ps-ecc 0.1.0-9

Generates Reed-Solomon error correction codes.
Documentation 
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use std::ops::BitXorAssign;

use crate::{finite_field::add, Polynomial};

impl BitXorAssign for Polynomial {
    fn bitxor_assign(&mut self, rhs: Self) {
        for (idx, &coef) in rhs.coefficients().iter().enumerate() {
            self.coefficients[idx] = add(self.coefficients[idx], coef);
        }

        self.degree = self.degree.max(rhs.degree);
        self.trim_degree();
    }
}

impl BitXorAssign<&Self> for Polynomial {
    fn bitxor_assign(&mut self, rhs: &Self) {
        BitXorAssign::bitxor_assign(self, *rhs);
    }
}

#[cfg(test)]
#[allow(clippy::expect_used)]
mod tests {
    use crate::Polynomial;

    #[test]
    fn xor_assign_basic() {
        let mut a = Polynomial::try_from(&[1u8, 2, 3][..]).expect("valid polynomial");
        let b = Polynomial::try_from(&[4u8, 5, 6][..]).expect("valid polynomial");

        a ^= b;

        assert_eq!(a.coefficients(), &[1 ^ 4, 2 ^ 5, 3 ^ 6]);
    }

    #[test]
    fn xor_assign_different_degrees() {
        let mut a = Polynomial::try_from(&[1u8, 2][..]).expect("valid polynomial");
        let b = Polynomial::try_from(&[3u8, 4, 5, 6][..]).expect("valid polynomial");

        a ^= b;

        assert_eq!(a.coefficients(), &[1 ^ 3, 2 ^ 4, 5, 6]);
    }

    #[test]
    fn xor_assign_cancels_to_zero() {
        let mut a = Polynomial::try_from(&[1u8, 2, 3][..]).expect("valid polynomial");
        let b = Polynomial::try_from(&[1u8, 2, 3][..]).expect("valid polynomial");

        a ^= b;

        assert_eq!(a.degree(), 0);
        assert_eq!(a.coefficients(), &[0]);
    }

    #[test]
    fn xor_assign_with_reference() {
        let mut a = Polynomial::try_from(&[1u8, 2, 3][..]).expect("valid polynomial");
        let b = Polynomial::try_from(&[4u8, 5, 6][..]).expect("valid polynomial");

        a ^= &b;

        assert_eq!(a.coefficients(), &[1 ^ 4, 2 ^ 5, 3 ^ 6]);
    }

    #[test]
    fn xor_assign_multiple() {
        let mut a = Polynomial::try_from(&[1u8][..]).expect("valid polynomial");
        let b = Polynomial::try_from(&[2u8][..]).expect("valid polynomial");
        let c = Polynomial::try_from(&[4u8][..]).expect("valid polynomial");

        a ^= b;
        a ^= c;

        assert_eq!(a.coefficients(), &[1 ^ 2 ^ 4]);
    }
}