Below code shows how to check XML element by preg_match

function crcExists($crc32) {
        $fp = @fopen( "./crc32.xml", "r");
        if ($fp) {
                while( !feof($fp)) {
                        $buff = fgets($fp, 10240);
                        $buff = trim($buff);
                        echo $buff . "\n";
                        $buff=str_replace("\n", "", $buff);
                        if (preg_match("/\<crc32\>" . $crc32 . "\<\/crc32\>/", $buff)) {
                                echo "url found<br>";
                                return true;
                        }
                }
                fclose($fp);
        }
        return false;
}