search for: is_contiguous_sequ

On Friday 15 May 2009 05:50, Jay Foad wrote: > > 3. Any comments on the patch itself? > > > > The one major thing to be aware of is that it isn't safe to use &V[0] > > when V is an empty std::vector > > Oh dear. That's a bit of a flaw in the plan. I suppose the solution is > to switch to SmallVector whenever this might be a problem. Or use iterators.

...… First, the above can be made safer so that ptr_range will reject e.g. std::list with a bit of metaprogramming: template<typename T> struct is_ptr { enum { value = false }; }; template<typename T> struct is_ptr<T*> { enum { value = true }; }; template<typename T> struct is_contiguous_sequence { enum { value = is_ptr<T::iterator>::value }; }; template<typename T, typename Alloc> struct is_contiguous_sequence<std::vector<T,Alloc> > { enum { value = true }; }; template<typename T, typename Ch, typename Alloc> struct is_contiguous_sequence<std::basic...

> 3. Any comments on the patch itself? > > The one major thing to be aware of is that it isn't safe to use &V[0] when V > is an empty std::vector Oh dear. That's a bit of a flaw in the plan. I suppose the solution is to switch to SmallVector whenever this might be a problem. I'm a bit concerned that any new &empty[0] problems that are introduced will go unnoticed.