boost/iterator/permutation_iterator.hpp

// (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 {
namespace iterators {
template< class ElementIterator
        , class IndexIterator>
class permutation_iterator
  : public iterator_adaptor<
             permutation_iterator<ElementIterator, IndexIterator>
           , IndexIterator, typename boost::detail::iterator_traits<ElementIterator>::value_type
           , use_default, typename boost::detail::iterator_traits<ElementIterator>::reference>
{
  typedef iterator_adaptor<
            permutation_iterator<ElementIterator, IndexIterator>
          , IndexIterator, typename boost::detail::iterator_traits<ElementIterator>::value_type
          , use_default, typename boost::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>
inline permutation_iterator<ElementIterator, IndexIterator>
make_permutation_iterator( ElementIterator e, IndexIterator i )
{
    return permutation_iterator<ElementIterator, IndexIterator>( e, i );
}
} // namespace iterators
using iterators::permutation_iterator;
using iterators::make_permutation_iterator;
} // namespace boost
#endif