1 // Boost.TypeErasure library
2 //
3 // Copyright 2011-2012 Steven Watanabe
4 //
5 // Distributed under the Boost Software License Version 1.0. (See
6 // accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 //
9 // $Id$
10
11 #if !defined(BOOST_PP_IS_ITERATING)
12
13 #ifndef BOOST_TYPE_ERASURE_TUPLE_HPP_INCLUDED
14 #define BOOST_TYPE_ERASURE_TUPLE_HPP_INCLUDED
15
16 #include <boost/config.hpp>
17
18
19 #ifdef BOOST_TYPE_ERASURE_DOXYGEN
20
21 namespace boost {
22 namespace type_erasure {
23
24 /**
25 * @ref tuple is a Boost.Fusion Random Access Sequence containing
26 * @ref any "anys". @c Concept specifies the \Concept for each
27 * of the elements. The remaining arguments must be (possibly const
28 * and/or reference qualified) placeholders, which are the
29 * @ref placeholder "placeholders" of the elements.
30 */
31 template<class Concept, class... T>
32 class tuple
33 {
34 public:
35 /**
36 * Constructs a tuple. Each element of @c args will
37 * be used to initialize the corresponding @ref any member.
38 * The @ref binding for the tuple elements is determined
39 * by mapping the placeholders in @c T to the corresponding
40 * types in @c U.
41 */
42 template<class... U>
43 explicit tuple(U&&... args);
44 };
45
46 /**
47 * Returns the Nth @ref any in the tuple.
48 */
49 template<int N, class Concept, class... T>
50 any<Concept, TN>& get(tuple<Concept, T...>& arg);
51 /** \overload */
52 template<int N, class Concept, class... T>
53 const any<Concept, TN>& get(const tuple<Concept, T...>& arg);
54
55 }
56 }
57
58 #elif !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
59
60 #include <boost/mpl/int.hpp>
61 #include <boost/mpl/bool.hpp>
62 #include <boost/mpl/map.hpp>
63 #include <boost/mpl/insert.hpp>
64 #include <boost/type_traits/remove_reference.hpp>
65 #include <boost/type_traits/remove_const.hpp>
66 #include <boost/fusion/include/category_of.hpp>
67 #include <boost/fusion/include/iterator_facade.hpp>
68 #include <boost/fusion/include/sequence_facade.hpp>
69 #include <boost/type_erasure/any.hpp>
70 #include <boost/type_erasure/static_binding.hpp>
71 #include <boost/type_erasure/config.hpp>
72
73 namespace boost {
74 namespace type_erasure {
75
76 template<class Concept, class... T>
77 struct cons;
78
79 template<class Concept>
80 struct cons<Concept>
81 {
82 template<class Binding>
consboost::type_erasure::cons83 cons(const Binding&) {}
84 };
85
86 template<class Concept, class T0, class... T>
87 struct cons<Concept, T0, T...>
88 {
89 typedef any<Concept, T0> value_type;
90 typedef cons<Concept, T...> rest_type;
91 template<class Binding, class U0, class... U>
consboost::type_erasure::cons92 cons(const Binding& b, U0&& u0, U&&... u)
93 : value(std::forward<U0>(u0), b),
94 rest(b, std::forward<U>(u)...)
