text: /////////////////////////////////////////////////////////////////////////////
  //
  // (C) Copyright Olaf Krzikalla 2004-2006.
  // (C) Copyright Ion Gaztanaga  2006-2013
  //
  // Distributed under 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)
  //
  // See http://www.boost.org/libs/intrusive for documentation.
  //
  /////////////////////////////////////////////////////////////////////////////
  
  #ifndef BOOST_INTRUSIVE_LIST_HOOK_HPP
  #define BOOST_INTRUSIVE_LIST_HOOK_HPP
  
  #include <boost/intrusive/detail/config_begin.hpp>
  #include <boost/intrusive/intrusive_fwd.hpp>
  
  #include <boost/intrusive/detail/list_node.hpp>
  #include <boost/intrusive/circular_list_algorithms.hpp>
  #include <boost/intrusive/options.hpp>
  #include <boost/intrusive/detail/generic_hook.hpp>
  
  #if defined(BOOST_HAS_PRAGMA_ONCE)
  #  pragma once
  #endif
  
  
  namespace boost {
  namespace intrusive {
  
  //! Helper metafunction to define a \c \c list_base_hook that yields to the same
  //! type when the same options (either explicitly or implicitly) are used.
  #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) || defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
  template<class ...Options>
  #else
  template<class O1 = void, class O2 = void, class O3 = void>
  #endif
  struct make_list_base_hook
  {
     /// @cond
     typedef typename pack_options
        < hook_defaults,
        #if !defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
        O1, O2, O3
        #else
        Options...
        #endif
        >::type packed_options;
  
     typedef generic_hook
     < CircularListAlgorithms
     , list_node_traits<typename packed_options::void_pointer>
     , typename packed_options::tag
     , packed_options::link_mode
     , ListBaseHookId
     > implementation_defined;
     /// @endcond
     typedef implementation_defined type;
  };
  
  //! Derive a class from this hook in order to store objects of that class
  //! in an list.
  //!
  //! The hook admits the following options: \c tag<>, \c void_pointer<> and
  //! \c link_mode<>.
  //!
  //! \c tag<> defines a tag to identify the node.
  //! The same tag value can be used in different classes, but if a class is
  //! derived from more than one \c list_base_hook, then each \c list_base_hook needs its
  //! unique tag.
  //!
  //! \c link_mode<> will specify the linking mode of the hook (\c normal_link,
  //! \c auto_unlink or \c safe_link).
  //!
  //! \c void_pointer<> is the pointer type that will be used internally in the hook
  //! and the container configured to use this hook.
  #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) || defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
  template<class ...Options>
  #else
  template<class O1, class O2, class O3>
  #endif
  class list_base_hook
     :  public make_list_base_hook
        #if !defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
        <O1, O2, O3>
        #else
        <Options...>
        #endif
        ::type
  {
     #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED)
     public:
     //! <b>Effects</b>: If link_mode is \c auto_unlink or \c safe_link
     //!   initializes the node to an unlinked state.
     //!
     //! <b>Throws</b>: Nothing.
     list_base_hook();
  
     //! <b>Effects</b>: If link_mode is \c auto_unlink or \c safe_link
     //!   initializes the node to an unlinked state. The argument is ignored.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Rationale</b>: Providing a copy-constructor
     //!   makes classes using the hook STL-compliant without forcing the
     //!   user to do some additional work. \c swap can be used to emulate
     //!   move-semantics.
     list_base_hook(const list_base_hook& );
  
     //! <b>Effects</b>: Empty function. The argument is ignored.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Rationale</b>: Providing an assignment operator
     //!   makes classes using the hook STL-compliant without forcing the
     //!   user to do some additional work. \c swap can be used to emulate
     //!   move-semantics.
     list_base_hook& operator=(const list_base_hook& );
  
     //! <b>Effects</b>: If link_mode is \c normal_link, the destructor does
     //!   nothing (ie. no code is generated). If link_mode is \c safe_link and the
     //!   object is stored in an list an assertion is raised. If link_mode is
     //!   \c auto_unlink and \c is_linked() is true, the node is unlinked.
     //!
     //! <b>Throws</b>: Nothing.
     ~list_base_hook();
  
     //! <b>Effects</b>: Swapping two nodes swaps the position of the elements
     //!   related to those nodes in one or two containers. That is, if the node
     //!   this is part of the element e1, the node x is part of the element e2
     //!   and both elements are included in the containers s1 and s2, then after
     //!   the swap-operation e1 is in s2 at the position of e2 and e2 is in s1
     //!   at the position of e1. If one element is not in a container, then
     //!   after the swap-operation the other element is not in a container.
     //!   Iterators to e1 and e2 related to those nodes are invalidated.
     //!
     //! <b>Complexity</b>: Constant
     //!
     //! <b>Throws</b>: Nothing.
     void swap_nodes(list_base_hook &other);
  
