1#ifndef BOOST_SERIALIZATION_VOID_CAST_HPP
2#define BOOST_SERIALIZATION_VOID_CAST_HPP
3
4// MS compatible compilers support #pragma once
5#if defined(_MSC_VER)
6# pragma once
7#endif
8
9/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
10// void_cast.hpp: interface for run-time casting of void pointers.
11
12// (C) Copyright 2002-2009 Robert Ramey - http://www.rrsd.com .
13// Use, modification and distribution is subject to the Boost Software
14// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
15// http://www.boost.org/LICENSE_1_0.txt)
16// gennadiy.rozental@tfn.com
17
18// See http://www.boost.org for updates, documentation, and revision history.
19
20#include <cstddef> // for ptrdiff_t
21#include <boost/config.hpp>
22#include <boost/noncopyable.hpp>
23
24#include <boost/serialization/smart_cast.hpp>
25#include <boost/serialization/singleton.hpp>
26#include <boost/serialization/force_include.hpp>
27#include <boost/serialization/type_info_implementation.hpp>
28#include <boost/serialization/extended_type_info.hpp>
29#include <boost/type_traits/is_virtual_base_of.hpp>
30#include <boost/type_traits/aligned_storage.hpp>
31#include <boost/serialization/void_cast_fwd.hpp>
32
33#include <boost/serialization/config.hpp>
34#include <boost/config/abi_prefix.hpp> // must be the last header
35
36#ifdef BOOST_MSVC
37# pragma warning(push)
38# pragma warning(disable : 4251 4231 4660 4275)
39#endif
40
41namespace boost {
42namespace serialization {
43
44class extended_type_info;
45
46// Given a void *, assume that it really points to an instance of one type
47// and alter it so that it would point to an instance of a related type.
48// Return the altered pointer. If there exists no sequence of casts that
49// can transform from_type to to_type, return a NULL.
50
51BOOST_SERIALIZATION_DECL void const *
52void_upcast(
53 extended_type_info const & derived,
54 extended_type_info const & base,
55 void const * const t
56);
57
58inline void *
59void_upcast(
60 extended_type_info const & derived,
61 extended_type_info const & base,
62 void * const t
63){
64 return const_cast<void*>(void_upcast(
65 derived,
66 base,
67 t: const_cast<void const *>(t)
68 ));
69}
70
71BOOST_SERIALIZATION_DECL void const *
72void_downcast(
73 extended_type_info const & derived,
74 extended_type_info const & base,
75 void const * const t
76);
77
78inline void *
79void_downcast(
80 extended_type_info const & derived,
81 extended_type_info const & base,
82 void * const t
83){
84 return const_cast<void*>(void_downcast(
85 derived,
86 base,
87 t: const_cast<void const *>(t)
88 ));
89}
90
91namespace void_cast_detail {
92
93class BOOST_SYMBOL_VISIBLE void_caster :
94 private boost::noncopyable
95{
96 friend
97 BOOST_SERIALIZATION_DECL void const *
98 boost::serialization::void_upcast(
99 extended_type_info const & derived,
100 extended_type_info const & base,
101 void const * const
102 );
103 friend
104 BOOST_SERIALIZATION_DECL void const *
105 boost::serialization::void_downcast(
106 extended_type_info const & derived,
107 extended_type_info const & base,
108 void const * const
109 );
110protected:
111 BOOST_SERIALIZATION_DECL void recursive_register(bool includes_virtual_base = false) const;
112 BOOST_SERIALIZATION_DECL void recursive_unregister() const;
113 virtual bool has_virtual_base() const = 0;
114public:
115 // Data members
116 const extended_type_info * m_derived;
117 const extended_type_info * m_base;
118 /*const*/ std::ptrdiff_t m_difference;
119 void_caster const * const m_parent;
120
121 // note that void_casters are keyed on value of
122 // member extended type info records - NOT their
123 // addresses. This is necessary in order for the
124 // void cast operations to work across dll and exe
125 // module boundaries.
