PHP截取中文字符串乱码问题解决

/**<br />	     * <br />	     * @todo 截取中文字符串不乱码<br />	     * @param string $str<br />	     * @param int $start<br />	     * @param int $length<br />	     * @param string $charset<br />	     * @param string $suffix<br />	     */<br />	    function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true) {<br />	        if(function_exists("mb_substr"))<br />	            $slice = mb_substr($str, $start, $length, $charset);<br />	        elseif(function_exists('iconv_substr')) {<br />	            $slice = iconv_substr($str,$start,$length,$charset);<br />	        }else{<br />	            $re['utf-8']   = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";<br />	            $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";<br />	            $re['gbk']    = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";<br />	            $re['big5']   = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";<br />	            preg_match_all($re[$charset], $str, $match);<br />	            $slice = join("",array_slice($match[0], $start, $length));<br />	        }<br />	        return $suffix ? $slice.'...' : $slice;<br />	    }