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1 | //----------------------------------------------------------------------------- |
2 | // boost variant/variant.hpp header file | |
3 | // See http://www.boost.org for updates, documentation, and revision history. | |
4 | //----------------------------------------------------------------------------- | |
5 | // | |
6 | // Copyright (c) 2002-2003 Eric Friedman, Itay Maman | |
7 | // Copyright (c) 2012-2016 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 | // Thanks to Adam Romanek for providing patches for exception-disabled env. | |
14 | ||
15 | #ifndef BOOST_VARIANT_VARIANT_HPP | |
16 | #define BOOST_VARIANT_VARIANT_HPP | |
17 | ||
18 | #include <cstddef> // for std::size_t | |
19 | #include <new> // for placement new | |
20 | ||
21 | #include <boost/type_index.hpp> | |
22 | ||
23 | #include <boost/variant/detail/config.hpp> | |
24 | #include <boost/mpl/aux_/value_wknd.hpp> | |
25 | ||
26 | #include <boost/variant/variant_fwd.hpp> | |
27 | #include <boost/variant/detail/backup_holder.hpp> | |
28 | #include <boost/variant/detail/enable_recursive_fwd.hpp> | |
29 | #include <boost/variant/detail/forced_return.hpp> | |
30 | #include <boost/variant/detail/initializer.hpp> | |
31 | #include <boost/variant/detail/make_variant_list.hpp> | |
32 | #include <boost/variant/detail/over_sequence.hpp> | |
33 | #include <boost/variant/detail/visitation_impl.hpp> | |
34 | #include <boost/variant/detail/hash_variant.hpp> | |
35 | ||
36 | #include <boost/variant/detail/generic_result_type.hpp> | |
37 | #include <boost/variant/detail/move.hpp> | |
38 | ||
39 | #include <boost/detail/no_exceptions_support.hpp> | |
40 | #include <boost/detail/reference_content.hpp> | |
41 | #include <boost/aligned_storage.hpp> | |
42 | #include <boost/blank.hpp> | |
43 | #include <boost/math/common_factor_ct.hpp> | |
44 | #include <boost/static_assert.hpp> | |
45 | #include <boost/preprocessor/cat.hpp> | |
46 | #include <boost/preprocessor/repeat.hpp> | |
47 | #include <boost/type_traits/alignment_of.hpp> | |
48 | #include <boost/type_traits/add_const.hpp> | |
49 | #include <boost/type_traits/has_nothrow_constructor.hpp> | |
50 | #include <boost/type_traits/has_nothrow_copy.hpp> | |
51 | #include <boost/type_traits/is_nothrow_move_assignable.hpp> | |
52 | #include <boost/type_traits/is_nothrow_move_constructible.hpp> | |
53 | #include <boost/type_traits/is_const.hpp> | |
54 | #include <boost/type_traits/is_same.hpp> | |
55 | #include <boost/type_traits/is_rvalue_reference.hpp> | |
56 | #include <boost/type_traits/is_constructible.hpp> | |
57 | #include <boost/type_traits/add_lvalue_reference.hpp> | |
58 | #include <boost/utility/enable_if.hpp> | |
59 | #include <boost/utility/declval.hpp> | |
60 | #include <boost/variant/recursive_wrapper_fwd.hpp> | |
61 | #include <boost/variant/static_visitor.hpp> | |
62 | ||
63 | #include <boost/mpl/assert.hpp> | |
64 | #include <boost/mpl/begin_end.hpp> | |
65 | #include <boost/mpl/bool.hpp> | |
66 | #include <boost/mpl/deref.hpp> | |
67 | #include <boost/mpl/empty.hpp> | |
68 | #include <boost/mpl/eval_if.hpp> | |
69 | #include <boost/mpl/find_if.hpp> | |
70 | #include <boost/mpl/fold.hpp> | |
71 | #include <boost/mpl/front.hpp> | |
72 | #include <boost/mpl/identity.hpp> | |
73 | #include <boost/mpl/if.hpp> | |
74 | #include <boost/mpl/int.hpp> | |
75 | #include <boost/mpl/is_sequence.hpp> | |
76 | #include <boost/mpl/iterator_range.hpp> | |
77 | #include <boost/mpl/iter_fold_if.hpp> | |
78 | #include <boost/mpl/logical.hpp> | |
79 | #include <boost/mpl/max_element.hpp> | |
80 | #include <boost/mpl/next.hpp> | |
81 | #include <boost/mpl/not.hpp> | |
82 | #include <boost/mpl/pair.hpp> | |
83 | #include <boost/mpl/protect.hpp> | |
84 | #include <boost/mpl/push_front.hpp> | |
85 | #include <boost/mpl/same_as.hpp> | |
86 | #include <boost/mpl/size_t.hpp> | |
87 | #include <boost/mpl/sizeof.hpp> | |
88 | #include <boost/mpl/transform.hpp> | |
89 | ||
90 | /////////////////////////////////////////////////////////////////////////////// | |
91 | // Implementation Macros: | |
92 | // | |
93 | // BOOST_VARIANT_VISITATION_UNROLLING_LIMIT | |
94 | // Defined in boost/variant/detail/visitation_impl.hpp. | |
95 | // | |
96 | // BOOST_VARIANT_MINIMIZE_SIZE | |
97 | // When #defined, implementation employs all known means to minimize the | |
98 | // size of variant obje cts. However, often unsuccessful due to alignment | |
99 | // issues, and potentially harmful to runtime speed, so not enabled by | |
100 | // default. (TODO: Investigate further.) | |
101 | ||
102 | #if defined(BOOST_VARIANT_MINIMIZE_SIZE) | |
103 | # include <climits> // for SCHAR_MAX | |
104 | # include <boost/mpl/eval_if.hpp> | |
105 | # include <boost/mpl/equal_to.hpp> | |
106 | # include <boost/mpl/identity.hpp> | |
107 | # include <boost/mpl/int.hpp> | |
108 | # include <boost/mpl/if.hpp> | |
109 | # include <boost/mpl/less.hpp> | |
110 | # include <boost/mpl/long.hpp> | |
111 | # include <boost/mpl/O1_size.hpp> | |
112 | #endif | |
113 | ||
114 | ||
115 | namespace boost { | |
116 | ||
117 | namespace detail { namespace variant { | |
118 | ||
119 | /////////////////////////////////////////////////////////////////////////////// | |
120 | // (detail) metafunction max_value | |
121 | // | |
122 | // Finds the maximum value of the unary metafunction F over Sequence. | |
123 | // | |
124 | template <typename Sequence, typename F> | |
125 | struct max_value | |
126 | { | |
127 | private: // helpers, for metafunction result (below) | |
128 | ||
129 | typedef typename mpl::transform1<Sequence, F>::type transformed_; | |
130 | typedef typename mpl::max_element<transformed_ | |
131 | ||
132 | >::type max_it; | |
133 | ||
134 | public: // metafunction result | |
135 | ||
136 | typedef typename mpl::deref<max_it>::type | |
137 | type; | |
138 | ||
139 | }; | |
140 | ||
141 | struct add_alignment | |
142 | { | |
143 | template <typename State, typename Item> | |
144 | struct apply | |
145 | : mpl::size_t< | |
146 | ::boost::math::static_lcm< | |
147 | BOOST_MPL_AUX_VALUE_WKND(State)::value | |
148 | , ::boost::alignment_of<Item>::value | |
149 | >::value | |
150 | > | |
151 | {}; | |
152 | }; | |
153 | ||
154 | /////////////////////////////////////////////////////////////////////////////// | |
155 | // (detail) metafunction find_fallback_type | |
156 | // | |
157 | // Provides a fallback (i.e., nothrow default-constructible) type from the | |
158 | // specified sequence, or no_fallback_type if not found. | |
159 | // | |
160 | // This implementation is designed to prefer boost::blank over other potential | |
161 | // fallback types, regardless of its position in the specified sequence. | |
162 | // | |
163 | ||
164 | class no_fallback_type; | |
165 | ||
166 | struct find_fallback_type_pred | |
167 | { | |
168 | template <typename Iterator> | |
169 | struct apply | |
170 | { | |
171 | private: | |
172 | typedef typename mpl::deref<Iterator>::type t_; | |
173 | ||
174 | public: | |
175 | typedef mpl::not_< has_nothrow_constructor<t_> > type; | |
176 | }; | |
177 | }; | |
178 | ||
179 | template <typename Types> | |
180 | struct find_fallback_type | |
181 | { | |
182 | private: // helpers, for metafunction result (below) | |
183 | ||
184 | typedef typename mpl::end<Types>::type end_it; | |
185 | ||
186 | // [Find the first suitable fallback type...] | |
187 | ||
188 | typedef typename mpl::iter_fold_if< | |
189 | Types | |
190 | , mpl::int_<0>, mpl::protect< mpl::next<> > | |
191 | , mpl::protect< find_fallback_type_pred > | |
192 | >::type first_result_; | |
193 | ||
194 | typedef typename first_result_::first first_result_index; | |
195 | typedef typename first_result_::second first_result_it; | |
196 | ||
197 | // [...now search the rest of the sequence for boost::blank...] | |
198 | ||
199 | typedef typename mpl::iter_fold_if< | |
200 | mpl::iterator_range< first_result_it,end_it > | |
201 | , first_result_index, mpl::protect< mpl::next<> > | |
202 | , mpl::protect< mpl::not_same_as<boost::blank> > | |
203 | >::type second_result_; | |
204 | ||
205 | typedef typename second_result_::second second_result_it; | |
206 | ||
207 | public: // metafunction result | |
208 | ||
209 | // [...and return the results of the search:] | |
210 | typedef typename mpl::eval_if< | |
211 | is_same< second_result_it,end_it > | |
212 | , mpl::if_< | |
213 | is_same< first_result_it,end_it > | |
214 | , mpl::pair< no_fallback_type,no_fallback_type > | |
215 | , first_result_ | |
216 | > | |
217 | , mpl::identity< second_result_ > | |
218 | >::type type; | |
219 | ||
220 | }; | |
221 | ||
222 | #ifndef BOOST_NO_CXX11_NOEXCEPT | |
223 | /////////////////////////////////////////////////////////////////////////////// | |
224 | // (detail) metafunction is_variant_move_noexcept_constructible | |
225 | // | |
226 | // Returns true_type if all the types are nothrow move constructible. | |
227 | // | |
228 | template <class Types> | |
229 | struct is_variant_move_noexcept_constructible { | |
230 | typedef typename boost::mpl::find_if< | |
231 | Types, mpl::not_<boost::is_nothrow_move_constructible<boost::mpl::_1> > | |
232 | >::type iterator_t; | |
233 | ||
234 | typedef typename boost::mpl::end<Types>::type end_t; | |
235 | typedef typename boost::is_same< | |
236 | iterator_t, end_t | |
237 | >::type type; | |
238 | }; | |
239 | ||
240 | /////////////////////////////////////////////////////////////////////////////// | |
241 | // (detail) metafunction is_variant_move_noexcept_assignable | |
242 | // | |
243 | // Returns true_type if all the types are nothrow move constructible. | |
244 | // | |
245 | template <class Types> | |
246 | struct is_variant_move_noexcept_assignable { | |
247 | typedef typename boost::mpl::find_if< | |
248 | Types, mpl::not_<boost::is_nothrow_move_assignable<boost::mpl::_1> > | |
249 | >::type iterator_t; | |
250 | ||
251 | typedef typename boost::mpl::end<Types>::type end_t; | |
252 | typedef typename boost::is_same< | |
253 | iterator_t, end_t | |
254 | >::type type; | |
255 | }; | |
256 | #endif // BOOST_NO_CXX11_NOEXCEPT | |
257 | ||
258 | /////////////////////////////////////////////////////////////////////////////// | |
259 | // (detail) metafunction is_variant_constructible_from | |
260 | // | |
261 | // Derives from true_type if at least one variant's type is constructible from T. | |
262 | // | |
263 | template <class T1, class T2> | |
264 | struct is_constructible_ext: | |
265 | boost::mpl::or_< | |
266 | boost::is_constructible< | |
267 | T1, | |
268 | T2 | |
269 | >, | |
270 | boost::is_constructible< | |
271 | T1, | |
272 | typename boost::add_lvalue_reference<T2>::type | |
