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1 : // Stack implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001-2021 Free Software Foundation, Inc.
4 : //
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 3, or (at your option)
9 : // any later version.
10 :
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.
15 :
16 : // Under Section 7 of GPL version 3, you are granted additional
17 : // permissions described in the GCC Runtime Library Exception, version
18 : // 3.1, as published by the Free Software Foundation.
19 :
20 : // You should have received a copy of the GNU General Public License and
21 : // a copy of the GCC Runtime Library Exception along with this program;
22 : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 : // <http://www.gnu.org/licenses/>.
24 :
25 : /*
26 : *
27 : * Copyright (c) 1994
28 : * Hewlett-Packard Company
29 : *
30 : * Permission to use, copy, modify, distribute and sell this software
31 : * and its documentation for any purpose is hereby granted without fee,
32 : * provided that the above copyright notice appear in all copies and
33 : * that both that copyright notice and this permission notice appear
34 : * in supporting documentation. Hewlett-Packard Company makes no
35 : * representations about the suitability of this software for any
36 : * purpose. It is provided "as is" without express or implied warranty.
37 : *
38 : *
39 : * Copyright (c) 1996,1997
40 : * Silicon Graphics Computer Systems, Inc.
41 : *
42 : * Permission to use, copy, modify, distribute and sell this software
43 : * and its documentation for any purpose is hereby granted without fee,
44 : * provided that the above copyright notice appear in all copies and
45 : * that both that copyright notice and this permission notice appear
46 : * in supporting documentation. Silicon Graphics makes no
47 : * representations about the suitability of this software for any
48 : * purpose. It is provided "as is" without express or implied warranty.
49 : */
50 :
51 : /** @file bits/stl_stack.h
52 : * This is an internal header file, included by other library headers.
53 : * Do not attempt to use it directly. @headername{stack}
54 : */
55 :
56 : #ifndef _STL_STACK_H
57 : #define _STL_STACK_H 1
58 :
59 : #include <bits/concept_check.h>
60 : #include <debug/debug.h>
61 : #if __cplusplus >= 201103L
62 : # include <bits/uses_allocator.h>
63 : #endif
64 :
65 : namespace std _GLIBCXX_VISIBILITY(default)
66 : {
67 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
68 :
69 : /**
70 : * @brief A standard container giving FILO behavior.
71 : *
72 : * @ingroup sequences
73 : *
74 : * @tparam _Tp Type of element.
75 : * @tparam _Sequence Type of underlying sequence, defaults to deque<_Tp>.
76 : *
77 : * Meets many of the requirements of a
78 : * <a href="tables.html#65">container</a>,
79 : * but does not define anything to do with iterators. Very few of the
80 : * other standard container interfaces are defined.
81 : *
82 : * This is not a true container, but an @e adaptor. It holds
83 : * another container, and provides a wrapper interface to that
84 : * container. The wrapper is what enforces strict
85 : * first-in-last-out %stack behavior.
86 : *
87 : * The second template parameter defines the type of the underlying
88 : * sequence/container. It defaults to std::deque, but it can be
89 : * any type that supports @c back, @c push_back, and @c pop_back,
90 : * such as std::list, std::vector, or an appropriate user-defined
91 : * type.
92 : *
93 : * Members not found in @a normal containers are @c container_type,
94 : * which is a typedef for the second Sequence parameter, and @c
95 : * push, @c pop, and @c top, which are standard %stack/FILO
96 : * operations.
97 : */
98 : template<typename _Tp, typename _Sequence = deque<_Tp> >
99 : class stack
100 : {
101 : #ifdef _GLIBCXX_CONCEPT_CHECKS
102 : // concept requirements
103 : typedef typename _Sequence::value_type _Sequence_value_type;
104 : # if __cplusplus < 201103L
105 : __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
106 : __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
107 : # endif
108 : __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
109 : #endif
110 :
111 : template<typename _Tp1, typename _Seq1>
112 : friend bool
113 : operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
114 :
115 : template<typename _Tp1, typename _Seq1>
116 : friend bool
117 : operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
118 :
119 : #if __cpp_lib_three_way_comparison
120 : template<typename _Tp1, three_way_comparable _Seq1>
121 : friend compare_three_way_result_t<_Seq1>
122 : operator<=>(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
123 : #endif
124 :
125 : #if __cplusplus >= 201103L
126 : template<typename _Alloc>
127 : using _Uses = typename
128 : enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
129 :
130 : #if __cplusplus >= 201703L
131 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
132 : // 2566. Requirements on the first template parameter of container
133 : // adaptors
134 : static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
135 : "value_type must be the same as the underlying container");
136 : #endif // C++17
137 : #endif // C++11
138 :
139 : public:
140 : typedef typename _Sequence::value_type value_type;
141 : typedef typename _Sequence::reference reference;
142 : typedef typename _Sequence::const_reference const_reference;
143 : typedef typename _Sequence::size_type size_type;
144 : typedef _Sequence container_type;
145 :
146 : protected:
147 : // See queue::c for notes on this name.
