一亩三分地

public function csubstr($str, $start=0, $length, $charset=”utf-8″, $suffix=true)
 {
  if(function_exists(“mb_substr”))
  {
   if(mb_strlen($str, $charset) <= $length) return $str;
   $slice = mb_substr($str, $start, $length, $charset);
  }
  else
  {
   $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, $match);
   if(count($match[0]) <= $length) return $str;
   $slice = join(“”,array_slice($match[0], $start, $length));
  }
  if($suffix) return $slice.”…”;
  return $slice;
 }