/**
 * Function returns XML string for input associative array.
 * @param Array $array Input associative array
 * @param String $wrap Wrapping tag
 * @param Boolean $upper To set tags in uppercase
 */
function array2xml($array, $wrap='ROW0', $upper=true) {
    // set initial value for XML string
    $xml = '';
    // wrap XML with $wrap TAG
    if ($wrap != null) {
        $xml .= "<$wrap>\n";
    }
    // main loop
    foreach ($array as $key=>$value) {
        // set tags in uppercase if needed
        if ($upper == true) {
            $key = strtoupper($key);
        }
        // append to XML string
        $xml .= "<$key>" . htmlspecialchars(trim($value)) . "</$key>";
    }
    // close wrap TAG if needed
    if ($wrap != null) {
        $xml .= "\n</$wrap>\n";
    }
    // return prepared XML string
    return $xml;
}