1 | // Boost result_of library |
2 | |
3 | // Copyright Douglas Gregor 2004. Use, modification and |
4 | // distribution is subject to the Boost Software License, Version |
5 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
6 | // http://www.boost.org/LICENSE_1_0.txt) |
7 | |
8 | // For more information, see http://www.boost.org/libs/utility |
9 | #ifndef BOOST_RESULT_OF_HPP |
10 | #define BOOST_RESULT_OF_HPP |
11 | |
12 | #include <boost/config.hpp> |
13 | #include <boost/detail/workaround.hpp> |
14 | #include <boost/type_traits/is_class.hpp> |
15 | #include <boost/type_traits/is_pointer.hpp> |
16 | #include <boost/type_traits/is_member_function_pointer.hpp> |
17 | #include <boost/type_traits/remove_cv.hpp> |
18 | #include <boost/type_traits/remove_reference.hpp> |
19 | #include <boost/type_traits/declval.hpp> |
20 | #include <boost/type_traits/conditional.hpp> |
21 | #include <boost/type_traits/type_identity.hpp> |
22 | #include <boost/type_traits/integral_constant.hpp> |
23 | #include <boost/core/enable_if.hpp> |
24 | |
25 | #ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES |
26 | # undef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES |
27 | # define BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES |
28 | #endif |
29 | #ifdef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES |
30 | # include <boost/preprocessor/cat.hpp> |
31 | # include <boost/preprocessor/iteration/iterate.hpp> |
32 | # include <boost/preprocessor/repetition/enum_params.hpp> |
33 | # include <boost/preprocessor/repetition/enum_trailing_params.hpp> |
34 | # include <boost/preprocessor/repetition/enum_binary_params.hpp> |
35 | # include <boost/preprocessor/repetition/enum_shifted_params.hpp> |
36 | # include <boost/preprocessor/facilities/intercept.hpp> |
37 | #endif |
38 | |
39 | #ifndef BOOST_UTILITY_DOCS |
40 | #ifndef BOOST_RESULT_OF_NUM_ARGS |
41 | # define BOOST_RESULT_OF_NUM_ARGS 16 |
42 | #endif |
43 | #endif // BOOST_UTILITY_DOCS |
44 | |
45 | // Use the decltype-based version of result_of by default if the compiler |
46 | // supports N3276 <http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2011/n3276.pdf>. |
47 | // The user can force the choice by defining BOOST_RESULT_OF_USE_DECLTYPE, |
48 | // BOOST_RESULT_OF_USE_TR1, or BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK but not more than one! |
49 | #if (defined(BOOST_RESULT_OF_USE_DECLTYPE) && defined(BOOST_RESULT_OF_USE_TR1)) || \ |
50 | (defined(BOOST_RESULT_OF_USE_DECLTYPE) && defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)) || \ |
51 | (defined(BOOST_RESULT_OF_USE_TR1) && defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)) |
52 | # error More than one of BOOST_RESULT_OF_USE_DECLTYPE, BOOST_RESULT_OF_USE_TR1 and \ |
53 | BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK cannot be defined at the same time. |
54 | #endif |
55 | |
56 | #ifndef BOOST_UTILITY_DOCS |
57 | #ifndef BOOST_RESULT_OF_USE_TR1 |
58 | # ifndef BOOST_RESULT_OF_USE_DECLTYPE |
59 | # ifndef BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK |
60 | # ifndef BOOST_NO_CXX11_DECLTYPE_N3276 // this implies !defined(BOOST_NO_CXX11_DECLTYPE) |
61 | # define BOOST_RESULT_OF_USE_DECLTYPE |
62 | # else |
63 | # define BOOST_RESULT_OF_USE_TR1 |
64 | # endif |
65 | # endif |
66 | # endif |
67 | #endif |
68 | #endif // BOOST_UTILITY_DOCS |
69 | |
70 | namespace boost { |
71 | |
72 | template<typename F> struct result_of; |
73 | template<typename F> struct tr1_result_of; // a TR1-style implementation of result_of |
74 | |
75 | #if !defined(BOOST_NO_SFINAE) |
76 | namespace detail { |
77 | |
78 | typedef char result_of_yes_type; // sizeof(result_of_yes_type) == 1 |
79 | typedef char (&result_of_no_type)[2]; // sizeof(result_of_no_type) == 2 |
80 | |
81 | template<class T> struct result_of_has_type {}; |
82 | |
83 | template<class T> struct result_of_has_result_type_impl |
84 | { |
85 | template<class U> static result_of_yes_type f( result_of_has_type<typename U::result_type>* ); |
86 | template<class U> static result_of_no_type f( ... ); |
87 | |
88 | typedef boost::integral_constant<bool, sizeof(f<T>(0)) == sizeof(result_of_yes_type)> type; |
89 | }; |
90 | |
91 | template<class T> struct result_of_has_result_type: result_of_has_result_type_impl<T>::type |
92 | { |
93 | }; |
94 | |
95 | // Work around a nvcc bug by only defining has_result when it's needed. |
96 | #ifdef BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK |
97 | |
98 | template<template<class> class C> struct result_of_has_template {}; |
99 | |
100 | template<class T> struct result_of_has_result_impl |
101 | { |
102 | template<class U> static result_of_yes_type f( result_of_has_template<U::template result>* ); |
103 | template<class U> static result_of_no_type f( ... ); |
104 | |
105 | typedef boost::integral_constant<bool, sizeof(f<T>(0)) == sizeof(result_of_yes_type)> type; |
106 | }; |
107 | |
