libstdc++
stl_stack.h
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1 // Stack implementation -*- C++ -*-
2 
3 // Copyright (C) 2001-2017 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
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10 
11 // This library is distributed in the hope that it will be useful,
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13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 
16 // Under Section 7 of GPL version 3, you are granted additional
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18 // 3.1, as published by the Free Software Foundation.
19 
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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_front,
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  // concept requirements
102  typedef typename _Sequence::value_type _Sequence_value_type;
103 #if __cplusplus < 201103L
104  __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
105  __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
106 #endif
107  __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
108 
109  template<typename _Tp1, typename _Seq1>
110  friend bool
111  operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
112 
113  template<typename _Tp1, typename _Seq1>
114  friend bool
115  operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
116 
117 #if __cplusplus >= 201103L
118  template<typename _Alloc>
119  using _Uses = typename
120  enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
121 #endif
122 
123  public:
124  typedef typename _Sequence::value_type value_type;
125  typedef typename _Sequence::reference reference;
126  typedef typename _Sequence::const_reference const_reference;
127  typedef typename _Sequence::size_type size_type;
128  typedef _Sequence container_type;
129 
130  protected:
131  // See queue::c for notes on this name.
132  _Sequence c;
133 
134  public:
135  // XXX removed old def ctor, added def arg to this one to match 14882
136  /**
137  * @brief Default constructor creates no elements.
138  */
139 #if __cplusplus < 201103L
140  explicit
141  stack(const _Sequence& __c = _Sequence())
142  : c(__c) { }
143 #else
144  template<typename _Seq = _Sequence, typename _Requires = typename
145  enable_if<is_default_constructible<_Seq>::value>::type>
147  : c() { }
148 
149  explicit
150  stack(const _Sequence& __c)
151  : c(__c) { }
152 
153  explicit
154  stack(_Sequence&& __c)
155  : c(std::move(__c)) { }
156 
157  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
158  explicit
159  stack(const _Alloc& __a)
160  : c(__a) { }
161 
162  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
163  stack(const _Sequence& __c, const _Alloc& __a)
164  : c(__c, __a) { }
165 
166  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
167  stack(_Sequence&& __c, const _Alloc& __a)
168  : c(std::move(__c), __a) { }
169 
170  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
171  stack(const stack& __q, const _Alloc& __a)
172  : c(__q.c, __a) { }
173 
174  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
175  stack(stack&& __q, const _Alloc& __a)
176  : c(std::move(__q.c), __a) { }
177 #endif
178 
179  /**
180  * Returns true if the %stack is empty.
181  */
182  bool
183  empty() const
184  { return c.empty(); }
185 
186  /** Returns the number of elements in the %stack. */
187  size_type
188  size() const
189  { return c.size(); }
190 
191  /**
192  * Returns a read/write reference to the data at the first
193  * element of the %stack.
194  */
195  reference
196  top()
197  {
198  __glibcxx_requires_nonempty();
199  return c.back();
200  }
201 
202  /**
203  * Returns a read-only (constant) reference to the data at the first
204  * element of the %stack.
205  */
206  const_reference
207  top() const
208  {
209  __glibcxx_requires_nonempty();
210  return c.back();
211  }
212 
213  /**
214  * @brief Add data to the top of the %stack.
215  * @param __x Data to be added.
216  *
217  * This is a typical %stack operation. The function creates an
218  * element at the top of the %stack and assigns the given data
219  * to it. The time complexity of the operation depends on the
220  * underlying sequence.
221  */
222  void
223  push(const value_type& __x)
224  { c.push_back(__x); }
225 
226 #if __cplusplus >= 201103L
227  void
228  push(value_type&& __x)
229  { c.push_back(std::move(__x)); }
230 
231 #if __cplusplus > 201402L
232  template<typename... _Args>
233  decltype(auto)
234  emplace(_Args&&... __args)
235  { return c.emplace_back(std::forward<_Args>(__args)...); }
236 #else
237  template<typename... _Args>
238  void
239  emplace(_Args&&... __args)
240  { c.emplace_back(std::forward<_Args>(__args)...); }
241 #endif
242 #endif
243 
244  /**
245  * @brief Removes first element.
