PKPFileUploadWizardHandler::_onlyNumbersDiffer PHP Method

    function _onlyNumbersDiffer($a, $b)
    {
        if ($a == $b) {
            return false;
        }
        $pattern = '/([^0-9]*)([0-9]*)([^0-9]*)/';
        $aMatchCount = preg_match_all($pattern, $a, $aMatches, PREG_SET_ORDER);
        $bMatchCount = preg_match_all($pattern, $b, $bMatches, PREG_SET_ORDER);
        if ($aMatchCount != $bMatchCount || $aMatchCount == 0) {
            return false;
        }
        // Check each match. If the 1st and 3rd (text) parts all match
        // then only numbers differ in the two supplied strings.
        for ($i = 0; $i < count($aMatches); $i++) {
            if ($aMatches[$i][1] != $bMatches[$i][1]) {
                return false;
            }
            if ($aMatches[$i][3] != $bMatches[$i][3]) {
                return false;
            }
        }
        // No counterexamples were found. Only numbers differ.
        return true;
    }