// Stack implementation -*- C++ -*-

// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/* NOTE: This is an internal header file, included by other STL headers.
 *   You should not attempt to use it directly.
 */

#ifndef __SGI_STL_INTERNAL_STACK_H
#define __SGI_STL_INTERNAL_STACK_H

#include <bits/concept_check.h>

namespace std
{

// Forward declarations of operators == and <, needed for friend declaration.

template <class _Tp, 
          class _Sequence = deque<_Tp> >
class stack;

template <class _Tp, class _Seq>
bool operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);

template <class _Tp, class _Seq>
bool operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);


template <class _Tp, class _Sequence>
class stack
{
  // concept requirements
  __glibcpp_class_requires(_Tp, _SGIAssignableConcept);
  __glibcpp_class_requires(_Sequence, _BackInsertionSequenceConcept);
  typedef typename _Sequence::value_type _Sequence_value_type;
  __glibcpp_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept);

  template <class _Tp1, class _Seq1>
  friend bool operator== (const stack<_Tp1, _Seq1>&,
                          const stack<_Tp1, _Seq1>&);
  template <class _Tp1, class _Seq1>
  friend bool operator< (const stack<_Tp1, _Seq1>&,
                         const stack<_Tp1, _Seq1>&);
public:
  typedef typename _Sequence::value_type      value_type;
  typedef typename _Sequence::size_type       size_type;
  typedef          _Sequence                  container_type;

  typedef typename _Sequence::reference       reference;
  typedef typename _Sequence::const_reference const_reference;
protected:
  _Sequence c;
public:
  stack() : c() {}
  explicit stack(const _Sequence& __s) : c(__s) {}

  bool empty() const { return c.empty(); }
  size_type size() const { return c.size(); }
  reference top() { return c.back(); }
  const_reference top() const { return c.back(); }
  void push(const value_type& __x) { c.push_back(__x); }
  void pop() { c.pop_back(); }
};

template <class _Tp, class _Seq>
bool operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return __x.c == __y.c;
}

template <class _Tp, class _Seq>
bool operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return __x.c < __y.c;
}

template <class _Tp, class _Seq>
bool operator!=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return !(__x == __y);
}

template <class _Tp, class _Seq>
bool operator>(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return __y < __x;
}

template <class _Tp, class _Seq>
bool operator<=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return !(__y < __x);
}

template <class _Tp, class _Seq>
bool operator>=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y)
{
  return !(__x < __y);
}

} // namespace std

#endif /* __SGI_STL_INTERNAL_STACK_H */

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// mode:C++
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