115 lines
4.2 KiB
C++
115 lines
4.2 KiB
C++
/**
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* Copyright (C) 2015 Topology LP
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* Copyright (C) 2018 Jakob Petsovits
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef CPPCODEC_DETAIL_HEX
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#define CPPCODEC_DETAIL_HEX
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#include <stdint.h>
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#include <stdlib.h> // for abort()
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#include "../data/access.hpp"
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#include "../parse_error.hpp"
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#include "stream_codec.hpp"
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namespace cppcodec {
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namespace detail {
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template <typename CodecVariant>
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class hex : public CodecVariant::template codec_impl<hex<CodecVariant>>
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{
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public:
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static inline constexpr uint8_t binary_block_size() { return 1; }
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static inline constexpr uint8_t encoded_block_size() { return 2; }
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static CPPCODEC_ALWAYS_INLINE constexpr uint8_t num_encoded_tail_symbols(uint8_t /*num_bytes*/) noexcept
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{
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// Hex encoding only works on full bytes so there are no tails,
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// no padding characters, and this function should (must) never be called.
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return 0;
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}
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template <uint8_t I>
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static CPPCODEC_ALWAYS_INLINE constexpr uint8_t index(
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const uint8_t* b /*binary block*/) noexcept
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{
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static_assert(I >= 0 && I < encoded_block_size(),
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"invalid encoding symbol index in a block");
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return (I == 0) ? (b[0] >> 4) // first 4 bits
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: /*I == 1*/ (b[0] & 0xF); // last 4 bits
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}
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// With only 2 bytes, enc<1> will always result in a full index() call and
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// enc<0> will be protected by a not-reached assertion, so we don't actually
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// care about index_last() except optimizing it out as good as possible.
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template <bool B>
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using uint8_if = typename std::enable_if<B, uint8_t>::type;
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template <uint8_t I>
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static CPPCODEC_ALWAYS_INLINE constexpr uint8_if<I == 0> index_last(
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const uint8_t* /*binary block*/) noexcept
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{
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return 0;
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}
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template <uint8_t I>
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static CPPCODEC_ALWAYS_INLINE uint8_if<I != 0> index_last(
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const uint8_t* /*binary block*/)
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{
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throw std::domain_error("invalid last encoding symbol index in a tail");
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}
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template <typename Result, typename ResultState>
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static CPPCODEC_ALWAYS_INLINE void decode_block(
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Result& decoded, ResultState&, const alphabet_index_t* idx);
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template <typename Result, typename ResultState>
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static CPPCODEC_ALWAYS_INLINE void decode_tail(
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Result& decoded, ResultState&, const alphabet_index_t* idx, size_t idx_len);
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};
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template <typename CodecVariant>
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template <typename Result, typename ResultState>
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CPPCODEC_ALWAYS_INLINE void hex<CodecVariant>::decode_block(
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Result& decoded, ResultState& state, const alphabet_index_t* idx)
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{
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data::put(decoded, state, static_cast<uint8_t>((idx[0] << 4) | idx[1]));
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}
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template <typename CodecVariant>
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template <typename Result, typename ResultState>
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CPPCODEC_ALWAYS_INLINE void hex<CodecVariant>::decode_tail(
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Result&, ResultState&, const alphabet_index_t*, size_t)
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{
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throw invalid_input_length(
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"odd-length hex input is not supported by the streaming octet decoder, "
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"use a place-based number decoder instead");
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}
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} // namespace detail
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} // namespace cppcodec
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#endif // CPPCODEC_DETAIL_HEX
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