148 : _Sequence c;
149 :
150 : public:
151 : // XXX removed old def ctor, added def arg to this one to match 14882
152 : /**
153 : * @brief Default constructor creates no elements.
154 : */
155 : #if __cplusplus < 201103L
156 : explicit
157 : stack(const _Sequence& __c = _Sequence())
158 : : c(__c) { }
159 : #else
160 : template<typename _Seq = _Sequence, typename _Requires = typename
161 : enable_if<is_default_constructible<_Seq>::value>::type>
162 5852 : stack()
163 5852 : : c() { }
164 :
165 : explicit
166 : stack(const _Sequence& __c)
167 : : c(__c) { }
168 :
169 : explicit
170 : stack(_Sequence&& __c)
171 : : c(std::move(__c)) { }
172 :
173 : template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
174 : explicit
175 : stack(const _Alloc& __a)
176 : : c(__a) { }
177 :
178 : template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
179 : stack(const _Sequence& __c, const _Alloc& __a)
180 : : c(__c, __a) { }
181 :
182 : template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
183 : stack(_Sequence&& __c, const _Alloc& __a)
184 : : c(std::move(__c), __a) { }
185 :
186 : template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
187 : stack(const stack& __q, const _Alloc& __a)
188 : : c(__q.c, __a) { }
189 :
190 : template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
191 : stack(stack&& __q, const _Alloc& __a)
192 : : c(std::move(__q.c), __a) { }
193 : #endif
194 :
195 : /**
196 : * Returns true if the %stack is empty.
197 : */
198 : _GLIBCXX_NODISCARD bool
199 17223 : empty() const
200 17223 : { return c.empty(); }
201 :
202 : /** Returns the number of elements in the %stack. */
203 : size_type
204 : size() const
205 : { return c.size(); }
206 :
207 : /**
208 : * Returns a read/write reference to the data at the first
209 : * element of the %stack.
210 : */
211 : reference
212 25375 : top()
213 : {
214 : __glibcxx_requires_nonempty();
215 25375 : return c.back();
216 : }
217 :
218 : /**
219 : * Returns a read-only (constant) reference to the data at the first
220 : * element of the %stack.
221 : */
222 : const_reference
223 : top() const
224 : {
225 : __glibcxx_requires_nonempty();
226 : return c.back();
227 : }
228 :
229 : /**
230 : * @brief Add data to the top of the %stack.
231 : * @param __x Data to be added.
232 : *
233 : * This is a typical %stack operation. The function creates an
234 : * element at the top of the %stack and assigns the given data
235 : * to it. The time complexity of the operation depends on the
236 : * underlying sequence.
237 : */
238 : void
239 18459 : push(const value_type& __x)
240 18459 : { c.push_back(__x); }
241 :
242 : #if __cplusplus >= 201103L
243 : void
244 6916 : push(value_type&& __x)
245 6916 : { c.push_back(std::move(__x)); }
246 :
247 : #if __cplusplus > 201402L
248 : template<typename... _Args>
249 : decltype(auto)
250 : emplace(_Args&&... __args)
251 : { return c.emplace_back(std::forward<_Args>(__args)...); }
252 : #else
253 : template<typename... _Args>
254 : void
255 : emplace(_Args&&... __args)
256 : { c.emplace_back(std::forward<_Args>(__args)...); }
257 : #endif
258 : #endif
259 :
260 : /**
261 : * @brief Removes first element.
262 : *
263 : * This is a typical %stack operation. It shrinks the %stack
264 : * by one. The time complexity of the operation depends on the
265 : * underlying sequence.
