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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11 // This library is distributed in the hope that it will be useful,
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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.
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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 #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 __cplusplus >= 201103L
120  template<typename _Alloc>
121  using _Uses = typename
122  enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
123 #endif
124 
125  public:
126  typedef typename _Sequence::value_type value_type;
127  typedef typename _Sequence::reference reference;
128  typedef typename _Sequence::const_reference const_reference;
129  typedef typename _Sequence::size_type size_type;
130  typedef _Sequence container_type;
131 
132  protected:
133  // See queue::c for notes on this name.
134  _Sequence c;
135 
136  public:
137  // XXX removed old def ctor, added def arg to this one to match 14882
138  /**
139  * @brief Default constructor creates no elements.
140  */
141 #if __cplusplus < 201103L
142  explicit
143  stack(const _Sequence& __c = _Sequence())
144  : c(__c) { }
145 #else
146  template<typename _Seq = _Sequence, typename _Requires = typename
147  enable_if<is_default_constructible<_Seq>::value>::type>
149  : c() { }
150 
151  explicit
152  stack(const _Sequence& __c)
153  : c(__c) { }
154 
155  explicit
156  stack(_Sequence&& __c)
157  : c(std::move(__c)) { }
158 
159  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
160  explicit
161  stack(const _Alloc& __a)
162  : c(__a) { }
163 
164  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
165  stack(const _Sequence& __c, const _Alloc& __a)
166  : c(__c, __a) { }
167 
168  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
169  stack(_Sequence&& __c, const _Alloc& __a)
170  : c(std::move(__c), __a) { }
171 
172  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
173  stack(const stack& __q, const _Alloc& __a)
174  : c(__q.c, __a) { }
175 
176  template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
177  stack(stack&& __q, const _Alloc& __a)
178  : c(std::move(__q.c), __a) { }
179 #endif
180 
181  /**
182  * Returns true if the %stack is empty.
183  */
184  bool
185  empty() const
186  { return c.empty(); }
187 
188  /** Returns the number of elements in the %stack. */
189  size_type
190  size() const
191  { return c.size(); }
192 
193  /**
194  * Returns a read/write reference to the data at the first
195  * element of the %stack.
196  */
197  reference
198  top()
199  {
200  __glibcxx_requires_nonempty();
201  return c.back();
202  }
203 
204  /**
205  * Returns a read-only (constant) reference to the data at the first
206  * element of the %stack.
207  */
208  const_reference
209  top() const
210  {
211  __glibcxx_requires_nonempty();
212  return c.back();
213  }
214 
215  /**
216  * @brief Add data to the top of the %stack.
217  * @param __x Data to be added.
218  *
219  * This is a typical %stack operation. The function creates an
220  * element at the top of the %stack and assigns the given data
221  * to it. The time complexity of the operation depends on the
222  * underlying sequence.
223  */
224  void
225  push(const value_type& __x)
226  { c.push_back(__x); }
227 
228 #if __cplusplus >= 201103L
229  void
230  push(value_type&& __x)
231  { c.push_back(std::move(__x)); }
232 
233 #if __cplusplus > 201402L
234  template<typename... _Args>
235  decltype(auto)
236  emplace(_Args&&... __args)
237  { return c.emplace_back(std::forward<_Args>(__args)...); }
238 #else
239  template<typename... _Args>
240  void
241  emplace(_Args&&... __args)
242  { c.emplace_back(std::forward<_Args>(__args)...); }
243 #endif
244 #endif
245 
246  /**
247  * @brief Removes first element.
248  *
249  * This is a typical %stack operation. It shrinks the %stack
250  * by one. The time complexity of the operation depends on the
251  * underlying sequence.
252  *
253  * Note that no data is returned, and if the first element's
254  * data is needed, it should be retrieved before pop() is
255  * called.
256  */
257  void
258  pop()
259  {
260  __glibcxx_requires_nonempty();
261  c.pop_back();
262  }
263 
264 #if __cplusplus >= 201103L
265  void
266  swap(stack& __s)
267 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
268  noexcept(__is_nothrow_swappable<_Sequence>::value)
269 #else
270  noexcept(__is_nothrow_swappable<_Tp>::value)
271 #endif
272  {
273  using std::swap;
274  swap(c, __s.c);
275  }
276 #endif // __cplusplus >= 201103L
277  };
278 
279  /**
280  * @brief Stack equality comparison.
281  * @param __x A %stack.
282  * @param __y A %stack of the same type as @a __x.
283  * @return True iff the size and elements of the stacks are equal.
284  *
285  * This is an equivalence relation. Complexity and semantics
286  * depend on the underlying sequence type, but the expected rules
287  * are: this relation is linear in the size of the sequences, and
288  * stacks are considered equivalent if their sequences compare
289  * equal.
290  */
291  template<typename _Tp, typename _Seq>
292  inline bool
293  operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
294  { return __x.c == __y.c; }
295 
296  /**
297  * @brief Stack ordering relation.
298  * @param __x A %stack.
299  * @param __y A %stack of the same type as @a x.
300  * @return True iff @a x is lexicographically less than @a __y.
301  *
302  * This is an total ordering relation. Complexity and semantics
303  * depend on the underlying sequence type, but the expected rules
304  * are: this relation is linear in the size of the sequences, the
305  * elements must be comparable with @c <, and
306  * std::lexicographical_compare() is usually used to make the
307  * determination.
308  */
309  template<typename _Tp, typename _Seq>
310  inline bool
311  operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
312  { return __x.c < __y.c; }
313 
314  /// Based on operator==
315  template<typename _Tp, typename _Seq>
316  inline bool
317  operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
318  { return !(__x == __y); }
319 
320  /// Based on operator<
321  template<typename _Tp, typename _Seq>
322  inline bool
323  operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
324  { return __y < __x; }
325 
326  /// Based on operator<
327  template<typename _Tp, typename _Seq>
328  inline bool
329  operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
330  { return !(__y < __x); }
331 
332  /// Based on operator<
333  template<typename _Tp, typename _Seq>
334  inline bool
335  operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
336  { return !(__x < __y); }
337 
338 #if __cplusplus >= 201103L
339  template<typename _Tp, typename _Seq>
340  inline
341 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
342  // Constrained free swap overload, see p0185r1
343  typename enable_if<__is_swappable<_Seq>::value>::type
344 #else
345  void
346 #endif
347  swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
348  noexcept(noexcept(__x.swap(__y)))
349  { __x.swap(__y); }
350 
351  template<typename _Tp, typename _Seq, typename _Alloc>
352  struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
353  : public uses_allocator<_Seq, _Alloc>::type { };
354 #endif // __cplusplus >= 201103L
355 
356 _GLIBCXX_END_NAMESPACE_VERSION
357 } // namespace
358 
359 #endif /* _STL_STACK_H */
void pop()
Removes first element.
Definition: stl_stack.h:258
void push(const value_type &__x)
Add data to the top of the stack.
Definition: stl_stack.h:225
stack()
Default constructor creates no elements.
Definition: stl_stack.h:148
bool empty() const
Definition: stl_stack.h:185
A standard container giving FILO behavior.
Definition: stl_stack.h:99
const_reference top() const
Definition: stl_stack.h:209
ISO C++ entities toplevel namespace is std.
reference top()
Definition: stl_stack.h:198
Declare uses_allocator so it can be specialized in <queue> etc.
Definition: memoryfwd.h:71
size_type size() const
Definition: stl_stack.h:190