[boost] Re: pointer_traits ?

From: Bohdan (warever_at_[hidden])
Date: 2002-09-25 05:10:46

"David B. Held" <dheld_at_[hidden]> wrote in message
news:amqs87$jd0$1_at_main.gmane.org...
> "Bohdan" <warever_at_[hidden]> wrote in message
> news:amqo40$888$1_at_main.gmane.org...
> > Does standart allow such iterators ?
>
> But, of course.  Pointers into arrays can be passed as iterators to
standard
> algorithms.  That was part of the motivation for the iterator design...to
> mimic builtin pointer types.  My STL implementation (RW) already has a
> specialization for T* (I assume it's standard).

I was unclear, sorry. I meant smart pointers lacking ++, -- operators.

> struct trivial_iterator_tag { };
>
> template <class T>
> struct iterator_traits< boost::shared_ptr<T> >
> {
>    typedef T value_type;
>    typedef std::ptrdiff_t difference_type;
>    typedef T* pointer;
>    typedef T& reference;
>    typedef trivial_iterator_tag iterator_category;
> };

difference_type for trivial_iterator ... maybe just void ?:

 struct trivial_iterator_tag { };

 template <class T>
 struct iterator_traits< boost::shared_ptr<T> >
 {
    typedef T                       value_type;
    typedef void                  difference_type;
    typedef T*                     pointer;
    typedef T&                    reference;
    typedef trivial_iterator_tag iterator_category;
 };