266 : *
267 : * Note that no data is returned, and if the first element's
268 : * data is needed, it should be retrieved before pop() is
269 : * called.
270 : */
271 : void
272 25375 : pop()
273 : {
274 : __glibcxx_requires_nonempty();
275 25375 : c.pop_back();
276 25375 : }
277 :
278 : #if __cplusplus >= 201103L
279 : void
280 : swap(stack& __s)
281 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
282 : noexcept(__is_nothrow_swappable<_Sequence>::value)
283 : #else
284 : noexcept(__is_nothrow_swappable<_Tp>::value)
285 : #endif
286 : {
287 : using std::swap;
288 : swap(c, __s.c);
289 : }
290 : #endif // __cplusplus >= 201103L
291 : };
292 :
293 : #if __cpp_deduction_guides >= 201606
294 : template<typename _Container,
295 : typename = _RequireNotAllocator<_Container>>
296 : stack(_Container) -> stack<typename _Container::value_type, _Container>;
297 :
298 : template<typename _Container, typename _Allocator,
299 : typename = _RequireNotAllocator<_Container>,
300 : typename = _RequireAllocator<_Allocator>>
301 : stack(_Container, _Allocator)
302 : -> stack<typename _Container::value_type, _Container>;
303 : #endif
304 :
305 : /**
306 : * @brief Stack equality comparison.
307 : * @param __x A %stack.
308 : * @param __y A %stack of the same type as @a __x.
309 : * @return True iff the size and elements of the stacks are equal.
310 : *
311 : * This is an equivalence relation. Complexity and semantics
312 : * depend on the underlying sequence type, but the expected rules
313 : * are: this relation is linear in the size of the sequences, and
314 : * stacks are considered equivalent if their sequences compare
315 : * equal.
316 : */
317 : template<typename _Tp, typename _Seq>
318 : inline bool
319 : operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
320 : { return __x.c == __y.c; }
321 :
322 : /**
323 : * @brief Stack ordering relation.
324 : * @param __x A %stack.
325 : * @param __y A %stack of the same type as @a x.
326 : * @return True iff @a x is lexicographically less than @a __y.
327 : *
328 : * This is an total ordering relation. Complexity and semantics
329 : * depend on the underlying sequence type, but the expected rules
330 : * are: this relation is linear in the size of the sequences, the
331 : * elements must be comparable with @c <, and
332 : * std::lexicographical_compare() is usually used to make the
333 : * determination.
334 : */
335 : template<typename _Tp, typename _Seq>
336 : inline bool
337 : operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
338 : { return __x.c < __y.c; }
339 :
340 : /// Based on operator==
341 : template<typename _Tp, typename _Seq>
342 : inline bool
343 : operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
344 : { return !(__x == __y); }
345 :
346 : /// Based on operator<
347 : template<typename _Tp, typename _Seq>
348 : inline bool
349 : operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
350 : { return __y < __x; }
351 :
352 : /// Based on operator<
353 : template<typename _Tp, typename _Seq>
354 : inline bool
355 : operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
356 : { return !(__y < __x); }
357 :
358 : /// Based on operator<
359 : template<typename _Tp, typename _Seq>
360 : inline bool
361 : operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
362 : { return !(__x < __y); }
363 :
364 : #if __cpp_lib_three_way_comparison
365 : template<typename _Tp, three_way_comparable _Seq>
366 : inline compare_three_way_result_t<_Seq>
367 : operator<=>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
368 : { return __x.c <=> __y.c; }
369 : #endif
370 :
371 : #if __cplusplus >= 201103L
372 : template<typename _Tp, typename _Seq>
373 : inline
374 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
375 : // Constrained free swap overload, see p0185r1
376 : typename enable_if<__is_swappable<_Seq>::value>::type
377 : #else
378 : void
379 : #endif
380 : swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
381 : noexcept(noexcept(__x.swap(__y)))
382 : { __x.swap(__y); }
383 :
384 : template<typename _Tp, typename _Seq, typename _Alloc>
385 : struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
386 : : public uses_allocator<_Seq, _Alloc>::type { };
387 : #endif // __cplusplus >= 201103L
388 :
389 : _GLIBCXX_END_NAMESPACE_VERSION
390 : } // namespace
391 :
392 : #endif /* _STL_STACK_H */
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