Remove duplicated code and make base64 error handling better

src/set3.rs

@@ -9,21 +9,12 @@ use rand::Rng;
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::collections::HashSet;
-use std::io::{BufRead, BufReader};
 
 pub fn challenge17() {
-    fn read(path: &str) -> Vec<Bytes> {
-        let file = std::fs::File::open(path).unwrap();
-        let br = BufReader::new(file);
-        br.lines()
-            .map(|line| BytesBase64::from_base64(&line.unwrap()).to_bytes())
-            .collect()
-    }
-
     let key = Bytes::random(16);
     let encrypt = || -> (Bytes, Bytes, usize) {
         // The first function should select at random one of the ten strings
-        let cleartexts = read("data/17.txt");
+        let cleartexts = utils::read_base64_lines("data/17.txt");
         let index: usize = rand::thread_rng().gen_range(0..cleartexts.len());
         let mut cleartext = Bytes(cleartexts[index].0.to_vec());
 
@@ -95,7 +86,7 @@ pub fn challenge17() {
         roundtrip.0.append(&mut clear_block.0);
     }
     roundtrip.remove_pkcs7(16);
-    let cleartexts = read("data/17.txt");
+    let cleartexts = utils::read_base64_lines("data/17.txt");
     let cleartext = Bytes(cleartexts[cleartext_index].0.to_vec());
     assert_eq!(roundtrip, cleartext);
     println!("[okay] Challenge 17: {}", roundtrip.to_utf8());
@@ -112,20 +103,13 @@ pub fn challenge18() {
     let cipher = BytesBase64::from_base64(
         "L77na/nrFsKvynd6HzOoG7GHTLXsTVu9qvY/2syLXzhPweyyMTJULu/6/kXX0KSvoOLSFQ==",
     )
+    .unwrap()
     .to_bytes();
     let cleartext = ctr::decrypt(&key, 0, &cipher).to_utf8();
     println!("[okay] Challenge 18: {cleartext}");
 }
 
 pub fn challenge19() {
-    fn read(path: &str) -> Vec<Bytes> {
-        let file = std::fs::File::open(path).unwrap();
-        let br = BufReader::new(file);
-        br.lines()
-            .map(|line| BytesBase64::from_base64(&line.unwrap()).to_bytes())
-            .collect()
-    }
-
     fn xor_to_char_set(letters: &Vec<u8>) -> HashMap<u8, RefCell<HashSet<u8>>> {
         let mut h = HashMap::new();
         for i in 0..255_u8 {
@@ -255,7 +239,7 @@ pub fn challenge19() {
         decrypts[37].borrow_mut()[30] = b'i';
     }
 
-    let plaintexts = read("data/19.txt");
+    let plaintexts = utils::read_base64_lines("data/19.txt");
     let key = Bytes::from_utf8("YELLOW SUBMARINE");
     let encrypt = |plaintext: &Bytes| -> Bytes { ctr::encrypt(&key, 0, plaintext) };
     let ciphers: Vec<Bytes> = plaintexts.iter().map(|ct| encrypt(&ct)).collect();
@@ -271,14 +255,6 @@ pub fn challenge19() {
 }
 
 pub fn challenge20() {
-    fn read(path: &str) -> Vec<Bytes> {
-        let file = std::fs::File::open(path).unwrap();
-        let br = BufReader::new(file);
-        br.lines()
-            .map(|line| BytesBase64::from_base64(&line.unwrap()).to_bytes())
-            .collect()
-    }
-
     fn attack(ciphers: Vec<Bytes>) -> Vec<Bytes> {
         let min_cipher_len = ciphers.iter().map(|c| c.len()).min().unwrap_or(0);
         let mut key: Vec<u8> = vec![];
@@ -294,7 +270,7 @@ pub fn challenge20() {
             .collect()
     }
 
-    let plaintexts = read("data/20.txt");
+    let plaintexts = utils::read_base64_lines("data/20.txt");
     let key = Bytes::from_utf8("YELLOW SUBMARINE");
     let encrypt = |plaintext: &Bytes| -> Bytes { ctr::encrypt(&key, 0, plaintext) };
     let ciphers: Vec<Bytes> = plaintexts.iter().map(|ct| encrypt(&ct)).collect();