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// -*- C++ -*-

// Copyright (C) 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// 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) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice and

// this permission notice appear in supporting documentation. None of

// the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied warranty.

/**

 * @file extract_key_example.cpp

 * An example of extracting keys from values.

 */

// For various associative containers

#include <ext/pb_assoc/assoc_cntnr.hpp>

// For binary_function

#include <functional>

// For assert

#include <cassert>

using namespace std;

/*

 * A functor for checking whether two tables share exactly the

 *      same keys.

 */

template<class Cntnr0, class Cntnr1>

struct compare_keys : public std::binary_function<

  Cntnr0,

  Cntnr1,

  bool>

{

  bool

  operator()(const Cntnr0& r_c0, const Cntnr1& r_c1)

  {

    // If the tables' sizes differ, they cannot share the same keys.

    if (r_c0.size() != r_c1.size())

      return (false);

    // Loop and check each key.

    for (typename Cntnr0::const_iterator it = r_c0.begin();

         it != r_c0.end(); ++it)

      if (r_c1.find(r_c0.extract_key(*it)) == r_c1.end())

        return (false);

    return (true);

  };

};

template<class Cntnr0, class Cntnr1>

bool

key_equiv(const Cntnr0& r_c0, const Cntnr1& r_c1)

{

  return (compare_keys<Cntnr0, Cntnr1>()(r_c0, r_c1));

}

int

main()

{

  /*

   * A collision-chaining hash-based associative container

   *    mapping integers to characters.

   */

  pb_assoc::cc_hash_assoc_cntnr<int, char> c0;

  /*

   * A red-black tree-based associative container

   *    mapping integers to doubles.

   */

  pb_assoc::tree_assoc_cntnr<int, double> c1;

  /*

   * A list-update associative container storing integers.

   */

  pb_assoc::lu_assoc_cntnr<int, pb_assoc::null_data_type> c2;

  /*

   * Since the objects are initially empty, they

   *    should all be equivalent.

   **/

  assert(key_equiv(c0, c0));

  assert(key_equiv(c0, c1));

  assert(key_equiv(c0, c2));

  // Insert some entries.

  c0.insert(std::make_pair(1, 'a'));

  c1.insert(std::make_pair(1, 'a'));

  c1.insert(std::make_pair(2, 'b'));

  c2.insert(1);

  // Only c0 and c2 contain a single key with value 1.

  assert(key_equiv(c0, c0));

  assert(key_equiv(c0, c1) == false);

  assert(key_equiv(c0, c2));

}