1 #ifndef BOOST_SERIALIZATION_BASE_OBJECT_HPP
2 #define BOOST_SERIALIZATION_BASE_OBJECT_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 // base_object.hpp:
11
12 // (C) Copyright 2002 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
17 // See http://www.boost.org for updates, documentation, and revision history.
18
19 // if no archive headers have been included this is a no op
20 // this is to permit BOOST_EXPORT etc to be included in a
21 // file declaration header
22
23 #include <boost/config.hpp>
24 #include <boost/detail/workaround.hpp>
25
26 #include <boost/mpl/eval_if.hpp>
27 #include <boost/mpl/int.hpp>
28 #include <boost/mpl/identity.hpp>
29
30 #include <boost/type_traits/is_base_and_derived.hpp>
31 #include <boost/type_traits/is_pointer.hpp>
32 #include <boost/type_traits/is_const.hpp>
33 #include <boost/type_traits/is_polymorphic.hpp>
34
35 #include <boost/static_assert.hpp>
36 #include <boost/serialization/access.hpp>
37 #include <boost/serialization/force_include.hpp>
38 #include <boost/serialization/void_cast_fwd.hpp>
39
40 namespace boost {
41 namespace serialization {
42
43 namespace detail
44 {
45 // get the base type for a given derived type
46 // preserving the const-ness
47 template<class B, class D>
48 struct base_cast
49 {
50 typedef typename
51 mpl::if_<
52 is_const<D>,
53 const B,
54 B
55 >::type type;
56 BOOST_STATIC_ASSERT(is_const<type>::value == is_const<D>::value);
57 };
58
59 // only register void casts if the types are polymorphic
60 template<class Base, class Derived>
61 struct base_register
62 {
63 struct polymorphic {
invokeboost::serialization::detail::base_register::polymorphic64 static void const * invoke(){
65 Base const * const b = 0;
66 Derived const * const d = 0;
67 return & void_cast_register(d, b);
68 }
69 };
70 struct non_polymorphic {
invokeboost::serialization::detail::base_register::non_polymorphic71 static void const * invoke(){
72 return 0;
73 }
74 };
invokeboost::serialization::detail::base_register75 static void const * invoke(){
76 typedef typename mpl::eval_if<
77 is_polymorphic<Base>,
78 mpl::identity<polymorphic>,
79 mpl::identity<non_polymorphic>
80 >::type type;
81 return type::invoke();
82 }
83 };
84
85 } // namespace detail
86 template<class Base, class Derived>
87 typename detail::base_cast<Base, Derived>::type &
base_object(Derived & d)88 base_object(Derived &d)
89 {
90 BOOST_STATIC_ASSERT(( is_base_and_derived<Base,Derived>::value));
91 BOOST_STATIC_ASSERT(! is_pointer<Derived>::value);
92 typedef typename detail::base_cast<Base, Derived>::type type;
93 detail::base_register<type, Derived>::invoke();
94 return access::cast_reference<type, Derived>(d);
95 }
96
97 } // namespace serialization
98 } // namespace boost
99
100 #endif // BOOST_SERIALIZATION_BASE_OBJECT_HPP
101