ceph/src/boost/libs/iterator/example/node_iterator3.hpp

   1 // Copyright David Abrahams 2004. Use, modification and distribution is
   2 // subject to the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4 #ifndef NODE_ITERATOR3_DWA2004110_HPP
   5 # define NODE_ITERATOR3_DWA2004110_HPP
   6
   7 # include "node.hpp"
   8 # include <boost/iterator/iterator_adaptor.hpp>
   9
  10 # ifndef BOOST_NO_SFINAE
  11 #  include <boost/type_traits/is_convertible.hpp>
  12 #  include <boost/utility/enable_if.hpp>
  13 # endif
  14
  15 template <class Value>
  16 class node_iter
  17   : public boost::iterator_adaptor<
  18         node_iter<Value>                // Derived
  19       , Value*                          // Base
  20       , boost::use_default              // Value
  21       , boost::forward_traversal_tag    // CategoryOrTraversal
  22     >
  23 {
  24  private:
  25     struct enabler {};  // a private type avoids misuse
  26
  27     typedef boost::iterator_adaptor<
  28         node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
  29     > super_t;
  30
  31  public:
  32     node_iter()
  33       : super_t(0) {}
  34
  35     explicit node_iter(Value* p)
  36       : super_t(p) {}
  37
  38     template <class OtherValue>
  39     node_iter(
  40         node_iter<OtherValue> const& other
  41 # ifndef BOOST_NO_SFINAE
  42       , typename boost::enable_if<
  43             boost::is_convertible<OtherValue*,Value*>
  44           , enabler
  45         >::type = enabler()
  46 # endif
  47     )
  48       : super_t(other.base()) {}
  49
  50 # if !BOOST_WORKAROUND(__GNUC__, == 2)
  51  private: // GCC2 can't grant friendship to template member functions
  52     friend class boost::iterator_core_access;
  53 # endif
  54     void increment() { this->base_reference() = this->base()->next(); }
  55 };
  56
  57 typedef node_iter<node_base> node_iterator;
  58 typedef node_iter<node_base const> node_const_iterator;
  59
  60 #endif // NODE_ITERATOR3_DWA2004110_HPP