multi_index/detail/index_node_base.hpp

0001 /* Copyright 2003-2023 Joaquin M Lopez Munoz.
0002  * Distributed under the Boost Software License, Version 1.0.
0003  * (See accompanying file LICENSE_1_0.txt or copy at
0004  * http://www.boost.org/LICENSE_1_0.txt)
0005  *
0006  * See http://www.boost.org/libs/multi_index for library home page.
0007  */
0008
0009 #ifndef BOOST_MULTI_INDEX_DETAIL_INDEX_NODE_BASE_HPP
0010 #define BOOST_MULTI_INDEX_DETAIL_INDEX_NODE_BASE_HPP
0011
0012 #if defined(_MSC_VER)
0013 #pragma once
0014 #endif
0015
0016 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
0017 #include <boost/type_traits/aligned_storage.hpp>
0018 #include <boost/type_traits/alignment_of.hpp>
0019
0020 #if !defined(BOOST_MULTI_INDEX_DISABLE_SERIALIZATION)
0021 #include <boost/core/serialization.hpp>
0022 #include <boost/multi_index/detail/bad_archive_exception.hpp>
0023 #include <boost/throw_exception.hpp>
0024 #endif
0025
0026 namespace boost{
0027
0028 namespace multi_index{
0029
0030 namespace detail{
0031
0032 /* index_node_base tops the node hierarchy of multi_index_container. It holds
0033  * the value of the element contained.
0034  */
0035
0036 template<typename Value>
0037 struct pod_value_holder
0038 {
0039   typename aligned_storage<
0040     sizeof(Value),
0041     alignment_of<Value>::value
0042   >::type                      space;
0043 };
0044
0045 template<typename Value,typename Allocator>
0046 struct index_node_base:private pod_value_holder<Value>
0047 {
0048   typedef index_node_base base_type; /* used for serialization purposes */
0049   typedef Value           value_type;
0050   typedef Allocator       allocator_type;
0051
0052 #include <boost/multi_index/detail/ignore_wstrict_aliasing.hpp>
0053
0054   value_type& value()
0055   {
0056     return *reinterpret_cast<value_type*>(&this->space);
0057   }
0058
0059   const value_type& value()const
0060   {
0061     return *reinterpret_cast<const value_type*>(&this->space);
0062   }
0063
0064 #include <boost/multi_index/detail/restore_wstrict_aliasing.hpp>
0065
0066   static index_node_base* from_value(const value_type* p)
0067   {
0068     return static_cast<index_node_base *>(
0069       reinterpret_cast<pod_value_holder<Value>*>( /* std 9.2.17 */
0070         const_cast<value_type*>(p)));
0071   }
0072
0073 private:
0074 #if !defined(BOOST_MULTI_INDEX_DISABLE_SERIALIZATION)
0075   friend class boost::serialization::access;
0076
0077   /* nodes do not emit any kind of serialization info. They are
0078    * fed to Boost.Serialization so that pointers to nodes are
0079    * tracked correctly.
0080    */
0081
0082   template<class Archive>
0083   void serialize(Archive&,const unsigned int)
0084   {
0085   }
0086 #endif
0087 };
0088
0089 template<typename Node,typename Value>
0090 Node* node_from_value(const Value* p)
0091 {
0092   typedef typename Node::allocator_type allocator_type;
0093   return static_cast<Node*>(
0094     index_node_base<Value,allocator_type>::from_value(p));
0095 }
0096
0097 } /* namespace multi_index::detail */
0098
0099 } /* namespace multi_index */
0100
0101 #if !defined(BOOST_MULTI_INDEX_DISABLE_SERIALIZATION)
0102 /* Index nodes never get constructed directly by Boost.Serialization,
0103  * as archives are always fed pointers to previously existent
0104  * nodes. So, if this is called it means we are dealing with a
0105  * somehow invalid archive.
0106  */
0107
0108 #if defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)
0109 namespace serialization{
0110 #else
0111 namespace multi_index{
0112 namespace detail{
0113 #endif
0114
0115 template<class Archive,typename Value,typename Allocator>
0116 inline void load_construct_data(
0117   Archive&,boost::multi_index::detail::index_node_base<Value,Allocator>*,
0118   const unsigned int)
0119 {
0120   throw_exception(boost::multi_index::detail::bad_archive_exception());
0121 }
0122
0123 #if defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)
0124 } /* namespace serialization */
0125 #else
0126 } /* namespace multi_index::detail */
0127 } /* namespace multi_index */
0128 #endif
0129
0130 #endif
0131
0132 } /* namespace boost */
0133
0134 #endif