3 // Copyright (C) 2007, 2008 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License
17 // along with this library; see the file COPYING. If not, write to
18 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
19 // Boston, MA 02110-1301, USA.
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
30 /** @file include/tuple
31 * This is a Standard C++ Library header.
34 #ifndef _GLIBCXX_CXX0X_TUPLE
35 #define _GLIBCXX_CXX0X_TUPLE 1
37 #pragma GCC system_header
39 #ifndef __GXX_EXPERIMENTAL_CXX0X__
40 # include <c++0x_warning.h>
47 // Adds a const reference to a non-reference type.
48 template<typename _Tp>
50 { typedef const _Tp& type; };
52 template<typename _Tp>
53 struct __add_c_ref<_Tp&>
54 { typedef _Tp& type; };
56 // Adds a reference to a non-reference type.
57 template<typename _Tp>
59 { typedef _Tp& type; };
61 template<typename _Tp>
62 struct __add_ref<_Tp&>
63 { typedef _Tp& type; };
65 template<int _Idx, typename _Head, bool _IsEmpty>
68 template<int _Idx, typename _Head>
69 struct _Head_base<_Idx, _Head, true>
75 _Head_base(const _Head& __h)
78 template<typename _UHead>
79 _Head_base(_UHead&& __h)
80 : _Head(std::forward<_UHead>(__h)) { }
82 _Head& _M_head() { return *this; }
83 const _Head& _M_head() const { return *this; }
86 template<int _Idx, typename _Head>
87 struct _Head_base<_Idx, _Head, false>
92 _Head_base(const _Head& __h)
93 : _M_head_impl(__h) { }
95 template<typename _UHead>
96 _Head_base(_UHead&& __h)
97 : _M_head_impl(std::forward<_UHead>(__h)) { }
99 _Head& _M_head() { return _M_head_impl; }
100 const _Head& _M_head() const { return _M_head_impl; }
106 * Contains the actual implementation of the @c tuple template, stored
107 * as a recursive inheritance hierarchy from the first element (most
108 * derived class) to the last (least derived class). The @c Idx
109 * parameter gives the 0-based index of the element stored at this
110 * point in the hierarchy; we use it to implement a constant-time
113 template<int _Idx, typename... _Elements>
117 * Zero-element tuple implementation. This is the basis case for the
118 * inheritance recursion.
121 struct _Tuple_impl<_Idx> { };
124 * Recursive tuple implementation. Here we store the @c Head element
125 * and derive from a @c Tuple_impl containing the remaining elements
126 * (which contains the @c Tail).
128 template<int _Idx, typename _Head, typename... _Tail>
129 struct _Tuple_impl<_Idx, _Head, _Tail...>
130 : public _Tuple_impl<_Idx + 1, _Tail...>,
131 private _Head_base<_Idx, _Head, std::is_empty<_Head>::value>
133 typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
134 typedef _Head_base<_Idx, _Head, std::is_empty<_Head>::value> _Base;
136 _Head& _M_head() { return _Base::_M_head(); }
137 const _Head& _M_head() const { return _Base::_M_head(); }
139 _Inherited& _M_tail() { return *this; }
140 const _Inherited& _M_tail() const { return *this; }
143 : _Inherited(), _Base() { }
146 _Tuple_impl(const _Head& __head, const _Tail&... __tail)
147 : _Inherited(__tail...), _Base(__head) { }
149 template<typename _UHead, typename... _UTail>
151 _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
152 : _Inherited(std::forward<_UTail>(__tail)...),
153 _Base(std::forward<_UHead>(__head)) { }
155 _Tuple_impl(const _Tuple_impl& __in)
156 : _Inherited(__in._M_tail()), _Base(__in._M_head()) { }
158 _Tuple_impl(_Tuple_impl&& __in)
159 : _Inherited(std::move<_Inherited&&>(__in._M_tail())),
160 _Base(std::forward<_Head>(__in._M_head())) { }
162 template<typename... _UElements>
163 _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
164 : _Inherited(__in._M_tail()), _Base(__in._M_head()) { }
166 template<typename... _UElements>
167 _Tuple_impl(_Tuple_impl<_Idx, _UElements...>&& __in)
168 : _Inherited(std::move<typename _Tuple_impl<_Idx, _UElements...>::
169 _Inherited&&>(__in._M_tail())),
170 _Base(std::forward<typename _Tuple_impl<_Idx, _UElements...>::
171 _Base>(__in._M_head())) { }
174 operator=(const _Tuple_impl& __in)
176 _M_head() = __in._M_head();
177 _M_tail() = __in._M_tail();
