//  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