blake2b_padding.hpp

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//---------------------------------------------------------------------------//
// Copyright (c) 2020 Alexander Sokolov <asokolov@nil.foundation>
// Copyright (c) 2020 Nikita Kaskov <nbering@nil.foundation>
// Copyright (c) 2020 Mikhail Komarov <nemo@nil.foundation>
//
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//---------------------------------------------------------------------------//
 
#ifndef CRYPTO3_BLAKE2B_PADDING_HPP
#define CRYPTO3_BLAKE2B_PADDING_HPP
 
#include <nil/crypto3/hash/detail/blake2b/blake2b_policy.hpp>
 
namespace nil {
    namespace crypto3 {
        namespace hashes {
            namespace detail {
                template<typename Hash>
                class blake2b_padding {
                    typedef Hash policy_type;
 
                    typedef typename policy_type::digest_endian endian_type;
 
                    constexpr static const std::size_t word_bits = policy_type::word_bits;
                    typedef typename policy_type::word_type word_type;
 
                    constexpr static const std::size_t block_bits = policy_type::block_bits;
                    constexpr static const std::size_t block_words = policy_type::block_words;
                    typedef typename policy_type::block_type block_type;
 
                    typedef ::nil::crypto3::detail::injector<endian_type, word_bits, block_words, block_bits>
                        injector_type;
 
                public:
                    void operator()(block_type &block, word_type total_seen) {
                        // Pad block with zero bits if it is empty or incomplete
                        if (!total_seen || total_seen % block_bits) {
                            word_type seen_words =
                                ((total_seen / word_bits) % block_words) + ((total_seen % word_bits) ? 1 : 0);
                            std::fill(block.begin() + seen_words, block.end(), 0);
                            // Pad with zeros last significant word if it is incomplete
                            if (total_seen % word_bits) {
                                word_type block_seen = total_seen % block_bits;
                                injector_type::inject(word_type(), word_bits - block_seen % word_bits, block,
                                                      block_seen);
                            }
                        }
                    }
                };
            }    // namespace detail
        }        // namespace hashes
    }            // namespace crypto3
}    // namespace nil
 
#endif    // CRYPTO3_BLAKE2B_PADDING_HPP