sha3 0.11.0-pre.3

Pure Rust implementation of SHA-3, a family of Keccak-based hash functions including the SHAKE family of eXtendable-Output Functions (XOFs), as well as the accelerated variant TurboSHAKE 
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const PLEN: usize = 25;
const DEFAULT_ROUND_COUNT: usize = 24;

#[derive(Clone)]
pub(crate) struct Sha3State<const ROUNDS: usize = DEFAULT_ROUND_COUNT> {
    pub state: [u64; PLEN],
}

impl<const ROUNDS: usize> Default for Sha3State<ROUNDS> {
    fn default() -> Self {
        Self {
            state: [0u64; PLEN],
        }
    }
}

impl<const ROUNDS: usize> Sha3State<ROUNDS> {
    pub fn absorb_block(&mut self, block: &[u8]) {
        debug_assert_eq!(block.len() % 8, 0);

        for (b, s) in block.chunks_exact(8).zip(self.state.iter_mut()) {
            *s ^= u64::from_le_bytes(b.try_into().unwrap());
        }

        keccak::p1600(&mut self.state, ROUNDS);
    }

    pub fn as_bytes(&self, out: &mut [u8]) {
        for (o, s) in out.chunks_mut(8).zip(self.state.iter()) {
            o.copy_from_slice(&s.to_le_bytes()[..o.len()]);
        }
    }

    pub fn permute(&mut self) {
        keccak::p1600(&mut self.state, ROUNDS);
    }
}