273 | > | |
274 | > | |
275 | {}; | |
276 | ||
277 | template <class T, class Types> | |
278 | struct is_variant_constructible_from: | |
279 | boost::mpl::not_< boost::is_same< | |
280 | typename boost::mpl::find_if< | |
281 | Types, | |
282 | is_constructible_ext<boost::mpl::_1, T> | |
283 | >::type, | |
284 | typename boost::mpl::end<Types>::type | |
285 | > > | |
286 | {}; | |
287 | ||
288 | template <BOOST_VARIANT_ENUM_PARAMS(typename T), class Types> | |
289 | struct is_variant_constructible_from< boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Types >: | |
290 | boost::is_same< | |
291 | typename boost::mpl::find_if< | |
292 | typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::recursive_enabled_types, | |
293 | mpl::not_< is_variant_constructible_from< boost::mpl::_1, Types> > | |
294 | >::type, | |
295 | typename boost::mpl::end< typename boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>::recursive_enabled_types >::type | |
296 | > | |
297 | {}; | |
298 | ||
299 | template <BOOST_VARIANT_ENUM_PARAMS(typename T), class Types> | |
300 | struct is_variant_constructible_from< const boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>& , Types >: | |
301 | is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Types > | |
302 | {}; | |
303 | ||
304 | template <BOOST_VARIANT_ENUM_PARAMS(typename T), class Types> | |
305 | struct is_variant_constructible_from< boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>& , Types >: | |
306 | is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Types > | |
307 | {}; | |
308 | ||
309 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
310 | ||
311 | template <BOOST_VARIANT_ENUM_PARAMS(typename T), class Types> | |
312 | struct is_variant_constructible_from< boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>&& , Types >: | |
313 | is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Types > | |
314 | {}; | |
315 | ||
316 | template <BOOST_VARIANT_ENUM_PARAMS(typename T), class Types> | |
317 | struct is_variant_constructible_from< boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const && , Types >: | |
318 | is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Types > | |
319 | {}; | |
320 | ||
321 | #endif // #ifndef BOOST_NO_CXX11_RVALUE_REFERENCE | |
322 | ||
323 | ||
324 | /////////////////////////////////////////////////////////////////////////////// | |
325 | // (detail) metafunction make_storage | |
326 | // | |
327 | // Provides an aligned storage type capable of holding any of the types | |
328 | // specified in the given type-sequence. | |
329 | // | |
330 | ||
331 | template <typename Types, typename NeverUsesBackupFlag> | |
332 | struct make_storage | |
333 | { | |
334 | private: // helpers, for metafunction result (below) | |
335 | ||
336 | typedef typename mpl::eval_if< | |
337 | NeverUsesBackupFlag | |
338 | , mpl::identity< Types > | |
339 | , mpl::push_front< | |
340 | Types, backup_holder<void*> | |
341 | > | |
342 | >::type types; | |
343 | ||
344 | typedef typename max_value< | |
345 | types, mpl::sizeof_<mpl::_1> | |
346 | >::type max_size; | |
347 | ||
348 | #if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551)) | |
349 | ||
350 | typedef typename mpl::fold< | |
351 | types | |
352 | , mpl::size_t<1> | |
353 | , add_alignment | |
354 | >::type max_alignment; | |
355 | ||
356 | #else // borland | |
357 | ||
358 | // temporary workaround -- use maximal alignment | |
359 | typedef mpl::size_t< -1 > max_alignment; | |
360 | ||
361 | #endif // borland workaround | |
362 | ||
363 | public: // metafunction result | |
364 | ||
365 | typedef ::boost::aligned_storage< | |
366 | BOOST_MPL_AUX_VALUE_WKND(max_size)::value | |
367 | , BOOST_MPL_AUX_VALUE_WKND(max_alignment)::value | |
368 | > type; | |
369 | }; | |
370 | ||
371 | /////////////////////////////////////////////////////////////////////////////// | |
372 | // (detail) class destroyer | |
373 | // | |
374 | // Internal visitor that destroys the value it visits. | |
375 | // | |
376 | struct destroyer | |
377 | : public static_visitor<> | |
378 | { | |
379 | public: // visitor interfaces | |
380 | ||
381 | template <typename T> | |
382 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
383 | internal_visit(T& operand, int) const BOOST_NOEXCEPT | |
384 | { | |
385 | operand.~T(); // must be noexcept | |
386 | ||
387 | #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551)) || \ | |
388 | BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
389 | operand; // suppresses warnings | |
390 | #endif | |
391 | ||
392 | BOOST_VARIANT_AUX_RETURN_VOID; | |
393 | } | |
394 | ||
395 | }; | |
396 | ||
397 | /////////////////////////////////////////////////////////////////////////////// | |
398 | // (detail) class template known_get | |
399 | // | |
400 | // Visitor that returns a reference to content of the specified type. | |
401 | // | |
402 | // Precondition: visited variant MUST contain logical content of type T. | |
403 | // | |
404 | template <typename T> | |
405 | class known_get | |
406 | : public static_visitor<T&> | |
407 | { | |
408 | ||
409 | public: // visitor interface | |
410 | ||
411 | T& operator()(T& operand) const BOOST_NOEXCEPT | |
412 | { | |
413 | return operand; | |
414 | } | |
415 | ||
416 | template <typename U> | |
417 | T& operator()(U&) const | |
418 | { | |
419 | // logical error to be here: see precondition above | |
420 | return ::boost::detail::variant::forced_return< T& >(); | |
421 | } | |
422 | }; | |
423 | ||
424 | /////////////////////////////////////////////////////////////////////////////// | |
425 | // (detail) class copy_into | |
426 | // | |
427 | // Internal visitor that copies the value it visits into the given buffer. | |
428 | // | |
429 | class copy_into | |
430 | : public static_visitor<> | |
431 | { | |
432 | private: // representation | |
433 | ||
434 | void* storage_; | |
435 | ||
436 | public: // structors | |
437 | ||
438 | explicit copy_into(void* storage) BOOST_NOEXCEPT | |
439 | : storage_(storage) | |
440 | { | |
441 | } | |
442 | ||
443 | public: // internal visitor interface | |
444 | ||
445 | template <typename T> | |
446 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
447 | internal_visit(boost::detail::variant::backup_holder<T>& operand, long) const | |
448 | { | |
449 | new(storage_) T( operand.get() ); | |
450 | BOOST_VARIANT_AUX_RETURN_VOID; | |
451 | } | |
452 | ||
453 | template <typename T> | |
454 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
455 | internal_visit(const boost::detail::variant::backup_holder<T>& operand, long) const | |
456 | { | |
457 | new(storage_) T( operand.get() ); | |
458 | BOOST_VARIANT_AUX_RETURN_VOID; | |
459 | } | |
460 | ||
461 | template <typename T> | |
462 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
463 | internal_visit(const T& operand, int) const | |
464 | { | |
465 | new(storage_) T(operand); | |
466 | BOOST_VARIANT_AUX_RETURN_VOID; | |
467 | } | |
468 | ||
469 | }; | |
470 | ||
471 | /////////////////////////////////////////////////////////////////////////////// | |
472 | // (detail) class move_into | |
473 | // | |
474 | // Internal visitor that moves the value it visits into the given buffer. | |
475 | // | |
476 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
477 | class move_into | |
478 | : public static_visitor<> | |
479 | { | |
480 | private: // representation | |
481 | ||
482 | void* storage_; | |
483 | ||
484 | public: // structors | |
485 | ||
486 | explicit move_into(void* storage) BOOST_NOEXCEPT | |
487 | : storage_(storage) | |
488 | { | |
489 | } | |
490 | ||
491 | public: // internal visitor interface | |
492 | ||
493 | template <typename T> | |
494 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
495 | internal_visit(boost::detail::variant::backup_holder<T>& operand, long) const | |
496 | { | |
497 | new(storage_) T( ::boost::detail::variant::move(operand.get()) ); | |
498 | BOOST_VARIANT_AUX_RETURN_VOID; | |
499 | } | |
500 | ||
501 | template <typename T> | |
502 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
503 | internal_visit(T& operand, int) const BOOST_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(T(boost::declval<T>()))) | |
504 | { | |
505 | new(storage_) T(::boost::detail::variant::move(operand)); | |
506 | BOOST_VARIANT_AUX_RETURN_VOID; | |
507 | } | |
508 | }; | |
509 | #endif | |
510 | ||
511 | /////////////////////////////////////////////////////////////////////////////// | |
512 | // (detail) class assign_storage | |
513 | // | |
514 | // Internal visitor that assigns the given storage (which must be a | |
515 | // constructed value of the same type) to the value it visits. | |
516 | // | |
517 | struct assign_storage | |
518 | : public static_visitor<> | |
519 | { | |
520 | private: // representation | |
521 | ||
522 | const void* rhs_storage_; | |
523 | ||
524 | public: // structors | |
525 | ||
526 | explicit assign_storage(const void* rhs_storage) BOOST_NOEXCEPT | |
527 | : rhs_storage_(rhs_storage) | |
528 | { | |
529 | } | |
530 | ||
531 | public: // internal visitor interfaces | |
532 | ||
533 | template <typename T> | |
534 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
535 | internal_visit(backup_holder<T>& lhs_content, long) const | |
536 | { | |
537 | lhs_content.get() | |
538 | = static_cast< const backup_holder<T>* >(rhs_storage_)->get(); | |
539 | BOOST_VARIANT_AUX_RETURN_VOID; | |
540 | } | |
541 | ||
542 | template <typename T> | |
543 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
544 | internal_visit(const backup_holder<T>& lhs_content, long) const | |
545 | { | |
546 | lhs_content.get() | |
547 | = static_cast< const backup_holder<T>* >(rhs_storage_)->get(); | |
548 | BOOST_VARIANT_AUX_RETURN_VOID; | |
549 | } | |
550 | ||
551 | template <typename T> | |
552 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
553 | internal_visit(T& lhs_content, int) const | |
554 | { | |
555 | // NOTE TO USER : | |
556 | // Compile error here indicates one of variant's bounded types does | |
557 | // not meet the requirements of the Assignable concept. Thus, | |
558 | // variant is not Assignable. | |
559 | // | |
560 | // Hint: Are any of the bounded types const-qualified or references? | |
561 | // | |
562 | lhs_content = *static_cast< const T* >(rhs_storage_); | |
563 | BOOST_VARIANT_AUX_RETURN_VOID; | |
564 | } | |
565 | ||
566 | }; | |
567 | ||
568 | /////////////////////////////////////////////////////////////////////////////// | |
569 | // (detail) class move_storage | |
570 | // | |
571 | // Internal visitor that moves the given storage (which must be a | |
572 | // constructed value of the same type) to the value it visits. | |
