php判断字符串是否base64编码

//判断字符串是否是base64编码
方法一
pubclic function base64($str)
{
     return $str = = base64_encode(base64_decode($str)) ? true : false;
    
    
}
方法二：

if($member['nickname'] == base64_encode(base64_decode($member['nickname'])))
{
    $member['nickname'] = base64_decode(($member['nickname']));
}