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#![warn(missing_docs)]
use regex::Regex;
use std::collections::HashMap;
use std::io::BufRead;
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum CountOption {
Char,
Word,
Line,
}
impl Default for CountOption {
fn default() -> Self {
CountOption::Word
}
}
pub fn count(input: impl BufRead, option: CountOption) -> HashMap<String, usize> {
let re = Regex::new(r"\w+").unwrap();
let mut freqs = HashMap::new();
for line in input.lines(){
let line = line.unwrap();
use crate::CountOption::*;
match option {
Char => {
for c in line.chars(){
*freqs.entry(c.to_string()).or_insert(0) += 1;
}
}
Word => {
for m in re.find_iter(&line) {
let word = m.as_str().to_string();
*freqs.entry(word).or_insert(0) += 1;
}
}
Line => *freqs.entry(line.to_string()).or_insert(0) += 1,
}
}
freqs
}
#[test]
fn word_count_works() {
use std::io::Cursor;
let mut exp = HashMap::new();
exp.insert("aa".to_string(), 1);
exp.insert("bb".to_string(), 2);
exp.insert("cc".to_string(), 1);
assert_eq!(count(Cursor::new("aa bb cc bb"), CountOption::Word), exp);
}
#[test]
fn word_count_works2() {
use std::io::Cursor;
let mut exp = HashMap::new();
exp.insert("aa".to_string(), 1);
exp.insert("bb".to_string(), 1);
exp.insert("dd".to_string(), 1);
assert_eq!(count(Cursor::new("aa bb dd"), CountOption::Word), exp);
}
macro_rules! assert_map {
($expr: expr, {$($key: expr => $value:expr), *}) => {
$(assert_eq!($expr[$key], $value));*
};
}
#[test]
fn word_count_works3() {
use std::io::Cursor;
let freqs = count(Cursor::new("aa cc dd"), CountOption::Word);
assert_eq!(freqs.len(), 3);
assert_map!(freqs, {"aa" => 1, "cc" => 1, "dd" => 1});
}
#[test]
#[should_panic]
fn word_count_do_not_contain_unkown_words() {
use std::io::Cursor;
count(
Cursor::new([
b'a',
0xf0, 0x90, 0x80,
0xe3, 0x81, 0x82,
]),
CountOption::Word,
);
}