50 lines
1.2 KiB
C++
50 lines
1.2 KiB
C++
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#ifndef LENGTH_CODING_HPP_UQ1OIDUN
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#define LENGTH_CODING_HPP_UQ1OIDUN
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#include <vanetza/common/byte_buffer.hpp>
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#include <boost/range/iterator_range.hpp>
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#include <cstdint>
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#include <tuple>
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namespace vanetza
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{
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namespace security
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{
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namespace v2
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{
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/**
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* Calculate length coding for variable length fields
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* \param length Data field length in bytes, e.g. size of a buffer
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* \return byte buffer containing encoded length, prepend to data
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*/
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ByteBuffer encode_length(std::uintmax_t length);
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/**
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* Extract length information
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* \param buffer Buffer with input data, shall start with first byte of encoded length
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* \return iterator pointing at start of payload buffer (begin indicates error) and its length
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*/
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std::tuple<ByteBuffer::const_iterator, std::uintmax_t> decode_length(const ByteBuffer& buffer);
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/**
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* Count number of leading one bits
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* \param a byte
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* \return number of leadings ones in given byte
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*/
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std::size_t count_leading_ones(std::uint8_t);
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/**
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* Determines the number of bytes, needed to store a given size
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* \param size
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* \return number of bytes needed to store length
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*/
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std::size_t length_coding_size(std::uintmax_t);
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} // namespace v2
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} // namespace security
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} // namespace vanetza
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#endif /* LENGTH_CODING_HPP_UQ1OIDUN */
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