95 {}
96 any<Concept, T0> value;
97 cons<Concept, T...> rest;
98 };
99
100 namespace detail {
101
102 template<int N, class Cons>
103 struct cons_advance
104 {
105 typedef typename cons_advance<N-1, Cons>::type::rest_type type;
callboost::type_erasure::detail::cons_advance106 static const type& call(const Cons& c)
107 {
108 return cons_advance<N-1, Cons>::call(c).rest;
109 }
110 };
111
112 template<class Cons>
113 struct cons_advance<0, Cons>
114 {
115 typedef Cons type;
callboost::type_erasure::detail::cons_advance116 static const type& call(const Cons& c)
117 {
118 return c;
119 }
120 };
121
122 template<class... T>
123 struct make_map;
124
125 template<class T0, class... T>
126 struct make_map<T0, T...>
127 {
128 typedef typename ::boost::mpl::insert<
129 typename ::boost::type_erasure::detail::make_map<T...>::type,
130 T0
131 >::type type;
132 };
133
134 template<>
135 struct make_map<>
136 {
137 typedef ::boost::mpl::map0<> type;
138 };
139
140 }
141
142 /** INTERNAL ONLY */
143 template<class Tuple, int N>
144 class tuple_iterator :
145 public ::boost::fusion::iterator_facade<
146 tuple_iterator<Tuple, N>,
147 ::boost::fusion::random_access_traversal_tag
148 >
149 {
150 public:
151 typedef ::boost::mpl::int_<N> index;
tuple_iterator(Tuple & t_arg)152 explicit tuple_iterator(Tuple& t_arg) : t(&t_arg) {}
153 template<class It>
154 struct value_of
155 {
156 typedef typename Tuple::template value_at<Tuple, mpl::int_<N> >::type type;
157 };
158 template<class It>
159 struct deref
160 {
161 typedef typename Tuple::template at<Tuple, mpl::int_<N> >::type type;
callboost::type_erasure::tuple_iterator::deref162 static type call(It it)
163 {
164 return Tuple::template at<Tuple, mpl::int_<N> >::call(*it.t);
165 }
166 };
167 template<class It, class M>
168 struct advance
169 {
170 typedef tuple_iterator<Tuple, (It::index::value+M::value)> type;
callboost::type_erasure::tuple_iterator::advance171 static type call(It it) { return type(*it.t); }
172 };
173 template<class It>
174 struct next : advance<It, ::boost::mpl::int_<1> > {};
175 template<class It>
176 struct prior : advance<It, ::boost::mpl::int_<-1> > {};
177 template<class It1, class It2>
178 struct distance
179 {
180 typedef typename ::boost::mpl::minus<
181 typename It2::index,
182 typename It1::index
183 >::type type;
callboost::type_erasure::tuple_iterator::distance184 static type call(It1, It2) { return type(); }
185 };
186 private:
187 Tuple* t;
188 };
189
190 template<class Concept, class... T>
191 class tuple :
192 public ::boost::fusion::sequence_facade<
193 ::boost::type_erasure::tuple<Concept, T...>,
194 ::boost::fusion::forward_traversal_tag
195 >
196 {
197 public:
198 template<class... U>
tuple(U &&...args)199 explicit tuple(U&&... args)
200 : impl(
201 ::boost::type_erasure::make_binding<
202 typename ::boost::type_erasure::detail::make_map<
203 ::boost::mpl::pair<
204 typename ::boost::remove_const<
205 typename ::boost::remove_reference<T>::type
206 >::type,
207 typename ::boost::remove_const<
208 typename ::boost::remove_reference<U>::type
209 >::type
210 >...
211 >::type
212 >(),
213 std::forward<U>(args)...)
214 {}
215
216 template<class Seq>
217 struct begin
218 {
219 typedef ::boost::type_erasure::tuple_iterator<
220 Seq,
221 0
222 > type;
callboost::type_erasure::tuple::begin223 static type call(Seq& seq) { return type(seq); }
224 };
225 template<class Seq>
226 struct end
227 {
228 typedef ::boost::type_erasure::tuple_iterator<
229 Seq,
230 sizeof...(T)
231 > type;
callboost::type_erasure::tuple::end232 static type call(Seq& seq) { return type(seq); }
233 };
234 template<class Seq>
235 struct size
236 {
237 typedef ::boost::mpl::int_<sizeof...(T)> type;
callboost::type_erasure::tuple::size238 static type call(Seq& seq) { return type(); }
239 };
240 template<class Seq>
241 struct empty
242 {
243 typedef ::boost::mpl::bool_<sizeof...(T) == 0> type;
callboost::type_erasure::tuple::empty244 static type call(Seq& seq) { return type(); }
245 };
246 template<class Seq, class N>
247 struct at
248 {
