boost/iterator/permutation_iterator.hpp

0001 // (C) Copyright Toon Knapen    2001.
0002 // (C) Copyright David Abrahams 2003.
0003 // (C) Copyright Roland Richter 2003.
0004 // Distributed under the Boost Software License, Version 1.0. (See
0005 // accompanying file LICENSE_1_0.txt or copy at
0006 // http://www.boost.org/LICENSE_1_0.txt)
0007
0008 #ifndef BOOST_PERMUTATION_ITERATOR_HPP
0009 #define BOOST_PERMUTATION_ITERATOR_HPP
0010
0011 #include <iterator>
0012
0013 #include <boost/iterator/iterator_adaptor.hpp>
0014
0015
0016 namespace boost {
0017 namespace iterators {
0018
0019 template< class ElementIterator
0020         , class IndexIterator>
0021 class permutation_iterator
0022   : public iterator_adaptor<
0023              permutation_iterator<ElementIterator, IndexIterator>
0024            , IndexIterator, typename std::iterator_traits<ElementIterator>::value_type
0025            , use_default, typename std::iterator_traits<ElementIterator>::reference>
0026 {
0027   typedef iterator_adaptor<
0028             permutation_iterator<ElementIterator, IndexIterator>
0029           , IndexIterator, typename std::iterator_traits<ElementIterator>::value_type
0030           , use_default, typename std::iterator_traits<ElementIterator>::reference> super_t;
0031
0032   friend class iterator_core_access;
0033
0034 public:
0035   permutation_iterator() : m_elt_iter() {}
0036
0037   explicit permutation_iterator(ElementIterator x, IndexIterator y)
0038       : super_t(y), m_elt_iter(x) {}
0039
0040   template<class OtherElementIterator, class OtherIndexIterator>
0041   permutation_iterator(
0042       permutation_iterator<OtherElementIterator, OtherIndexIterator> const& r
0043       , typename enable_if_convertible<OtherElementIterator, ElementIterator>::type* = 0
0044       , typename enable_if_convertible<OtherIndexIterator, IndexIterator>::type* = 0
0045       )
0046     : super_t(r.base()), m_elt_iter(r.m_elt_iter)
0047   {}
0048
0049 private:
0050     typename super_t::reference dereference() const
0051         { return *(m_elt_iter + *this->base()); }
0052
0053 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
0054     template <class,class> friend class permutation_iterator;
0055 #else
0056  public:
0057 #endif
0058     ElementIterator m_elt_iter;
0059 };
0060
0061
0062 template <class ElementIterator, class IndexIterator>
0063 inline permutation_iterator<ElementIterator, IndexIterator>
0064 make_permutation_iterator( ElementIterator e, IndexIterator i )
0065 {
0066     return permutation_iterator<ElementIterator, IndexIterator>( e, i );
0067 }
0068
0069 } // namespace iterators
0070
0071 using iterators::permutation_iterator;
0072 using iterators::make_permutation_iterator;
0073
0074 } // namespace boost
0075
0076 #endif