// URL, Mail을 자동으로 체크하여 링크만듬
function autolink($str) {
 // URL 치환
$homepage_pattern = "/([^\"\'\=\>])(mms|http|HTTP|ftp|FTP|telnet|TELNET|news)\:\/\/(.[^\r\n\s\<\"\')]+)/i";
 $str = preg_replace($homepage_pattern,"\\1\\2://\\3", " ".$str);

 // 메일 치환
$email_pattern = "/([ \n]+)([a-z0-9\_\-\.]+)@([a-z0-9\_\-\.]+)/i";
 $and_pattern = array(" at ","[at]","{at}","(at)","_at_","~at~","(골뱅이)","[달팽이]");
 $str = preg_replace($email_pattern,"\\1\\2".$and_pattern[rand(0, count($and_pattern)-1)]."\\3", " ".$str);

 return $str;
}