249 typedef typename ::boost::type_erasure::detail::cons_advance<
250 N::value,
251 ::boost::type_erasure::cons<Concept, T...>
252 >::type::value_type value_type;
253 typedef typename ::boost::mpl::if_< ::boost::is_const<Seq>,
254 const value_type&,
255 value_type&
256 >::type type;
callboost::type_erasure::tuple::at257 static type call(Seq& seq)
258 {
259 return const_cast<type>(
260 ::boost::type_erasure::detail::cons_advance<
261 N::value,
262 ::boost::type_erasure::cons<Concept, T...>
263 >::call(seq.impl).value
264 );
265 }
266 };
267 template<class Seq, class N>
268 struct value_at
269 {
270 typedef typename ::boost::type_erasure::detail::cons_advance<
271 N::value,
272 ::boost::type_erasure::cons<Concept, T...>
273 >::type::value_type value_type;
274 };
275 ::boost::type_erasure::cons<Concept, T...> impl;
276 };
277
278 template<int N, class Concept, class... T>
279 typename ::boost::type_erasure::detail::cons_advance<
280 N,
281 ::boost::type_erasure::cons<Concept, T...>
get(::boost::type_erasure::tuple<Concept,T...> & t)282 >::type::value_type& get(::boost::type_erasure::tuple<Concept, T...>& t)
283 {
284 return const_cast<
285 typename ::boost::type_erasure::detail::cons_advance<
286 N,
287 ::boost::type_erasure::cons<Concept, T...>
288 >::type::value_type&
289 >(
290 ::boost::type_erasure::detail::cons_advance<N,
291 ::boost::type_erasure::cons<Concept, T...>
292 >::call(t.impl).value
293 );
294 }
295
296 template<int N, class Concept, class... T>
297 const typename ::boost::type_erasure::detail::cons_advance<
298 N,
299 ::boost::type_erasure::cons<Concept, T...>
get(const::boost::type_erasure::tuple<Concept,T...> & t)300 >::type::value_type& get(const ::boost::type_erasure::tuple<Concept, T...>& t)
301 {
302 return ::boost::type_erasure::detail::cons_advance<
303 N,
304 ::boost::type_erasure::cons<Concept, T...>
305 >::call(t.impl).value;
306 }
307
308 }
309 }
310
311 #else
312
313 #include <boost/mpl/int.hpp>
314 #include <boost/mpl/minus.hpp>
315 #include <boost/mpl/equal_to.hpp>
316 #include <boost/mpl/map.hpp>
317 #include <boost/fusion/include/category_of.hpp>
318 #include <boost/fusion/include/iterator_facade.hpp>
319 #include <boost/fusion/include/sequence_facade.hpp>
320 #include <boost/preprocessor/cat.hpp>
321 #include <boost/preprocessor/iteration/iterate.hpp>
322 #include <boost/preprocessor/repetition/repeat.hpp>
323 #include <boost/preprocessor/repetition/enum.hpp>
324 #include <boost/preprocessor/repetition/enum_params.hpp>
325 #include <boost/preprocessor/repetition/enum_trailing_params.hpp>
326 #include <boost/preprocessor/repetition/enum_binary_params.hpp>
327 #include <boost/preprocessor/repetition/enum_trailing_binary_params.hpp>
328 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
329 #include <boost/type_erasure/any.hpp>
330 #include <boost/type_erasure/static_binding.hpp>
331 #include <boost/type_erasure/config.hpp>
332
333 namespace boost {
334 namespace type_erasure {
335
336 /** INTERNAL ONLY */
337 struct na {};
338
339 namespace detail {
340
341 template<int N, class Tuple>
342 struct get_impl;
343
344 template<class Concept,
345 BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(
346 BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, class T, ::boost::type_erasure::na)>
347 struct tuple_storage;
348
349 }
350
351 /** INTERNAL ONLY */
352 template<class Tuple, int N>
353 class tuple_iterator :
354 public ::boost::fusion::iterator_facade<
355 tuple_iterator<Tuple, N>,
356 ::boost::fusion::random_access_traversal_tag
357 >
358 {
359 public:
360 typedef ::boost::mpl::int_<N> index;
tuple_iterator(Tuple & t_arg)361 explicit tuple_iterator(Tuple& t_arg) : t(&t_arg) {}
362 template<class It>
363 struct value_of
364 {
365 typedef typename ::boost::type_erasure::detail::get_impl<
366 It::index::value,
367 Tuple
368 >::value_type type;
369 };
370 template<class It>
371 struct deref :
372 ::boost::type_erasure::detail::get_impl<It::index::value, Tuple>
373 {
374 typedef typename ::boost::type_erasure::detail::get_impl<
375 It::index::value,
