Corrado Zoccolo wrote:
> BTW, the idea of the hand made vtable born in the discussion with gpd. My
> first implementation used just one function ptr to encapsulate all the
> behaviour (with a signature to fit all the methods), and was substantially
> less efficient than the current solution.
Instead of a hand make vtable, why not this?
struct impl_base
{
virtual void something(void*) = 0;
};
template<typename T>
struct impl
{
void something(void* p)
{
// do something useful
}
};
template<typename T>
class poly
{
template<typename U>
poly(const U& u)
{
new(&type_info) impl<U>;
...
}
typename boost::aligned_storage<
sizeof(impl<T>),
boost::alignment_of< impl<T> >
>::type type_info;
};
This simply assumes that all instances of impl have the same size and
alignment.
_______________________________________________
Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
