117 lines
3.2 KiB
C++
117 lines
3.2 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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* 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_FRAME_H
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#define M17_FRAME_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 <cstring>
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#include <string>
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#include "M17Datatypes.h"
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/**
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* This class describes and handles a generic M17 data frame.
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*/
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class M17Frame
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{
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public:
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/**
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* Constructor.
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*/
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M17Frame()
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{
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clear();
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}
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/**
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* Destructor.
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*/
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~M17Frame(){ }
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/**
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* Clear the frame content, filling it with zeroes.
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*/
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void clear()
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{
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memset(&data, 0x00, sizeof(dataFrame_t));
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}
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/**
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* Set frame sequence number.
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*
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* @param seqNum: frame number, between 0 and 0x7FFF.
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*/
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void setFrameNumber(const uint16_t seqNum)
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{
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// NOTE: M17 fields are big-endian, we need to swap bytes
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data.frameNum = __builtin_bswap16(seqNum & 0x7fff);
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}
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/**
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* Mark this frame as the last one in the transmission, informing the
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* receiver that transmission ends.
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*/
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void lastFrame()
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{
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data.frameNum |= 0x0080;
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}
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/**
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* Access frame payload.
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*
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* @return a reference to frame's paylod field, allowing for both read and
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* write access.
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*/
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payload_t& payload()
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{
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return data.payload;
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}
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/**
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* Get underlying data.
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*
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* @return a pointer to const uint8_t allowing direct access to frame data.
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*/
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const uint8_t *getData()
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{
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return reinterpret_cast < const uint8_t * > (&data);
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}
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private:
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/**
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* Data structure corresponding to a full M17 data frame.
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*/
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typedef struct
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{
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uint16_t frameNum; ///< Frame number
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payload_t payload; ///< Payload data
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}
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__attribute__((packed)) dataFrame_t;
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dataFrame_t data; ///< Underlying frame data.
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};
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#endif /* M17_FRAME_H */
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