thinkphp截取字符串函数无法显示省略号怎么解决？

function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
{
  if(function_exists("mb_substr")) {
   if($suffix)
  {
     if($str==mb_substr($str, $start, $length, $charset))
     {
      return mb_substr($str, $start, $length, $charset);
     }
     else
     {
      return mb_substr($str, $start, $length, $charset)."...";
     }
 } // www.jb200.com
    else
 {
   return mb_substr($str, $start, $length, $charset);
  }
  }
  elseif(function_exists('iconv_substr')) {
   if($suffix)
  {
     if($str==iconv_substr($str,$start,$length,$charset))
     {
      return iconv_substr($str,$start,$length,$charset);
     }
     else
     {
      return iconv_substr($str,$start,$length,$charset)."...";
     }
   }
    else
 {
   return iconv_substr($str,$start,$length,$charset);
  }
  }
  $re['utf-8']  = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/";
  $re['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";
  $re['gbk']  = "/[x01-x7f]|[x81-xfe][x40-xfe]/";
  $re['big5']  = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";
  preg_match_all($re[$charset], $str, $match);
  $slice = join("",array_slice($match[0], $start, $length));
  if($suffix) return $slice."…";
  return $slice;
}