246  *
247  * This is a typical %stack operation. It shrinks the %stack
248  * by one. The time complexity of the operation depends on the
249  * underlying sequence.
250  *
251  * Note that no data is returned, and if the first element's
252  * data is needed, it should be retrieved before pop() is
253  * called.
254  */
255  void
256  pop()
257  {
258  __glibcxx_requires_nonempty();
259  c.pop_back();
260  }
261 
262 #if __cplusplus >= 201103L
263  void
264  swap(stack& __s)
265 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
266  noexcept(__is_nothrow_swappable<_Sequence>::value)
267 #else
268  noexcept(__is_nothrow_swappable<_Tp>::value)
269 #endif
270  {
271  using std::swap;
272  swap(c, __s.c);
273  }
274 #endif // __cplusplus >= 201103L
275  };
276 
277  /**
278  * @brief Stack equality comparison.
279  * @param __x A %stack.
280  * @param __y A %stack of the same type as @a __x.
281  * @return True iff the size and elements of the stacks are equal.
282  *
283  * This is an equivalence relation. Complexity and semantics
284  * depend on the underlying sequence type, but the expected rules
285  * are: this relation is linear in the size of the sequences, and
286  * stacks are considered equivalent if their sequences compare
287  * equal.
288  */
289  template<typename _Tp, typename _Seq>
290  inline bool
291  operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
292  { return __x.c == __y.c; }
293 
294  /**
295  * @brief Stack ordering relation.
296  * @param __x A %stack.
297  * @param __y A %stack of the same type as @a x.
298  * @return True iff @a x is lexicographically less than @a __y.
299  *
300  * This is an total ordering relation. Complexity and semantics
301  * depend on the underlying sequence type, but the expected rules
302  * are: this relation is linear in the size of the sequences, the
303  * elements must be comparable with @c <, and
304  * std::lexicographical_compare() is usually used to make the
305  * determination.
306  */
307  template<typename _Tp, typename _Seq>
308  inline bool
309  operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
310  { return __x.c < __y.c; }
311 
312  /// Based on operator==
313  template<typename _Tp, typename _Seq>
314  inline bool
315  operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
316  { return !(__x == __y); }
317 
318  /// Based on operator<
319  template<typename _Tp, typename _Seq>
320  inline bool
321  operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
322  { return __y < __x; }
323 
324  /// Based on operator<
325  template<typename _Tp, typename _Seq>
326  inline bool
327  operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
328  { return !(__y < __x); }
329 
330  /// Based on operator<
331  template<typename _Tp, typename _Seq>
332  inline bool
333  operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
334  { return !(__x < __y); }
335 
336 #if __cplusplus >= 201103L
337  template<typename _Tp, typename _Seq>
338  inline
339 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
340  // Constrained free swap overload, see p0185r1
341  typename enable_if<__is_swappable<_Seq>::value>::type
342 #else
343  void
344 #endif
345  swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
346  noexcept(noexcept(__x.swap(__y)))
347  { __x.swap(__y); }
348 
349  template<typename _Tp, typename _Seq, typename _Alloc>
350  struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
351  : public uses_allocator<_Seq, _Alloc>::type { };
352 #endif // __cplusplus >= 201103L
353 
354 _GLIBCXX_END_NAMESPACE_VERSION
355 } // namespace
356 
357 #endif /* _STL_STACK_H */
stack()
Default constructor creates no elements.
Definition: stl_stack.h:146
bool empty() const
Definition: stl_stack.h:183
ISO C++ entities toplevel namespace is std.
size_type size() const
Definition: stl_stack.h:188
void push(const value_type &__x)
Add data to the top of the stack.
Definition: stl_stack.h:223
reference top()
Definition: stl_stack.h:196
const_reference top() const
Definition: stl_stack.h:207
A standard container giving FILO behavior.
Definition: stl_stack.h:99
void pop()
Removes first element.
Definition: stl_stack.h:256
Declare uses_allocator so it can be specialized in <queue> etc.
Definition: memoryfwd.h:71