openethereum/crates/util/keccak-hasher/src/lib.rs

// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

//! Hasher implementation for the Keccak-256 hash
extern crate ethereum_types;
extern crate hash_db;
extern crate plain_hasher;
extern crate tiny_keccak;

use ethereum_types::H256;
use hash_db::Hasher;
use plain_hasher::PlainHasher;
use tiny_keccak::Keccak;
/// Concrete `Hasher` impl for the Keccak-256 hash
#[derive(Default, Debug, Clone, PartialEq)]
pub struct KeccakHasher;
impl Hasher for KeccakHasher {
    type Out = H256;
    type StdHasher = PlainHasher;
    const LENGTH: usize = 32;
    fn hash(x: &[u8]) -> Self::Out {
        let mut out = [0; 32];
        Keccak::keccak256(x, &mut out);
        out.into()
    }
}