1 //-----------------------------------------------------------------------------
2 // boost variant/get.hpp header file
3 // See http://www.boost.org for updates, documentation, and revision history.
4 //-----------------------------------------------------------------------------
5 //
6 // Copyright (c) 2003 Eric Friedman, Itay Maman
7 // Copyright (c) 2014 Antony Polukhin
8 //
9 // Distributed under the Boost Software License, Version 1.0. (See
10 // accompanying file LICENSE_1_0.txt or copy at
11 // http://www.boost.org/LICENSE_1_0.txt)
12
13 #ifndef BOOST_VARIANT_GET_HPP
14 #define BOOST_VARIANT_GET_HPP
15
16 #include <exception>
17
18 #include <boost/config.hpp>
19 #include <boost/detail/workaround.hpp>
20 #include <boost/static_assert.hpp>
21 #include <boost/throw_exception.hpp>
22 #include <boost/utility/addressof.hpp>
23 #include <boost/variant/variant_fwd.hpp>
24 #include <boost/variant/detail/element_index.hpp>
25 #include <boost/variant/detail/move.hpp>
26
27 #include <boost/type_traits/add_reference.hpp>
28 #include <boost/type_traits/add_pointer.hpp>
29 #include <boost/type_traits/is_lvalue_reference.hpp>
30
31 namespace boost {
32
33 #if defined(BOOST_CLANG)
34 # pragma clang diagnostic push
35 # pragma clang diagnostic ignored "-Wweak-vtables"
36 #endif
37 //////////////////////////////////////////////////////////////////////////
38 // class bad_get
39 //
40 // The exception thrown in the event of a failed get of a value.
41 //
42 class BOOST_SYMBOL_VISIBLE bad_get
43 : public std::exception
44 {
45 public: // std::exception implementation
46
47 virtual const char * what() const BOOST_NOEXCEPT_OR_NOTHROW
48 {
49 return "boost::bad_get: "
50 "failed value get using boost::get";
51 }
52
53 };
54 #if defined(BOOST_CLANG)
55 # pragma clang diagnostic pop
56 #endif
57
58
59 //////////////////////////////////////////////////////////////////////////
60 // function template get<T>
61 //
62 // Retrieves content of given variant object if content is of type T.
63 // Otherwise: pointer ver. returns 0; reference ver. throws bad_get.
64 //
65
66 namespace detail { namespace variant {
67
68 // (detail) class template get_visitor
69 //
70 // Generic static visitor that: if the value is of the specified type,
71 // returns a pointer to the value it visits; else a null pointer.
72 //
73 template <typename T>
74 struct get_visitor
75 {
76 private: // private typedefs
77
78 typedef typename add_pointer<T>::type pointer;
79 typedef typename add_reference<T>::type reference;
80
81 public: // visitor typedefs
82
83 typedef pointer result_type;
84
85 public: // visitor interfaces
86
87 pointer operator()(reference operand) const BOOST_NOEXCEPT
88 {
89 return boost::addressof(operand);
90 }
91
92 template <typename U>
93 pointer operator()(const U&) const BOOST_NOEXCEPT
94 {
95 return static_cast<pointer>(0);
96 }
97 };
98
99 }} // namespace detail::variant
100
101 #ifndef BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE
102 # if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551))
103 # define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t)
104 # else
105 # define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t) \
106 , t* = 0
107 # endif
108 #endif
109
110 /////////////////////////////////////////////////////////////////////////////////////////////////////////////
111 // relaxed_get<U>(variant) methods
112 //
113 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
114 inline
115 typename add_pointer<U>::type
116 relaxed_get(
117 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
118 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
119 ) BOOST_NOEXCEPT
120 {
121 typedef typename add_pointer<U>::type U_ptr;
122 if (!operand) return static_cast<U_ptr>(0);
123
124 detail::variant::get_visitor<U> v;
125 return operand->apply_visitor(v);
126 }
127
128 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
129 inline
130 typename add_pointer<const U>::type
131 relaxed_get(
132 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
133 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
134 ) BOOST_NOEXCEPT
135 {
136 typedef typename add_pointer<const U>::type U_ptr;
137 if (!operand) return static_cast<U_ptr>(0);
138
139 detail::variant::get_visitor<const U> v;
140 return operand->apply_visitor(v);
141 }
142
143 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
144 inline
145 typename add_reference<U>::type
146 relaxed_get(
147 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
148 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
149 )
150 {
151 typedef typename add_pointer<U>::type U_ptr;
152 U_ptr result = relaxed_get<U>(boost::addressof(operand));
153
154 if (!result)
155 boost::throw_exception(bad_get());
156 return *result;
157 }
158
159 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
160 inline
161 typename add_reference<const U>::type
162 relaxed_get(
163 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
164 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
165 )
166 {
167 typedef typename add_pointer<const U>::type U_ptr;
168 U_ptr result = relaxed_get<const U>(boost::addressof(operand));
169
170 if (!result)
|
(1) Event fun_call_w_exception: |
Called function throws an exception of type "boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_get> >". [details] |
171 boost::throw_exception(bad_get());
172 return *result;
173 }
174
175 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
176
177 #if defined(BOOST_MSVC) && (_MSC_VER < 1900) // MSVC-2014 has fixed the incorrect diagnostics.
