cryptopals 0.1.0

mod basics {
    extern crate base64;
    use std::u8;

    /// Turn a hexadecimal string into a vector of bytes.
    pub fn to_bytes(hex: &String) -> Vec<u8> {
        let mut bytes = Vec::new();

        for i in 0..(hex.len() / 2) {
            let res = u8::from_str_radix(&hex[(2 * i)..(2 * i + 2)], 16);
            match res {
                Ok(v) => bytes.push(v),
                Err(e) => println!("Problem with hex: {}", e),
            };
        }

        return bytes;
    }

    /// Turn a vector of bytes into its hexadecimal representation in a `String`.
    pub fn to_hex(bytes: Vec<u8>) -> String {
        let strs: Vec<String> = bytes.iter().map(|b| format!("{:X}", b)).collect();
        strs.join("").to_lowercase()
    }


    /// Translate a `String` originally written in hexadecimal to base64.
    /// Please note that this function should only be use to pretty print.
    pub fn hex_to_base64(hex: &String) -> String {
        let bytes = to_bytes(&hex);
        return base64::encode(&bytes);
    }


    /// Perform an XOR operation per element in two byte vectors of equal length.
    pub fn xor(a: &Vec<u8>, b: &Vec<u8>) -> Vec<u8> {
        if a.len() != b.len() {
            panic!("Different buffer sizes: {} and {}", a.len(), b.len());
        }

        let mut result: Vec<u8> = Vec::new();

        for (x, y) in a.iter().zip(b.iter()) {
            result.push(x ^ y);
        }

        return result;
    }
}

#[cfg(test)]
mod basics_tests {
    use super::basics::*;

    #[test]
    fn hex_to_base64_test() {
        let hex = String::from(
            "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f6\
             9736f6e6f7573206d757368726f6f6d",
        );
        let oct = String::from(
            "SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t",
        );

        assert_eq!(hex_to_base64(&hex), oct);
    }

    #[test]
    fn xor_test() {
        let a = String::from("1c0111001f010100061a024b53535009181c");
        let b = String::from("686974207468652062756c6c277320657965");
        let solution = String::from("746865206b696420646f6e277420706c6179");

        let result = to_hex(xor(&to_bytes(&a), &to_bytes(&b)));

        assert_eq!(result, solution);
    }
}