122 lines
4.1 KiB
C++
122 lines
4.1 KiB
C++
/***************************************************************************
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* Copyright (C) 2021 by Federico Amedeo Izzo IU2NUO, *
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* Niccolò Izzo IU2KIN *
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* Frederik Saraci IU2NRO *
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* Silvano Seva IU2KWO *
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* *
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* Adapted from original code written by Rob Riggs, Mobilinkd LLC *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#ifndef M17_CODE_PUNCTURING_H
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#define M17_CODE_PUNCTURING_H
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#ifndef __cplusplus
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#error This header is C++ only!
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#endif
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#include <experimental/array>
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#include "M17Utils.h"
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/**
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* Puncture matrix for linx setup frame.
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*/
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static constexpr auto LSF_PUNCTURE = std::experimental::make_array< uint8_t >
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(
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1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1,
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0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1,
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1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1
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);
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/**
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* Puncture matrix for audio frames.
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*/
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static constexpr auto DATA_PUNCTURE = std::experimental::make_array< uint8_t >
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(
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1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 0
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);
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/**
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* Apply a given puncturing scheme to a byte array.
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*
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* \param input: input byte array.
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* \param output: output byte array, containing puntured data.
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* \param puncture: puncturing matrix, stored as an array of 8 bit values.
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* \return resulting bit count after punturing.
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*/
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template < size_t IN, size_t OUT, size_t P >
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size_t puncture(const std::array< uint8_t, IN >& input,
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std::array< uint8_t, OUT >& output,
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const std::array< uint8_t, P >& puncture)
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{
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size_t outIndex = 0;
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size_t punctIndex = 0;
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size_t bit_count = 0;
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for(size_t i = 0; i < 8*IN && outIndex < 8*OUT; i++)
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{
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if(puncture[punctIndex++])
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{
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setBit(output, outIndex++, getBit(input, i));
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bit_count++;
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}
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if(punctIndex == P) punctIndex = 0;
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}
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return bit_count;
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}
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/**
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* Apply the inverse puncturing scheme to a byte array, thus expanding its bits.
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*
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* \param input: input byte array, containing puntured data.
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* \param output: output byte array, containing depuntured data.
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* \param puncture: puncturing matrix, stored as an array of 8 bit values.
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* \return number of zero bits added to the input sequence for depunturing.
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*/
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template < size_t IN, size_t OUT, size_t P >
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size_t depuncture(const std::array< uint8_t, IN >& input,
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std::array< uint8_t, OUT >& output,
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const std::array< uint8_t, P >& puncture)
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{
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size_t inpIndex = 0;
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size_t punctIndex = 0;
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size_t bit_count = 0;
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for(size_t i = 0; i < 8*OUT && inpIndex < 8*IN; i++)
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{
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if(puncture[punctIndex++])
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{
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setBit(output, i, getBit(input, inpIndex++));
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}
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else
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{
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setBit(output, i, 0);
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bit_count++;
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}
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if(punctIndex == P) punctIndex = 0;
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}
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return bit_count;
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}
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#endif /* M17_CODE_PUNCTURING_H */
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