产生类似GUID的唯一ID

function puid($seperator='')
{
    //产生类似GUID的唯一ID，名为Php Unique ID或Personal Unique ID，简称PUID
    $mstime = str_replace( ' ', '@', microtime() );
    $address= ''; //$_SERVER['SERVER_NAME'].'('.$_SERVER['SCRIPT_NAME'].')<<'.$_SERVER['REMOTE_ADDR'].'#'.$_SERVER['HTTP_USER_AGENT'];
    $rnd = mt_rand(10000,99999).'-'.mt_rand(10000,99999).'-'.mt_rand(10000,99999).'-'.mt_rand(10000,99999).'-'.mt_rand(10000,99999);
    $pre_hash = $mstime.$address.$rnd;
    $aft_hash = strtoupper(md5($pre_hash));
    return $seperator?substr($aft_hash,0,8).$seperator.substr($aft_hash,8,4).$seperator.substr($aft_hash,12,4).$seperator.substr($aft_hash,16,4).$seperator.substr($aft_hash,20):$aft_hash;
}