126 bool operator<(const void_caster & rhs) const;
127
128 const void_caster & operator*(){
129 return *this;
130 }
131 // each derived class must re-implement these;
132 virtual void const * upcast(void const * const t) const = 0;
133 virtual void const * downcast(void const * const t) const = 0;
134 // Constructor
135 void_caster(
136 extended_type_info const * derived,
137 extended_type_info const * base,
138 std::ptrdiff_t difference = 0,
139 void_caster const * const parent = 0
140 ) :
141 m_derived(derived),
142 m_base(base),
143 m_difference(difference),
144 m_parent(parent)
145 {}
146 virtual ~void_caster(){}
147};
148
149#ifdef BOOST_MSVC
150# pragma warning(push)
151# pragma warning(disable : 4251 4231 4660 4275 4511 4512)
152#endif
153
154template <class Derived, class Base>
155class BOOST_SYMBOL_VISIBLE void_caster_primitive :
156 public void_caster
157{
158 void const * downcast(void const * const t) const BOOST_OVERRIDE {
159 const Derived * d =
160 boost::serialization::smart_cast<const Derived *, const Base *>(
161 static_cast<const Base *>(t)
162 );
163 return d;
164 }
165 void const * upcast(void const * const t) const BOOST_OVERRIDE {
166 const Base * b =
167 boost::serialization::smart_cast<const Base *, const Derived *>(
168 static_cast<const Derived *>(t)
169 );
170 return b;
171 }
172 bool has_virtual_base() const BOOST_OVERRIDE {
173 return false;
174 }
175public:
176 void_caster_primitive();
177 ~void_caster_primitive() BOOST_OVERRIDE;
178
179private:
180 static std::ptrdiff_t base_offset() {
181 typename boost::aligned_storage<sizeof(Derived)>::type data;
182 return reinterpret_cast<char*>(&data)
183 - reinterpret_cast<char*>(
184 static_cast<Base*>(
185 reinterpret_cast<Derived*>(&data)));
186 }
187};
188
189template <class Derived, class Base>
190void_caster_primitive<Derived, Base>::void_caster_primitive() :
191 void_caster(
192 & type_info_implementation<Derived>::type::get_const_instance(),
193 & type_info_implementation<Base>::type::get_const_instance(),
194 base_offset()
195 )
196{
197 recursive_register();
198}
199
200template <class Derived, class Base>
201void_caster_primitive<Derived, Base>::~void_caster_primitive(){
202 recursive_unregister();
203}
204
205template <class Derived, class Base>
206class BOOST_SYMBOL_VISIBLE void_caster_virtual_base :
207 public void_caster
208{
209 bool has_virtual_base() const BOOST_OVERRIDE {
210 return true;
211 }
212public:
213 void const * downcast(void const * const t) const BOOST_OVERRIDE {
214 const Derived * d =
215 dynamic_cast<const Derived *>(
216 static_cast<const Base *>(t)
217 );
218 return d;
219 }
220 void const * upcast(void const * const t) const BOOST_OVERRIDE {
221 const Base * b =
222 dynamic_cast<const Base *>(
223 static_cast<const Derived *>(t)
224 );
225 return b;
226 }
227 void_caster_virtual_base();
228 ~void_caster_virtual_base() BOOST_OVERRIDE;
229};
230
231#ifdef BOOST_MSVC
232#pragma warning(pop)
233#endif
234
235template <class Derived, class Base>
236void_caster_virtual_base<Derived,Base>::void_caster_virtual_base() :
237 void_caster(
238 & (type_info_implementation<Derived>::type::get_const_instance()),
239 & (type_info_implementation<Base>::type::get_const_instance())
240 )
241{
242 recursive_register(includes_virtual_base: true);
243}
244
245template <class Derived, class Base>
246void_caster_virtual_base<Derived,Base>::~void_caster_virtual_base(){
247 recursive_unregister();
248}
249
250template <class Derived, class Base>
251struct BOOST_SYMBOL_VISIBLE void_caster_base :
252 public void_caster
253{
254 typedef
255 typename mpl::eval_if<boost::is_virtual_base_of<Base,Derived>,
256 mpl::identity<
257 void_cast_detail::void_caster_virtual_base<Derived, Base>
258 >
259 ,// else
260 mpl::identity<
261 void_cast_detail::void_caster_primitive<Derived, Base>
262 >
263 >::type type;
264};
265
266} // void_cast_detail
267
268template<class Derived, class Base>
269BOOST_DLLEXPORT
270inline const void_cast_detail::void_caster & void_cast_register(
271 Derived const * /* dnull = NULL */,
272 Base const * /* bnull = NULL */
273){
274 typedef
275 typename mpl::eval_if<boost::is_virtual_base_of<Base,Derived>,
276 mpl::identity<
277 void_cast_detail::void_caster_virtual_base<Derived, Base>
278 >
279 ,// else
280 mpl::identity<
281 void_cast_detail::void_caster_primitive<Derived, Base>
282 >
283 >::type typex;
284 return singleton<typex>::get_const_instance();
285}
286
287template<class Derived, class Base>
288class BOOST_SYMBOL_VISIBLE void_caster :
289 public void_cast_detail::void_caster_base<Derived, Base>::type
290{
291};
292
293} // namespace serialization
294} // namespace boost
295
296#ifdef BOOST_MSVC
297# pragma warning(pop)
298#endif
299
300#include <boost/config/abi_suffix.hpp> // pops abi_suffix.hpp pragmas
301
302#endif // BOOST_SERIALIZATION_VOID_CAST_HPP
303