boost/boost/property_map_iterator.hpp

   1 // (C) Copyright Jeremy Siek, 2001.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 //  See http://www.boost.org/libs/property_map for documentation.
   7
   8 #ifndef BOOST_PROPERTY_MAP_ITERATOR_HPP
   9 #define BOOST_PROPERTY_MAP_ITERATOR_HPP
  10
  11 #include <boost/property_map.hpp>
  12 #include <boost/iterator/iterator_adaptor.hpp>
  13 #include <boost/mpl/if.hpp>
  14 #include <boost/type_traits/is_same.hpp>
  15
  16 namespace boost {
  17
  18   //======================================================================
  19   // property iterator, generalized from ideas by François Faure
  20
  21   namespace detail {
  22
  23     template <class Iterator, class LvaluePropertyMap>
  24     class lvalue_pmap_iter
  25       : public iterator_adaptor< lvalue_pmap_iter< Iterator, LvaluePropertyMap >,
  26                                  Iterator,
  27                                  typename property_traits<LvaluePropertyMap>::value_type,
  28                                  use_default,
  29                                  typename property_traits<LvaluePropertyMap>::reference>
  30     {
  31       friend class boost::iterator_core_access;
  32
  33       typedef iterator_adaptor< lvalue_pmap_iter< Iterator, LvaluePropertyMap >,
  34                                 Iterator,
  35                                 typename property_traits<LvaluePropertyMap>::value_type,
  36                                 use_default,
  37                                 typename property_traits<LvaluePropertyMap>::reference> super_t;
  38
  39     public:
  40       lvalue_pmap_iter() { }
  41       lvalue_pmap_iter(Iterator const&     it,
  42                        LvaluePropertyMap m)
  43         : super_t(it),
  44           m_map(m) {}
  45
  46     private:
  47       typename super_t::reference
  48       dereference() const
  49       {
  50         return m_map[*(this->base_reference())];
  51       }
  52
  53       LvaluePropertyMap m_map;
  54     };
  55
  56     template <class Iterator, class ReadablePropertyMap>
  57     class readable_pmap_iter :
  58       public iterator_adaptor< readable_pmap_iter< Iterator, ReadablePropertyMap >,
  59                                Iterator,
  60                                typename property_traits<ReadablePropertyMap>::value_type,
  61                                use_default,
  62                                typename property_traits<ReadablePropertyMap>::value_type>
  63
  64
  65     {
  66       friend class boost::iterator_core_access;
  67
  68       typedef iterator_adaptor< readable_pmap_iter< Iterator, ReadablePropertyMap >,
  69                                 Iterator,
  70                                 typename property_traits<ReadablePropertyMap>::value_type,
  71                                 use_default,
  72                                 typename property_traits<ReadablePropertyMap>::value_type> super_t;
  73
  74     public:
  75       readable_pmap_iter() { }
  76       readable_pmap_iter(Iterator const&     it,
  77                          ReadablePropertyMap m)
  78         : super_t(it),
  79           m_map(m) {}
  80
  81     private:
  82       typename super_t::reference
  83       dereference() const
  84       {
  85         return get(m_map, *(this->base_reference()));
  86       }
  87
  88       ReadablePropertyMap m_map;
  89     };
  90
  91
  92   } // namespace detail
  93
  94   template <class PropertyMap, class Iterator>
  95   struct property_map_iterator_generator :
  96     mpl::if_< is_same< typename property_traits<PropertyMap>::category, lvalue_property_map_tag>,
  97               detail::lvalue_pmap_iter<Iterator, PropertyMap>,
  98               detail::readable_pmap_iter<Iterator, PropertyMap> >
  99   {};
 100
 101   template <class PropertyMap, class Iterator>
 102   typename property_map_iterator_generator<PropertyMap, Iterator>::type
 103   make_property_map_iterator(PropertyMap pmap, Iterator iter)
 104   {
 105     typedef typename property_map_iterator_generator<PropertyMap,
 106       Iterator>::type Iter;
 107     return Iter(iter, pmap);
 108   }
 109
 110 } // namespace boost
 111
 112 #endif // BOOST_PROPERTY_MAP_ITERATOR_HPP
 113