376 Tuple
377 >::type type;
callboost::type_erasure::tuple_iterator::deref378 static type call(It it)
379 {
380 return ::boost::type_erasure::detail::get_impl<
381 It::index::value,
382 Tuple
383 >::call(*it.t);
384 }
385 };
386 template<class It, class M>
387 struct advance
388 {
389 typedef tuple_iterator<Tuple, (It::index::value+M::value)> type;
callboost::type_erasure::tuple_iterator::advance390 static type call(It it) { return type(*it.t); }
391 };
392 template<class It>
393 struct next : advance<It, ::boost::mpl::int_<1> > {};
394 template<class It>
395 struct prior : advance<It, ::boost::mpl::int_<-1> > {};
396 template<class It1, class It2>
397 struct distance
398 {
399 typedef typename ::boost::mpl::minus<
400 typename It2::index,
401 typename It1::index
402 >::type type;
callboost::type_erasure::tuple_iterator::distance403 static type call(It1, It2) { return type(); }
404 };
405 private:
406 Tuple* t;
407 };
408
409 /** INTERNAL ONLY */
410 template<class Derived>
411 struct tuple_base :
412 ::boost::fusion::sequence_facade<
413 Derived,
414 ::boost::fusion::random_access_traversal_tag
415 >
416 {
417 template<class Seq>
418 struct begin
419 {
420 typedef ::boost::type_erasure::tuple_iterator<Seq, 0> type;
callboost::type_erasure::tuple_base::begin421 static type call(Seq& seq) { return type(seq); }
422 };
423 template<class Seq>
424 struct end
425 {
426 typedef ::boost::type_erasure::tuple_iterator<
427 Seq,
428 Seq::tuple_size::value
429 > type;
callboost::type_erasure::tuple_base::end430 static type call(Seq& seq) { return type(seq); }
431 };
432 template<class Seq>
433 struct size
434 {
435 typedef typename Seq::tuple_size type;
callboost::type_erasure::tuple_base::size436 static type call(Seq& seq) { return type(); }
437 };
438 template<class Seq>
439 struct empty
440 {
441 typedef typename boost::mpl::equal_to<
442 typename Seq::tuple_size,
443 boost::mpl::int_<0>
444 >::type type;
callboost::type_erasure::tuple_base::empty445 static type call(Seq& seq) { return type(); }
446 };
447 template<class Seq, class N>
448 struct at : ::boost::type_erasure::detail::get_impl<N::value, Seq> {};
449 template<class Seq, class N>
450 struct value_at
451 {
452 typedef typename ::boost::type_erasure::detail::get_impl<
453 N::value,
454 Seq
455 >::value_type type;
456 };
457 };
458
459 template<class Concept,
460 BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(
461 BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, class T, ::boost::type_erasure::na)>
462 class tuple;
463
464 template<
465 int N,
466 class Concept
467 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, class T)
468 >
469 typename detail::get_impl<
470 N,
471 tuple<
472 Concept
473 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
474 >
get(tuple<Concept BOOST_PP_ENUM_TRAILING_PARAMS (BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE,T)> & arg)475 >::type get(
476 tuple<
477 Concept
478 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
479 >& arg)
480 {
481 return detail::get_impl<
482 N,
483 tuple<
484 Concept
485 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
486 >
487 >::call(arg);
488 }
489
490 template<
491 int N,
492 class Concept
493 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, class T)
494 >
495 typename detail::get_impl<
496 N,
497 const tuple<
498 Concept
499 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
500 >
get(const tuple<Concept BOOST_PP_ENUM_TRAILING_PARAMS (BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE,T)> & arg)501 >::type get(
502 const tuple<
503 Concept
504 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
505 >& arg)
506 {
507 return detail::get_impl<
508 N,
509 const tuple<
510 Concept
511 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE, T)
512 >
513 >::call(arg);
514 }
515
516 /** INTERNAL ONLY */
517 #define BOOST_PP_FILENAME_1 <boost/type_erasure/tuple.hpp>
518 /** INTERNAL ONLY */
519 #define BOOST_PP_ITERATION_LIMITS (0, BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE)
520 #include BOOST_PP_ITERATE()
