On Sun, Oct 16, 2011 at 6:22 PM, Rhys Ulerich <rhys.ulerich@gmail.com> wrote:
Why? The class owns the content. A range does not own the content.
Because the class knows its end. A shared_array does not know its end. And because your implementation is-an iterator_range.
That's because shared_array is handicapped. ;) boost/std::array knows it's size. Even the size of a C array can be determined.
Re: Peter Dimov's comment that:
One question you'll invariably get from people is why you don't store begin into the shared_ptr, eliminating one pointer...
shared_ptr<T> begin_; size_t size_;
If one thinks of the class as a resource-owning iterator_range, I think a three member (shared_ptr/iterator_range) implementation gives more flexibility (e.g. sub range instances could track resource ownership against the same shared_ptr).
If one thinks of the class as a shared_array with a length function, the two member (shared_ptr/size_t) implementation is definitely more space efficient. In that case, I'd personally not publicly inherit from iterator_range and would follow Peter's implementation suggestion (possibly using a shared_array instead of a shared_ptr).
Both allow sub ranges. But yeah, a 3 ptr class (begin, end and counter) is ideal. Olaf