178 # pragma warning(push)
179 # pragma warning(disable: 4172) // returning address of local variable or temporary
180 #endif
181
182 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
183 inline
184 U&&
185 relaxed_get(
186 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand
187 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
188 )
189 {
190 typedef typename add_pointer<U>::type U_ptr;
191 U_ptr result = relaxed_get<U>(boost::addressof(operand));
192
193 if (!result)
194 boost::throw_exception(bad_get());
195 return static_cast<U&&>(*result);
196 }
197
198 #if defined(BOOST_MSVC) && (_MSC_VER < 1900)
199 # pragma warning(pop)
200 #endif
201
202 #endif
203
204 /////////////////////////////////////////////////////////////////////////////////////////////////////////////
205 // strict_get<U>(variant) methods
206 //
207 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
208 inline
209 typename add_pointer<U>::type
210 strict_get(
211 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
212 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
213 ) BOOST_NOEXCEPT
214 {
215 BOOST_STATIC_ASSERT_MSG(
216 (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
217 "boost::variant does not contain specified type U, "
218 "call to boost::get<U>(boost::variant<T...>*) will always return NULL"
219 );
220
221 return relaxed_get<U>(operand);
222 }
223
224 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
225 inline
226 typename add_pointer<const U>::type
227 strict_get(
228 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
229 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
230 ) BOOST_NOEXCEPT
231 {
232 BOOST_STATIC_ASSERT_MSG(
233 (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value),
234 "boost::variant does not contain specified type U, "
235 "call to boost::get<U>(const boost::variant<T...>*) will always return NULL"
236 );
237
238 return relaxed_get<U>(operand);
239 }
240
241 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
242 inline
243 typename add_reference<U>::type
244 strict_get(
245 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
246 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
247 )
248 {
249 BOOST_STATIC_ASSERT_MSG(
250 (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
251 "boost::variant does not contain specified type U, "
252 "call to boost::get<U>(boost::variant<T...>&) will always throw boost::bad_get exception"
253 );
254
255 return relaxed_get<U>(operand);
256 }
257
258 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
259 inline
260 typename add_reference<const U>::type
261 strict_get(
262 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
263 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
264 )
265 {
266 BOOST_STATIC_ASSERT_MSG(
267 (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value),
268 "boost::variant does not contain specified type U, "
269 "call to boost::get<U>(const boost::variant<T...>&) will always throw boost::bad_get exception"
270 );
271
|
(1) Event fun_call_w_exception: |
Called function throws an exception of type "boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_get> >". [details] |
272 return relaxed_get<U>(operand);
273 }
274
275 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
276 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
277 inline
278 U&&
279 strict_get(
280 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand
281 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
282 )
283 {
284 BOOST_STATIC_ASSERT_MSG(
285 (!boost::is_lvalue_reference<U>::value),
286 "remove ampersand '&' from template type U in boost::get<U>(boost::variant<T...>&&) "
287 );
288
289 BOOST_STATIC_ASSERT_MSG(
290 (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
291 "boost::variant does not contain specified type U, "
292 "call to boost::get<U>(const boost::variant<T...>&) will always throw boost::bad_get exception"
293 );
294
295 return relaxed_get<U>(detail::variant::move(operand));
296 }
297 #endif
298
299 /////////////////////////////////////////////////////////////////////////////////////////////////////////////
300 // get<U>(variant) methods
301 //
302
303 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
304 inline
305 typename add_pointer<U>::type
306 get(
307 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
308 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
309 ) BOOST_NOEXCEPT
310 {
311 #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
312 return relaxed_get<U>(operand);
313 #else
314 return strict_get<U>(operand);
315 #endif
316
317 }
318
319 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
320 inline
321 typename add_pointer<const U>::type
322 get(
323 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
324 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
325 ) BOOST_NOEXCEPT
326 {
327 #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
328 return relaxed_get<U>(operand);
329 #else
330 return strict_get<U>(operand);
331 #endif
332 }
333
334 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
335 inline
336 typename add_reference<U>::type
337 get(
338 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
339 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
340 )
341 {
342 #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
343 return relaxed_get<U>(operand);
344 #else
345 return strict_get<U>(operand);
346 #endif
347 }
348
349 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
350 inline
351 typename add_reference<const U>::type
352 get(
353 const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
354 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
355 )
356 {
357 #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
358 return relaxed_get<U>(operand);
359 #else
|
(1) Event fun_call_w_exception: |
Called function throws an exception of type "boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_get> >". [details] |
360 return strict_get<U>(operand);
361 #endif
362 }
363
364 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
365 template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
366 inline
367 U&&
368 get(
369 boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand
370 BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
371 )
372 {
373 #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
374 return relaxed_get<U>(detail::variant::move(operand));
375 #else
376 return strict_get<U>(detail::variant::move(operand));
377 #endif
378 }
379 #endif
380
381 } // namespace boost
382
383 #endif // BOOST_VARIANT_GET_HPP
384