fingerprint_fingerprint_with_id

use std::array::fold;
use std::math::fp2::Fp2;
use std::math::fp2::add_ext;
use std::math::fp2::mul_ext;
use std::math::fp2::from_base;

/// Maps [x_1, x_2, ..., x_n] to its Read-Solomon fingerprint, using a challenge alpha: $\sum_{i=1}^n alpha**{(n - i)} * x_i$
let<T: Add + Mul + FromLiteral> fingerprint: T[], Fp2<T> -> Fp2<T> = |expr_array, alpha| fold(
    expr_array,
    from_base(0),
    |sum_acc, el| add_ext(mul_ext(alpha, sum_acc), from_base(el))
);

/// Maps [x_1, x_2, ..., x_n] to its Read-Solomon fingerprint, using a challenge alpha: $\sum_{i=1}^n alpha**{(n - i)} * x_i$
let<T: Add + Mul + FromLiteral> fingerprint_with_id: T, T[], Fp2<T> -> Fp2<T> = |id, expr_array, alpha| fold(
    expr_array,
    from_base(id),
    |sum_acc, el| add_ext(mul_ext(alpha, sum_acc), from_base(el))
);