//  interator.hpp workarounds for non-conforming standard libraries  ---------//

//  (C) Copyright Beman Dawes 2000. Distributed under the Boost

//  Software License, Version 1.0. (See accompanying file

//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

//  See http://www.boost.org/libs/utility for documentation.

//  Revision History

//  12 Jan 01 added <cstddef> for std::ptrdiff_t (Jens Maurer)

//  28 Jun 00 Workarounds to deal with known MSVC bugs (David Abrahams)

//  26 Jun 00 Initial version (Jeremy Siek)

#ifndef BOOST_ITERATOR_HPP

#define BOOST_ITERATOR_HPP

#include <iterator>

#include <cstddef>           // std::ptrdiff_t

#include <boost/config.hpp>

namespace boost

{

# if defined(BOOST_NO_STD_ITERATOR) && !defined(BOOST_MSVC_STD_ITERATOR)

  template <class Category, class T,

    class Distance = std::ptrdiff_t,

    class Pointer = T*, class Reference = T&>

  struct iterator

  {

    typedef T         value_type;

    typedef Distance  difference_type;

    typedef Pointer   pointer;

    typedef Reference reference;

    typedef Category  iterator_category;

  };

# else

  // declare iterator_base in namespace detail to work around MSVC bugs which

  // prevent derivation from an identically-named class in a different namespace.

  namespace detail {

   template <class Category, class T, class Distance, class Pointer, class Reference>

#  if !defined(BOOST_MSVC_STD_ITERATOR)

   struct iterator_base : std::iterator<Category, T, Distance, Pointer, Reference> {};

#  else

   struct iterator_base : std::iterator<Category, T, Distance>

   {

     typedef Reference reference;

     typedef Pointer pointer;

     typedef Distance difference_type;

   };

#  endif

  }

  template <class Category, class T, class Distance = std::ptrdiff_t,

            class Pointer = T*, class Reference = T&>

  struct iterator : boost::detail::iterator_base<Category, T, Distance, Pointer, Reference> {};

# endif

} // namespace boost

#endif // BOOST_ITERATOR_HPP