573 | // | |
574 | struct move_storage | |
575 | : public static_visitor<> | |
576 | { | |
577 | private: // representation | |
578 | ||
579 | void* rhs_storage_; | |
580 | ||
581 | public: // structors | |
582 | ||
583 | explicit move_storage(void* rhs_storage) BOOST_NOEXCEPT | |
584 | : rhs_storage_(rhs_storage) | |
585 | { | |
586 | } | |
587 | ||
588 | public: // internal visitor interfaces | |
589 | ||
590 | template <typename T> | |
591 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
592 | internal_visit(backup_holder<T>& lhs_content, long) const | |
593 | { | |
594 | lhs_content.get() | |
595 | = ::boost::detail::variant::move(static_cast<backup_holder<T>* >(rhs_storage_)->get()); | |
596 | BOOST_VARIANT_AUX_RETURN_VOID; | |
597 | } | |
598 | ||
599 | template <typename T> | |
600 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
601 | internal_visit(const backup_holder<T>& lhs_content, long) const | |
602 | { | |
603 | lhs_content.get() | |
604 | = ::boost::detail::variant::move(static_cast<backup_holder<T>* >(rhs_storage_)->get()); | |
605 | BOOST_VARIANT_AUX_RETURN_VOID; | |
606 | } | |
607 | ||
608 | template <typename T> | |
609 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
610 | internal_visit(T& lhs_content, int) const | |
611 | { | |
612 | // NOTE TO USER : | |
613 | // Compile error here indicates one of variant's bounded types does | |
614 | // not meet the requirements of the Assignable concept. Thus, | |
615 | // variant is not Assignable. | |
616 | // | |
617 | // Hint: Are any of the bounded types const-qualified or references? | |
618 | // | |
619 | lhs_content = ::boost::detail::variant::move(*static_cast<T* >(rhs_storage_)); | |
620 | BOOST_VARIANT_AUX_RETURN_VOID; | |
621 | } | |
622 | ||
623 | }; | |
624 | ||
625 | /////////////////////////////////////////////////////////////////////////////// | |
626 | // (detail) class direct_assigner | |
627 | // | |
628 | // Generic static visitor that: if and only if the visited value is of the | |
629 | // specified type, assigns the given value to the visited value and returns | |
630 | // true; else returns false. | |
631 | // | |
632 | template <typename T> | |
633 | class direct_assigner | |
634 | : public static_visitor<bool> | |
635 | { | |
636 | private: // representation | |
637 | ||
638 | const T& rhs_; | |
639 | ||
640 | public: // structors | |
641 | ||
642 | explicit direct_assigner(const T& rhs) BOOST_NOEXCEPT | |
643 | : rhs_(rhs) | |
644 | { | |
645 | } | |
646 | ||
647 | public: // visitor interface | |
648 | ||
649 | bool operator()(T& lhs) | |
650 | { | |
651 | lhs = rhs_; | |
652 | return true; | |
653 | } | |
654 | ||
655 | template <typename U> | |
656 | bool operator()(U&) BOOST_NOEXCEPT | |
657 | { | |
658 | return false; | |
659 | } | |
660 | ||
661 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
662 | private: | |
663 | // silence MSVC warning C4512: assignment operator could not be generated | |
664 | direct_assigner& operator= (direct_assigner const&); | |
665 | #endif | |
666 | }; | |
667 | ||
668 | /////////////////////////////////////////////////////////////////////////////// | |
669 | // (detail) class direct_mover | |
670 | // | |
671 | // Generic static visitor that: if and only if the visited value is of the | |
672 | // specified type, move assigns the given value to the visited value and returns | |
673 | // true; else returns false. | |
674 | // | |
675 | template <typename T> | |
676 | class direct_mover | |
677 | : public static_visitor<bool> | |
678 | { | |
679 | private: // representation | |
680 | ||
681 | T& rhs_; | |
682 | ||
683 | public: // structors | |
684 | ||
685 | explicit direct_mover(T& rhs) BOOST_NOEXCEPT | |
686 | : rhs_(rhs) | |
687 | { | |
688 | } | |
689 | ||
690 | public: // visitor interface | |
691 | ||
692 | bool operator()(T& lhs) | |
693 | { | |
694 | lhs = ::boost::detail::variant::move(rhs_); | |
695 | return true; | |
696 | } | |
697 | ||
698 | template <typename U> | |
699 | bool operator()(U&) BOOST_NOEXCEPT | |
700 | { | |
701 | return false; | |
702 | } | |
703 | ||
704 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
705 | private: | |
706 | // silence MSVC warning C4512: assignment operator could not be generated | |
707 | direct_mover& operator= (direct_mover const&); | |
708 | #endif | |
709 | }; | |
710 | ||
711 | ||
712 | /////////////////////////////////////////////////////////////////////////////// | |
713 | // (detail) class backup_assigner | |
714 | // | |
715 | // Internal visitor that "assigns" the given value to the visited value, | |
716 | // using backup to recover if the destroy-copy sequence fails. | |
717 | // | |
718 | // NOTE: This needs to be a friend of variant, as it needs access to | |
719 | // indicate_which, indicate_backup_which, etc. | |
720 | // | |
721 | template <typename Variant> | |
722 | class backup_assigner | |
723 | : public static_visitor<> | |
724 | { | |
725 | private: // representation | |
726 | ||
727 | Variant& lhs_; | |
728 | int rhs_which_; | |
729 | const void* rhs_content_; | |
730 | void (*copy_rhs_content_)(void*, const void*); | |
731 | ||
732 | public: // structors | |
733 | ||
734 | template<class RhsT> | |
735 | backup_assigner(Variant& lhs, int rhs_which, const RhsT& rhs_content) | |
736 | : lhs_(lhs) | |
737 | , rhs_which_(rhs_which) | |
738 | , rhs_content_(&rhs_content) | |
739 | , copy_rhs_content_(&construct_impl<RhsT>) | |
740 | { | |
741 | } | |
742 | ||
743 | private: // helpers, for visitor interface (below) | |
744 | ||
745 | template<class RhsT> | |
746 | static void construct_impl(void* addr, const void* obj) | |
747 | { | |
748 | new(addr) RhsT(*static_cast<const RhsT*>(obj)); | |
749 | } | |
750 | ||
751 | template <typename LhsT> | |
752 | void backup_assign_impl( | |
753 | backup_holder<LhsT>& lhs_content | |
754 | , mpl::false_ // is_nothrow_move_constructible | |
755 | , long | |
756 | ) | |
757 | { | |
758 | // Move lhs content to backup... | |
759 | backup_holder<LhsT> backup_lhs_content(0); | |
760 | backup_lhs_content.swap(lhs_content); // nothrow | |
761 | ||
762 | // ...destroy lhs content... | |
763 | lhs_content.~backup_holder<LhsT>(); // nothrow | |
764 | ||
765 | BOOST_TRY | |
766 | { | |
767 | // ...and attempt to copy rhs content into lhs storage: | |
768 | copy_rhs_content_(lhs_.storage_.address(), rhs_content_); | |
769 | } | |
770 | BOOST_CATCH (...) | |
771 | { | |
772 | // In case of failure, copy backup pointer to lhs storage... | |
773 | new(lhs_.storage_.address()) | |
774 | backup_holder<LhsT>( 0 ); // nothrow | |
775 | ||
776 | static_cast<backup_holder<LhsT>* >(lhs_.storage_.address()) | |
777 | ->swap(backup_lhs_content); // nothrow | |
778 | ||
779 | // ...and rethrow: | |
780 | BOOST_RETHROW; | |
781 | } | |
782 | BOOST_CATCH_END | |
783 | ||
784 | // In case of success, indicate new content type: | |
785 | lhs_.indicate_which(rhs_which_); // nothrow | |
786 | } | |
787 | ||
788 | template <typename LhsT> | |
789 | void backup_assign_impl( | |
790 | LhsT& lhs_content | |
791 | , mpl::true_ // is_nothrow_move_constructible | |
792 | , int | |
793 | ) | |
794 | { | |
795 | // Move lhs content to backup... | |
796 | LhsT backup_lhs_content( | |
797 | ::boost::detail::variant::move(lhs_content) | |
798 | ); // nothrow | |
799 | ||
800 | // ...destroy lhs content... | |
801 | lhs_content.~LhsT(); // nothrow | |
802 | ||
803 | BOOST_TRY | |
804 | { | |
805 | // ...and attempt to copy rhs content into lhs storage: | |
806 | copy_rhs_content_(lhs_.storage_.address(), rhs_content_); | |
807 | } | |
808 | BOOST_CATCH (...) | |
809 | { | |
810 | // In case of failure, restore backup content to lhs storage... | |
811 | new(lhs_.storage_.address()) | |
812 | LhsT( | |
813 | ::boost::detail::variant::move(backup_lhs_content) | |
814 | ); // nothrow | |
815 | ||
816 | // ...and rethrow: | |
817 | BOOST_RETHROW; | |
818 | } | |
819 | BOOST_CATCH_END | |
820 | ||
821 | // In case of success, indicate new content type: | |
822 | lhs_.indicate_which(rhs_which_); // nothrow | |
823 | } | |
824 | ||
825 | template <typename LhsT> | |
826 | void backup_assign_impl( | |
827 | LhsT& lhs_content | |
828 | , mpl::false_ // is_nothrow_move_constructible | |
829 | , int | |
830 | ) | |
831 | { | |
832 | // Backup lhs content... | |
833 | LhsT* backup_lhs_ptr = new LhsT(lhs_content); | |
834 | ||
835 | // ...destroy lhs content... | |
836 | lhs_content.~LhsT(); // nothrow | |
837 | ||
838 | BOOST_TRY | |
839 | { | |
840 | // ...and attempt to copy rhs content into lhs storage: | |
841 | copy_rhs_content_(lhs_.storage_.address(), rhs_content_); | |
842 | } | |
843 | BOOST_CATCH (...) | |
844 | { | |
845 | // In case of failure, copy backup pointer to lhs storage... | |
846 | new(lhs_.storage_.address()) | |
847 | backup_holder<LhsT>( backup_lhs_ptr ); // nothrow | |
848 | ||
849 | // ...indicate now using backup... | |
850 | lhs_.indicate_backup_which( lhs_.which() ); // nothrow | |
851 | ||
852 | // ...and rethrow: | |
853 | BOOST_RETHROW; | |
854 | } | |
855 | BOOST_CATCH_END | |
856 | ||
857 | // In case of success, indicate new content type... | |
858 | lhs_.indicate_which(rhs_which_); // nothrow | |
859 | ||
860 | // ...and delete backup: | |
861 | delete backup_lhs_ptr; // nothrow | |
862 | } | |
863 | ||
864 | public: // visitor interface | |
865 | ||
866 | template <typename LhsT> | |
867 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
868 | internal_visit(LhsT& lhs_content, int) | |
869 | { | |
870 | typedef typename is_nothrow_move_constructible<LhsT>::type | |
871 | nothrow_move; | |
872 | ||
873 | backup_assign_impl( lhs_content, nothrow_move(), 1L); | |
874 | ||
875 | BOOST_VARIANT_AUX_RETURN_VOID; | |
876 | } | |
877 | ||
878 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
879 | private: | |
880 | // silence MSVC warning C4512: assignment operator could not be generated | |
881 | backup_assigner& operator= (backup_assigner const&); | |
882 | #endif | |
883 | }; | |
884 | ||
885 | /////////////////////////////////////////////////////////////////////////////// | |
886 | // (detail) class swap_with | |
887 | // | |
888 | // Visitor that swaps visited value with content of given variant. | |
889 | // | |
890 | // Precondition: Given variant MUST have same logical type as visited value. | |
891 | // | |
892 | template <typename Variant> | |
893 | struct swap_with | |
894 | : public static_visitor<> | |
895 | { | |
896 | private: // representation | |
897 | ||
898 | Variant& toswap_; | |
899 | ||
900 | public: // structors | |
901 | ||
902 | explicit swap_with(Variant& toswap) BOOST_NOEXCEPT | |
903 | : toswap_(toswap) | |
