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// Types used in iterator implementation -*- C++ -*-

// Copyright (C) 2001, 2002, 2004 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.

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// 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

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// 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

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// file does not by itself cause the resulting executable to be covered by

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// invalidate any other reasons why the executable file might be covered by

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/*

 *

 * 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) 1996-1998

 * 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.

 */

/** @file stl_iterator_base_types.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 *

 *  This file contains all of the general iterator-related utility types,

 *  such as iterator_traits and struct iterator.

 */

#ifndef _ITERATOR_BASE_TYPES_H

#define _ITERATOR_BASE_TYPES_H 1

#pragma GCC system_header

namespace std

{

  //@{

  /**

   *  @defgroup iterator_tags Iterator Tags

   *  These are empty types, used to distinguish different iterators.  The

   *  distinction is not made by what they contain, but simply by what they

   *  are.  Different underlying algorithms can then be used based on the

   *  different operations supporetd by different iterator types.

  */

  ///  Marking input iterators.

  struct input_iterator_tag {};

  ///  Marking output iterators.

  struct output_iterator_tag {};

  /// Forward iterators support a superset of input iterator operations.

  struct forward_iterator_tag : public input_iterator_tag {};

  /// Bidirectional iterators support a superset of forward iterator

  /// operations.

  struct bidirectional_iterator_tag : public forward_iterator_tag {};

  /// Random-access iterators support a superset of bidirectional iterator

  /// operations.

  struct random_access_iterator_tag : public bidirectional_iterator_tag {};

  //@}

  /**

   *  @brief  Common %iterator class.

   *

   *  This class does nothing but define nested typedefs.  %Iterator classes

   *  can inherit from this class to save some work.  The typedefs are then

   *  used in specializations and overloading.

   *

   *  In particular, there are no default implementations of requirements

   *  such as @c operator++ and the like.  (How could there be?)

  */

  template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,

           typename _Pointer = _Tp*, typename _Reference = _Tp&>

    struct iterator

    {

      /// One of the @link iterator_tags tag types@endlink.

      typedef _Category  iterator_category;

      /// The type "pointed to" by the iterator.

      typedef _Tp        value_type;

      /// Distance between iterators is represented as this type.

      typedef _Distance  difference_type;

      /// This type represents a pointer-to-value_type.

      typedef _Pointer   pointer;

      /// This type represents a reference-to-value_type.

      typedef _Reference reference;

    };

  /**

   *  This class does nothing but define nested typedefs.  The general

   *  version simply "forwards" the nested typedefs from the Iterator

   *  argument.  Specialized versions for pointers and pointers-to-const

   *  provide tighter, more correct semantics.

  */

  template<typename _Iterator>

    struct iterator_traits

    {

      typedef typename _Iterator::iterator_category iterator_category;

      typedef typename _Iterator::value_type        value_type;

      typedef typename _Iterator::difference_type   difference_type;

      typedef typename _Iterator::pointer           pointer;

      typedef typename _Iterator::reference         reference;

    };

  template<typename _Tp>

    struct iterator_traits<_Tp*>

    {

      typedef random_access_iterator_tag iterator_category;

      typedef _Tp                         value_type;

      typedef ptrdiff_t                   difference_type;

      typedef _Tp*                        pointer;

      typedef _Tp&                        reference;

    };

  template<typename _Tp>

    struct iterator_traits<const _Tp*>

    {

      typedef random_access_iterator_tag iterator_category;

      typedef _Tp                         value_type;

      typedef ptrdiff_t                   difference_type;

      typedef const _Tp*                  pointer;

      typedef const _Tp&                  reference;

    };

  /**

   *  @if maint

   *  This function is not a part of the C++ standard but is syntactic

   *  sugar for internal library use only.

   *  @endif

  */

  template<typename _Iter>

    inline typename iterator_traits<_Iter>::iterator_category

    __iterator_category(const _Iter&)

    { return typename iterator_traits<_Iter>::iterator_category(); }

} // namespace std

#endif /* _ITERATOR_BASE_TYPES_H */