字符串截取函数

 1 /**
 2      +----------------------------------------------------------
 3      * 字符串截取，支持中文和其他编码
 4      +----------------------------------------------------------
 5      * @static
 6      * @access public
 7      +----------------------------------------------------------
 8      * @param string $str 需要转换的字符串
 9      * @param string $start 开始位置
10      * @param string $length 截取长度
11      * @param string $charset 编码格式
12      * @param string $suffix 截断显示字符
13      +----------------------------------------------------------
14      * @return string
15      +----------------------------------------------------------
16      */
17 function msubstr2($str, $start=0, $length, $suffix=true, $charset="utf-8")
18 {
19     if(function_exists("mb_substr")){
20         if ($suffix && strlen($str)>$length)
21         return mb_substr($str, $start, $length, $charset)."...";
22         else
23         return mb_substr($str, $start, $length, $charset);
24     }
25     elseif(function_exists('iconv_substr')) {
26         if ($suffix && strlen($str)>$length)
27         return iconv_substr($str,$start,$length,$charset)."...";
28         else
29         return iconv_substr($str,$start,$length,$charset);
30     }
31     $re['utf-8']   = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
32     $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
33     $re['gbk']    = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
34     $re['big5']   = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
35     preg_match_all($re[$charset], $str, $match);
36     $slice = join("",array_slice($match[0], $start, $length));
37     if($suffix) return $slice."…";
38     return $slice;
39 }