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

   1 // Stack implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  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 #include <debug/debug.h>
  66
  67 _GLIBCXX_BEGIN_NAMESPACE(std)
  68
  69   // Forward declarations of operators == and <, needed for friend
  70   // declaration.
  71   template<typename _Tp, typename _Sequence = deque<_Tp> >
  72     class stack;
  73
  74   template<typename _Tp, typename _Seq>
  75     inline bool
  76     operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);
  77
  78   template<typename _Tp, typename _Seq>
  79     inline bool
  80     operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);
  81
  82   /**
  83    *  @brief  A standard container giving FILO behavior.
  84    *
  85    *  @ingroup Containers
  86    *  @ingroup Sequences
  87    *
  88    *  Meets many of the requirements of a
  89    *  <a href="tables.html#65">container</a>,
  90    *  but does not define anything to do with iterators.  Very few of the
  91    *  other standard container interfaces are defined.
  92    *
  93    *  This is not a true container, but an @e adaptor.  It holds
  94    *  another container, and provides a wrapper interface to that
  95    *  container.  The wrapper is what enforces strict
  96    *  first-in-last-out %stack behavior.
  97    *
  98    *  The second template parameter defines the type of the underlying
  99    *  sequence/container.  It defaults to std::deque, but it can be
 100    *  any type that supports @c back, @c push_back, and @c pop_front,
 101    *  such as std::list, std::vector, or an appropriate user-defined
 102    *  type.
 103    *
 104    *  Members not found in "normal" containers are @c container_type,
 105    *  which is a typedef for the second Sequence parameter, and @c
 106    *  push, @c pop, and @c top, which are standard %stack/FILO
 107    *  operations.
 108   */
 109   template<typename _Tp, typename _Sequence>
 110     class stack
 111     {
 112       // concept requirements
 113       typedef typename _Sequence::value_type _Sequence_value_type;
 114       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
 115       __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
 116       __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
 117
 118       template<typename _Tp1, typename _Seq1>
 119         friend bool
 120         operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
 121
 122       template<typename _Tp1, typename _Seq1>
 123         friend bool
 124         operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
 125
 126     public:
 127       typedef typename _Sequence::value_type                value_type;
 128       typedef typename _Sequence::reference                 reference;
 129       typedef typename _Sequence::const_reference           const_reference;
 130       typedef typename _Sequence::size_type                 size_type;
 131       typedef          _Sequence                            container_type;
 132
 133     protected:
 134       //  See queue::c for notes on this name.
 135       _Sequence c;
 136
 137     public:
 138       // XXX removed old def ctor, added def arg to this one to match 14882
 139       /**
 140        *  @brief  Default constructor creates no elements.
 141        */
 142       explicit
 143       stack(const _Sequence& __c = _Sequence())
 144       : c(__c) {}
 145
 146       /**
 147        *  Returns true if the %stack is empty.
 148        */
 149       bool
 150       empty() const
 151       { return c.empty(); }
 152
 153       /**  Returns the number of elements in the %stack.  */
 154       size_type
 155       size() const
 156       { return c.size(); }
 157
 158       /**
 159        *  Returns a read/write reference to the data at the first
 160        *  element of the %stack.
 161        */
 162       reference
 163       top()
 164       {
 165         __glibcxx_requires_nonempty();
 166         return c.back();
 167       }
 168
 169       /**
 170        *  Returns a read-only (constant) reference to the data at the first
 171        *  element of the %stack.
 172        */
 173       const_reference
 174       top() const
 175       {
 176         __glibcxx_requires_nonempty();
 177         return c.back();
 178       }
 179
 180       /**
 181        *  @brief  Add data to the top of the %stack.
 182        *  @param  x  Data to be added.
 183        *
 184        *  This is a typical %stack operation.  The function creates an
 185        *  element at the top of the %stack and assigns the given data
 186        *  to it.  The time complexity of the operation depends on the
 187        *  underlying sequence.
 188        */
 189       void
 190       push(const value_type& __x)
 191       { c.push_back(__x); }
 192
 193       /**
 194        *  @brief  Removes first element.
 195        *
 196        *  This is a typical %stack operation.  It shrinks the %stack
 197        *  by one.  The time complexity of the operation depends on the
 198        *  underlying sequence.
 199        *
 200        *  Note that no data is returned, and if the first element's
 201        *  data is needed, it should be retrieved before pop() is
 202        *  called.
 203        */
 204       void
 205       pop()
 206       {
 207         __glibcxx_requires_nonempty();
 208         c.pop_back();
 209       }
 210     };
 211
 212   /**
 213    *  @brief  Stack equality comparison.
 214    *  @param  x  A %stack.
 215    *  @param  y  A %stack of the same type as @a x.
 216    *  @return  True iff the size and elements of the stacks are equal.
 217    *
 218    *  This is an equivalence relation.  Complexity and semantics
 219    *  depend on the underlying sequence type, but the expected rules
 220    *  are: this relation is linear in the size of the sequences, and
 221    *  stacks are considered equivalent if their sequences compare
 222    *  equal.
 223   */
 224   template<typename _Tp, typename _Seq>
 225     inline bool
 226     operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 227     { return __x.c == __y.c; }
 228
 229   /**
 230    *  @brief  Stack ordering relation.
 231    *  @param  x  A %stack.
 232    *  @param  y  A %stack of the same type as @a x.
 233    *  @return  True iff @a x is lexicographically less than @a y.
 234    *
 235    *  This is an total ordering relation.  Complexity and semantics
 236    *  depend on the underlying sequence type, but the expected rules
 237    *  are: this relation is linear in the size of the sequences, the
 238    *  elements must be comparable with @c <, and
 239    *  std::lexicographical_compare() is usually used to make the
 240    *  determination.
 241   */
 242   template<typename _Tp, typename _Seq>
 243     inline bool
 244     operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 245     { return __x.c < __y.c; }
 246
 247   /// Based on operator==
 248   template<typename _Tp, typename _Seq>
 249     inline bool
 250     operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 251     { return !(__x == __y); }
 252
 253   /// Based on operator<
 254   template<typename _Tp, typename _Seq>
 255     inline bool
 256     operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 257     { return __y < __x; }
 258
 259   /// Based on operator<
 260   template<typename _Tp, typename _Seq>
 261     inline bool
 262     operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 263     { return !(__y < __x); }
 264
 265   /// Based on operator<
 266   template<typename _Tp, typename _Seq>
 267     inline bool
 268     operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
 269     { return !(__x < __y); }
 270
 271 _GLIBCXX_END_NAMESPACE
 272
 273 #endif /* _STACK_H */