1// Types used in iterator implementation -*- C++ -*- 2 3// Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc. 4// 5// This file is part of the GNU ISO C++ Library. This library is free 6// software; you can redistribute it and/or modify it under the 7// terms of the GNU General Public License as published by the 8// Free Software Foundation; either version 2, or (at your option) 9// any later version. 10 11// This library is distributed in the hope that it will be useful, 12// but WITHOUT ANY WARRANTY; without even the implied warranty of 13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14// GNU General Public License for more details. 15 16// You should have received a copy of the GNU General Public License along 17// with this library; see the file COPYING. If not, write to the Free 18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 19// USA. 20 21// As a special exception, you may use this file as part of a free software 22// library without restriction. Specifically, if other files instantiate 23// templates or use macros or inline functions from this file, or you compile 24// this file and link it with other files to produce an executable, this 25// file does not by itself cause the resulting executable to be covered by 26// the GNU General Public License. This exception does not however 27// invalidate any other reasons why the executable file might be covered by 28// the GNU General Public License. 29 30/* 31 * 32 * Copyright (c) 1994 33 * Hewlett-Packard Company 34 * 35 * Permission to use, copy, modify, distribute and sell this software 36 * and its documentation for any purpose is hereby granted without fee, 37 * provided that the above copyright notice appear in all copies and 38 * that both that copyright notice and this permission notice appear 39 * in supporting documentation. Hewlett-Packard Company makes no 40 * representations about the suitability of this software for any 41 * purpose. It is provided "as is" without express or implied warranty. 42 * 43 * 44 * Copyright (c) 1996-1998 45 * Silicon Graphics Computer Systems, Inc. 46 * 47 * Permission to use, copy, modify, distribute and sell this software 48 * and its documentation for any purpose is hereby granted without fee, 49 * provided that the above copyright notice appear in all copies and 50 * that both that copyright notice and this permission notice appear 51 * in supporting documentation. Silicon Graphics makes no 52 * representations about the suitability of this software for any 53 * purpose. It is provided "as is" without express or implied warranty. 54 */ 55 56/** @file stl_iterator_base_types.h 57 * This is an internal header file, included by other library headers. 58 * You should not attempt to use it directly. 59 * 60 * This file contains all of the general iterator-related utility types, 61 * such as iterator_traits and struct iterator. 62 */ 63 64#ifndef _ITERATOR_BASE_TYPES_H 65#define _ITERATOR_BASE_TYPES_H 1 66 67#pragma GCC system_header 68 69namespace std 70{ 71 //@{ 72 /** 73 * @defgroup iterator_tags Iterator Tags 74 * These are empty types, used to distinguish different iterators. The 75 * distinction is not made by what they contain, but simply by what they 76 * are. Different underlying algorithms can then be used based on the 77 * different operations supporetd by different iterator types. 78 */ 79 /// Marking input iterators. 80 struct input_iterator_tag {}; 81 /// Marking output iterators. 82 struct output_iterator_tag {}; 83 /// Forward iterators support a superset of input iterator operations. 84 struct forward_iterator_tag : public input_iterator_tag {}; 85 /// Bidirectional iterators support a superset of forward iterator 86 /// operations. 87 struct bidirectional_iterator_tag : public forward_iterator_tag {}; 88 /// Random-access iterators support a superset of bidirectional iterator 89 /// operations. 90 struct random_access_iterator_tag : public bidirectional_iterator_tag {}; 91 //@} 92 93 94 /** 95 * @brief Common %iterator class. 96 * 97 * This class does nothing but define nested typedefs. %Iterator classes 98 * can inherit from this class to save some work. The typedefs are then 99 * used in specializations and overloading. 100 * 101 * In particular, there are no default implementations of requirements 102 * such as @c operator++ and the like. (How could there be?) 103 */ 104 template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, 105 typename _Pointer = _Tp*, typename _Reference = _Tp&> 106 struct iterator 107 { 108 /// One of the @link iterator_tags tag types@endlink. 109 typedef _Category iterator_category; 110 /// The type "pointed to" by the iterator. 111 typedef _Tp value_type; 112 /// Distance between iterators is represented as this type. 113 typedef _Distance difference_type; 114 /// This type represents a pointer-to-value_type. 115 typedef _Pointer pointer; 116 /// This type represents a reference-to-value_type. 117 typedef _Reference reference; 118 }; 119 120 /** 121 * This class does nothing but define nested typedefs. The general 122 * version simply "forwards" the nested typedefs from the Iterator 123 * argument. Specialized versions for pointers and pointers-to-const 124 * provide tighter, more correct semantics. 125 */ 126 template<typename _Iterator> 127 struct iterator_traits 128 { 129 typedef typename _Iterator::iterator_category iterator_category; 130 typedef typename _Iterator::value_type value_type; 131 typedef typename _Iterator::difference_type difference_type; 132 typedef typename _Iterator::pointer pointer; 133 typedef typename _Iterator::reference reference; 134 }; 135 136 template<typename _Tp> 137 struct iterator_traits<_Tp*> 138 { 139 typedef random_access_iterator_tag iterator_category; 140 typedef _Tp value_type; 141 typedef ptrdiff_t difference_type; 142 typedef _Tp* pointer; 143 typedef _Tp& reference; 144 }; 145 146 template<typename _Tp> 147 struct iterator_traits<const _Tp*> 148 { 149 typedef random_access_iterator_tag iterator_category; 150 typedef _Tp value_type; 151 typedef ptrdiff_t difference_type; 152 typedef const _Tp* pointer; 153 typedef const _Tp& reference; 154 }; 155 156 /** 157 * @if maint 158 * This function is not a part of the C++ standard but is syntactic 159 * sugar for internal library use only. 160 * @endif 161 */ 162 template<typename _Iter> 163 inline typename iterator_traits<_Iter>::iterator_category 164 __iterator_category(const _Iter&) 165 { return typename iterator_traits<_Iter>::iterator_category(); } 166 167} // namespace std 168 169#endif /* _ITERATOR_BASE_TYPES_H */ 170 171