// 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. // 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) 1996-1998 * 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 */