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1 | /* Copyright 2003-2015 Joaquin M Lopez Munoz. | |
2 | * Distributed under the Boost Software License, Version 1.0. | |
3 | * (See accompanying file LICENSE_1_0.txt or copy at | |
4 | * http://www.boost.org/LICENSE_1_0.txt) | |
5 | * | |
6 | * See http://www.boost.org/libs/multi_index for library home page. | |
7 | */ | |
8 | ||
9 | #ifndef BOOST_MULTI_INDEX_MEMBER_HPP | |
10 | #define BOOST_MULTI_INDEX_MEMBER_HPP | |
11 | ||
12 | #if defined(_MSC_VER) | |
13 | #pragma once | |
14 | #endif | |
15 | ||
16 | #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ | |
17 | #include <boost/mpl/if.hpp> | |
18 | #include <boost/type_traits/is_const.hpp> | |
19 | #include <boost/utility/enable_if.hpp> | |
20 | #include <cstddef> | |
21 | ||
22 | #if !defined(BOOST_NO_SFINAE) | |
23 | #include <boost/type_traits/is_convertible.hpp> | |
24 | #endif | |
25 | ||
26 | namespace boost{ | |
27 | ||
28 | template<class T> class reference_wrapper; /* fwd decl. */ | |
29 | ||
30 | namespace multi_index{ | |
31 | ||
32 | namespace detail{ | |
33 | ||
34 | /* member is a read/write key extractor for accessing a given | |
35 | * member of a class. | |
36 | * Additionally, member is overloaded to support referece_wrappers | |
37 | * of T and "chained pointers" to T's. By chained pointer to T we mean | |
38 | * a type P such that, given a p of Type P | |
39 | * *...n...*x is convertible to T&, for some n>=1. | |
40 | * Examples of chained pointers are raw and smart pointers, iterators and | |
41 | * arbitrary combinations of these (vg. T** or unique_ptr<T*>.) | |
42 | */ | |
43 | ||
44 | template<class Class,typename Type,Type Class::*PtrToMember> | |
45 | struct const_member_base | |
46 | { | |
47 | typedef Type result_type; | |
48 | ||
49 | template<typename ChainedPtr> | |
50 | ||
51 | #if !defined(BOOST_NO_SFINAE) | |
52 | typename disable_if< | |
53 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type | |
54 | #else | |
55 | Type& | |
56 | #endif | |
57 | ||
58 | operator()(const ChainedPtr& x)const | |
59 | { | |
60 | return operator()(*x); | |
61 | } | |
62 | ||
63 | Type& operator()(const Class& x)const | |
64 | { | |
65 | return x.*PtrToMember; | |
66 | } | |
67 | ||
68 | Type& operator()(const reference_wrapper<const Class>& x)const | |
69 | { | |
70 | return operator()(x.get()); | |
71 | } | |
72 | ||
73 | Type& operator()(const reference_wrapper<Class>& x)const | |
74 | { | |
75 | return operator()(x.get()); | |
76 | } | |
77 | }; | |
78 | ||
79 | template<class Class,typename Type,Type Class::*PtrToMember> | |
80 | struct non_const_member_base | |
81 | { | |
82 | typedef Type result_type; | |
83 | ||
84 | template<typename ChainedPtr> | |
85 | ||
86 | #if !defined(BOOST_NO_SFINAE) | |
87 | typename disable_if< | |
88 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type | |
89 | #else | |
90 | Type& | |
91 | #endif | |
92 | ||
93 | operator()(const ChainedPtr& x)const | |
94 | { | |
95 | return operator()(*x); | |
96 | } | |
97 | ||
98 | const Type& operator()(const Class& x)const | |
99 | { | |
100 | return x.*PtrToMember; | |
101 | } | |
102 | ||
103 | Type& operator()(Class& x)const | |
104 | { | |
105 | return x.*PtrToMember; | |
106 | } | |
107 | ||
108 | const Type& operator()(const reference_wrapper<const Class>& x)const | |
109 | { | |
110 | return operator()(x.get()); | |
111 | } | |
112 | ||
113 | Type& operator()(const reference_wrapper<Class>& x)const | |
114 | { | |
115 | return operator()(x.get()); | |
116 | } | |
117 | }; | |
118 | ||
119 | } /* namespace multi_index::detail */ | |
120 | ||
121 | template<class Class,typename Type,Type Class::*PtrToMember> | |
122 | struct member: | |
123 | mpl::if_c< | |
124 | is_const<Type>::value, | |
125 | detail::const_member_base<Class,Type,PtrToMember>, | |
126 | detail::non_const_member_base<Class,Type,PtrToMember> | |
127 | >::type | |
128 | { | |
129 | }; | |
130 | ||
131 | namespace detail{ | |
132 | ||
133 | /* MSVC++ 6.0 does not support properly pointers to members as | |
134 | * non-type template arguments, as reported in | |
135 | * http://support.microsoft.com/default.aspx?scid=kb;EN-US;249045 | |
136 | * A similar problem (though not identical) is shown by MSVC++ 7.0. | |
