字数限制截取

/**

 * 字数限制截取

 * 在字数不多余情况下不加...

 * */

function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true){

    if(mb_strlen($str,$charset)>$length){

         if(function_exists("mb_substr")){

             if($suffix){

                 return mb_substr($str, $start, $length, $charset)."...";

             }else{

                 return mb_substr($str, $start, $length, $charset);

             }

         }elseif(function_exists('iconv_substr')) {

             if($suffix){

                 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."...";

         }else{

             return $slice;

         }

    }else{

         return $str;

    }

}