map
        .iter()
        .filter(|(k, _)| k.is_alphabetic())
        .map(|(_, v)| v)
        .sum();
    let mut vec: Vec<_> = map.into_iter().collect();
    vec.sort_unstable();
    vec.into_iter().for_each(|(k, v)| {
        println!(
            "{} &\\text{{:}}& {:3} \\to{{}} {:.2} \\\\",
            k,
            v,
            f64::from(v) / f64::from(sum)
        )
    });
    println!("sum &\\text{{:}}& {}", sum);
}

fn create_map<P: AsRef<Path>>(path: P) -> std::io::Result<HashMap<char, char>> {
    let read = BufReader::new(File::open(path)?);
    let mut map = HashMap::new();
    for line in read.lines() {
        if let Ok(line) = line {
            let chars: Vec<char> = line.chars().collect();
            if chars.len() != 2 {
                eprintln!("Invalid line {}", line);
            } else {
                map.insert(chars[0], chars[1]);
            }
        }
    }
    Ok(map)
}

fn main() {
    count();
    let args: Vec<_> = std::env::args().collect();
    let target = &args[1];
    let map = create_map(&args[2]).unwrap();
    let read = BufReader::new(File::open(target).unwrap());
    for line in read.lines() {
        if let Ok(line) = line {
            let s: String = line
                .chars()
                .map(|c| map.get(&c).cloned().unwrap_or(c))
                .collect();
            println!("{}", s);
        }
    }
}