SMARTY 截取中文乱码

function smarty_modifier_truncate($string, $sublen = 80, $etc = '...',$break_words = false, $code ='UTF-8',  $middle = false)
{
    $start=0;

    if($code == 'UTF-8')
    {
        $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";
        preg_match_all($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;
    }
}