thinkphp截取中文字符串的程序代码

function truncate_cn($string,$length=0,$ellipsis='…',$start=0){
 $string=strip_tags($string);
 $string=preg_replace('/n/is','',$string);
 //$string=preg_replace('/ |　/is','',$string);//清除字符串中的空格
 $string=preg_replace('/ /is','',$string);
 preg_match_all("/[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]/",$string,$string);
 if(is_array($string)&&!empty($string[0])){
  $string=implode('',$string[0]);
  if(strlen($string)<$start+1){
   return '';
  }
  preg_match_all("/./su",$string,$ar);
  $string2='';
  $tstr='';
  //www.111com.net
  for($i=0;isset($ar[0][$i]);$i++){
   if(strlen($tstr)<$start){
    $tstr.=$ar[0][$i];
   }else{
    if(strlen($string2)<$length+strlen($ar[0][$i])){
     $string2.=$ar[0][$i];
    }else{
     break;
    }
   }
  }
  return $string==$string2?$string2:$string2.$ellipsis;
 }else{
  $string='';
 }
 return $string;
}

{$info.subject|truncate_cn=40,'',0}