105 lines
3.1 KiB
C++
105 lines
3.1 KiB
C++
/*
|
|
be_matter_verhoeff.cpp - implements the Verhoeff algorithm to compute a checksum digit for QR Code
|
|
|
|
Copyright (C) 2023 Stephan Hadinger & Theo Arends
|
|
|
|
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 <string.h>
|
|
#include <stdbool.h>
|
|
#include "be_constobj.h"
|
|
#include "be_mapping.h"
|
|
|
|
// code inspired from https://www.programmingalgorithms.com/algorithm/verhoeff-algorithm/c/
|
|
|
|
static const int8_t _multiplicationTable[10][10] = {
|
|
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
|
|
{ 1, 2, 3, 4, 0, 6, 7, 8, 9, 5 },
|
|
{ 2, 3, 4, 0, 1, 7, 8, 9, 5, 6 },
|
|
{ 3, 4, 0, 1, 2, 8, 9, 5, 6, 7 },
|
|
{ 4, 0, 1, 2, 3, 9, 5, 6, 7, 8 },
|
|
{ 5, 9, 8, 7, 6, 0, 4, 3, 2, 1 },
|
|
{ 6, 5, 9, 8, 7, 1, 0, 4, 3, 2 },
|
|
{ 7, 6, 5, 9, 8, 2, 1, 0, 4, 3 },
|
|
{ 8, 7, 6, 5, 9, 3, 2, 1, 0, 4 },
|
|
{ 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 }
|
|
};
|
|
|
|
static const int8_t _permutationTable[10][10] = {
|
|
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
|
|
{ 1, 5, 7, 6, 2, 8, 3, 0, 9, 4 },
|
|
{ 5, 8, 0, 3, 7, 9, 6, 1, 4, 2 },
|
|
{ 8, 9, 1, 6, 0, 4, 3, 5, 2, 7 },
|
|
{ 9, 4, 5, 3, 1, 2, 6, 8, 7, 0 },
|
|
{ 4, 2, 8, 6, 5, 7, 3, 9, 0, 1 },
|
|
{ 2, 7, 9, 3, 8, 0, 6, 4, 1, 5 },
|
|
{ 7, 0, 4, 6, 9, 1, 3, 2, 5, 8 }
|
|
};
|
|
|
|
static const int8_t _inverseTable[10] = { 0, 4, 3, 2, 1, 5, 6, 7, 8, 9 };
|
|
|
|
static char ret_digit[] = "0"; // used as a placeholder to return a single digit string
|
|
|
|
const char* vh_checksum(const char* number) {
|
|
int32_t c = 0;
|
|
int32_t len = strlen(number);
|
|
|
|
for (int32_t i = 0; i < len; ++i) {
|
|
int8_t digit = number[len - i - 1] - '0';
|
|
if (digit < 0) { digit = 0; }
|
|
if (digit > 9) { digit = 9; }
|
|
c = _multiplicationTable[c][_permutationTable[((i + 1) % 8)][digit]];
|
|
}
|
|
|
|
ret_digit[0] = _inverseTable[c] + '0';
|
|
return ret_digit;
|
|
}
|
|
BE_FUNC_CTYPE_DECLARE(vh_checksum, "s", "s")
|
|
|
|
static bbool vh_validate(char* number) {
|
|
int32_t c = 0;
|
|
int32_t len = strlen(number);
|
|
|
|
for (int32_t i = 0; i < len; ++i) {
|
|
int8_t digit = number[len - i - 1] - '0';
|
|
if (digit < 0) { digit = 0; }
|
|
if (digit > 9) { digit = 9; }
|
|
c = _multiplicationTable[c][_permutationTable[(i % 8)][digit]];
|
|
}
|
|
return c == 0;
|
|
}
|
|
BE_FUNC_CTYPE_DECLARE(vh_validate, "b", "s")
|
|
|
|
#include "be_fixed_be_class_Matter_Verhoeff.h"
|
|
|
|
/* @const_object_info_begin
|
|
class be_class_Matter_Verhoeff (scope: global, name: Matter_Verhoeff, strings: weak) {
|
|
checksum, static_ctype_func(vh_checksum)
|
|
validate, static_ctype_func(vh_validate)
|
|
}
|
|
@const_object_info_end */
|
|
|
|
|
|
/*
|
|
|
|
# Unit tests
|
|
import matter
|
|
|
|
assert(matter.Verhoeff.checksum("236") == "3")
|
|
assert(matter.Verhoeff.validate("236"))
|
|
assert(matter.Verhoeff.checksum("58564") == "9")
|
|
assert(matter.Verhoeff.validate("585649"))
|
|
|
|
*/ |