Re: [boost] using boost's reverse iterators with standard containers

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2001-12-09 22:09:49

How about a free-function solution instead?

template <typename Container>
typename boost::reference_iterator_generator<
    typename Container::iterator>::type
rbegin(Container& c) {
  return make_reverse_iterator(c.end());
}

// similarly for rend and the const versions...

Cheers,
Jeremy

On Sun, 9 Dec 2001, Dan Gohman wrote:
> Here's a class that wraps std::list, acting just like std::list except
> using the boost reverse iterators for rbegin and rend. One could wrap
> other containers in a similar manner. The primary benefit is that the
> boost reverse iterators handle interactions between const and non-const
> iterators better, which makes them more convenient.
>
> Would this be a useful thing, or should one just get in the habit of
> using make_reverse_iterator all the time? The reverse iteration stuff
> arguably doesn't belong in the container classes in the first place, so
> maybe the make_reverse_iterator way is better after all.
>
>
> #include <list>
> #include <boost/iterator_adaptors.hpp>
>
> template<class Type, class Alloc = std::allocator<Type> >
> class list : public std::list<Type, Alloc> {
> private:
>     typedef std::list<Type, Alloc> parent_type;
> public:
>     typedef boost::reverse_iterator_generator<parent_type::iterator>::type reverse_iterator;
>     typedef boost::reverse_iterator_generator<parent_type::const_iterator>::type const_reverse_iterator;
>
>     list() {}
>     list(size_type n): parent_type(n) {}
>     list(size_type n, Type const& t): parent_type(n, t) {}
>     list(parent_type const& other): parent_type(other) {}
>     template<class InputIterator> list(InputIterator f, InputIterator l): parent_type(f, l) {}
>
>     reverse_iterator rbegin() { return reverse_iterator(parent_type::end()); }
>     reverse_iterator rend() { return reverse_iterator(parent_type::begin()); }
>     const_reverse_iterator rbegin() const { return reverse_iterator(parent_type::end()); }
>     const_reverse_iterator rend() const { return reverse_iterator(parent_type::begin()); }
> };
>
> --
> Dan Gohman
> gohmandj_at_[hidden]
>
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----------------------------------------------------------------------
 Jeremy Siek                          http://www.osl.iu.edu/~jsiek/
 Ph.D. Student, Indiana Univ. B'ton   email: jsiek_at_[hidden]
 C++ Booster (http://www.boost.org)   office phone: [phone]
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