     //! <b>Precondition</b>: link_mode must be \c safe_link or \c auto_unlink.
     //!
     //! <b>Returns</b>: true, if the node belongs to a container, false
     //!   otherwise. This function can be used to test whether \c list::iterator_to
     //!   will return a valid iterator.
     //!
     //! <b>Complexity</b>: Constant
     bool is_linked() const;
  
     //! <b>Effects</b>: Removes the node if it's inserted in a container.
     //!   This function is only allowed if link_mode is \c auto_unlink.
     //!
     //! <b>Throws</b>: Nothing.
     void unlink();
     #endif
  };
  
  //! Helper metafunction to define a \c \c list_member_hook that yields to the same
  //! type when the same options (either explicitly or implicitly) are used.
  #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) || defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
  template<class ...Options>
  #else
  template<class O1 = void, class O2 = void, class O3 = void>
  #endif
  struct make_list_member_hook
  {
     /// @cond
     typedef typename pack_options
        < hook_defaults,
        #if !defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
        O1, O2, O3
        #else
        Options...
        #endif
        >::type packed_options;
  
     typedef generic_hook
     < CircularListAlgorithms
     , list_node_traits<typename packed_options::void_pointer>
     , member_tag
     , packed_options::link_mode
     , NoBaseHookId
     > implementation_defined;
     /// @endcond
     typedef implementation_defined type;
  };
  
  //! Store this hook in a class to be inserted
  //! in an list.
  //!
  //! The hook admits the following options: \c void_pointer<> and
  //! \c link_mode<>.
  //!
  //! \c link_mode<> will specify the linking mode of the hook (\c normal_link,
  //! \c auto_unlink or \c safe_link).
  //!
  //! \c void_pointer<> is the pointer type that will be used internally in the hook
  //! and the container configured to use this hook.
  #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) || defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
  template<class ...Options>
  #else
  template<class O1, class O2, class O3>
  #endif
  class list_member_hook
     :  public make_list_member_hook
        #if !defined(BOOST_INTRUSIVE_VARIADIC_TEMPLATES)
        <O1, O2, O3>
        #else
        <Options...>
        #endif
        ::type
  {
     #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED)
     public:
     //! <b>Effects</b>: If link_mode is \c auto_unlink or \c safe_link
     //!   initializes the node to an unlinked state.
     //!
     //! <b>Throws</b>: Nothing.
     list_member_hook();
  
     //! <b>Effects</b>: If link_mode is \c auto_unlink or \c safe_link
     //!   initializes the node to an unlinked state. The argument is ignored.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Rationale</b>: Providing a copy-constructor
     //!   makes classes using the hook STL-compliant without forcing the
     //!   user to do some additional work. \c swap can be used to emulate
     //!   move-semantics.
     list_member_hook(const list_member_hook& );
  
     //! <b>Effects</b>: Empty function. The argument is ignored.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Rationale</b>: Providing an assignment operator
     //!   makes classes using the hook STL-compliant without forcing the
     //!   user to do some additional work. \c swap can be used to emulate
     //!   move-semantics.
     list_member_hook& operator=(const list_member_hook& );
  
     //! <b>Effects</b>: If link_mode is \c normal_link, the destructor does
     //!   nothing (ie. no code is generated). If link_mode is \c safe_link and the
     //!   object is stored in an list an assertion is raised. If link_mode is
     //!   \c auto_unlink and \c is_linked() is true, the node is unlinked.
     //!
     //! <b>Throws</b>: Nothing.
     ~list_member_hook();
  
     //! <b>Effects</b>: Swapping two nodes swaps the position of the elements
     //!   related to those nodes in one or two containers. That is, if the node
     //!   this is part of the element e1, the node x is part of the element e2
     //!   and both elements are included in the containers s1 and s2, then after
     //!   the swap-operation e1 is in s2 at the position of e2 and e2 is in s1
     //!   at the position of e1. If one element is not in a container, then
     //!   after the swap-operation the other element is not in a container.
     //!   Iterators to e1 and e2 related to those nodes are invalidated.
     //!
     //! <b>Complexity</b>: Constant
     //!
     //! <b>Throws</b>: Nothing.
     void swap_nodes(list_member_hook &other);
  
     //! <b>Precondition</b>: link_mode must be \c safe_link or \c auto_unlink.
     //!
     //! <b>Returns</b>: true, if the node belongs to a container, false
     //!   otherwise. This function can be used to test whether \c list::iterator_to
     //!   will return a valid iterator.
     //!
     //! <b>Complexity</b>: Constant
     bool is_linked() const;
  
     //! <b>Effects</b>: Removes the node if it's inserted in a container.
     //!   This function is only allowed if link_mode is \c auto_unlink.
     //!
     //! <b>Throws</b>: Nothing.
     void unlink();
     #endif
  };
  
  } //namespace intrusive
  } //namespace boost
  
  #include <boost/intrusive/detail/config_end.hpp>
  
  #endif //BOOST_INTRUSIVE_LIST_HOOK_HPP
  