An implementation of Analog cellular networks like A-Netz, B-Netz, C-Netz, NMT, AMPS, TACS, JTACS, Radiocom 2000, IMTS, MPT1327, Eurosignal and more http://osmocom-analog.eversberg.eu/
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osmocom-analog/src/magnetic/iso7811.c

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3.2 KiB

/* ISO 7811 encoder/decoder
*
* (C) 2021 by Andreas Eversberg <jolly@eversberg.eu>
* All Rights Reserved
*
* 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/>.
*/
#include <stdint.h>
#include <string.h>
#include "iso7811.h"
/* Given is a string with or without start and end sentinel. Returned are
* bytes containing 5 bits each. These bits shall be sent LSB first.
* A lead-in and a start sentinel is added prior encoded string data.
* An end sentinel, a LRC and a lead-out is added after string data.
*/
int encode_track(uint8_t *data, const char *string, int lead_in, int lead_out)
{
int i;
uint8_t bits, lrc;
i = 0;
lrc = 0;
/* lead-in */
for (lead_in += i; i < lead_in; i++)
data[i] = 0;
/* start sentinel */
if (*string == ';')
string++;
bits = 0x0b;
data[i++] = bits;
lrc ^= bits;
/* string */
while (*string && *string != '?') {
if (*string >= 0x30 && *string < 0x40)
bits = *string - 0x30;
else
bits = 0;
data[i] = bits & 0x0f;
lrc ^= bits;
bits ^= bits >> 2;
bits ^= bits >> 1;
bits &= 1;
data[i] |= (bits ^ 1) << 4;
string++;
i++;
}
/* end sentinel */
bits = 0x1f;
data[i++] = bits;
lrc ^= bits;
/* LRC */
data[i] = lrc & 0x0f;
lrc ^= lrc >> 2;
lrc ^= lrc >> 1;
lrc &= 1;
data[i] |= (lrc ^ 1) << 4;
i++;
/* lead-out */
for (lead_out += i; i < lead_out; i++)
data[i] = 0;
return i;
}
/* n0nnnnnn=sssss0000 (in case of 7 digits) */
int cnetz_card(char *string, const char *number, const char *sicherung)
{
int len;
/* number */
len = strlen(number);
*string++ = *number++;
if (len == 7)
*string++ = '0';
else if (len == 8)
*string++ = *number++;
else
return 0;
*string++ = *number++;
*string++ = *number++;
*string++ = *number++;
*string++ = *number++;
*string++ = *number++;
*string++ = *number++;
/* field seperator */
*string++ = '=';
/* security code */
len = strlen(sicherung);
if (len < 5)
*string++ = '0';
else
*string++ = *sicherung++;
if (len < 4)
*string++ = '0';
else
*string++ = *sicherung++;
if (len < 3)
*string++ = '0';
else
*string++ = *sicherung++;
if (len < 2)
*string++ = '0';
else
*string++ = *sicherung++;
*string++ = *sicherung++;
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '\0';
return 18;
}
/* 0:500000=000000000 */
int bsa44_service(char *string)
{
*string++ = '0';
*string++ = ':';
*string++ = '5';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '=';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '0';
*string++ = '\0';
return 18;
}