function smarty_modifier_truncate($string,$sublen=80,$etc='...',$break_words=false,$middle=false){  
        $start=0;  
        $code="UTF-8";  
        if($code=='UTF-8'){  
            //如果有中文则减去中文的个数  
            $cncount=cncount($string);  
            if($cncount>($sublen/2)){  
                $sublen=ceil($sublen/2);  
            }else{  
               $sublen=$sublen-$cncount;  
           }  
            
           $pa="/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";  
           preg_match_all($pa,$string,$t_string);  
            
           if(count($t_string[0])-$start>$sublen)  
               return join('',array_slice($t_string[0],$start,$sublen))."...";  
           return join('',array_slice($t_string[0],$start,$sublen));  
       }else{  
           $start=$start*2;  
           $sublen=$sublen*2;  
           $strlen=strlen($string);  
           $tmpstr='';  
            
           for($i=0;$i<$strlen;$i++){  
               if($i>=$start&&$i<($start+$sublen)){  
                   if(ord(substr($string,$i,1))>129){  
                       $tmpstr.=substr($string,$i,2);  
                   }else{  
                       $tmpstr.=substr($string,$i,1);  
                   }  
               }  
               if(ord(substr($string,$i,1))>129)  
                   $i++;  
           }  
           if(strlen($tmpstr)<$strlen)  
               $tmpstr.="...";  
           return $tmpstr;  
       }  
    
   }  
    
   function cncount($str){  
       $len=strlen($str);  
       $cncount=0;  
        
       for($i=0;$i<$len;$i++){  
           $temp_str=substr($str,$i,1);  
            
           if(ord($temp_str)>127){  
               $cncount++;  
           }  
       }  
        
       return ceil($cncount/3);  
   }