php解决ltrim和rtrim中文乱码

if(!function_exists('mb_ltrim')){
    function mb_ltrim($str, $char){
        if(empty($str)) return '';
        while (mb_substr($str, 0, 1) == $char){
            $str = mb_substr($str, 1);
        }
        return $str;
    }
}
if(!function_exists('mb_rtrim')){
    function mb_rtrim($str, $char){
        if(empty($str)) return '';
        while (mb_substr($str, -1, 1) == $char){
            $str = mb_substr($str, 0, -1);
        }
        return $str;
    }
}