182 operator=(_Tuple_impl&& __in)
184 _M_head() = std::move(__in._M_head());
185 _M_tail() = std::move(__in._M_tail());
189 template<typename... _UElements>
191 operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
193 _M_head() = __in._M_head();
194 _M_tail() = __in._M_tail();
198 template<typename... _UElements>
200 operator=(_Tuple_impl<_Idx, _UElements...>&& __in)
202 _M_head() = std::move(__in._M_head());
203 _M_tail() = std::move(__in._M_tail());
208 template<typename... _Elements>
209 class tuple : public _Tuple_impl<0, _Elements...>
211 typedef _Tuple_impl<0, _Elements...> _Inherited;
218 tuple(const _Elements&... __elements)
219 : _Inherited(__elements...) { }
221 template<typename... _UElements>
223 tuple(_UElements&&... __elements)
224 : _Inherited(std::forward<_UElements>(__elements)...) { }
226 tuple(const tuple& __in)
227 : _Inherited(static_cast<const _Inherited&>(__in)) { }
230 : _Inherited(std::move<_Inherited>(__in)) { }
232 template<typename... _UElements>
233 tuple(const tuple<_UElements...>& __in)
234 : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
237 template<typename... _UElements>
238 tuple(tuple<_UElements...>&& __in)
239 : _Inherited(std::move<_Tuple_impl<0, _UElements...> >(__in)) { }
241 // XXX http://gcc.gnu.org/ml/libstdc++/2008-02/msg00047.html
242 template<typename... _UElements>
243 tuple(tuple<_UElements...>& __in)
244 : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
248 operator=(const tuple& __in)
250 static_cast<_Inherited&>(*this) = __in;
255 operator=(tuple&& __in)
257 static_cast<_Inherited&>(*this) = std::move(__in);
261 template<typename... _UElements>
263 operator=(const tuple<_UElements...>& __in)
265 static_cast<_Inherited&>(*this) = __in;
269 template<typename... _UElements>
271 operator=(tuple<_UElements...>&& __in)
273 static_cast<_Inherited&>(*this) = std::move(__in);
278 template<> class tuple<> { };
280 // 2-element tuple, with construction and assignment from a pair.
281 template<typename _T1, typename _T2>
282 class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
284 typedef _Tuple_impl<0, _T1, _T2> _Inherited;
291 tuple(const _T1& __a1, const _T2& __a2)
292 : _Inherited(__a1, __a2) { }
294 template<typename _U1, typename _U2>
296 tuple(_U1&& __a1, _U2&& __a2)
297 : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
299 tuple(const tuple& __in)
300 : _Inherited(static_cast<const _Inherited&>(__in)) { }
303 : _Inherited(std::move<_Inherited>(__in)) { }
305 template<typename _U1, typename _U2>
306 tuple(const tuple<_U1, _U2>& __in)
307 : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
309 template<typename _U1, typename _U2>
310 tuple(tuple<_U1, _U2>&& __in)
311 : _Inherited(std::move<_Tuple_impl<0, _U1, _U2> >(__in)) { }
313 template<typename _U1, typename _U2>
314 tuple(const pair<_U1, _U2>& __in)
315 : _Inherited(__in.first, __in.second) { }
317 template<typename _U1, typename _U2>
318 tuple(pair<_U1, _U2>&& __in)
319 : _Inherited(std::move(__in.first), std::move(__in.second)) { }
322 operator=(const tuple& __in)
324 static_cast<_Inherited&>(*this) = __in;
329 operator=(tuple&& __in)
331 static_cast<_Inherited&>(*this) = std::move(__in);
335 template<typename _U1, typename _U2>
337 operator=(const tuple<_U1, _U2>& __in)
339 static_cast<_Inherited&>(*this) = __in;
343 template<typename _U1, typename _U2>
345 operator=(tuple<_U1, _U2>&& __in)
347 static_cast<_Inherited&>(*this) = std::move(__in);
351 template<typename _U1, typename _U2>
353 operator=(const pair<_U1, _U2>& __in)
355 this->_M_head() = __in.first;
356 this->_M_tail()._M_head() = __in.second;
360 template<typename _U1, typename _U2>
362 operator=(pair<_U1, _U2>&& __in)
364 this->_M_head() = std::move(__in.first);
365 this->_M_tail()._M_head() = std::move(__in.second);
371 /// Gives the type of the ith element of a given tuple type.
372 template<int __i, typename _Tp>
373 struct tuple_element;
376 * Recursive case for tuple_element: strip off the first element in
377 * the tuple and retrieve the (i-1)th element of the remaining tuple.
