diff options
Diffstat (limited to 'src/magnetic/iso7811.c')
| -rw-r--r-- | src/magnetic/iso7811.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/magnetic/iso7811.c b/src/magnetic/iso7811.c new file mode 100644 index 0000000..214251e --- /dev/null +++ b/src/magnetic/iso7811.c @@ -0,0 +1,162 @@ +/* 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; +} + |