Last active
March 1, 2020 15:44
-
-
Save wurin7i/5657244 to your computer and use it in GitHub Desktop.
Damm validation & generation code in PHP.Damm algorithm is a check digit algorithm that detects all single-digit errors and all adjacent transposition errors.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<?php | |
/** | |
* The Damm check digit | |
* For more information cf. http://en.wikipedia.org/wiki/Damm_algorithm | |
* totally anti-symmetric quasigroup | |
* | |
* @author Wuri Nugrahadi <w.nugrahadi@gmail.com> | |
*/ | |
if (! function_exists('taq')) | |
{ | |
function taq($digits) | |
{ | |
$taq_table = array( | |
'0317598642', '7092154863', '4206871359', '1750983426', '6123045978', | |
'3674209581', '5869720134', '8945362017', '9438617205', '2581436790'); | |
$interim = 0; | |
foreach (str_split($digits) as $digit) { | |
if (! preg_match('~\d~', $digit)) | |
{ | |
return FALSE; | |
} | |
$interim = substr($taq_table[$interim], $digit, 1); | |
} | |
return $interim; | |
} | |
} | |
if (! function_exists('calc_check_digit')) | |
{ | |
function calc_check_digit($digits) | |
{ | |
return $digits.taq($digits); | |
} | |
} | |
if (! function_exists('is_check_digit_valid')) | |
{ | |
function is_check_digit_valid($digits) | |
{ | |
return taq($digits) == 0; | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function taq(digits) | |
{ | |
var taqTable = ['0317598642', '7092154863', '4206871359', '1750983426', '6123045978', '3674209581', '5869720134', '8945362017', '9438617205', '2581436790']; | |
var interim = 0; | |
var chars = digits.split(''); | |
var index, len; | |
for (index = 0, len = chars.length; index < len; ++index) { | |
var digit = parseInt(chars[index]); | |
var taqRow = taqTable[interim]; | |
var strInterim = taqRow.substr(digit, 1); | |
interim = parseInt(strInterim); | |
} | |
return interim; | |
} | |
console.log(taq('8436714657207786')); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment