中文截取，支持gb2312,gbk,utf-8,big5

 

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

{ 

if(function_exists("mb_substr")) 

return mb_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; 

}