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/* (C) 2011 by Holger Hans Peter Freyther
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdio.h>
#include <osmocom/core/bits.h>
#include "tetra_common.h"
#include <lower_mac/crc_simple.h>
int main(int argc, char **argv)
{
uint8_t input1[] = { 0x01 };
uint16_t crc;
crc = crc16_itut_bytes(0x0, input1, 8);
printf("The CRC is now: %u/0x%x\n", crc, crc);
crc = crc16_itut_bits(0x0, input1, 1);
printf("The CRC is now: %d/0x%x\n", crc, crc);
crc = crc16_itut_bytes(0xFFFF, input1, 8);
printf("The CRC is now: %u/0x%x\n", crc, crc);
crc = crc16_itut_bits(0xFFFF, input1, 1);
printf("The CRC is now: %d/0x%x\n", crc, crc);
/* actual CRC-CCIT usage */
uint8_t input2[] = {
0, 0, 0, 1, 0, 0, 0, 0,
1, 0, 1, 1, 0, 0, 0, 0,
1, 0, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 1, 1,
0, 0, 0, 0, 0, 1, 1, 1,
1, 1, 0, 1, 0, 0, 1, 1,
0, 0, 1, 1,
/* checksum */
1, 1, 0, 1, 1, 1, 1, 0,
1, 1, 1, 1, 0, 0, 0, 1,
/* tail bits */
0, 0, 0, 0 };
crc = ~crc16_itut_bits(0xffff, input2, 60);
printf("The CRC is now: %d/0x%x\n", crc, crc);
/* swap the bytes */
crc = (crc << 8) | (crc >> 8);
osmo_pbit2ubit(&input2[60], (uint8_t *)&crc, 16);
crc = crc16_itut_bits(0xFFFF, input2, 60 + 16);
printf("The CRC is now: %d/0x%x\n", crc, crc);
if (crc == 0x1d0f)
printf("Decoded successfully.\n");
else
printf("Failed to decode.\n");
return 0;
}
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