Emarref\Jwt\Encoding\Base64::urlDecode PHP Метод

    protected function urlDecode($value)
    {
        $urlUnsafeReplacements = array_flip(self::$urlSafeReplacements);
        $value = strtr($value, $urlUnsafeReplacements);
        switch (strlen($value) % 4) {
            case 0:
                // No pad chars in this case
                break;
            case 2:
                $value .= '==';
                break;
            case 3:
                $value .= '=';
                break;
            case 1:
            default:
                throw new \RuntimeException('Value could not be decoded from URL safe representation.');
        }
        return $value;
    }