Credit Card Identification and Validation Class - The credit_card class
provides methods for cleaning, validating and identifying the type of credit card numbers.
<?php
class credit_card
{
function clean_no ($cc_no)
{
// Remove non-numeric characters from $cc_no
return ereg_replace ('[^0-9]+', '', $cc_no);
}
function identify ($cc_no)
{
$cc_no = credit_card::clean_no ($cc_no);
// Get card type based on prefix and length of card number
if (ereg ('^4(.{12}|.{15})$', $cc_no))
return 'Visa';
if (ereg ('^5[1-5].{14}$', $cc_no))
return 'Mastercard';
if (ereg ('^3[47].{13}$', $cc_no))
return 'American Express';
if (ereg ('^3(0[0-5].{11}|[68].{12})$', $cc_no))
return 'Diners Club/Carte Blanche';
if (ereg ('^6011.{12}$', $cc_no))
return 'Discover Card';
if (ereg ('^(3.{15}|(2131|1800).{11})$', $cc_no))
return 'JCB';
if (ereg ('^2(014|149).{11})$', $cc_no))
return 'enRoute';
return 'unknown';
}
function validate ($cc_no)
{
// Reverse and clean the number
$cc_no = strrev (credit_card::clean_no ($cc_no));
// VALIDATION ALGORITHM
// Loop through the number one digit at a time
// Double the value of every second digit (starting from the right)
// Concatenate the new values with the unaffected digits
for ($ndx = 0; $ndx < strlen ($cc_no); ++$ndx)
$digits .= ($ndx % 2) ? $cc_no[$ndx] * 2 : $cc_no[$ndx];
// Add all of the single digits together
for ($ndx = 0; $ndx < strlen ($digits); ++$ndx)
$sum += $digits[$ndx];
// Valid card numbers will be transformed into a multiple of 10
return ($sum % 10) ? FALSE : TRUE;
}
function check ($cc_no)
{
$valid = credit_card::validate ($cc_no);
$type = credit_card::identify ($cc_no);
return array ($valid, $type, 'valid' => $valid, 'type' => $type);
}
}
?>