904 | { | |
905 | } | |
906 | ||
907 | public: // internal visitor interfaces | |
908 | ||
909 | template <typename T> | |
910 | void operator()(T& operand) const | |
911 | { | |
912 | // Since the precondition ensures types are same, get T... | |
913 | known_get<T> getter; | |
914 | T& other = toswap_.apply_visitor(getter); | |
915 | ||
916 | // ...and swap: | |
917 | ::boost::detail::variant::move_swap( operand, other ); | |
918 | } | |
919 | ||
920 | private: | |
921 | swap_with& operator=(const swap_with&); | |
922 | ||
923 | }; | |
924 | ||
925 | /////////////////////////////////////////////////////////////////////////////// | |
926 | // (detail) class reflect | |
927 | // | |
928 | // Generic static visitor that performs a typeid on the value it visits. | |
929 | // | |
930 | ||
931 | class reflect | |
932 | : public static_visitor<const boost::typeindex::type_info&> | |
933 | { | |
934 | public: // visitor interfaces | |
935 | ||
936 | template <typename T> | |
937 | const boost::typeindex::type_info& operator()(const T&) const BOOST_NOEXCEPT | |
938 | { | |
939 | return boost::typeindex::type_id<T>().type_info(); | |
940 | } | |
941 | ||
942 | }; | |
943 | ||
944 | /////////////////////////////////////////////////////////////////////////////// | |
945 | // (detail) class comparer | |
946 | // | |
947 | // Generic static visitor that compares the content of the given lhs variant | |
948 | // with the visited rhs content using Comp. | |
949 | // | |
950 | // Precondition: lhs.which() == rhs.which() | |
951 | // | |
952 | template <typename Variant, typename Comp> | |
953 | class comparer | |
954 | : public static_visitor<bool> | |
955 | { | |
956 | private: // representation | |
957 | ||
958 | const Variant& lhs_; | |
959 | ||
960 | public: // structors | |
961 | ||
962 | explicit comparer(const Variant& lhs) BOOST_NOEXCEPT | |
963 | : lhs_(lhs) | |
964 | { | |
965 | } | |
966 | ||
967 | public: // visitor interfaces | |
968 | ||
969 | template <typename T> | |
970 | bool operator()(T& rhs_content) const | |
971 | { | |
972 | // Since the precondition ensures lhs and rhs types are same, get T... | |
973 | known_get<T> getter; | |
974 | const T& lhs_content = lhs_.apply_visitor(getter); | |
975 | ||
976 | // ...and compare lhs and rhs contents: | |
977 | return Comp()(lhs_content, rhs_content); | |
978 | } | |
979 | ||
980 | private: | |
981 | comparer& operator=(const comparer&); | |
982 | ||
983 | }; | |
984 | ||
985 | /////////////////////////////////////////////////////////////////////////////// | |
986 | // (detail) class equal_comp | |
987 | // | |
988 | // Generic function object compares lhs with rhs using operator==. | |
989 | // | |
990 | struct equal_comp | |
991 | { | |
992 | template <typename T> | |
993 | bool operator()(const T& lhs, const T& rhs) const | |
994 | { | |
995 | return lhs == rhs; | |
996 | } | |
997 | }; | |
998 | ||
999 | /////////////////////////////////////////////////////////////////////////////// | |
1000 | // (detail) class less_comp | |
1001 | // | |
1002 | // Generic function object compares lhs with rhs using operator<. | |
1003 | // | |
1004 | struct less_comp | |
1005 | { | |
1006 | template <typename T> | |
1007 | bool operator()(const T& lhs, const T& rhs) const | |
1008 | { | |
1009 | return lhs < rhs; | |
1010 | } | |
1011 | }; | |
1012 | ||
1013 | /////////////////////////////////////////////////////////////////////////////// | |
1014 | // (detail) class template invoke_visitor | |
1015 | // | |
1016 | // Internal visitor that invokes the given visitor using: | |
1017 | // * for wrappers (e.g., recursive_wrapper), the wrapper's held value. | |
1018 | // * for all other values, the value itself. | |
1019 | // | |
1020 | template <typename Visitor> | |
1021 | class invoke_visitor | |
1022 | { | |
1023 | private: // representation | |
1024 | ||
1025 | Visitor& visitor_; | |
1026 | ||
1027 | public: // visitor typedefs | |
1028 | ||
1029 | typedef typename Visitor::result_type | |
1030 | result_type; | |
1031 | ||
1032 | public: // structors | |
1033 | ||
1034 | explicit invoke_visitor(Visitor& visitor) BOOST_NOEXCEPT | |
1035 | : visitor_(visitor) | |
1036 | { | |
1037 | } | |
1038 | ||
1039 | #if !defined(BOOST_NO_VOID_RETURNS) | |
1040 | ||
1041 | public: // internal visitor interfaces | |
1042 | ||
1043 | template <typename T> | |
1044 | result_type internal_visit(T& operand, int) | |
1045 | { | |
1046 | return visitor_(operand); | |
1047 | } | |
1048 | ||
1049 | # if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0564)) | |
1050 | template <typename T> | |
1051 | result_type internal_visit(const T& operand, int) | |
1052 | { | |
1053 | return visitor_(operand); | |
1054 | } | |
1055 | # endif | |
1056 | ||
1057 | #else // defined(BOOST_NO_VOID_RETURNS) | |
1058 | ||
1059 | private: // helpers, for internal visitor interfaces (below) | |
1060 | ||
1061 | template <typename T> | |
1062 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1063 | visit_impl(T& operand, mpl::false_) | |
1064 | { | |
1065 | return visitor_(operand); | |
1066 | } | |
1067 | ||
1068 | template <typename T> | |
1069 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
1070 | visit_impl(T& operand, mpl::true_) | |
1071 | { | |
1072 | visitor_(operand); | |
1073 | BOOST_VARIANT_AUX_RETURN_VOID; | |
1074 | } | |
1075 | ||
1076 | public: // internal visitor interfaces | |
1077 | ||
1078 | template <typename T> | |
1079 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1080 | internal_visit(T& operand, int) | |
1081 | { | |
1082 | typedef typename is_same<result_type, void>::type | |
1083 | has_void_result_type; | |
1084 | ||
1085 | return visit_impl(operand, has_void_result_type()); | |
1086 | } | |
1087 | ||
1088 | #endif // BOOST_NO_VOID_RETURNS) workaround | |
1089 | ||
1090 | public: // internal visitor interfaces, cont. | |
1091 | ||
1092 | template <typename T> | |
1093 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1094 | internal_visit(boost::recursive_wrapper<T>& operand, long) | |
1095 | { | |
1096 | return internal_visit( operand.get(), 1L ); | |
1097 | } | |
1098 | ||
1099 | template <typename T> | |
1100 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1101 | internal_visit(const boost::recursive_wrapper<T>& operand, long) | |
1102 | { | |
1103 | return internal_visit( operand.get(), 1L ); | |
1104 | } | |
1105 | ||
1106 | template <typename T> | |
1107 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1108 | internal_visit(boost::detail::reference_content<T>& operand, long) | |
1109 | { | |
1110 | return internal_visit( operand.get(), 1L ); | |
1111 | } | |
1112 | ||
1113 | template <typename T> | |
1114 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1115 | internal_visit(const boost::detail::reference_content<T>& operand, long) | |
1116 | { | |
1117 | return internal_visit( operand.get(), 1L ); | |
1118 | } | |
1119 | ||
1120 | template <typename T> | |
1121 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1122 | internal_visit(boost::detail::variant::backup_holder<T>& operand, long) | |
1123 | { | |
1124 | return internal_visit( operand.get(), 1L ); | |
1125 | } | |
1126 | ||
1127 | template <typename T> | |
1128 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) | |
1129 | internal_visit(const boost::detail::variant::backup_holder<T>& operand, long) | |
1130 | { | |
1131 | return internal_visit( operand.get(), 1L ); | |
1132 | } | |
1133 | ||
1134 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
1135 | private: | |
1136 | // silence MSVC warning C4512: assignment operator could not be generated | |
1137 | invoke_visitor& operator= (invoke_visitor const&); | |
1138 | #endif | |
1139 | }; | |
1140 | ||
1141 | }} // namespace detail::variant | |
1142 | ||
1143 | /////////////////////////////////////////////////////////////////////////////// | |
1144 | // class template variant (concept inspired by Andrei Alexandrescu) | |
1145 | // | |
1146 | // See docs and boost/variant/variant_fwd.hpp for more information. | |
1147 | // | |
1148 | template < | |
1149 | typename T0_ | |
1150 | , BOOST_VARIANT_ENUM_SHIFTED_PARAMS(typename T) | |
1151 | > | |
1152 | class variant | |
1153 | { | |
1154 | private: // helpers, for typedefs (below) | |
1155 | ||
1156 | typedef variant wknd_self_t; | |
1157 | ||
1158 | struct is_recursive_ | |
1159 | : detail::variant::is_recursive_flag<T0_> | |
1160 | { | |
1161 | }; | |
1162 | ||
1163 | typedef typename mpl::eval_if< | |
1164 | is_recursive_ | |
1165 | , T0_ | |
1166 | , mpl::identity< T0_ > | |
1167 | >::type unwrapped_T0_; | |
1168 | ||
1169 | struct is_sequence_based_ | |
1170 | : detail::variant::is_over_sequence<unwrapped_T0_> | |
1171 | { | |
1172 | }; | |
1173 | ||
1174 | #if !defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT) | |
1175 | ||
1176 | private: // helpers, for typedefs (below) | |
1177 | ||
1178 | typedef typename mpl::eval_if< | |
1179 | is_sequence_based_ | |
1180 | , unwrapped_T0_ // over_sequence<...>::type | |
1181 | , detail::variant::make_variant_list< | |
1182 | unwrapped_T0_ | |
1183 | , BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T) | |
1184 | > | |
1185 | >::type specified_types; | |
1186 | ||
1187 | BOOST_STATIC_ASSERT(( | |
1188 | ::boost::mpl::not_< mpl::empty<specified_types> >::value | |
1189 | )); | |
1190 | ||
1191 | public: // public typedefs | |
1192 | typedef typename mpl::eval_if< | |
1193 | is_recursive_ | |
1194 | , mpl::transform< | |
1195 | specified_types | |
1196 | , mpl::protect< | |
1197 | detail::variant::quoted_enable_recursive<wknd_self_t> | |
1198 | > | |
1199 | > | |
1200 | , mpl::identity< specified_types > | |
1201 | >::type recursive_enabled_types; // used by is_variant_constructible_from<> trait | |
1202 | ||
1203 | typedef typename mpl::transform< | |
1204 | recursive_enabled_types | |
1205 | , unwrap_recursive<mpl::_1> | |
1206 | >::type types; | |
1207 | ||
1208 | private: // internal typedefs | |
1209 | ||
1210 | typedef typename mpl::transform< | |
1211 | recursive_enabled_types | |
1212 | , mpl::protect< detail::make_reference_content<> > | |
1213 | >::type internal_types; | |
1214 | ||
1215 | typedef typename mpl::front< | |
1216 | internal_types | |
1217 | >::type internal_T0; | |
1218 | ||
1219 | #else // defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT) | |
1220 | ||
1221 | private: // helpers, for typedefs (below) | |
1222 | ||
1223 | typedef unwrapped_T0_ T0; | |
1224 | ||
1225 | #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS(z,N,_) \ | |
1226 | typedef typename mpl::eval_if< \ | |
1227 | is_recursive_ \ | |
1228 | , detail::variant::enable_recursive< \ | |
