165 lines
6.6 KiB
C++
165 lines
6.6 KiB
C++
// Types used in iterator implementation -*- C++ -*-
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// Copyright (C) 2001, 2002 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996-1998
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_iterator_base_types.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*
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* This file contains all of the general iterator-related utility types,
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* such as iterator_traits and struct iterator.
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*/
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#ifndef __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H
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#define __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H
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#pragma GCC system_header
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namespace std
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{
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/** @{
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* @defgroup iterator_tags Iterator Tags
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* These are empty types, used to distinguish different iterators. The
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* distinction is not made by what they contain, but simply by what they
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* are. Different underlying algorithms can then be used based on the
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* different operations supporetd by different iterator types.
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*/
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/// Marking input iterators.
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struct input_iterator_tag {};
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/// Marking output iterators.
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struct output_iterator_tag {};
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/// Forward iterators support a superset of input iterator operations.
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struct forward_iterator_tag : public input_iterator_tag {};
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/// Bidirectional iterators support a superset of forward iterator operations.
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struct bidirectional_iterator_tag : public forward_iterator_tag {};
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/// Random-access iterators support a superset of bidirectional iterator operations.
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struct random_access_iterator_tag : public bidirectional_iterator_tag {};
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//@}
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/**
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* @brief Common %iterator class.
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*
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* This class does nothing but define nested typedefs. %Iterator classes
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* can inherit from this class to save some work. The typedefs are then
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* used in specializations and overloading.
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*
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* In particular, there are no default implementations of requirements
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* such as @c operator++ and the like. (How could there be?)
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*/
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template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
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typename _Pointer = _Tp*, typename _Reference = _Tp&>
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struct iterator
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{
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/// One of the @link iterator_tags tag types@endlink.
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typedef _Category iterator_category;
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/// The type "pointed to" by the iterator.
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typedef _Tp value_type;
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/// Distance between iterators is represented as this type.
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typedef _Distance difference_type;
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/// This type represents a pointer-to-value_type.
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typedef _Pointer pointer;
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/// This type represents a reference-to-value_type.
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typedef _Reference reference;
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};
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/**
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* This class does nothing but define nested typedefs. The general
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* version simply "forwards" the nested typedefs from the Iterator
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* argument. Specialized versions for pointers and pointers-to-const
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* provide tighter, more correct semantics.
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*/
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template<typename _Iterator>
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struct iterator_traits {
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typedef typename _Iterator::iterator_category iterator_category;
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typedef typename _Iterator::value_type value_type;
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typedef typename _Iterator::difference_type difference_type;
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typedef typename _Iterator::pointer pointer;
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typedef typename _Iterator::reference reference;
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};
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template<typename _Tp>
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struct iterator_traits<_Tp*> {
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typedef random_access_iterator_tag iterator_category;
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typedef _Tp value_type;
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typedef ptrdiff_t difference_type;
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typedef _Tp* pointer;
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typedef _Tp& reference;
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};
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template<typename _Tp>
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struct iterator_traits<const _Tp*> {
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typedef random_access_iterator_tag iterator_category;
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typedef _Tp value_type;
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typedef ptrdiff_t difference_type;
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typedef const _Tp* pointer;
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typedef const _Tp& reference;
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};
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/**
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* @if maint
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* This function is not a part of the C++ standard but is syntactic
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* sugar for internal library use only.
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* @endif
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*/
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template<typename _Iter>
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inline typename iterator_traits<_Iter>::iterator_category
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__iterator_category(const _Iter&)
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{ return typename iterator_traits<_Iter>::iterator_category(); }
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} // namespace std
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#endif /* __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H */
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