libstdc++-v3/include/bits/stl_stack.h

   1 // Stack implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001-2018 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 __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>
 148         stack()
 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 */