/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2018 Danny Robson <danny@nerdcruft.net>
 */

#ifndef CRUFT_CRYPTO_HASH_BLAKE2_HPP
#define CRUFT_CRYPTO_HASH_BLAKE2_HPP

#include <cruft/util/view.hpp>

#include <array>


namespace cruft::crypto::hash {
    // RFC7693: The BLAKE2 Cryptographic Hash and Message Authentication Code
    class blake2 {
    public:
        using salt_t = std::array<uint8_t,64>;
        using digest_t = std::array<uint8_t,64>;

        blake2 () noexcept;
        blake2 (const salt_t&) noexcept;
        blake2 (util::view<const uint8_t*> key);

        digest_t operator() (util::view<const uint8_t*>) const noexcept;

    private:
        using state_t = std::array<uint64_t,8>;

        // we store zero padded salt because it simplifies later state
        // updates, not because it's a functional requirement. either way we
        // need to copy at least 64 bytes, so the user shouldn't be copying
        // these too much regardless.
        std::array<uint8_t,128> m_salt;
        uint64_t m_keylen;
    };
};

#endif