xor.rs

pub fn repeating_character_xor(a: &[u8], b: u8) -> Vec<u8> {
    return a.iter().map(|x| *x ^ b).collect();
}

pub fn repeating_xor(a: &[u8], b: &[u8]) -> Vec<u8> {
    let cycle = b.iter().cycle();

    return cycle.zip(a.iter()).map ( |(a, b)| *a ^ *b ).collect();
}

pub fn fixed_xor(a: &[u8], b: &[u8]) -> Vec<u8> {
    return a.iter().zip(b.iter()).map ( |(x, y)| *x ^ *y ).collect()
}

pub fn fixed_xor_mut(a: &mut[u8], b: &[u8]) {
    for (&mut x, &y) in a.iter_mut().zip(b.iter()) {
        x ^ y
    }
}

#[cfg(test)]
mod tests {
    use xor::*;
    use rustc_serialize::hex::FromHex;

    #[test]
    fn test_repeating_xor() {
        let a = vec![0u8, 0u8];
        let b = vec![1u8];

        let r = repeating_xor(&a, &b);
        assert_eq!(r, &[1u8, 1u8]);
    }

    #[test]
    fn test_fixed_xor() {
        let a = "1c0111001f010100061a024b53535009181c".from_hex().unwrap();
        let b = "686974207468652062756c6c277320657965".from_hex().unwrap();
        let c = "746865206b696420646f6e277420706c6179".from_hex().unwrap();

        let r = fixed_xor(&a, &b);
        assert_eq!(c, r);
    }

    #[test]
    fn test_fixed_xor_mut() {
        let mut a = "1c0111001f010100061a024b53535009181c".from_hex().unwrap();
        let b = "686974207468652062756c6c277320657965".from_hex().unwrap();
        let mut c = "746865206b696420646f6e277420706c6179".from_hex().unwrap();

        fixed_xor_mut(&mut a, &b);
        assert_eq!(a, c.as_slice());
    }
}