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F4KXL_DStarGateway/APRS/APRSUtils.cpp

62 lines
1.8 KiB

/*
* Copyright (C) 2021-2022 by Geoffrey Merck F4FXL / KC3FRA
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <boost/algorithm/string.hpp>
#include "APRSUtils.h"
void CAPRSUtils::dstarCallsignToAPRS(std::string& dstarCallsign)
{
if(dstarCallsign[dstarCallsign.length() - 1] == ' ') {
boost::trim(dstarCallsign);
} else {
//loop until got rid of all double blanks
while(dstarCallsign.find(" ") != std::string::npos) {
boost::replace_all(dstarCallsign, " ", " ");
}
boost::replace_all(dstarCallsign, " ", "-");//replace remaining blank with a -
}
}
unsigned int CAPRSUtils::calcGPSAIcomCRC(const std::string& gpsa)
{
unsigned int icomcrc = 0xFFFFU;
unsigned int dataBegin = 0U;
if(boost::starts_with(gpsa, "$$CRC") && gpsa.length() >= 10 && gpsa[9] == ',')
dataBegin = 10U;
auto length = gpsa.length();
for (unsigned int j = dataBegin; j < length; j++) {
unsigned char ch = (unsigned char)gpsa[j];
for (unsigned int i = 0U; i < 8U; i++) {
bool xorflag = (((icomcrc ^ ch) & 0x01U) == 0x01U);
icomcrc >>= 1;
if (xorflag)
icomcrc ^= 0x8408U;
ch >>= 1;
}
}
return ~icomcrc & 0xFFFFU;
}

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