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

   1 // Stack implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996,1997
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 /** @file stl_stack.h
  57  *  This is an internal header file, included by other library headers.
  58  *  You should not attempt to use it directly.
  59  */
  60
  61 #ifndef _STACK_H
  62 #define _STACK_H 1
  63
  64 #include <bits/concept_check.h>
  65
  66 namespace std
  67 {
  68   // Forward declarations of operators == and <, needed for friend declaration.
  69
  70   template <typename _Tp, typename _Sequence = deque<_Tp> >
  71   class stack;
  72
  73   template <typename _Tp, typename _Seq>
  74   inline bool operator==(const stack<_Tp,_Seq>& __x,
  75                          const stack<_Tp,_Seq>& __y);
  76
  77   template <typename _Tp, typename _Seq>
  78   inline bool operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);
  79
  80
  81   /**
  82    *  @brief  A standard container giving FILO behavior.
  83    *
  84    *  @ingroup Containers
  85    *  @ingroup Sequences
  86    *
  87    *  Meets many of the requirements of a
  88    *  <a href="tables.html#65">container</a>,
  89    *  but does not define anything to do with iterators.  Very few of the
  90    *  other standard container interfaces are defined.
  91    *
  92    *  This is not a true container, but an @e adaptor.  It holds another
  93    *  container, and provides a wrapper interface to that container.  The
  94    *  wrapper is what enforces strict first-in-last-out %stack behavior.
  95    *
  96    *  The second template parameter defines the type of the underlying
  97    *  sequence/container.  It defaults to std::deque, but it can be any type
  98    *  that supports @c back, @c push_back, and @c pop_front, such as
  99    *  std::list, std::vector, or an appropriate user-defined type.
 100    *
 101    *  Members not found in "normal" containers are @c container_type,
 102    *  which is a typedef for the second Sequence parameter, and @c push,
 103    *  @c pop, and @c top, which are standard %stack/FILO operations.
 104   */
 105   template <typename _Tp, typename _Sequence>
 106     class stack
 107   {
 108     // concept requirements
 109     typedef typename _Sequence::value_type _Sequence_value_type;
 110     __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
 111     __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
 112     __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
 113
 114     template <typename _Tp1, typename _Seq1>
 115     friend bool operator== (const stack<_Tp1, _Seq1>&,
 116                             const stack<_Tp1, _Seq1>&);
 117     template <typename _Tp1, typename _Seq1>
 118     friend bool operator< (const stack<_Tp1, _Seq1>&,
 119                            const stack<_Tp1, _Seq1>&);
 120
 121   public:
 122     typedef typename _Sequence::value_type                value_type;
 123     typedef typename _Sequence::reference                 reference;
 124     typedef typename _Sequence::const_reference           const_reference;
 125     typedef typename _Sequence::size_type                 size_type;
 126     typedef          _Sequence                            container_type;
 127
 128   protected:
 129     //  See queue::c for notes on this name.
 130     _Sequence c;
 131
 132   public:
 133     // XXX removed old def ctor, added def arg to this one to match 14882
 134     /**
 135      *  @brief  Default constructor creates no elements.
 136     */
 137     explicit
 138     stack(const _Sequence& __c = _Sequence())
 139     : c(__c) {}
 140
 141     /**
 142      *  Returns true if the %stack is empty.
 143     */
 144     bool
 145     empty() const { return c.empty(); }
 146
 147     /**  Returns the number of elements in the %stack.  */
 148     size_type
 149     size() const { return c.size(); }
 150
 151     /**
 152      *  Returns a read/write reference to the data at the first element of the
 153      *  %stack.
 154     */
 155     reference
 156     top() { return c.back(); }
 157
 158     /**
 159      *  Returns a read-only (constant) reference to the data at the first
 160      *  element of the %stack.
 161     */
 162     const_reference
 163     top() const { return c.back(); }
 164
 165     /**
 166      *  @brief  Add data to the top of the %stack.
 167      *  @param  x  Data to be added.
 168      *
 169      *  This is a typical %stack operation.  The function creates an element at
 170      *  the top of the %stack and assigns the given data to it.
 171      *  The time complexity of the operation depends on the underlying
 172      *  sequence.
 173     */
 174     void
 175     push(const value_type& __x) { c.push_back(__x); }
 176
 177     /**
 178      *  @brief  Removes first element.
 179      *
 180      *  This is a typical %stack operation.  It shrinks the %stack by one.
 181      *  The time complexity of the operation depends on the underlying
 182      *  sequence.
 183      *
 184      *  Note that no data is returned, and if the first element's data is
 185      *  needed, it should be retrieved before pop() is called.
 186     */
 187     void
 188     pop() { c.pop_back(); }
 189   };
 190
 191
 192   /**
 193    *  @brief  Stack equality comparison.
 194    *  @param  x  A %stack.
 195    *  @param  y  A %stack of the same type as @a x.
 196    *  @return  True iff the size and elements of the stacks are equal.
 197    *
 198    *  This is an equivalence relation.  Complexity and semantics depend on the
 199    *  underlying sequence type, but the expected rules are:  this relation is
 200    *  linear in the size of the sequences, and stacks are considered equivalent
 201    *  if their sequences compare equal.
 202   */
 203   template <typename _Tp, typename _Seq>
 204     inline bool
 205     operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 206     { return __x.c == __y.c; }
 207
 208   /**
 209    *  @brief  Stack ordering relation.
 210    *  @param  x  A %stack.
 211    *  @param  y  A %stack of the same type as @a x.
 212    *  @return  True iff @a x is lexicographically less than @a y.
 213    *
 214    *  This is an total ordering relation.  Complexity and semantics depend on
 215    *  the underlying sequence type, but the expected rules are:  this relation
 216    *  is linear in the size of the sequences, the elements must be comparable
 217    *  with @c <, and std::lexicographical_compare() is usually used to make the
 218    *  determination.
 219   */
 220   template <typename _Tp, typename _Seq>
 221     inline bool
 222     operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 223     { return __x.c < __y.c; }
 224
 225   /// Based on operator==
 226   template <typename _Tp, typename _Seq>
 227     inline bool
 228     operator!=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 229     { return !(__x == __y); }
 230
 231   /// Based on operator<
 232   template <typename _Tp, typename _Seq>
 233     inline bool
 234     operator>(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 235     { return __y < __x; }
 236
 237   /// Based on operator<
 238   template <typename _Tp, typename _Seq>
 239     inline bool
 240     operator<=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 241     { return !(__y < __x); }
 242
 243   /// Based on operator<
 244   template <typename _Tp, typename _Seq>
 245     inline bool
 246     operator>=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
 247     { return !(__x < __y); }
 248 } // namespace std
 249
 250 #endif /* _STACK_H */