iterator/example/node_iterator2.hpp

74 lines
1.8 KiB
C++

// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef NODE_ITERATOR2_DWA2004110_HPP
# define NODE_ITERATOR2_DWA2004110_HPP
# include "node.hpp"
# include <boost/iterator/iterator_facade.hpp>
# ifndef BOOST_NO_SFINAE
# include <boost/type_traits/is_convertible.hpp>
# include <boost/utility/enable_if.hpp>
# endif
template <class Value>
class node_iter
: public boost::iterator_facade<
node_iter<Value>
, Value
, boost::forward_traversal_tag
>
{
private:
struct enabler {}; // a private type avoids misuse
public:
node_iter()
: m_node(0) {}
explicit node_iter(Value* p)
: m_node(p) {}
template <class OtherValue>
node_iter(
node_iter<OtherValue> const& other
# ifndef BOOST_NO_SFINAE
, typename boost::enable_if<
boost::is_convertible<OtherValue*,Value*>
, enabler
>::type = enabler()
# endif
)
: m_node(other.m_node) {}
# if !BOOST_WORKAROUND(__GNUC__, == 2)
private: // GCC2 can't grant friendship to template member functions
friend class boost::iterator_core_access;
# endif
template <class OtherValue>
bool equal(node_iter<OtherValue> const& other) const
{
return this->m_node == other.m_node;
}
void increment() { m_node = m_node->next(); }
Value& dereference() const { return *m_node; }
# ifdef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
public:
# else
private:
template <class> friend class node_iter;
# endif
Value* m_node;
};
typedef node_iter<node_base> node_iterator;
typedef node_iter<node_base const> node_const_iterator;
#endif // NODE_ITERATOR2_DWA2004110_HPP