72 lines
1.9 KiB
C++
72 lines
1.9 KiB
C++
/*
|
|
* Copyright (C) 2020 by Jonathan Naylor G4KLX
|
|
*
|
|
* 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 "M17Utils.h"
|
|
|
|
#include <cassert>
|
|
|
|
const std::string M17_CHARS = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/.";
|
|
|
|
void CM17Utils::encodeCallsign(const std::string& callsign, unsigned char* encoded)
|
|
{
|
|
assert(encoded != NULL);
|
|
|
|
unsigned int len = callsign.size();
|
|
if (len > 9U)
|
|
len = 9U;
|
|
|
|
uint64_t enc = 0ULL;
|
|
for (int i = len - 1; i >= 0; i--) {
|
|
size_t pos = M17_CHARS.find(callsign[i]);
|
|
if (pos == std::string::npos)
|
|
pos = 0ULL;
|
|
|
|
enc *= 40ULL;
|
|
enc += pos;
|
|
}
|
|
|
|
encoded[0U] = enc >> 40;
|
|
encoded[1U] = enc >> 32;
|
|
encoded[2U] = enc >> 24;
|
|
encoded[3U] = enc >> 16;
|
|
encoded[4U] = enc >> 8;
|
|
encoded[5U] = enc >> 0;
|
|
}
|
|
|
|
void CM17Utils::decodeCallsign(const unsigned char* encoded, std::string& callsign)
|
|
{
|
|
assert(encoded != NULL);
|
|
|
|
callsign.empty();
|
|
|
|
uint64_t enc = (uint64_t(encoded[0U]) << 40) +
|
|
(uint64_t(encoded[1U]) << 32) +
|
|
(uint64_t(encoded[2U]) << 24) +
|
|
(uint64_t(encoded[3U]) << 16) +
|
|
(uint64_t(encoded[4U]) << 8) +
|
|
(uint64_t(encoded[5U]) << 0);
|
|
|
|
if (enc >= 262144000000000ULL) // 40^9
|
|
return;
|
|
|
|
while (enc > 0ULL) {
|
|
callsign += " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."[enc % 40ULL];
|
|
enc /= 40ULL;
|
|
}
|
|
}
|
|
|