1229 | BOOST_PP_CAT(T,N) \ | |
1230 | , wknd_self_t \ | |
1231 | > \ | |
1232 | , mpl::identity< BOOST_PP_CAT(T,N) > \ | |
1233 | >::type BOOST_PP_CAT(recursive_enabled_T,N); \ | |
1234 | /**/ | |
1235 | ||
1236 | BOOST_PP_REPEAT( | |
1237 | BOOST_VARIANT_LIMIT_TYPES | |
1238 | , BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS | |
1239 | , _ | |
1240 | ) | |
1241 | ||
1242 | #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS | |
1243 | ||
1244 | #define BOOST_VARIANT_AUX_UNWRAP_RECURSIVE_TYPEDEFS(z,N,_) \ | |
1245 | typedef typename unwrap_recursive< \ | |
1246 | BOOST_PP_CAT(recursive_enabled_T,N) \ | |
1247 | >::type BOOST_PP_CAT(public_T,N); \ | |
1248 | /**/ | |
1249 | ||
1250 | BOOST_PP_REPEAT( | |
1251 | BOOST_VARIANT_LIMIT_TYPES | |
1252 | , BOOST_VARIANT_AUX_UNWRAP_RECURSIVE_TYPEDEFS | |
1253 | , _ | |
1254 | ) | |
1255 | ||
1256 | #undef BOOST_VARIANT_AUX_UNWRAP_RECURSIVE_TYPEDEFS | |
1257 | ||
1258 | public: // public typedefs | |
1259 | ||
1260 | typedef typename detail::variant::make_variant_list< | |
1261 | BOOST_VARIANT_ENUM_PARAMS(public_T) | |
1262 | >::type types; | |
1263 | ||
1264 | private: // helpers, for internal typedefs (below) | |
1265 | ||
1266 | #define BOOST_VARIANT_AUX_MAKE_REFERENCE_CONTENT_TYPEDEFS(z,N,_) \ | |
1267 | typedef detail::make_reference_content< \ | |
1268 | BOOST_PP_CAT(recursive_enabled_T,N) \ | |
1269 | >::type BOOST_PP_CAT(internal_T,N); \ | |
1270 | /**/ | |
1271 | ||
1272 | BOOST_PP_REPEAT( | |
1273 | BOOST_VARIANT_LIMIT_TYPES | |
1274 | , BOOST_VARIANT_AUX_MAKE_REFERENCE_CONTENT_TYPEDEFS | |
1275 | , _ | |
1276 | ) | |
1277 | ||
1278 | #undef BOOST_VARIANT_AUX_MAKE_REFERENCE_CONTENT_TYPEDEFS | |
1279 | ||
1280 | private: // internal typedefs | |
1281 | ||
1282 | typedef typename detail::variant::make_variant_list< | |
1283 | BOOST_VARIANT_ENUM_PARAMS(internal_T) | |
1284 | >::type internal_types; | |
1285 | ||
1286 | private: // static precondition assertions | |
1287 | ||
1288 | // NOTE TO USER : | |
1289 | // variant< type-sequence > syntax is not supported on this compiler! | |
1290 | // | |
1291 | BOOST_MPL_ASSERT_NOT(( is_sequence_based_ )); | |
1292 | ||
1293 | #endif // BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT workaround | |
1294 | ||
1295 | private: // helpers, for representation (below) | |
1296 | ||
1297 | typedef typename detail::variant::find_fallback_type< | |
1298 | internal_types | |
1299 | >::type fallback_type_result_; | |
1300 | ||
1301 | typedef typename fallback_type_result_::first | |
1302 | fallback_type_index_; | |
1303 | typedef typename fallback_type_result_::second | |
1304 | fallback_type_; | |
1305 | ||
1306 | struct has_fallback_type_ | |
1307 | : mpl::not_< | |
1308 | is_same< fallback_type_, detail::variant::no_fallback_type > | |
1309 | > | |
1310 | { | |
1311 | }; | |
1312 | ||
1313 | typedef has_fallback_type_ | |
1314 | never_uses_backup_flag; | |
1315 | ||
1316 | typedef typename detail::variant::make_storage< | |
1317 | internal_types, never_uses_backup_flag | |
1318 | >::type storage_t; | |
1319 | ||
1320 | #ifndef BOOST_NO_CXX11_NOEXCEPT | |
1321 | typedef typename detail::variant::is_variant_move_noexcept_constructible< | |
1322 | internal_types | |
1323 | > variant_move_noexcept_constructible; | |
1324 | ||
1325 | typedef typename detail::variant::is_variant_move_noexcept_assignable< | |
1326 | internal_types | |
1327 | > variant_move_noexcept_assignable; | |
1328 | ||
1329 | #endif | |
1330 | ||
1331 | private: // helpers, for representation (below) | |
1332 | ||
1333 | // which_ on: | |
1334 | // * [0, size<internal_types>) indicates stack content | |
1335 | // * [-size<internal_types>, 0) indicates pointer to heap backup | |
1336 | // if which_ >= 0: | |
1337 | // * then which() -> which_ | |
1338 | // * else which() -> -(which_ + 1) | |
1339 | ||
1340 | #if !defined(BOOST_VARIANT_MINIMIZE_SIZE) | |
1341 | ||
1342 | typedef int which_t; | |
1343 | ||
1344 | #else // defined(BOOST_VARIANT_MINIMIZE_SIZE) | |
1345 | ||
1346 | // [if O1_size available, then attempt which_t size optimization...] | |
1347 | // [select signed char if fewer than SCHAR_MAX types, else signed int:] | |
1348 | typedef typename mpl::eval_if< | |
1349 | mpl::equal_to< mpl::O1_size<internal_types>, mpl::long_<-1> > | |
1350 | , mpl::identity< int > | |
1351 | , mpl::if_< | |
1352 | mpl::less< mpl::O1_size<internal_types>, mpl::int_<SCHAR_MAX> > | |
1353 | , signed char | |
1354 | , int | |
1355 | > | |
1356 | >::type which_t; | |
1357 | ||
1358 | #endif // BOOST_VARIANT_MINIMIZE_SIZE switch | |
1359 | ||
1360 | // representation -- private when possible | |
1361 | #if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) | |
1362 | private: | |
1363 | #else | |
1364 | public: | |
1365 | #endif | |
1366 | ||
1367 | which_t which_; | |
1368 | storage_t storage_; | |
1369 | ||
1370 | void indicate_which(int which_arg) BOOST_NOEXCEPT | |
1371 | { | |
1372 | which_ = static_cast<which_t>( which_arg ); | |
1373 | } | |
1374 | ||
1375 | void indicate_backup_which(int which_arg) BOOST_NOEXCEPT | |
1376 | { | |
1377 | which_ = static_cast<which_t>( -(which_arg + 1) ); | |
1378 | } | |
1379 | ||
1380 | private: // helpers, for queries (below) | |
1381 | ||
1382 | bool using_backup() const BOOST_NOEXCEPT | |
1383 | { | |
1384 | return which_ < 0; | |
1385 | } | |
1386 | ||
1387 | public: // queries | |
1388 | ||
1389 | int which() const BOOST_NOEXCEPT | |
1390 | { | |
1391 | // If using heap backup... | |
1392 | if (using_backup()) | |
1393 | // ...then return adjusted which_: | |
1394 | return -(which_ + 1); | |
1395 | ||
1396 | // Otherwise, return which_ directly: | |
1397 | return which_; | |
1398 | } | |
1399 | ||
1400 | private: // helpers, for structors (below) | |
1401 | ||
1402 | struct initializer | |
1403 | : BOOST_VARIANT_AUX_INITIALIZER_T( | |
1404 | recursive_enabled_types, recursive_enabled_T | |
1405 | ) | |
1406 | { | |
1407 | }; | |
1408 | ||
1409 | void destroy_content() BOOST_NOEXCEPT | |
1410 | { | |
1411 | detail::variant::destroyer visitor; | |
1412 | this->internal_apply_visitor(visitor); | |
1413 | } | |
1414 | ||
1415 | public: // structors | |
1416 | ||
1417 | ~variant() BOOST_NOEXCEPT | |
1418 | { | |
1419 | destroy_content(); | |
1420 | } | |
1421 | ||
1422 | variant() | |
1423 | #if !(defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x5130)) | |
1424 | BOOST_NOEXCEPT_IF(boost::has_nothrow_constructor<internal_T0>::value) | |
1425 | #endif | |
1426 | { | |
1427 | #ifdef _MSC_VER | |
1428 | #pragma warning( push ) | |
1429 | // behavior change: an object of POD type constructed with an initializer of the form () will be default-initialized | |
1430 | #pragma warning( disable : 4345 ) | |
1431 | #endif | |
1432 | // NOTE TO USER : | |
1433 | // Compile error from here indicates that the first bound | |
1434 | // type is not default-constructible, and so variant cannot | |
1435 | // support its own default-construction. | |
1436 | // | |
1437 | new( storage_.address() ) internal_T0(); | |
1438 | indicate_which(0); // zero is the index of the first bounded type | |
1439 | #ifdef _MSC_VER | |
1440 | #pragma warning( pop ) | |
1441 | #endif | |
1442 | } | |
1443 | ||
1444 | private: // helpers, for structors, cont. (below) | |
1445 | ||
1446 | class convert_copy_into | |
1447 | : public static_visitor<int> | |
1448 | { | |
1449 | private: // representation | |
1450 | ||
1451 | void* storage_; | |
1452 | ||
1453 | public: // structors | |
1454 | ||
1455 | explicit convert_copy_into(void* storage) BOOST_NOEXCEPT | |
1456 | : storage_(storage) | |
1457 | { | |
1458 | } | |
1459 | ||
1460 | public: // internal visitor interfaces (below) | |
1461 | ||
1462 | template <typename T> | |
1463 | int internal_visit(T& operand, int) const | |
1464 | { | |
1465 | // NOTE TO USER : | |
1466 | // Compile error here indicates one of the source variant's types | |
1467 | // cannot be unambiguously converted to the destination variant's | |
1468 | // types (or that no conversion exists). | |
1469 | // | |
1470 | return initializer::initialize(storage_, operand); | |
1471 | } | |
1472 | ||
1473 | # if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0564)) | |
1474 | template <typename T> | |
1475 | result_type internal_visit(const T& operand, int) const | |
1476 | { | |
1477 | return initializer::initialize(storage_, operand); | |
1478 | } | |
1479 | # endif | |
1480 | ||
1481 | template <typename T> | |
1482 | int internal_visit(boost::detail::reference_content<T>& operand, long) const | |
1483 | { | |
1484 | return internal_visit( operand.get(), 1L ); | |
1485 | } | |
1486 | ||
1487 | template <typename T> | |
1488 | int internal_visit(const boost::detail::reference_content<T>& operand, long) const | |
1489 | { | |
1490 | return internal_visit( operand.get(), 1L ); | |
1491 | } | |
1492 | ||
1493 | template <typename T> | |
1494 | int internal_visit(boost::detail::variant::backup_holder<T>& operand, long) const | |
1495 | { | |
1496 | return internal_visit( operand.get(), 1L ); | |
1497 | } | |
1498 | ||
1499 | template <typename T> | |
1500 | int internal_visit(const boost::detail::variant::backup_holder<T>& operand, long) const | |
1501 | { | |
1502 | return internal_visit( operand.get(), 1L ); | |
1503 | } | |
1504 | ||
1505 | template <typename T> | |
1506 | int internal_visit(boost::recursive_wrapper<T>& operand, long) const | |
1507 | { | |
1508 | return internal_visit( operand.get(), 1L ); | |
1509 | } | |
1510 | ||
1511 | template <typename T> | |
1512 | int internal_visit(const boost::recursive_wrapper<T>& operand, long) const | |
1513 | { | |
1514 | return internal_visit( operand.get(), 1L ); | |
1515 | } | |
1516 | ||
1517 | }; | |
1518 | ||
1519 | friend class convert_copy_into; | |
1520 | ||
1521 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1522 | class convert_move_into | |
1523 | : public static_visitor<int> | |
1524 | { | |
1525 | private: // representation | |
1526 | ||
1527 | void* storage_; | |
1528 | ||
1529 | public: // structors | |
1530 | ||
1531 | explicit convert_move_into(void* storage) BOOST_NOEXCEPT | |
1532 | : storage_(storage) | |
1533 | { | |
1534 | } | |
1535 | ||
1536 | public: // internal visitor interfaces (below) | |
1537 | ||
1538 | template <typename T> | |
1539 | int internal_visit(T& operand, int) const | |
1540 | { | |
1541 | // NOTE TO USER : | |
1542 | // Compile error here indicates one of the source variant's types | |
1543 | // cannot be unambiguously converted to the destination variant's | |
1544 | // types (or that no conversion exists). | |
1545 | // | |
1546 | return initializer::initialize(storage_, detail::variant::move(operand) ); | |
