// (C) Copyright Toon Knapen    2001.

// (C) Copyright David Abrahams 2003.

// (C) Copyright Roland Richter 2003.

// 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)

#ifndef BOOST_PERMUTATION_ITERATOR_HPP

#define BOOST_PERMUTATION_ITERATOR_HPP

#include <iterator>

#include <boost/iterator/iterator_adaptor.hpp>

namespace boost

{

template< class ElementIterator

        , class IndexIterator>

class permutation_iterator

  : public iterator_adaptor< 

             permutation_iterator<ElementIterator, IndexIterator>

           , IndexIterator, typename detail::iterator_traits<ElementIterator>::value_type

           , use_default, typename detail::iterator_traits<ElementIterator>::reference>

{

  typedef iterator_adaptor< 

            permutation_iterator<ElementIterator, IndexIterator>

          , IndexIterator, typename detail::iterator_traits<ElementIterator>::value_type

          , use_default, typename detail::iterator_traits<ElementIterator>::reference> super_t;

  friend class iterator_core_access;

public:

  permutation_iterator() : m_elt_iter() {}

  explicit permutation_iterator(ElementIterator x, IndexIterator y) 

      : super_t(y), m_elt_iter(x) {}

  template<class OtherElementIterator, class OtherIndexIterator>

  permutation_iterator(

      permutation_iterator<OtherElementIterator, OtherIndexIterator> const& r

      , typename enable_if_convertible<OtherElementIterator, ElementIterator>::type* = 0

      , typename enable_if_convertible<OtherIndexIterator, IndexIterator>::type* = 0

      )

    : super_t(r.base()), m_elt_iter(r.m_elt_iter)

  {}

private:

    typename super_t::reference dereference() const

        { return *(m_elt_iter + *this->base()); }

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

    template <class,class> friend class permutation_iterator;

#else

 public:

#endif 

    ElementIterator m_elt_iter;

};

template <class ElementIterator, class IndexIterator>

permutation_iterator<ElementIterator, IndexIterator> 

make_permutation_iterator( ElementIterator e, IndexIterator i )

{

    return permutation_iterator<ElementIterator, IndexIterator>( e, i );

}

} // namespace boost

#endif