/**
* Epand 8
*
* Expand a 8-digit UPC-E code to UPC-A 12 digit code.
* The first digit becomes the UPC-E Check Number and then the
* first and last digits are stripped. The last digit is then
* re-appended as the check digit;
*
* @param string $upc UPC-E Code to expand
* @return Returns the expanded UPC code
*/
private static function expand8($upc)
{
// Get literal first and last digits
$first = substr($upc, 0, 1);
$last = substr($upc, 7, 1);
// Strip UPC to middle 6 digits
$upc = substr($upc, 1, 6);
// Create UPC from 6 digit value
$upc = UpcEExpander::createUpcA($upc, $last, $last);
// Get new check digit and append
$checkDigit = \ProductValidator\UpcValidator\UpcValidator::getCheckDigit($upc);
$upc = substr($upc, 0, 11) . $checkDigit;
return $upc;
}
