截图多余字符，中英文，避免截取中文乱码

截图多余字符，中英文都可以，避免截取中文结尾？？乱码！！

function utf8_strlen($string = null) {
// 将字符串分解为单元
preg_match_all('/./us', $string, $match);
// 返回单元个数
return count($match[0]);
}
function sub_content($content, $length){
$len = utf8_strlen($content);
for($i = 0 ; $i < $len ; $i++){
$arr[$i] = mb_substr($content,$i,1,'utf-8');
}
$get_length = 0;
$result = '';
foreach($arr as $code){
$result .= $code;
if(strlen($code) > 1){
$get_length += 2;
}else{
$get_length += 1;
}
if($get_length >= $length){
break;
}
}
return $result;
}
echo sub_content($rows["Description"],18);
/**
* 字符串截取，支持中文和其他编码
* @param string $str
* @param int $start
* @param int $length
* @param string $charset
* @param boolean $suffix
* @return string
*/
function w_substr($str, $start = 0, $length, $charset = "utf-8", $suffix = TRUE) {
$suffix_str = $suffix ? '…' : '';
if(function_exists('mb_substr')) {
return mb_substr($str, $start, $length, $charset) . $suffix_str;
} elseif(function_exists('iconv_substr')) {
return iconv_substr($str, $start, $length, $charset) . $suffix_str;
} else {
$pattern = array();
$pattern['utf-8'] = '/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/';
$pattern['gb2312'] = '/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/';
$pattern['gbk'] = '/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/';
$pattern['big5'] = '/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/';
preg_match_all($pattern[$charset], $str, $matches);
$slice = implode("", array_slice($matches[0], $start, $length));
return $slice . $suffix_str;
}
}