163 lines
3.2 KiB
C
163 lines
3.2 KiB
C
/* ISO 7811 encoder/decoder
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*
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* (C) 2021 by Andreas Eversberg <jolly@eversberg.eu>
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* All Rights Reserved
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <string.h>
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#include "iso7811.h"
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/* Given is a string with or without start and end sentinel. Returned are
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* bytes containing 5 bits each. These bits shall be sent LSB first.
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* A lead-in and a start sentinel is added prior encoded string data.
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* An end sentinel, a LRC and a lead-out is added after string data.
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*/
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int encode_track(uint8_t *data, const char *string, int lead_in, int lead_out)
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{
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int i;
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uint8_t bits, lrc;
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i = 0;
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lrc = 0;
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/* lead-in */
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for (lead_in += i; i < lead_in; i++)
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data[i] = 0;
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/* start sentinel */
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if (*string == ';')
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string++;
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bits = 0x0b;
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data[i++] = bits;
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lrc ^= bits;
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/* string */
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while (*string && *string != '?') {
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if (*string >= 0x30 && *string < 0x40)
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bits = *string - 0x30;
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else
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bits = 0;
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data[i] = bits & 0x0f;
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lrc ^= bits;
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bits ^= bits >> 2;
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bits ^= bits >> 1;
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bits &= 1;
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data[i] |= (bits ^ 1) << 4;
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string++;
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i++;
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}
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/* end sentinel */
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bits = 0x1f;
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data[i++] = bits;
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lrc ^= bits;
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/* LRC */
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data[i] = lrc & 0x0f;
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lrc ^= lrc >> 2;
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lrc ^= lrc >> 1;
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lrc &= 1;
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data[i] |= (lrc ^ 1) << 4;
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i++;
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/* lead-out */
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for (lead_out += i; i < lead_out; i++)
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data[i] = 0;
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return i;
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}
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/* n0nnnnnn=sssss0000 (in case of 7 digits) */
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int cnetz_card(char *string, const char *number, const char *sicherung)
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{
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int len;
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/* number */
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len = strlen(number);
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*string++ = *number++;
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if (len == 7)
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*string++ = '0';
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else if (len == 8)
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*string++ = *number++;
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else
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return 0;
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*string++ = *number++;
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*string++ = *number++;
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*string++ = *number++;
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*string++ = *number++;
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*string++ = *number++;
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*string++ = *number++;
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/* field seperator */
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*string++ = '=';
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/* security code */
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len = strlen(sicherung);
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if (len < 5)
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*string++ = '0';
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else
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*string++ = *sicherung++;
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if (len < 4)
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*string++ = '0';
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else
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*string++ = *sicherung++;
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if (len < 3)
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*string++ = '0';
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else
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*string++ = *sicherung++;
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if (len < 2)
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*string++ = '0';
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else
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*string++ = *sicherung++;
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*string++ = *sicherung++;
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '\0';
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return 18;
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}
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/* 0:500000=000000000 */
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int bsa44_service(char *string)
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{
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*string++ = '0';
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*string++ = ':';
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*string++ = '5';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '=';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '0';
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*string++ = '\0';
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return 18;
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}
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