168 lines
4.9 KiB
C++
168 lines
4.9 KiB
C++
/***************************************************************************
|
|
* Copyright (C) 2021 by Federico Amedeo Izzo IU2NUO, *
|
|
* Niccolò Izzo IU2KIN *
|
|
* Frederik Saraci IU2NRO *
|
|
* Silvano Seva IU2KWO *
|
|
* *
|
|
* This program is free software; you can redistribute it and/or modify *
|
|
* it under the terms of the GNU General Public License as published by *
|
|
* the Free Software Foundation; either version 3 of the License, or *
|
|
* (at your option) any later version. *
|
|
* *
|
|
* This program is distributed in the hope that it will be useful, *
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
|
|
* GNU General Public License for more details. *
|
|
* *
|
|
* You should have received a copy of the GNU General Public License *
|
|
* along with this program; if not, see <http://www.gnu.org/licenses/> *
|
|
***************************************************************************/
|
|
|
|
#ifndef M17_LINKSETUPFRAME_H
|
|
#define M17_LINKSETUPFRAME_H
|
|
|
|
#ifndef __cplusplus
|
|
#error This header is C++ only!
|
|
#endif
|
|
|
|
#include <string>
|
|
#include <array>
|
|
#include "M17Datatypes.h"
|
|
|
|
class M17FrameDecoder;
|
|
|
|
/**
|
|
* This class describes and handles an M17 Link Setup Frame.
|
|
* By default the frame contains a broadcast destination address, unless a
|
|
* specific address is set by calling the corresponding function.
|
|
*/
|
|
class M17LinkSetupFrame
|
|
{
|
|
public:
|
|
|
|
/**
|
|
* Constructor.
|
|
*/
|
|
M17LinkSetupFrame();
|
|
|
|
/**
|
|
* Destructor.
|
|
*/
|
|
~M17LinkSetupFrame();
|
|
|
|
/**
|
|
* Clear the frame content, filling it with zeroes and resetting the
|
|
* destination address to broadcast.
|
|
*/
|
|
void clear();
|
|
|
|
/**
|
|
* Set source callsign.
|
|
*
|
|
* @param callsign: string containing the source callsign.
|
|
*/
|
|
void setSource(const std::string& callsign);
|
|
|
|
/**
|
|
* Get source callsign.
|
|
*
|
|
* @return: string containing the source callsign.
|
|
*/
|
|
std::string getSource();
|
|
|
|
/**
|
|
* Set destination callsign.
|
|
*
|
|
* @param callsign: string containing the destination callsign.
|
|
*/
|
|
void setDestination(const std::string& callsign);
|
|
|
|
/**
|
|
* Get destination callsign.
|
|
*
|
|
* @return: string containing the destination callsign.
|
|
*/
|
|
std::string getDestination();
|
|
|
|
/**
|
|
* Get stream type field.
|
|
*
|
|
* @return a copy of the frame's tream type field.
|
|
*/
|
|
streamType_t getType();
|
|
|
|
/**
|
|
* Set stream type field.
|
|
*
|
|
* @param type: stream type field to be written.
|
|
*/
|
|
void setType(streamType_t type);
|
|
|
|
/**
|
|
* Get metadata field.
|
|
*
|
|
* @return a reference to frame's metadata field, allowing for both read and
|
|
* write access.
|
|
*/
|
|
meta_t& metadata();
|
|
|
|
/**
|
|
* Compute a new CRC over the frame content and update the corresponding
|
|
* field.
|
|
*/
|
|
void updateCrc();
|
|
|
|
/**
|
|
* Check if frame data is valid that is, if the CRC computed over the LSF
|
|
* fields matches the one carried by the LSF itself.
|
|
*
|
|
* @return true if CRC of LSF data matches the one stored in the LSF itself,
|
|
* false otherwise.
|
|
*/
|
|
bool valid();
|
|
|
|
/**
|
|
* Get underlying data.
|
|
*
|
|
* @return a pointer to const uint8_t allowing direct access to LSF data.
|
|
*/
|
|
const uint8_t *getData();
|
|
|
|
/**
|
|
* Generate one of the six possible LSF chunks for embedding in data frame's
|
|
* LICH field. Output is the Golay (24,12) encoded LSF chunk.
|
|
*
|
|
* @param segmentNum: segment number, between 0 and 5.
|
|
* @return Golay (24,12) encoded LSF chunk.
|
|
*/
|
|
lich_t generateLichSegment(const uint8_t segmentNum);
|
|
|
|
private:
|
|
|
|
/**
|
|
* Compute the CRC16 of a given chunk of data using the polynomial 0x5935
|
|
* with an initial value set to 0xFFFF, as per M17 specification.
|
|
*
|
|
* \param data: pointer to the data block.
|
|
* \param len: lenght of the data block, in bytes.
|
|
* \return computed CRC16 over the data block.
|
|
*/
|
|
uint16_t crc16(const void *data, const size_t len);
|
|
|
|
|
|
struct __attribute__((packed))
|
|
{
|
|
call_t dst; ///< Destination callsign
|
|
call_t src; ///< Source callsign
|
|
streamType_t type; ///< Stream type information
|
|
meta_t meta; ///< Metadata
|
|
uint16_t crc; ///< CRC
|
|
}
|
|
data; ///< Frame data.
|
|
|
|
// Frame decoder class needs to access raw frame data
|
|
friend class M17FrameDecoder;
|
|
};
|
|
|
|
#endif /* M17_LINKSETUPFRAME_H */
|