Getting a reference from a pointer inside a pointer_variant

[brenoguim]

Hey!
One of the problems I faced when implementing my tiny::pointer_variant<T*, U*> was to get a T**. Since (in my implementation), the first item of the variant has a 0 bit tag, the pointer actually has a non-dirty bit pattern, so it should be possible to take the pointer to the element inside the variant.
I had a hard time implementing that without violating strict aliasing rules. (And I still don't know if I was able to implement that without UB).

The motivation to get a T** is to be able to create a tiny::pointer_dyn_array<T*>, which is a pointer_variant<T*, T**>, and contains the T* when the array has size 1 (therefore avoiding allocation and indirection in size=1).
Since the tiny::pointer_dyn_array<T*> has a begin/end interface, it's necessary to get the T** from the variants first element.

Is there a plan to implement a pointer_dyn_array? I'm curious to know how you'd implement that.

[foonathan]

Yes, I plan on implementing that but haven’t thought about the problem yet.