137 | * We provide an alternative to member<> accepting offsets instead | |
138 | * of pointers to members. This happens to work even for non-POD | |
139 | * types (although the standard forbids use of offsetof on these), | |
140 | * so it serves as a workaround in this compiler for all practical | |
141 | * purposes. | |
142 | * Surprisingly enough, other compilers, like Intel C++ 7.0/7.1 and | |
143 | * Visual Age 6.0, have similar bugs. This replacement of member<> | |
144 | * can be used for them too. | |
145 | * | |
146 | * Support for such old compilers is dropped and | |
147 | * [non_]const_member_offset_base is deprecated. | |
148 | */ | |
149 | ||
150 | template<class Class,typename Type,std::size_t OffsetOfMember> | |
151 | struct const_member_offset_base | |
152 | { | |
153 | typedef Type result_type; | |
154 | ||
155 | template<typename ChainedPtr> | |
156 | ||
157 | #if !defined(BOOST_NO_SFINAE) | |
158 | typename disable_if< | |
159 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type | |
160 | #else | |
161 | Type& | |
162 | #endif | |
163 | ||
164 | operator()(const ChainedPtr& x)const | |
165 | { | |
166 | return operator()(*x); | |
167 | } | |
168 | ||
169 | Type& operator()(const Class& x)const | |
170 | { | |
171 | return *static_cast<const Type*>( | |
172 | static_cast<const void*>( | |
173 | static_cast<const char*>( | |
174 | static_cast<const void *>(&x))+OffsetOfMember)); | |
175 | } | |
176 | ||
177 | Type& operator()(const reference_wrapper<const Class>& x)const | |
178 | { | |
179 | return operator()(x.get()); | |
180 | } | |
181 | ||
182 | Type& operator()(const reference_wrapper<Class>& x)const | |
183 | { | |
184 | return operator()(x.get()); | |
185 | } | |
186 | }; | |
187 | ||
188 | template<class Class,typename Type,std::size_t OffsetOfMember> | |
189 | struct non_const_member_offset_base | |
190 | { | |
191 | typedef Type result_type; | |
192 | ||
193 | template<typename ChainedPtr> | |
194 | ||
195 | #if !defined(BOOST_NO_SFINAE) | |
196 | typename disable_if< | |
197 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type | |
198 | #else | |
199 | Type& | |
200 | #endif | |
201 | ||
202 | operator()(const ChainedPtr& x)const | |
203 | { | |
204 | return operator()(*x); | |
205 | } | |
206 | ||
207 | const Type& operator()(const Class& x)const | |
208 | { | |
209 | return *static_cast<const Type*>( | |
210 | static_cast<const void*>( | |
211 | static_cast<const char*>( | |
212 | static_cast<const void *>(&x))+OffsetOfMember)); | |
213 | } | |
214 | ||
215 | Type& operator()(Class& x)const | |
216 | { | |
217 | return *static_cast<Type*>( | |
218 | static_cast<void*>( | |
219 | static_cast<char*>(static_cast<void *>(&x))+OffsetOfMember)); | |
220 | } | |
221 | ||
222 | const Type& operator()(const reference_wrapper<const Class>& x)const | |
223 | { | |
224 | return operator()(x.get()); | |
225 | } | |
226 | ||
227 | Type& operator()(const reference_wrapper<Class>& x)const | |
228 | { | |
229 | return operator()(x.get()); | |
230 | } | |
231 | }; | |
232 | ||
233 | } /* namespace multi_index::detail */ | |
234 | ||
235 | template<class Class,typename Type,std::size_t OffsetOfMember> | |
236 | struct member_offset: | |
237 | mpl::if_c< | |
238 | is_const<Type>::value, | |
239 | detail::const_member_offset_base<Class,Type,OffsetOfMember>, | |
240 | detail::non_const_member_offset_base<Class,Type,OffsetOfMember> | |
241 | >::type | |
242 | { | |
243 | }; | |
244 | ||
245 | /* BOOST_MULTI_INDEX_MEMBER resolves to member in the normal cases, | |
246 | * and to member_offset as a workaround in those defective compilers for | |
247 | * which BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is defined. | |
248 | */ | |
249 | ||
250 | #if defined(BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS) | |
251 | #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \ | |
252 | ::boost::multi_index::member_offset< Class,Type,offsetof(Class,MemberName) > | |
253 | #else | |
254 | #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \ | |
255 | ::boost::multi_index::member< Class,Type,&Class::MemberName > | |
256 | #endif | |
257 | ||
258 | } /* namespace multi_index */ | |
259 | ||
260 | } /* namespace boost */ | |
261 | ||
262 | #endif |