/**

* 中文截取函数

*/

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

if(function_exists("mb_substr"))

$slice = mb_substr($str, $start, $length, $charset);

elseif(function_exists('iconv_substr')) {

$slice = iconv_substr($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);

$slice = join("",array_slice($match[0], $start, $length));

}

if(strlen($str) > strlen($slice)){

return $suffix ? $slice.'...' : $slice;

}else{

return $slice;

}

}