379 template<int __i, typename _Head, typename... _Tail>
380 struct tuple_element<__i, tuple<_Head, _Tail...> >
381 : tuple_element<__i - 1, tuple<_Tail...> > { };
384 * Basis case for tuple_element: The first element is the one we're seeking.
386 template<typename _Head, typename... _Tail>
387 struct tuple_element<0, tuple<_Head, _Tail...> >
392 /// Finds the size of a given tuple type.
393 template<typename _Tp>
396 /// @brief class tuple_size
397 template<typename... _Elements>
398 struct tuple_size<tuple<_Elements...> >
400 static const int value = sizeof...(_Elements);
403 template<typename... _Elements>
404 const int tuple_size<tuple<_Elements...> >::value;
406 template<int __i, typename _Head, typename... _Tail>
407 inline typename __add_ref<_Head>::type
408 __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t)
409 { return __t._M_head(); }
411 template<int __i, typename _Head, typename... _Tail>
412 inline typename __add_c_ref<_Head>::type
413 __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t)
414 { return __t._M_head(); }
416 // Return a reference (const reference) to the ith element of a tuple.
417 // Any const or non-const ref elements are returned with their original type.
418 template<int __i, typename... _Elements>
419 inline typename __add_ref<
420 typename tuple_element<__i, tuple<_Elements...> >::type
422 get(tuple<_Elements...>& __t)
423 { return __get_helper<__i>(__t); }
425 template<int __i, typename... _Elements>
426 inline typename __add_c_ref<
427 typename tuple_element<__i, tuple<_Elements...> >::type
429 get(const tuple<_Elements...>& __t)
430 { return __get_helper<__i>(__t); }
432 // This class helps construct the various comparison operations on tuples
433 template<int __check_equal_size, int __i, int __j,
434 typename _Tp, typename _Up>
435 struct __tuple_compare;
437 template<int __i, int __j, typename _Tp, typename _Up>
438 struct __tuple_compare<0, __i, __j, _Tp, _Up>
440 static bool __eq(const _Tp& __t, const _Up& __u)
442 return (get<__i>(__t) == get<__i>(__u) &&
443 __tuple_compare<0, __i+1, __j, _Tp, _Up>::__eq(__t, __u));
446 static bool __less(const _Tp& __t, const _Up& __u)
448 return ((get<__i>(__t) < get<__i>(__u))
449 || !(get<__i>(__u) < get<__i>(__t)) &&
450 __tuple_compare<0, __i+1, __j, _Tp, _Up>::__less(__t, __u));
454 template<int __i, typename _Tp, typename _Up>
455 struct __tuple_compare<0, __i, __i, _Tp, _Up>
457 static bool __eq(const _Tp&, const _Up&)
460 static bool __less(const _Tp&, const _Up&)
464 template<typename... _TElements, typename... _UElements>
466 operator==(const tuple<_TElements...>& __t,
467 const tuple<_UElements...>& __u)
469 typedef tuple<_TElements...> _Tp;
470 typedef tuple<_UElements...> _Up;
471 return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
472 0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
475 template<typename... _TElements, typename... _UElements>
477 operator<(const tuple<_TElements...>& __t,
478 const tuple<_UElements...>& __u)
480 typedef tuple<_TElements...> _Tp;
481 typedef tuple<_UElements...> _Up;
482 return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
483 0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
486 template<typename... _TElements, typename... _UElements>
488 operator!=(const tuple<_TElements...>& __t,
489 const tuple<_UElements...>& __u)
490 { return !(__t == __u); }
492 template<typename... _TElements, typename... _UElements>
494 operator>(const tuple<_TElements...>& __t,
495 const tuple<_UElements...>& __u)
496 { return __u < __t; }
498 template<typename... _TElements, typename... _UElements>
500 operator<=(const tuple<_TElements...>& __t,
501 const tuple<_UElements...>& __u)
502 { return !(__u < __t); }
504 template<typename... _TElements, typename... _UElements>
506 operator>=(const tuple<_TElements...>& __t,
507 const tuple<_UElements...>& __u)
508 { return !(__t < __u); }
511 template<typename... _Elements>
512 inline tuple<typename __decay_and_strip<_Elements>::__type...>
513 make_tuple(_Elements&&... __args)
515 typedef tuple<typename __decay_and_strip<_Elements>::__type...>
517 return __result_type(std::forward<_Elements>(__args)...);