1547 | } | |
1548 | ||
1549 | template <typename T> | |
1550 | int internal_visit(boost::detail::reference_content<T>& operand, long) const | |
1551 | { | |
1552 | return internal_visit( operand.get(), 1L ); | |
1553 | } | |
1554 | ||
1555 | template <typename T> | |
1556 | int internal_visit(const boost::detail::reference_content<T>& operand, long) const | |
1557 | { | |
1558 | return internal_visit( operand.get(), 1L ); | |
1559 | } | |
1560 | ||
1561 | template <typename T> | |
1562 | int internal_visit(boost::detail::variant::backup_holder<T>& operand, long) const | |
1563 | { | |
1564 | return internal_visit( operand.get(), 1L ); | |
1565 | } | |
1566 | ||
1567 | template <typename T> | |
1568 | int internal_visit(const boost::detail::variant::backup_holder<T>& operand, long) const | |
1569 | { | |
1570 | return internal_visit( operand.get(), 1L ); | |
1571 | } | |
1572 | ||
1573 | template <typename T> | |
1574 | int internal_visit(boost::recursive_wrapper<T>& operand, long) const | |
1575 | { | |
1576 | return internal_visit( operand.get(), 1L ); | |
1577 | } | |
1578 | ||
1579 | template <typename T> | |
1580 | int internal_visit(const boost::recursive_wrapper<T>& operand, long) const | |
1581 | { | |
1582 | return internal_visit( operand.get(), 1L ); | |
1583 | } | |
1584 | }; | |
1585 | ||
1586 | friend class convert_move_into; | |
1587 | #endif | |
1588 | ||
1589 | private: // helpers, for structors, below | |
1590 | ||
1591 | template <typename T> | |
1592 | void convert_construct( | |
1593 | T& operand | |
1594 | , int | |
1595 | , mpl::false_ = mpl::false_() // is_foreign_variant | |
1596 | ) | |
1597 | { | |
1598 | // NOTE TO USER : | |
1599 | // Compile error here indicates that the given type is not | |
1600 | // unambiguously convertible to one of the variant's types | |
1601 | // (or that no conversion exists). | |
1602 | // | |
1603 | indicate_which( | |
1604 | initializer::initialize( | |
1605 | storage_.address() | |
1606 | , operand | |
1607 | ) | |
1608 | ); | |
1609 | } | |
1610 | ||
1611 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1612 | template <typename T> | |
1613 | typename boost::enable_if<boost::is_rvalue_reference<T&&> >::type convert_construct( | |
1614 | T&& operand | |
1615 | , int | |
1616 | , mpl::false_ = mpl::false_() // is_foreign_variant | |
1617 | ) | |
1618 | { | |
1619 | // NOTE TO USER : | |
1620 | // Compile error here indicates that the given type is not | |
1621 | // unambiguously convertible to one of the variant's types | |
1622 | // (or that no conversion exists). | |
1623 | // | |
1624 | indicate_which( | |
1625 | initializer::initialize( | |
1626 | storage_.address() | |
1627 | , detail::variant::move(operand) | |
1628 | ) | |
1629 | ); | |
1630 | } | |
1631 | #endif | |
1632 | ||
1633 | template <typename Variant> | |
1634 | void convert_construct( | |
1635 | Variant& operand | |
1636 | , long | |
1637 | , mpl::true_// is_foreign_variant | |
1638 | ) | |
1639 | { | |
1640 | convert_copy_into visitor(storage_.address()); | |
1641 | indicate_which( | |
1642 | operand.internal_apply_visitor(visitor) | |
1643 | ); | |
1644 | } | |
1645 | ||
1646 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1647 | template <typename Variant> | |
1648 | typename boost::enable_if<boost::is_rvalue_reference<Variant&&> >::type convert_construct( | |
1649 | Variant&& operand | |
1650 | , long | |
1651 | , mpl::true_// is_foreign_variant | |
1652 | ) | |
1653 | { | |
1654 | convert_move_into visitor(storage_.address()); | |
1655 | indicate_which( | |
1656 | operand.internal_apply_visitor(visitor) | |
1657 | ); | |
1658 | } | |
1659 | #endif | |
1660 | ||
1661 | template <typename Variant> | |
1662 | void convert_construct_variant(Variant& operand) | |
1663 | { | |
1664 | // [Determine if the given variant is itself a bounded type, or if its | |
1665 | // content needs to be converted (i.e., it is a 'foreign' variant):] | |
1666 | // | |
1667 | ||
1668 | typedef typename mpl::find_if< | |
1669 | types | |
1670 | , is_same< | |
1671 | add_const<mpl::_1> | |
1672 | , const Variant | |
1673 | > | |
1674 | >::type found_it; | |
1675 | ||
1676 | typedef typename mpl::end<types>::type not_found; | |
1677 | typedef typename is_same< | |
1678 | found_it, not_found | |
1679 | >::type is_foreign_variant; | |
1680 | ||
1681 | // Convert construct from operand: | |
1682 | convert_construct( | |
1683 | operand, 1L | |
1684 | , is_foreign_variant() | |
1685 | ); | |
1686 | } | |
1687 | ||
1688 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1689 | template <typename Variant> | |
1690 | typename boost::enable_if<boost::is_rvalue_reference<Variant&&> >::type convert_construct_variant(Variant&& operand) | |
1691 | { | |
1692 | // [Determine if the given variant is itself a bounded type, or if its | |
1693 | // content needs to be converted (i.e., it is a 'foreign' variant):] | |
1694 | // | |
1695 | ||
1696 | typedef typename mpl::find_if< | |
1697 | types | |
1698 | , is_same< | |
1699 | add_const<mpl::_1> | |
1700 | , const Variant | |
1701 | > | |
1702 | >::type found_it; | |
1703 | ||
1704 | typedef typename mpl::end<types>::type not_found; | |
1705 | typedef typename is_same< | |
1706 | found_it, not_found | |
1707 | >::type is_foreign_variant; | |
1708 | ||
1709 | // Convert move construct from operand: | |
1710 | convert_construct( | |
1711 | detail::variant::move(operand), 1L | |
1712 | , is_foreign_variant() | |
1713 | ); | |
1714 | } | |
1715 | #endif | |
1716 | ||
1717 | template <BOOST_VARIANT_ENUM_PARAMS(typename U)> | |
1718 | typename boost::enable_if<mpl::or_< | |
1719 | boost::is_same<boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>, variant>, | |
1720 | boost::detail::variant::is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>&, internal_types> | |
1721 | > >::type convert_construct( | |
1722 | boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>& operand | |
1723 | , long | |
1724 | ) | |
1725 | { | |
1726 | convert_construct_variant(operand); | |
1727 | } | |
1728 | ||
1729 | template <BOOST_VARIANT_ENUM_PARAMS(typename U)> | |
1730 | typename boost::enable_if<mpl::or_< | |
1731 | boost::is_same<boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>, variant>, | |
1732 | boost::detail::variant::is_variant_constructible_from<const boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>&, internal_types> | |
1733 | > >::type convert_construct( | |
1734 | const boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>& operand | |
1735 | , long | |
1736 | ) | |
1737 | { | |
1738 | convert_construct_variant(operand); | |
1739 | } | |
1740 | ||
1741 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1742 | template <BOOST_VARIANT_ENUM_PARAMS(typename U)> | |
1743 | typename boost::enable_if<mpl::or_< | |
1744 | boost::is_same<boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>, variant>, | |
1745 | boost::detail::variant::is_variant_constructible_from<boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>&&, internal_types> | |
1746 | > >::type convert_construct( | |
1747 | boost::variant<BOOST_VARIANT_ENUM_PARAMS(U)>&& operand | |
1748 | , long | |
1749 | ) | |
1750 | { | |
1751 | convert_construct_variant( detail::variant::move(operand) ); | |
1752 | } | |
1753 | #endif | |
1754 | ||
1755 | public: // structors, cont. | |
1756 | ||
1757 | template <typename T> | |
1758 | variant(const T& operand, | |
1759 | typename boost::enable_if<mpl::and_< | |
1760 | mpl::not_< boost::is_same<T, variant> >, | |
1761 | boost::detail::variant::is_variant_constructible_from<const T&, internal_types> | |
1762 | > >::type* = 0) | |
1763 | { | |
1764 | convert_construct(operand, 1L); | |
1765 | } | |
1766 | ||
1767 | template <typename T> | |
1768 | variant( | |
1769 | T& operand | |
1770 | , typename boost::enable_if<mpl::and_< | |
1771 | mpl::not_< is_const<T> >, | |
1772 | mpl::not_< boost::is_same<T, variant> >, | |
1773 | boost::detail::variant::is_variant_constructible_from<T&, internal_types> | |
1774 | > >::type* = 0 | |
1775 | ) | |
1776 | { | |
1777 | convert_construct(operand, 1L); | |
1778 | } | |
1779 | ||
1780 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1781 | template <class T> | |
1782 | variant(T&& operand, | |
1783 | typename boost::enable_if<mpl::and_< | |
1784 | boost::is_rvalue_reference<T&&>, | |
1785 | mpl::not_< boost::is_const<T> >, | |
1786 | mpl::not_< boost::is_same<T, variant> >, | |
1787 | boost::detail::variant::is_variant_constructible_from<T&&, internal_types> | |
1788 | > >::type* = 0) | |
1789 | { | |
1790 | convert_construct( detail::variant::move(operand), 1L); | |
1791 | } | |
1792 | #endif | |
1793 | ||
1794 | public: // structors, cont. | |
1795 | ||
1796 | // [MSVC6 requires copy constructor appear after template constructors] | |
1797 | variant(const variant& operand) | |
1798 | { | |
1799 | // Copy the value of operand into *this... | |
1800 | detail::variant::copy_into visitor( storage_.address() ); | |
1801 | operand.internal_apply_visitor(visitor); | |
1802 | ||
1803 | // ...and activate the *this's primary storage on success: | |
1804 | indicate_which(operand.which()); | |
1805 | } | |
1806 | ||
1807 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1808 | variant(variant&& operand) BOOST_NOEXCEPT_IF(variant_move_noexcept_constructible::type::value) | |
1809 | { | |
1810 | // Move the value of operand into *this... | |
1811 | detail::variant::move_into visitor( storage_.address() ); | |
1812 | operand.internal_apply_visitor(visitor); | |
1813 | ||
1814 | // ...and activate the *this's primary storage on success: | |
1815 | indicate_which(operand.which()); | |
1816 | } | |
1817 | #endif | |
1818 | ||
1819 | private: // helpers, for modifiers (below) | |
1820 | ||
1821 | # if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) | |
1822 | template <typename Variant> | |
1823 | friend class detail::variant::backup_assigner; | |
1824 | # endif | |
1825 | ||
1826 | // class assigner | |
1827 | // | |
1828 | // Internal visitor that "assigns" the visited value to the given variant | |
1829 | // by appropriate destruction and copy-construction. | |
1830 | // | |
1831 | ||
1832 | class assigner | |
1833 | : public static_visitor<> | |
1834 | { | |
1835 | protected: // representation | |
1836 | ||
1837 | variant& lhs_; | |
1838 | const int rhs_which_; | |
1839 | ||
1840 | public: // structors | |
1841 | ||
1842 | assigner(variant& lhs, int rhs_which) BOOST_NOEXCEPT | |
1843 | : lhs_(lhs) | |
1844 | , rhs_which_(rhs_which) | |
1845 | { | |
1846 | } | |
1847 | ||
1848 | protected: // helpers, for internal visitor interface (below) | |
1849 | ||
