boost/iterator/indirect_iterator.hpp

0001 // (C) Copyright David Abrahams 2002.
0002 // (C) Copyright Jeremy Siek    2002.
0003 // (C) Copyright Thomas Witt    2002.
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 #ifndef BOOST_INDIRECT_ITERATOR_23022003THW_HPP
0008 #define BOOST_INDIRECT_ITERATOR_23022003THW_HPP
0009
0010 #include <boost/iterator/iterator_adaptor.hpp>
0011
0012 #include <boost/pointee.hpp>
0013 #include <boost/indirect_reference.hpp>
0014
0015 #include <boost/detail/indirect_traits.hpp>
0016
0017 #include <boost/type_traits/is_same.hpp>
0018 #include <boost/type_traits/add_reference.hpp>
0019
0020 #include <boost/mpl/bool.hpp>
0021 #include <boost/mpl/identity.hpp>
0022 #include <boost/mpl/eval_if.hpp>
0023 #include <boost/mpl/not.hpp>
0024 #include <boost/mpl/has_xxx.hpp>
0025
0026 #include <iterator>
0027
0028 #ifdef BOOST_MPL_CFG_NO_HAS_XXX
0029 # include <boost/shared_ptr.hpp>
0030 # include <boost/scoped_ptr.hpp>
0031 # include <boost/mpl/bool.hpp>
0032 # include <memory>
0033 #endif
0034
0035 #include <boost/iterator/detail/config_def.hpp> // must be last #include
0036
0037 namespace boost {
0038 namespace iterators {
0039
0040   template <class Iter, class Value, class Category, class Reference, class Difference>
0041   class indirect_iterator;
0042
0043   namespace detail
0044   {
0045     template <class Iter, class Value, class Category, class Reference, class Difference>
0046     struct indirect_base
0047     {
0048         typedef typename std::iterator_traits<Iter>::value_type dereferenceable;
0049
0050         typedef iterator_adaptor<
0051             indirect_iterator<Iter, Value, Category, Reference, Difference>
0052           , Iter
0053           , typename ia_dflt_help<
0054                 Value, pointee<dereferenceable>
0055             >::type
0056           , Category
0057           , typename ia_dflt_help<
0058                 Reference
0059               , mpl::eval_if<
0060                     is_same<Value,use_default>
0061                   , indirect_reference<dereferenceable>
0062                   , add_reference<Value>
0063                 >
0064             >::type
0065           , Difference
0066         > type;
0067     };
0068
0069     template <>
0070     struct indirect_base<int, int, int, int, int> {};
0071   } // namespace detail
0072
0073
0074   template <
0075       class Iterator
0076     , class Value = use_default
0077     , class Category = use_default
0078     , class Reference = use_default
0079     , class Difference = use_default
0080   >
0081   class indirect_iterator
0082     : public detail::indirect_base<
0083         Iterator, Value, Category, Reference, Difference
0084       >::type
0085   {
0086       typedef typename detail::indirect_base<
0087           Iterator, Value, Category, Reference, Difference
0088       >::type super_t;
0089
0090       friend class iterator_core_access;
0091
0092    public:
0093       indirect_iterator() {}
0094
0095       indirect_iterator(Iterator iter)
0096         : super_t(iter) {}
0097
0098       template <
0099           class Iterator2, class Value2, class Category2
0100         , class Reference2, class Difference2
0101       >
0102       indirect_iterator(
0103           indirect_iterator<
0104                Iterator2, Value2, Category2, Reference2, Difference2
0105           > const& y
0106         , typename enable_if_convertible<Iterator2, Iterator>::type* = 0
0107       )
0108         : super_t(y.base())
0109       {}
0110
0111   private:
0112       typename super_t::reference dereference() const
0113       {
0114 # if BOOST_WORKAROUND(BOOST_BORLANDC, < 0x5A0 )
0115           return const_cast<super_t::reference>(**this->base());
0116 # else
0117           return **this->base();
0118 # endif
0119       }
0120   };
0121
0122   template <class Iter>
0123   inline
0124   indirect_iterator<Iter> make_indirect_iterator(Iter x)
0125   {
0126     return indirect_iterator<Iter>(x);
0127   }
0128
0129   template <class Traits, class Iter>
0130   inline
0131   indirect_iterator<Iter,Traits> make_indirect_iterator(Iter x, Traits* = 0)
0132   {
0133     return indirect_iterator<Iter, Traits>(x);
0134   }
0135
0136 } // namespace iterators
0137
0138 using iterators::indirect_iterator;
0139 using iterators::make_indirect_iterator;
0140
0141 } // namespace boost
0142
0143 #include <boost/iterator/detail/config_undef.hpp>
0144
0145 #endif // BOOST_INDIRECT_ITERATOR_23022003THW_HPP