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<?php

/**
 * Function: FormatCreditCard
 * Author : Nikhil Ben Kuruvilla
 * Date : 14th july 2010
 */
function FormatCreditCard($cc) {
    // REMOVE EXTRA DATA IF ANY
    $cc = str_replace(array('-', ' '), '', $cc);

    // GET THE CREDIT CARD LENGTH
    $cc_length = strlen($cc);


    $newCreditCard = substr($cc, -4);

    for ($i = $cc_length - 5; $i >= 0; $i--) {
        // ADDS HYPHEN HERE
        if ((($i + 1) - $cc_length) % 4 == 0) {
            $newCreditCard = '-' . $newCreditCard;
        }
        $newCreditCard = $cc[$i] . $newCreditCard;
    }

    // REPLACE CHARACTERS WITH X EXCEPT FIRST FOUR AND LAST FOUR
    for ($i = 4; $i < $cc_length - 4; $i++) {
        if ($newCreditCard[$i] == '-') {
            continue;
        }
        $newCreditCard[$i] = 'X';
    }

    // RETURN THE FINAL FORMATED AND MASKED CREDIT CARD NO
    return $newCreditCard;
}
?>