1850 | template <typename RhsT, typename B1, typename B2> | |
1851 | void assign_impl( | |
1852 | const RhsT& rhs_content | |
1853 | , mpl::true_ // has_nothrow_copy | |
1854 | , B1 // is_nothrow_move_constructible | |
1855 | , B2 // has_fallback_type | |
1856 | ) const BOOST_NOEXCEPT | |
1857 | { | |
1858 | // Destroy lhs's content... | |
1859 | lhs_.destroy_content(); // nothrow | |
1860 | ||
1861 | // ...copy rhs content into lhs's storage... | |
1862 | new(lhs_.storage_.address()) | |
1863 | RhsT( rhs_content ); // nothrow | |
1864 | ||
1865 | // ...and indicate new content type: | |
1866 | lhs_.indicate_which(rhs_which_); // nothrow | |
1867 | } | |
1868 | ||
1869 | template <typename RhsT, typename B> | |
1870 | void assign_impl( | |
1871 | const RhsT& rhs_content | |
1872 | , mpl::false_ // has_nothrow_copy | |
1873 | , mpl::true_ // is_nothrow_move_constructible | |
1874 | , B // has_fallback_type | |
1875 | ) const | |
1876 | { | |
1877 | // Attempt to make a temporary copy (so as to move it below)... | |
1878 | RhsT temp(rhs_content); | |
1879 | ||
1880 | // ...and upon success destroy lhs's content... | |
1881 | lhs_.destroy_content(); // nothrow | |
1882 | ||
1883 | // ...move the temporary copy into lhs's storage... | |
1884 | new(lhs_.storage_.address()) | |
1885 | RhsT( detail::variant::move(temp) ); // nothrow | |
1886 | ||
1887 | // ...and indicate new content type: | |
1888 | lhs_.indicate_which(rhs_which_); // nothrow | |
1889 | } | |
1890 | ||
1891 | void construct_fallback() const BOOST_NOEXCEPT { | |
1892 | // In case of failure, default-construct fallback type in lhs's storage... | |
1893 | new (lhs_.storage_.address()) | |
1894 | fallback_type_; // nothrow | |
1895 | ||
1896 | // ...indicate construction of fallback type... | |
1897 | lhs_.indicate_which( | |
1898 | BOOST_MPL_AUX_VALUE_WKND(fallback_type_index_)::value | |
1899 | ); // nothrow | |
1900 | } | |
1901 | ||
1902 | template <typename RhsT> | |
1903 | void assign_impl( | |
1904 | const RhsT& rhs_content | |
1905 | , mpl::false_ // has_nothrow_copy | |
1906 | , mpl::false_ // is_nothrow_move_constructible | |
1907 | , mpl::true_ // has_fallback_type | |
1908 | ) const | |
1909 | { | |
1910 | // Destroy lhs's content... | |
1911 | lhs_.destroy_content(); // nothrow | |
1912 | ||
1913 | BOOST_TRY | |
1914 | { | |
1915 | // ...and attempt to copy rhs's content into lhs's storage: | |
1916 | new(lhs_.storage_.address()) | |
1917 | RhsT( rhs_content ); | |
1918 | } | |
1919 | BOOST_CATCH (...) | |
1920 | { | |
1921 | construct_fallback(); | |
1922 | ||
1923 | // ...and rethrow: | |
1924 | BOOST_RETHROW; | |
1925 | } | |
1926 | BOOST_CATCH_END | |
1927 | ||
1928 | // In the event of success, indicate new content type: | |
1929 | lhs_.indicate_which(rhs_which_); // nothrow | |
1930 | } | |
1931 | ||
1932 | template <typename RhsT> | |
1933 | void assign_impl( | |
1934 | const RhsT& rhs_content | |
1935 | , mpl::false_ // has_nothrow_copy | |
1936 | , mpl::false_ // is_nothrow_move_constructible | |
1937 | , mpl::false_ // has_fallback_type | |
1938 | ) const | |
1939 | { | |
1940 | detail::variant::backup_assigner<wknd_self_t> | |
1941 | visitor(lhs_, rhs_which_, rhs_content); | |
1942 | lhs_.internal_apply_visitor(visitor); | |
1943 | } | |
1944 | ||
1945 | public: // internal visitor interfaces | |
1946 | ||
1947 | template <typename RhsT> | |
1948 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
1949 | internal_visit(const RhsT& rhs_content, int) const | |
1950 | { | |
1951 | typedef typename has_nothrow_copy<RhsT>::type | |
1952 | nothrow_copy; | |
1953 | typedef typename mpl::or_< // reduces compile-time | |
1954 | nothrow_copy | |
1955 | , is_nothrow_move_constructible<RhsT> | |
1956 | >::type nothrow_move_constructor; | |
1957 | ||
1958 | assign_impl( | |
1959 | rhs_content | |
1960 | , nothrow_copy() | |
1961 | , nothrow_move_constructor() | |
1962 | , has_fallback_type_() | |
1963 | ); | |
1964 | ||
1965 | BOOST_VARIANT_AUX_RETURN_VOID; | |
1966 | } | |
1967 | ||
1968 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
1969 | private: | |
1970 | // silence MSVC warning C4512: assignment operator could not be generated | |
1971 | assigner& operator= (assigner const&); | |
1972 | #endif | |
1973 | }; | |
1974 | ||
1975 | friend class assigner; | |
1976 | ||
1977 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
1978 | // class move_assigner | |
1979 | // | |
1980 | // Internal visitor that "move assigns" the visited value to the given variant | |
1981 | // by appropriate destruction and move-construction. | |
1982 | // | |
1983 | ||
1984 | class move_assigner | |
1985 | : public assigner | |
1986 | { | |
1987 | public: // structors | |
1988 | ||
1989 | move_assigner(variant& lhs, int rhs_which) BOOST_NOEXCEPT | |
1990 | : assigner(lhs, rhs_which) | |
1991 | { | |
1992 | } | |
1993 | ||
1994 | private: // helpers, for internal visitor interface (below) | |
1995 | ||
1996 | template <typename RhsT, typename B2> | |
1997 | void assign_impl( | |
1998 | RhsT& rhs_content | |
1999 | , mpl::true_ // has_nothrow_copy | |
2000 | , mpl::false_ // is_nothrow_move_constructible | |
2001 | , B2 // has_fallback_type | |
2002 | ) const BOOST_NOEXCEPT | |
2003 | { | |
2004 | assigner::assign_impl(rhs_content, mpl::true_(), mpl::false_(), B2()); | |
2005 | } | |
2006 | ||
2007 | template <typename RhsT, typename B, typename B2> | |
2008 | void assign_impl( | |
2009 | RhsT& rhs_content | |
2010 | , B // has_nothrow_copy | |
2011 | , mpl::true_ // is_nothrow_move_constructible | |
2012 | , B2 // has_fallback_type | |
2013 | ) const BOOST_NOEXCEPT | |
2014 | { | |
2015 | // ...destroy lhs's content... | |
2016 | assigner::lhs_.destroy_content(); // nothrow | |
2017 | ||
2018 | // ...move the rhs_content into lhs's storage... | |
2019 | new(assigner::lhs_.storage_.address()) | |
2020 | RhsT( detail::variant::move(rhs_content) ); // nothrow | |
2021 | ||
2022 | // ...and indicate new content type: | |
2023 | assigner::lhs_.indicate_which(assigner::rhs_which_); // nothrow | |
2024 | } | |
2025 | ||
2026 | template <typename RhsT> | |
2027 | void assign_impl( | |
2028 | RhsT& rhs_content | |
2029 | , mpl::false_ // has_nothrow_copy | |
2030 | , mpl::false_ // is_nothrow_move_constructible | |
2031 | , mpl::true_ // has_fallback_type | |
2032 | ) const | |
2033 | { | |
2034 | // Destroy lhs's content... | |
2035 | assigner::lhs_.destroy_content(); // nothrow | |
2036 | ||
2037 | BOOST_TRY | |
2038 | { | |
2039 | // ...and attempt to copy rhs's content into lhs's storage: | |
2040 | new(assigner::lhs_.storage_.address()) | |
2041 | RhsT( detail::variant::move(rhs_content) ); | |
2042 | } | |
2043 | BOOST_CATCH (...) | |
2044 | { | |
2045 | assigner::construct_fallback(); | |
2046 | ||
2047 | // ...and rethrow: | |
2048 | BOOST_RETHROW; | |
2049 | } | |
2050 | BOOST_CATCH_END | |
2051 | ||
2052 | // In the event of success, indicate new content type: | |
2053 | assigner::lhs_.indicate_which(assigner::rhs_which_); // nothrow | |
2054 | } | |
2055 | ||
2056 | template <typename RhsT> | |
2057 | void assign_impl( | |
2058 | RhsT& rhs_content | |
2059 | , mpl::false_ // has_nothrow_copy | |
2060 | , mpl::false_ // is_nothrow_move_constructible | |
2061 | , mpl::false_ // has_fallback_type | |
2062 | ) const | |
2063 | { | |
2064 | assigner::assign_impl(rhs_content, mpl::false_(), mpl::false_(), mpl::false_()); | |
2065 | } | |
2066 | ||
2067 | public: // internal visitor interfaces | |
2068 | ||
2069 | template <typename RhsT> | |
2070 | BOOST_VARIANT_AUX_RETURN_VOID_TYPE | |
2071 | internal_visit(RhsT& rhs_content, int) const | |
2072 | { | |
2073 | typedef typename is_nothrow_move_constructible<RhsT>::type | |
2074 | nothrow_move_constructor; | |
2075 | typedef typename mpl::or_< // reduces compile-time | |
2076 | nothrow_move_constructor | |
2077 | , has_nothrow_copy<RhsT> | |
2078 | >::type nothrow_copy; | |
2079 | ||
2080 | assign_impl( | |
2081 | rhs_content | |
2082 | , nothrow_copy() | |
2083 | , nothrow_move_constructor() | |
2084 | , has_fallback_type_() | |
2085 | ); | |
2086 | ||
2087 | BOOST_VARIANT_AUX_RETURN_VOID; | |
2088 | } | |
2089 | ||
2090 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) | |
2091 | private: | |
2092 | // silence MSVC warning C4512: assignment operator could not be generated | |
2093 | move_assigner& operator= (move_assigner const&); | |
2094 | #endif | |
2095 | }; | |
2096 | ||
2097 | friend class move_assigner; | |
2098 | #endif // BOOST_NO_CXX11_RVALUE_REFERENCES | |
2099 | ||
2100 | void variant_assign(const variant& rhs) | |
2101 | { | |
2102 | // If the contained types are EXACTLY the same... | |
2103 | if (which_ == rhs.which_) | |
2104 | { | |
2105 | // ...then assign rhs's storage to lhs's content: | |
2106 | detail::variant::assign_storage visitor(rhs.storage_.address()); | |
2107 | this->internal_apply_visitor(visitor); | |
2108 | } | |
2109 | else | |
2110 | { | |
2111 | // Otherwise, perform general (copy-based) variant assignment: | |
2112 | assigner visitor(*this, rhs.which()); | |
2113 | rhs.internal_apply_visitor(visitor); | |
2114 | } | |
2115 | } | |
2116 | ||
2117 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
2118 | void variant_assign(variant&& rhs) | |
2119 | { | |
2120 | // If the contained types are EXACTLY the same... | |
2121 | if (which_ == rhs.which_) | |
2122 | { | |
2123 | // ...then move rhs's storage to lhs's content: | |
2124 | detail::variant::move_storage visitor(rhs.storage_.address()); | |
2125 | this->internal_apply_visitor(visitor); | |
2126 | } | |
2127 | else | |
2128 | { | |
2129 | // Otherwise, perform general (move-based) variant assignment: | |
2130 | move_assigner visitor(*this, rhs.which()); | |
2131 | rhs.internal_apply_visitor(visitor); | |
2132 | } | |
2133 | } | |
2134 | #endif // BOOST_NO_CXX11_RVALUE_REFERENCES | |
2135 | ||
2136 | private: // helpers, for modifiers (below) | |
2137 | ||
2138 | template <typename T> | |
2139 | void assign(const T& rhs) | |
2140 | { | |
2141 | // If direct T-to-T assignment is not possible... | |
2142 | detail::variant::direct_assigner<T> direct_assign(rhs); | |
2143 | if (this->apply_visitor(direct_assign) == false) | |
2144 | { | |
2145 | // ...then convert rhs to variant and assign: | |
2146 | // | |
2147 | // While potentially inefficient, the following construction of a | |
2148 | // variant allows T as any type convertible to one of the bounded | |
2149 | // types without excessive code redundancy. | |
2150 | // | |
2151 | variant temp(rhs); | |
2152 | variant_assign( detail::variant::move(temp) ); | |
2153 | } | |
2154 | } | |
2155 | ||
2156 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
