hex.hpp

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//---------------------------------------------------------------------------//
// Copyright (c) 2018-2020 Mikhail Komarov <nemo@nil.foundation>
// Copyright (c) 2019 Aleksey Moskvin <zerg1996@yandex.ru>
//
// 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_CODEC_HEX_HPP
#define CRYPTO3_CODEC_HEX_HPP
 
#include <iterator>
#include <stdexcept>
#include <type_traits>
 
#include <nil/crypto3/codec/detail/hex_policy.hpp>
#include <nil/crypto3/codec/detail/codec_modes.hpp>
#include <nil/crypto3/codec/detail/fixed_block_stream_processor.hpp>
 
#include <nil/crypto3/codec/codec_state.hpp>
 
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
 
#include <boost/exception/exception.hpp>
#include <boost/exception/info.hpp>
#include <boost/throw_exception.hpp>
 
namespace nil {
    namespace crypto3 {
        namespace codec {
 
            struct hex_decode_error : virtual boost::exception, virtual std::exception {};
 
            struct not_enough_input : virtual hex_decode_error {};
 
            struct non_hex_input : virtual hex_decode_error {};
            typedef boost::error_info<struct bad_char_, char> bad_char;
 
            namespace detail {
                template<typename Iterator>
                struct hex_iterator_traits {
                    typedef typename std::iterator_traits<Iterator>::value_type value_type;
                };
 
                template<typename Container>
                struct hex_iterator_traits<std::back_insert_iterator<Container>> {
                    typedef typename Container::value_type value_type;
                };
 
                template<typename Container>
                struct hex_iterator_traits<std::front_insert_iterator<Container>> {
                    typedef typename Container::value_type value_type;
                };
 
                template<typename Container>
                struct hex_iterator_traits<std::insert_iterator<Container>> {
                    typedef typename Container::value_type value_type;
                };
 
                template<typename T, typename charType, typename traits>
                struct hex_iterator_traits<std::ostream_iterator<T, charType, traits>> {
                    typedef T value_type;
                };
 
                template<typename Iterator>
                inline static bool iter_end(Iterator current, Iterator last) {
                    return current == last;
                }
 
                template<typename T>
                inline static bool ptr_end(const T *ptr, const T * /*end*/) {
                    return *ptr == '\0';
                }
            }    // namespace detail
 
            template<typename Mode = mode::upper>
            class hex {
                typedef typename detail::hex_policy<Mode> policy_type;
 
            public:
                typedef typename policy_type::mode_type mode_type;
 
                typedef nop_finalizer encoding_finalizer_type;
                typedef nop_finalizer decoding_finalizer_type;
                typedef nop_preprocessor encoding_preprocessor_type;
                typedef nop_preprocessor decoding_preprocessor_type;
 
                typedef typename detail::isomorphic_encoding_mode<hex<Mode>> stream_encoder_type;
                typedef typename detail::isomorphic_decoding_mode<hex<Mode>> stream_decoder_type;
 
                constexpr static const std::size_t encoded_value_bits = policy_type::encoded_value_bits;
                typedef typename policy_type::encoded_value_type encoded_value_type;
 
                constexpr static const std::size_t decoded_value_bits = policy_type::decoded_value_bits;
                typedef typename policy_type::decoded_value_type decoded_value_type;
 
                constexpr static const std::size_t encoded_block_values = policy_type::encoded_block_values;
                constexpr static const std::size_t encoded_block_bits = policy_type::encoded_block_bits;
                typedef typename policy_type::encoded_block_type encoded_block_type;
 
                constexpr static const std::size_t decoded_block_values = policy_type::decoded_block_values;
                constexpr static const std::size_t decoded_block_bits = policy_type::decoded_block_bits;
                typedef typename policy_type::decoded_block_type decoded_block_type;
 
                static encoded_block_type encode(const decoded_block_type &plaintext) {
                    BOOST_STATIC_ASSERT(std::tuple_size<decoded_block_type>::value == 1);
 
                    encoded_block_type res = {0};
 
                    typename encoded_block_type::iterator p = res.end();
                    typename decoded_block_type::value_type integral_plaintext = plaintext.back();
 
                    for (std::size_t i = 0; i < encoded_block_bits / CHAR_BIT && p != res.begin();
                         ++i, integral_plaintext >>= 4) {
                        *--p = policy_type::constants()[integral_plaintext & 0x0F];
                    }
 
                    return res;
                }
 
                static decoded_block_type decode(const encoded_block_type &plaintext) {
                    BOOST_STATIC_ASSERT(std::tuple_size<decoded_block_type>::value == 1);
 
                    decoded_block_type res = {0};
 
                    for (const typename encoded_block_type::value_type &v : plaintext) {
                        res[0] = (16 * res[0]) + hex_char_to_int(v);
                    }
 
                    return res;
                }
 
                template<typename ProcessingMode>
                using accumulator_mode_type = accumulators::preprocessing_accumulator_mode<ProcessingMode>;
 
                template<typename ProcessingMode, typename StateAccumulator, std::size_t ValueBits>
                struct stream_processor {
                    struct params_type {
                        typedef typename stream_endian::little_octet_big_bit endian_type;
 
                        constexpr static const std::size_t value_bits = ValueBits;
                        constexpr static const std::size_t length_bits = CHAR_BIT * CHAR_BIT;
                    };
 
                    typedef fixed_block_stream_processor<ProcessingMode, StateAccumulator, params_type> type;
                };
 
            protected:
                template<typename T>
                static uint8_t hex_char_to_int(T val) {
                    char c = static_cast<char>(val);
                    uint8_t retval = 0;
                    if (c >= '0' && c <= '9') {
                        retval = static_cast<uint8_t>(c - '0');
                    } else if (c >= 'A' && c <= 'F') {
                        retval = static_cast<uint8_t>(c - 'A' + 10);
                    } else if (c >= 'a' && c <= 'f') {
                        retval = static_cast<uint8_t>(c - 'a' + 10);
                    } else {
                        BOOST_THROW_EXCEPTION(non_hex_input() << bad_char(c));
                    }
                    return static_cast<char>(retval);
                }
            };
        }    // namespace codec
    }        // namespace crypto3
}    // namespace nil
 
#endif