arb_hash 0.1.5

Arbitrary block length hash function, potentially cryptographically secure.
Documentation 
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use crate::block::xor_blocks;

//Returns the hash of an input byte array
// - input: some input block, don't use one less than 3 bytes, larger is better but slower
// - rounds: 1 round is sufficient, but 2 rounds *might* be better distributed
pub fn arb_hash(input: &[u8], rounds: u64) -> Vec<u8> {
    const SHIFTS: [u32; 5] = [1, 2, 3, 5, 7];
    let mut output = Vec::from(input);
    let len: usize = input.len();
    for _rnd in 0..rounds {
        for b_shift in 0..len {
            for elem in 0..len {
                let shift = SHIFTS[(b_shift + elem) % 5];
                output[elem] = output[elem].wrapping_add(output[(elem + 1) % len]);
                output[(elem + 2) % len] ^= output[elem];
                output[(elem + 2) % len] = output[(elem + 2) % len].rotate_left(shift);
            }
        }
    }
    xor_blocks(&output, input)
}