2157 | template <typename T> | |
2158 | void move_assign(T&& rhs) | |
2159 | { | |
2160 | // If direct T-to-T move assignment is not possible... | |
2161 | detail::variant::direct_mover<T> direct_move(rhs); | |
2162 | if (this->apply_visitor(direct_move) == false) | |
2163 | { | |
2164 | // ...then convert rhs to variant and assign: | |
2165 | // | |
2166 | // While potentially inefficient, the following construction of a | |
2167 | // variant allows T as any type convertible to one of the bounded | |
2168 | // types without excessive code redundancy. | |
2169 | // | |
2170 | variant temp( detail::variant::move(rhs) ); | |
2171 | variant_assign( detail::variant::move(temp) ); | |
2172 | } | |
2173 | } | |
2174 | #endif // BOOST_NO_CXX11_RVALUE_REFERENCES | |
2175 | ||
2176 | public: // modifiers | |
2177 | ||
2178 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
2179 | template <class T> | |
2180 | typename boost::enable_if< | |
2181 | boost::mpl::and_< | |
2182 | boost::is_rvalue_reference<T&&>, | |
2183 | mpl::not_< boost::is_const<T> >, | |
2184 | boost::detail::variant::is_variant_constructible_from<T&&, internal_types> | |
2185 | >, | |
2186 | variant& | |
2187 | >::type operator=(T&& rhs) | |
2188 | { | |
2189 | move_assign( detail::variant::move(rhs) ); | |
2190 | return *this; | |
2191 | } | |
2192 | #endif // BOOST_NO_CXX11_RVALUE_REFERENCES | |
2193 | ||
2194 | template <typename T> | |
2195 | typename boost::enable_if< | |
2196 | mpl::or_< | |
2197 | boost::is_same<T, variant>, | |
2198 | boost::detail::variant::is_variant_constructible_from<const T&, internal_types> | |
2199 | >, | |
2200 | variant& | |
2201 | >::type operator=(const T& rhs) | |
2202 | { | |
2203 | assign(rhs); | |
2204 | return *this; | |
2205 | } | |
2206 | ||
2207 | // [MSVC6 requires copy assign appear after templated operator=] | |
2208 | variant& operator=(const variant& rhs) | |
2209 | { | |
2210 | variant_assign(rhs); | |
2211 | return *this; | |
2212 | } | |
2213 | ||
2214 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
2215 | variant& operator=(variant&& rhs) | |
2216 | #if !defined(__GNUC__) || (__GNUC__ != 4) || (__GNUC_MINOR__ > 6) || defined(__clang__) | |
2217 | BOOST_NOEXCEPT_IF(variant_move_noexcept_constructible::type::value && variant_move_noexcept_assignable::type::value) | |
2218 | #endif | |
2219 | { | |
2220 | variant_assign( detail::variant::move(rhs) ); | |
2221 | return *this; | |
2222 | } | |
2223 | #endif // BOOST_NO_CXX11_RVALUE_REFERENCES | |
2224 | ||
2225 | void swap(variant& rhs) | |
2226 | { | |
2227 | // If the contained types are the same... | |
2228 | if (which() == rhs.which()) | |
2229 | { | |
2230 | // ...then swap the values directly: | |
2231 | detail::variant::swap_with<variant> visitor(rhs); | |
2232 | this->apply_visitor(visitor); | |
2233 | } | |
2234 | else | |
2235 | { | |
2236 | // ...otherwise, perform general variant swap: | |
2237 | variant tmp( detail::variant::move(rhs) ); | |
2238 | rhs = detail::variant::move(*this); | |
2239 | *this = detail::variant::move(tmp); | |
2240 | } | |
2241 | } | |
2242 | ||
2243 | public: // queries | |
2244 | ||
2245 | // | |
2246 | // NOTE: member which() defined above. | |
2247 | // | |
2248 | ||
2249 | bool empty() const BOOST_NOEXCEPT | |
2250 | { | |
2251 | return false; | |
2252 | } | |
2253 | ||
2254 | const boost::typeindex::type_info& type() const | |
2255 | { | |
2256 | detail::variant::reflect visitor; | |
2257 | return this->apply_visitor(visitor); | |
2258 | } | |
2259 | ||
2260 | public: // prevent comparison with foreign types | |
2261 | ||
2262 | template <typename U> | |
2263 | void operator==(const U&) const | |
2264 | { | |
2265 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2266 | } | |
2267 | ||
2268 | template <typename U> | |
2269 | void operator<(const U&) const | |
2270 | { | |
2271 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2272 | } | |
2273 | ||
2274 | template <typename U> | |
2275 | void operator!=(const U&) const | |
2276 | { | |
2277 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2278 | } | |
2279 | ||
2280 | template <typename U> | |
2281 | void operator>(const U&) const | |
2282 | { | |
2283 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2284 | } | |
2285 | ||
2286 | template <typename U> | |
2287 | void operator<=(const U&) const | |
2288 | { | |
2289 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2290 | } | |
2291 | ||
2292 | template <typename U> | |
2293 | void operator>=(const U&) const | |
2294 | { | |
2295 | BOOST_STATIC_ASSERT( false && sizeof(U) ); | |
2296 | } | |
2297 | ||
2298 | public: // comparison operators | |
2299 | ||
2300 | // [MSVC6 requires these operators appear after template operators] | |
2301 | ||
2302 | bool operator==(const variant& rhs) const | |
2303 | { | |
2304 | if (this->which() != rhs.which()) | |
2305 | return false; | |
2306 | ||
2307 | detail::variant::comparer< | |
2308 | variant, detail::variant::equal_comp | |
2309 | > visitor(*this); | |
2310 | return rhs.apply_visitor(visitor); | |
2311 | } | |
2312 | ||
2313 | bool operator<(const variant& rhs) const | |
2314 | { | |
2315 | // | |
2316 | // Dirk Schreib suggested this collating order. | |
2317 | // | |
2318 | ||
2319 | if (this->which() != rhs.which()) | |
2320 | return this->which() < rhs.which(); | |
2321 | ||
2322 | detail::variant::comparer< | |
2323 | variant, detail::variant::less_comp | |
2324 | > visitor(*this); | |
2325 | return rhs.apply_visitor(visitor); | |
2326 | } | |
2327 | ||
2328 | /////////////////////////////////////////////////////////////////////////////// | |
2329 | // comparison operators != > <= >= | |
2330 | inline bool operator!=(const variant& rhs) const | |
2331 | { | |
2332 | return !(*this == rhs); | |
2333 | } | |
2334 | ||
2335 | inline bool operator>(const variant& rhs) const | |
2336 | { | |
2337 | return rhs < *this; | |
2338 | } | |
2339 | ||
2340 | inline bool operator<=(const variant& rhs) const | |
2341 | { | |
2342 | return !(*this > rhs); | |
2343 | } | |
2344 | ||
2345 | inline bool operator>=(const variant& rhs) const | |
2346 | { | |
2347 | return !(*this < rhs); | |
2348 | } | |
2349 | ||
2350 | // helpers, for visitation support (below) -- private when possible | |
2351 | #if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) | |
2352 | ||
2353 | template < BOOST_VARIANT_ENUM_PARAMS(typename U) > | |
2354 | friend class variant; | |
2355 | ||
2356 | private: | |
2357 | ||
2358 | #else// defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) | |
2359 | ||
2360 | public: | |
2361 | ||
2362 | #endif// !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) | |
2363 | ||
2364 | template <typename Visitor, typename VoidPtrCV> | |
2365 | static | |
2366 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE( | |
2367 | typename Visitor::result_type | |
2368 | ) | |
2369 | internal_apply_visitor_impl( | |
2370 | int internal_which | |
2371 | , int logical_which | |
2372 | , Visitor& visitor | |
2373 | , VoidPtrCV storage | |
2374 | ) | |
2375 | { | |
2376 | typedef mpl::int_<0> first_which; | |
2377 | typedef typename mpl::begin<internal_types>::type first_it; | |
2378 | typedef typename mpl::end<internal_types>::type last_it; | |
2379 | ||
2380 | typedef detail::variant::visitation_impl_step< | |
2381 | first_it, last_it | |
2382 | > first_step; | |
2383 | ||
2384 | return detail::variant::visitation_impl( | |
2385 | internal_which, logical_which | |
2386 | , visitor, storage, mpl::false_() | |
2387 | , never_uses_backup_flag() | |
2388 | , static_cast<first_which*>(0), static_cast<first_step*>(0) | |
2389 | ); | |
2390 | } | |
2391 | ||
2392 | template <typename Visitor> | |
2393 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE( | |
2394 | typename Visitor::result_type | |
2395 | ) | |
2396 | internal_apply_visitor(Visitor& visitor) | |
2397 | { | |
2398 | return internal_apply_visitor_impl( | |
2399 | which_, which(), visitor, storage_.address() | |
2400 | ); | |
2401 | } | |
2402 | ||
2403 | template <typename Visitor> | |
2404 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE( | |
2405 | typename Visitor::result_type | |
2406 | ) | |
2407 | internal_apply_visitor(Visitor& visitor) const | |
2408 | { | |
2409 | return internal_apply_visitor_impl( | |
2410 | which_, which(), visitor, storage_.address() | |
2411 | ); | |
2412 | } | |
2413 | ||
2414 | public: // visitation support | |
2415 | ||
2416 | template <typename Visitor> | |
2417 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE( | |
2418 | typename Visitor::result_type | |
2419 | ) | |
2420 | apply_visitor(Visitor& visitor) | |
2421 | { | |
2422 | detail::variant::invoke_visitor<Visitor> invoker(visitor); | |
2423 | return this->internal_apply_visitor(invoker); | |
2424 | } | |
2425 | ||
2426 | template <typename Visitor> | |
2427 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE( | |
2428 | typename Visitor::result_type | |
2429 | ) | |
2430 | apply_visitor(Visitor& visitor) const | |
2431 | { | |
2432 | detail::variant::invoke_visitor<Visitor> invoker(visitor); | |
2433 | return this->internal_apply_visitor(invoker); | |
2434 | } | |
2435 | ||
2436 | }; // class variant | |
2437 | ||
2438 | /////////////////////////////////////////////////////////////////////////////// | |
2439 | // metafunction make_variant_over | |
2440 | // | |
2441 | // See docs and boost/variant/variant_fwd.hpp for more information. | |
2442 | // | |
2443 | template <typename Types> | |
2444 | struct make_variant_over | |
2445 | { | |
2446 | private: // precondition assertions | |
2447 | ||
2448 | BOOST_STATIC_ASSERT(( ::boost::mpl::is_sequence<Types>::value )); | |
2449 | ||
2450 | public: // metafunction result | |
2451 | ||
2452 | typedef variant< | |
2453 | detail::variant::over_sequence< Types > | |
2454 | > type; | |
2455 | ||
2456 | }; | |
2457 | ||
2458 | ||
2459 | /////////////////////////////////////////////////////////////////////////////// | |
2460 | // function template swap | |
2461 | // | |
2462 | // Swaps two variants of the same type (i.e., identical specification). | |
2463 | // | |
2464 | template < BOOST_VARIANT_ENUM_PARAMS(typename T) > | |
2465 | inline void swap( | |
2466 | variant< BOOST_VARIANT_ENUM_PARAMS(T) >& lhs | |
2467 | , variant< BOOST_VARIANT_ENUM_PARAMS(T) >& rhs | |
2468 | ) | |
2469 | { | |
2470 | lhs.swap(rhs); | |
2471 | } | |
2472 | ||
2473 | } // namespace boost | |
2474 | ||
2475 | // implementation additions | |
2476 | ||
2477 | #if !defined(BOOST_NO_IOSTREAM) | |
2478 | #include <boost/variant/detail/variant_io.hpp> | |
2479 | #endif // BOOST_NO_IOSTREAM | |
2480 | ||
2481 | #endif // BOOST_VARIANT_VARIANT_HPP |