[boost] Re: Re: optional<>: size optimization

From: Gennadiy Rozental (gennadiy.rozental_at_[hidden])
Date: 2003-04-20 04:52:42

> In fact, it might be tempting to use the other bits as well.
> For example, I'd imagine a variant implementation that uses
> 8 bits to flag the currently active type. I imagine this interface:
>
>     template <class T>
>     class aligned_storage
>     {
>         public:
>
>         void const*     address() const;
>         void*           address();
>
>         unsigned char   tag() const;
>         void            tag(unsigned char data);
>     };

In fact it might be tempting to use all of them available:

template <class T>
class aligned_storage
{
    typedef ... max_size_type_that_fit_in_padding;
public:

    void const*      address() const;
    void*               address();

    max_size_type_that_fit_in_padding   tag() const;
    void                 tag(max_size_type_that_fit_in_padding data);
};

Gennadiy.