108 | template<class T> struct result_of_has_result: result_of_has_result_impl<T>::type |
109 | { |
110 | }; |
111 | |
112 | #endif |
113 | |
114 | template<typename F, typename FArgs, bool HasResultType> struct tr1_result_of_impl; |
115 | |
116 | template<typename F> struct cpp0x_result_of; |
117 | |
118 | #ifdef BOOST_NO_SFINAE_EXPR |
119 | |
120 | // There doesn't seem to be any other way to turn this off such that the presence of |
121 | // the user-defined operator,() below doesn't cause spurious warning all over the place, |
122 | // so unconditionally and globally turn it off. (https://svn.boost.org/trac10/ticket/7663) |
123 | #ifdef BOOST_MSVC |
124 | # pragma warning(disable: 4913) // user defined binary operator ',' exists but no overload could convert all operands, default built-in binary operator ',' used |
125 | #endif |
126 | |
127 | struct result_of_private_type {}; |
128 | |
129 | struct result_of_weird_type { |
130 | friend result_of_private_type operator,(result_of_private_type, result_of_weird_type); |
131 | }; |
132 | |
133 | template<typename T> |
134 | result_of_no_type result_of_is_private_type(T const &); |
135 | result_of_yes_type result_of_is_private_type(result_of_private_type); |
136 | |
137 | #ifdef BOOST_MSVC |
138 | # pragma warning(push) |
139 | # pragma warning(disable: 4512) // assignment operator could not be generated. |
140 | #endif |
141 | template<typename C> |
142 | struct result_of_callable_class : C { |
143 | result_of_callable_class(); |
144 | typedef result_of_private_type const &(*pfn_t)(...); |
145 | operator pfn_t() const volatile; |
146 | }; |
147 | #ifdef BOOST_MSVC |
148 | # pragma warning(pop) |
149 | #endif |
150 | |
151 | template<typename C> |
152 | struct result_of_wrap_callable_class { |
153 | typedef result_of_callable_class<C> type; |
154 | }; |
155 | |
156 | template<typename C> |
157 | struct result_of_wrap_callable_class<C const> { |
158 | typedef result_of_callable_class<C> const type; |
159 | }; |
160 | |
161 | template<typename C> |
162 | struct result_of_wrap_callable_class<C volatile> { |
163 | typedef result_of_callable_class<C> volatile type; |
164 | }; |
165 | |
166 | template<typename C> |
167 | struct result_of_wrap_callable_class<C const volatile> { |
168 | typedef result_of_callable_class<C> const volatile type; |
169 | }; |
170 | |
171 | template<typename C> |
172 | struct result_of_wrap_callable_class<C &> { |
173 | typedef typename result_of_wrap_callable_class<C>::type &type; |
174 | }; |
175 | |
176 | template<typename F, bool TestCallability = true> struct cpp0x_result_of_impl; |
177 | |
178 | #else // BOOST_NO_SFINAE_EXPR |
179 | |
180 | template<typename T> |
181 | struct result_of_always_void |
182 | { |
183 | typedef void type; |
184 | }; |
185 | |
186 | template<typename F, typename Enable = void> struct cpp0x_result_of_impl {}; |
187 | |
188 | #endif // BOOST_NO_SFINAE_EXPR |
189 | |
190 | template<typename F> |
191 | struct result_of_void_impl |
192 | { |
193 | typedef void type; |
194 | }; |
195 | |
196 | template<typename R> |
197 | struct result_of_void_impl<R (*)(void)> |
198 | { |
199 | typedef R type; |
200 | }; |
201 | |
202 | template<typename R> |
203 | struct result_of_void_impl<R (&)(void)> |
204 | { |
205 | typedef R type; |
206 | }; |
207 | |
208 | // Determine the return type of a function pointer or pointer to member. |
209 | template<typename F, typename FArgs> |
210 | struct result_of_pointer |
211 | : tr1_result_of_impl<typename remove_cv<F>::type, FArgs, false> { }; |
212 | |
213 | template<typename F, typename FArgs> |
214 | struct tr1_result_of_impl<F, FArgs, true> |
215 | { |
216 | typedef typename F::result_type type; |
217 | }; |
218 | |
219 | template<typename FArgs> |
220 | struct is_function_with_no_args : false_type {}; |
221 | |
222 | template<typename F> |
223 | struct is_function_with_no_args<F(void)> : true_type {}; |
224 | |
225 | template<typename F, typename FArgs> |
226 | struct result_of_nested_result : F::template result<FArgs> |
227 | {}; |
228 | |
229 | template<typename F, typename FArgs> |
230 | struct tr1_result_of_impl<F, FArgs, false> |
231 | : conditional<is_function_with_no_args<FArgs>::value, |
232 | result_of_void_impl<F>, |
233 | result_of_nested_result<F, FArgs> >::type |
234 | {}; |
235 | |
236 | } // end namespace detail |
237 | |
238 | #ifndef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES |
239 | # include <boost/utility/detail/result_of_variadic.hpp> |
240 | #else |
241 | # define BOOST_PP_ITERATION_PARAMS_1 (3,(0,BOOST_RESULT_OF_NUM_ARGS,<boost/utility/detail/result_of_iterate.hpp>)) |
242 | # include BOOST_PP_ITERATE() |
243 | #endif |
244 | |
245 | #if 0 |
246 | // inform dependency trackers, as they can't see through macro includes |
247 | #include <boost/utility/detail/result_of_iterate.hpp> |
248 | #endif |
249 | |
250 | #else |
251 | # define BOOST_NO_RESULT_OF 1 |
252 | #endif |
253 | |
254 | } |
255 | |
256 | #endif // BOOST_RESULT_OF_HPP |
257 | |