520 template<int...> struct __index_holder { };
522 template<int __i, typename _IdxHolder, typename... _Elements>
523 struct __index_holder_impl;
525 template<int __i, int... _Indexes, typename _IdxHolder, typename... _Elements>
526 struct __index_holder_impl<__i, __index_holder<_Indexes...>,
527 _IdxHolder, _Elements...>
529 typedef typename __index_holder_impl<__i + 1,
530 __index_holder<_Indexes..., __i>,
531 _Elements...>::type type;
534 template<int __i, int... _Indexes>
535 struct __index_holder_impl<__i, __index_holder<_Indexes...> >
536 { typedef __index_holder<_Indexes...> type; };
538 template<typename... _Elements>
539 struct __make_index_holder
540 : __index_holder_impl<0, __index_holder<>, _Elements...> { };
542 template<typename... _TElements, int... _TIdx,
543 typename... _UElements, int... _UIdx>
544 inline tuple<_TElements..., _UElements...>
545 __tuple_cat_helper(const tuple<_TElements...>& __t,
546 const __index_holder<_TIdx...>&,
547 const tuple<_UElements...>& __u,
548 const __index_holder<_UIdx...>&)
549 { return tuple<_TElements..., _UElements...>(get<_TIdx>(__t)...,
550 get<_UIdx>(__u)...); }
552 template<typename... _TElements, int... _TIdx,
553 typename... _UElements, int... _UIdx>
554 inline tuple<_TElements..., _UElements...>
555 __tuple_cat_helper(tuple<_TElements...>&& __t,
556 const __index_holder<_TIdx...>&,
557 const tuple<_UElements...>& __u,
558 const __index_holder<_UIdx...>&)
559 { return tuple<_TElements..., _UElements...>
560 (std::move(get<_TIdx>(__t))..., get<_UIdx>(__u)...); }
562 template<typename... _TElements, int... _TIdx,
563 typename... _UElements, int... _UIdx>
564 inline tuple<_TElements..., _UElements...>
565 __tuple_cat_helper(const tuple<_TElements...>& __t,
566 const __index_holder<_TIdx...>&,
567 tuple<_UElements...>&& __u,
568 const __index_holder<_UIdx...>&)
569 { return tuple<_TElements..., _UElements...>
570 (get<_TIdx>(__t)..., std::move(get<_UIdx>(__u))...); }
572 template<typename... _TElements, int... _TIdx,
573 typename... _UElements, int... _UIdx>
574 inline tuple<_TElements..., _UElements...>
575 __tuple_cat_helper(tuple<_TElements...>&& __t,
576 const __index_holder<_TIdx...>&,
577 tuple<_UElements...>&& __u,
578 const __index_holder<_UIdx...>&)
579 { return tuple<_TElements..., _UElements...>
580 (std::move(get<_TIdx>(__t))..., std::move(get<_UIdx>(__u))...); }
582 template<typename... _TElements, typename... _UElements>
583 inline tuple<_TElements..., _UElements...>
584 tuple_cat(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u)
586 return __tuple_cat_helper(__t, typename
587 __make_index_holder<_TElements...>::type(),
589 __make_index_holder<_UElements...>::type());
592 template<typename... _TElements, typename... _UElements>
593 inline tuple<_TElements..., _UElements...>
594 tuple_cat(tuple<_TElements...>&& __t, const tuple<_UElements...>& __u)
596 return __tuple_cat_helper(std::move(__t), typename
597 __make_index_holder<_TElements...>::type(),
599 __make_index_holder<_UElements...>::type());
602 template<typename... _TElements, typename... _UElements>
603 inline tuple<_TElements..., _UElements...>
604 tuple_cat(const tuple<_TElements...>& __t, tuple<_UElements...>&& __u)
606 return __tuple_cat_helper(__t, typename
607 __make_index_holder<_TElements...>::type(),
608 std::move(__u), typename
609 __make_index_holder<_UElements...>::type());
612 template<typename... _TElements, typename... _UElements>
613 inline tuple<_TElements..., _UElements...>
614 tuple_cat(tuple<_TElements...>&& __t, tuple<_UElements...>&& __u)
616 return __tuple_cat_helper(std::move(__t), typename
617 __make_index_holder<_TElements...>::type(),
618 std::move(__u), typename
619 __make_index_holder<_UElements...>::type());
622 template<typename... _Elements>
623 inline tuple<_Elements&...>
624 tie(_Elements&... __args)
625 { return tuple<_Elements&...>(__args...); }
627 // A class (and instance) which can be used in 'tie' when an element
628 // of a tuple is not required
629 struct _Swallow_assign
633 operator=(const _Tp&)
637 // TODO: Put this in some kind of shared file.
640 _Swallow_assign ignore;
641 }; // anonymous namespace
644 #endif // _GLIBCXX_CXX0X_TUPLE