return text;
    };

function replace_URLtolink($text) {
    // grab anything that looks like a URL...
    $urls = array();
   
    // build the patterns
    $scheme = '(https?\:\/\/|ftps?\:\/\/)?';
    $www = '([\w]+\.)';
    $local = 'localhost';
    $ip = '(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})';
    $name = '([\w0-9]+)';
    $tld = '(\w{2,4})';
    $port = '(:[0-9]+)?';
    $the_rest = '(\/?([\w#!:.?+=&%@!\-\/]+))?';
    $pattern = $scheme.'('.$ip.$port.'|'.$www.$name.$tld.$port.'|'.$local.$port.')'.$the_rest;
    $pattern = '/'.$pattern.'/is';
   
    // Get the URLs
    $c = preg_match_all($pattern, $text, $m);
   
    if ($c) {
        $urls = $m[0];
    }
   
    // Replace all the URLs
    if (! empty($urls)) {
        foreach ($urls as $url) {
            $pos = strpos('http\:\/\/', $url);
           
            if (($pos && $pos != 0) || !$pos) {
                $fullurl = 'http://'.$url;
            } else {
                $fullurl = $url;
            }
           
            $link = ''.$url.'';
           
            $text = str_replace($url, $link, $text);
        }
    }
   
    return $text;
}