php mb_chunk_split函数支持宽字符分割

/**
 * 分割字符串
 * @param String $str  要分割的字符串
 * @param int $length  指定的长度
 * @param String $end  在分割后的字符串块追加的内容
 */
function mb_chunk_split($string, $length, $end, $once = false){
    $string = iconv('gb2312', 'utf-8//ignore', $string);
    $array = array();
    $strlen = mb_strlen($string);
    while($strlen){
        $array[] = mb_substr($string, 0, $length, "utf-8");
        if($once)
            return $array[0] . $end;
        $string = mb_substr($string, $length, $strlen, "utf-8");
        $strlen = mb_strlen($string);
    }
    return implode($end, $array);
}

$str = 's六一马上$就dfs要到$@#了';
$str1 = 'aabbccddeefff';
echo mb_chunk_split($str, 3, '...', true); //s六一...马上$...就df...s要到...$@#...了
echo "";
echo mb_chunk_split($str1, 2, '...'); //aa...bb...cc...dd...ee...ff...f