521
522 }
523 }
524
525 #endif
526
527 #endif
528
529 #else
530
531 #define N BOOST_PP_ITERATION()
532
533 #define BOOST_TYPE_ERASURE_TAG_TYPEDEF(z, n, data) \
534 typedef BOOST_PP_CAT(T, n) BOOST_PP_CAT(tag_type, n); \
535 typedef typename ::boost::remove_reference<BOOST_PP_CAT(T, n)>::type \
536 BOOST_PP_CAT(tag, n);
537
538 #define BOOST_TYPE_ERASURE_PAIR(z, n, data) \
539 ::boost::mpl::pair<BOOST_PP_CAT(tag, n), BOOST_PP_CAT(U, n)>
540
541 #define BOOST_TYPE_ERASURE_CONSTRUCT(z, n, data)\
542 BOOST_PP_CAT(t, n)(BOOST_PP_CAT(u, n), table)
543
544 #define BOOST_TYPE_ERASURE_TUPLE_MEMBER(z, n, data)\
545 ::boost::type_erasure::any<Concept, BOOST_PP_CAT(T, n)> BOOST_PP_CAT(t, n);
546
547 #if N == 1
548 #define BOOST_TYPE_ERASURE_EXPLICIT explicit
549 #else
550 #define BOOST_TYPE_ERASURE_EXPLICIT
551 #endif
552
553 namespace detail {
554
555 template<class Concept BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)>
556 struct tuple_storage
557 #if N != BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE
558 <Concept BOOST_PP_ENUM_TRAILING_PARAMS(N, T)>
559 #endif
560 {
561 #if N
562 template<class Table BOOST_PP_ENUM_TRAILING_PARAMS(N, class U)>
tuple_storagedetail::tuple_storage563 tuple_storage(
564 const Table& table BOOST_PP_ENUM_TRAILING_BINARY_PARAMS(N, U, &u))
565 :
566 BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_CONSTRUCT, ~) {}
567 #else
568 template<class Table>
569 explicit tuple_storage(const Table&) {}
570 #endif
571 BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_TUPLE_MEMBER, `)
572 };
573
574 #if N != BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE
575
576 template<class Tuple>
577 struct get_impl<N, Tuple>
578 {
579 typedef any<
580 typename Tuple::concept_type,
581 typename Tuple::BOOST_PP_CAT(tag_type, N)
582 > value_type;
583 typedef value_type& type;
calldetail::get_impl584 static type call(Tuple& arg)
585 { return arg.impl.BOOST_PP_CAT(t, N); }
586 };
587
588 template<class Tuple>
589 struct get_impl<N, const Tuple>
590 {
591 typedef any<
592 typename Tuple::concept_type,
593 typename Tuple::BOOST_PP_CAT(tag_type, N)
594 > value_type;
595 typedef const value_type& type;
calldetail::get_impl596 static type call(const Tuple& arg)
597 { return arg.impl.BOOST_PP_CAT(t, N); }
598 };
599
600 #endif
601
602 }
603
604 template<class Concept BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)>
605 class tuple
606 #if N != BOOST_TYPE_ERASURE_MAX_TUPLE_SIZE
607 <Concept BOOST_PP_ENUM_TRAILING_PARAMS(N, T)>
608 #endif
609 : public tuple_base<tuple<Concept BOOST_PP_ENUM_TRAILING_PARAMS(N, T)> >
610 {
611 typedef Concept concept_type;
612 BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_TAG_TYPEDEF, ~)
613 public:
614 typedef ::boost::mpl::int_<N> tuple_size;
615 #if N
616 template<BOOST_PP_ENUM_PARAMS(N, class U)>
617 #endif
618 BOOST_TYPE_ERASURE_EXPLICIT
tuple(BOOST_PP_ENUM_BINARY_PARAMS (N,U,& u))619 tuple(BOOST_PP_ENUM_BINARY_PARAMS(N, U, &u)) :
620 impl(
621 ::boost::type_erasure::make_binding<
622 ::boost::mpl::map<
623 BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_PAIR, ~)
624 >
625 >()
626 BOOST_PP_ENUM_TRAILING_PARAMS(N, u)
627 )
628 {}
629 #if N
630 template<BOOST_PP_ENUM_PARAMS(N, class U)>
631 BOOST_TYPE_ERASURE_EXPLICIT
tuple(BOOST_PP_ENUM_BINARY_PARAMS (N,const U,& u))632 tuple(BOOST_PP_ENUM_BINARY_PARAMS(N, const U, &u)) :
633 impl(
634 ::boost::type_erasure::make_binding<
635 ::boost::mpl::map<
636 BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_PAIR, ~)
637 >
638 >()
639 BOOST_PP_ENUM_TRAILING_PARAMS(N, u)
640 )
641 {}
642 #endif
643 private:
644 template<int M, class Tuple>
645 friend struct ::boost::type_erasure::detail::get_impl;
646 ::boost::type_erasure::detail::tuple_storage<
647 Concept
648 BOOST_PP_ENUM_TRAILING_PARAMS(N, T)
649 > impl;
650 };
651
652 #undef BOOST_TYPE_ERASURE_EXPLICIT
653 #undef BOOST_TYPE_ERASURE_TUPLE_MEMBER
654 #undef BOOST_TYPE_ERASURE_CONSTRUCT
655 #undef BOOST_TYPE_ERASURE_PAIR
656 #undef BOOST_TYPE_ERASURE_TAG_TYPEDEF
657 #undef N
658
659 #endif
660