boost/iterator/indirect_iterator.hpp

   1 // (C) Copyright David Abrahams 2002.
   2 // (C) Copyright Jeremy Siek    2002.
   3 // (C) Copyright Thomas Witt    2002.
   4 // Distributed under the Boost Software License, Version 1.0. (See
   5 // accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 #ifndef BOOST_INDIRECT_ITERATOR_23022003THW_HPP
   8 #define BOOST_INDIRECT_ITERATOR_23022003THW_HPP
   9
  10 #include <boost/iterator.hpp>
  11 #include <boost/iterator/iterator_adaptor.hpp>
  12
  13 #include <boost/pointee.hpp>
  14 #include <boost/indirect_reference.hpp>
  15 #include <boost/detail/iterator.hpp>
  16
  17 #include <boost/detail/indirect_traits.hpp>
  18
  19 #include <boost/type_traits/is_same.hpp>
  20 #include <boost/type_traits/add_reference.hpp>
  21
  22 #include <boost/mpl/bool.hpp>
  23 #include <boost/mpl/identity.hpp>
  24 #include <boost/mpl/eval_if.hpp>
  25 #include <boost/mpl/not.hpp>
  26 #include <boost/mpl/has_xxx.hpp>
  27
  28 #ifdef BOOST_MPL_CFG_NO_HAS_XXX
  29 # include <boost/shared_ptr.hpp>
  30 # include <boost/scoped_ptr.hpp>
  31 # include <boost/mpl/bool.hpp>
  32 # include <memory>
  33 #endif
  34
  35 #include <boost/iterator/detail/config_def.hpp> // must be last #include
  36
  37 namespace boost
  38 {
  39   template <class Iter, class Value, class Category, class Reference, class Difference>
  40   class indirect_iterator;
  41
  42   namespace detail
  43   {
  44     template <class Iter, class Value, class Category, class Reference, class Difference>
  45     struct indirect_base
  46     {
  47         typedef typename iterator_traits<Iter>::value_type dereferenceable;
  48
  49         typedef iterator_adaptor<
  50             indirect_iterator<Iter, Value, Category, Reference, Difference>
  51           , Iter
  52           , typename ia_dflt_help<
  53                 Value, pointee<dereferenceable>
  54             >::type
  55           , Category
  56           , typename ia_dflt_help<
  57                 Reference
  58               , mpl::eval_if<
  59                     is_same<Value,use_default>
  60                   , indirect_reference<dereferenceable>
  61                   , add_reference<Value>
  62                 >
  63             >::type
  64           , Difference
  65         > type;
  66     };
  67
  68     template <>
  69     struct indirect_base<int, int, int, int, int> {};
  70   } // namespace detail
  71
  72
  73   template <
  74       class Iterator
  75     , class Value = use_default
  76     , class Category = use_default
  77     , class Reference = use_default
  78     , class Difference = use_default
  79   >
  80   class indirect_iterator
  81     : public detail::indirect_base<
  82         Iterator, Value, Category, Reference, Difference
  83       >::type
  84   {
  85       typedef typename detail::indirect_base<
  86           Iterator, Value, Category, Reference, Difference
  87       >::type super_t;
  88
  89       friend class iterator_core_access;
  90
  91    public:
  92       indirect_iterator() {}
  93
  94       indirect_iterator(Iterator iter)
  95         : super_t(iter) {}
  96
  97       template <
  98           class Iterator2, class Value2, class Category2
  99         , class Reference2, class Difference2
 100       >
 101       indirect_iterator(
 102           indirect_iterator<
 103                Iterator2, Value2, Category2, Reference2, Difference2
 104           > const& y
 105         , typename enable_if_convertible<Iterator2, Iterator>::type* = 0
 106       )
 107         : super_t(y.base())
 108       {}
 109
 110   private:
 111       typename super_t::reference dereference() const
 112       {
 113 # if BOOST_WORKAROUND(__BORLANDC__, < 0x5A0 )
 114           return const_cast<super_t::reference>(**this->base());
 115 # else
 116           return **this->base();
 117 # endif
 118       }
 119   };
 120
 121   template <class Iter>
 122   inline
 123   indirect_iterator<Iter> make_indirect_iterator(Iter x)
 124   {
 125     return indirect_iterator<Iter>(x);
 126   }
 127
 128   template <class Traits, class Iter>
 129   inline
 130   indirect_iterator<Iter,Traits> make_indirect_iterator(Iter x, Traits* = 0)
 131   {
 132     return indirect_iterator<Iter, Traits>(x);
 133   }
 134
 135 } // namespace boost
 136
 137 #include <boost/iterator/detail/config_undef.hpp>
 138
 139 #endif // BOOST_INDIRECT_ITERATOR_23022003THW_HPP