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

   1 // Stack implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001-2016 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_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       explicit
 145       stack(const _Sequence& __c)
 146       : c(__c) { }
 147
 148       explicit
 149       stack(_Sequence&& __c = _Sequence())
 150       : c(std::move(__c)) { }
 151
 152       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
 153         explicit
 154         stack(const _Alloc& __a)
 155         : c(__a) { }
 156
 157       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
 158         stack(const _Sequence& __c, const _Alloc& __a)
 159         : c(__c, __a) { }
 160
 161       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
 162         stack(_Sequence&& __c, const _Alloc& __a)
 163         : c(std::move(__c), __a) { }
 164
 165       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
 166         stack(const stack& __q, const _Alloc& __a)
 167         : c(__q.c, __a) { }
 168
 169       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
 170         stack(stack&& __q, const _Alloc& __a)
 171         : c(std::move(__q.c), __a) { }
 172 #endif
 173
 174       /**
 175        *  Returns true if the %stack is empty.
 176        */
 177       bool
 178       empty() const
 179       { return c.empty(); }
 180
 181       /**  Returns the number of elements in the %stack.  */
 182       size_type
 183       size() const
 184       { return c.size(); }
 185
 186       /**
 187        *  Returns a read/write reference to the data at the first
 188        *  element of the %stack.
 189        */
 190       reference
 191       top()
 192       {
 193         __glibcxx_requires_nonempty();
 194         return c.back();
 195       }
 196
 197       /**
 198        *  Returns a read-only (constant) reference to the data at the first
 199        *  element of the %stack.
 200        */
 201       const_reference
 202       top() const
 203       {
 204         __glibcxx_requires_nonempty();
 205         return c.back();
 206       }
 207
 208       /**
 209        *  @brief  Add data to the top of the %stack.
 210        *  @param  __x  Data to be added.
 211        *
 212        *  This is a typical %stack operation.  The function creates an
 213        *  element at the top of the %stack and assigns the given data
 214        *  to it.  The time complexity of the operation depends on the
 215        *  underlying sequence.
 216        */
 217       void
 218       push(const value_type& __x)
 219       { c.push_back(__x); }
 220
 221 #if __cplusplus >= 201103L
 222       void
 223       push(value_type&& __x)
 224       { c.push_back(std::move(__x)); }
 225
 226 #if __cplusplus > 201402L
 227       template<typename... _Args>
 228         decltype(auto)
 229         emplace(_Args&&... __args)
 230         { return c.emplace_back(std::forward<_Args>(__args)...); }
 231 #else
 232       template<typename... _Args>
 233         void
 234         emplace(_Args&&... __args)
 235         { c.emplace_back(std::forward<_Args>(__args)...); }
 236 #endif
 237 #endif
 238
 239       /**
 240        *  @brief  Removes first element.
 241        *
 242        *  This is a typical %stack operation.  It shrinks the %stack
 243        *  by one.  The time complexity of the operation depends on the
 244        *  underlying sequence.
 245        *
 246        *  Note that no data is returned, and if the first element's
 247        *  data is needed, it should be retrieved before pop() is
 248        *  called.
 249        */
 250       void
 251       pop()
 252       {
 253         __glibcxx_requires_nonempty();
 254         c.pop_back();
 255       }
 256
 257 #if __cplusplus >= 201103L
 258       void
 259       swap(stack& __s)
 260 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
 261       noexcept(__is_nothrow_swappable<_Sequence>::value)
 262 #else
 263       noexcept(__is_nothrow_swappable<_Tp>::value)
 264 #endif
 265       {
 266         using std::swap;
 267         swap(c, __s.c);
 268       }
 269 #endif // __cplusplus >= 201103L
 270     };
 271
 272   /**
 273    *  @brief  Stack equality comparison.
 274    *  @param  __x  A %stack.
 275    *  @param  __y  A %stack of the same type as @a __x.
 276    *  @return  True iff the size and elements of the stacks are equal.
 277    *
 278    *  This is an equivalence relation.  Complexity and semantics
 279    *  depend on the underlying sequence type, but the expected rules
 280    *  are: this relation is linear in the size of the sequences, and
 281    *  stacks are considered equivalent if their sequences compare
 282    *  equal.
 283   */
 284   template<typename _Tp, typename _Seq>
 285     inline bool
 286     operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 287     { return __x.c == __y.c; }
 288
 289   /**
 290    *  @brief  Stack ordering relation.
 291    *  @param  __x  A %stack.
 292    *  @param  __y  A %stack of the same type as @a x.
 293    *  @return  True iff @a x is lexicographically less than @a __y.
 294    *
 295    *  This is an total ordering relation.  Complexity and semantics
 296    *  depend on the underlying sequence type, but the expected rules
 297    *  are: this relation is linear in the size of the sequences, the
 298    *  elements must be comparable with @c <, and
 299    *  std::lexicographical_compare() is usually used to make the
 300    *  determination.
 301   */
 302   template<typename _Tp, typename _Seq>
 303     inline bool
 304     operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 305     { return __x.c < __y.c; }
 306
 307   /// Based on operator==
 308   template<typename _Tp, typename _Seq>
 309     inline bool
 310     operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 311     { return !(__x == __y); }
 312
 313   /// Based on operator<
 314   template<typename _Tp, typename _Seq>
 315     inline bool
 316     operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 317     { return __y < __x; }
 318
 319   /// Based on operator<
 320   template<typename _Tp, typename _Seq>
 321     inline bool
 322     operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 323     { return !(__y < __x); }
 324
 325   /// Based on operator<
 326   template<typename _Tp, typename _Seq>
 327     inline bool
 328     operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 329     { return !(__x < __y); }
 330
 331 #if __cplusplus >= 201103L
 332   template<typename _Tp, typename _Seq>
 333     inline
 334 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
 335     // Constrained free swap overload, see p0185r1
 336     typename enable_if<__is_swappable<_Seq>::value>::type
 337 #else
 338     void
 339 #endif
 340     swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
 341     noexcept(noexcept(__x.swap(__y)))
 342     { __x.swap(__y); }
 343
 344   template<typename _Tp, typename _Seq, typename _Alloc>
 345     struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
 346     : public uses_allocator<_Seq, _Alloc>::type { };
 347 #endif // __cplusplus >= 201103L
 348
 349 _GLIBCXX_END_NAMESPACE_VERSION
 350 } // namespace
 351
 352 #endif /* _STL_STACK_H */