1// Types used in iterator implementation -*- C++ -*- 2 3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 4// Free Software Foundation, Inc. 5// 6// This file is part of the GNU ISO C++ Library. This library is free 7// software; you can redistribute it and/or modify it under the 8// terms of the GNU General Public License as published by the 9// Free Software Foundation; either version 3, or (at your option) 10// any later version. 11 12// This library is distributed in the hope that it will be useful, 13// but WITHOUT ANY WARRANTY; without even the implied warranty of 14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15// GNU General Public License for more details. 16 17// Under Section 7 of GPL version 3, you are granted additional 18// permissions described in the GCC Runtime Library Exception, version 19// 3.1, as published by the Free Software Foundation. 20 21// You should have received a copy of the GNU General Public License and 22// a copy of the GCC Runtime Library Exception along with this program; 23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24// <http://www.gnu.org/licenses/>. 25 26/* 27 * 28 * Copyright (c) 1994 29 * Hewlett-Packard Company 30 * 31 * Permission to use, copy, modify, distribute and sell this software 32 * and its documentation for any purpose is hereby granted without fee, 33 * provided that the above copyright notice appear in all copies and 34 * that both that copyright notice and this permission notice appear 35 * in supporting documentation. Hewlett-Packard Company makes no 36 * representations about the suitability of this software for any 37 * purpose. It is provided "as is" without express or implied warranty. 38 * 39 * 40 * Copyright (c) 1996-1998 41 * Silicon Graphics Computer Systems, Inc. 42 * 43 * Permission to use, copy, modify, distribute and sell this software 44 * and its documentation for any purpose is hereby granted without fee, 45 * provided that the above copyright notice appear in all copies and 46 * that both that copyright notice and this permission notice appear 47 * in supporting documentation. Silicon Graphics makes no 48 * representations about the suitability of this software for any 49 * purpose. It is provided "as is" without express or implied warranty. 50 */ 51 52/** @file stl_iterator_base_types.h 53 * This is an internal header file, included by other library headers. 54 * You should not attempt to use it directly. 55 * 56 * This file contains all of the general iterator-related utility types, 57 * such as iterator_traits and struct iterator. 58 */ 59 60#ifndef _STL_ITERATOR_BASE_TYPES_H 61#define _STL_ITERATOR_BASE_TYPES_H 1 62 63#pragma GCC system_header 64 65#include <bits/c++config.h> 66#include <cstddef> 67 68_GLIBCXX_BEGIN_NAMESPACE(std) 69 70 /** 71 * @defgroup iterators Iterators 72 * Abstractions for uniform iterating through various underlying types. 73 */ 74 //@{ 75 76 /** 77 * @defgroup iterator_tags Iterator Tags 78 * These are empty types, used to distinguish different iterators. The 79 * distinction is not made by what they contain, but simply by what they 80 * are. Different underlying algorithms can then be used based on the 81 * different operations supported by different iterator types. 82 */ 83 //@{ 84 /// Marking input iterators. 85 struct input_iterator_tag { }; 86 87 /// Marking output iterators. 88 struct output_iterator_tag { }; 89 90 /// Forward iterators support a superset of input iterator operations. 91 struct forward_iterator_tag : public input_iterator_tag { }; 92 93 /// Bidirectional iterators support a superset of forward iterator 94 /// operations. 95 struct bidirectional_iterator_tag : public forward_iterator_tag { }; 96 97 /// Random-access iterators support a superset of bidirectional 98 /// iterator operations. 99 struct random_access_iterator_tag : public bidirectional_iterator_tag { }; 100 //@} 101 102 /** 103 * @brief Common %iterator class. 104 * 105 * This class does nothing but define nested typedefs. %Iterator classes 106 * can inherit from this class to save some work. The typedefs are then 107 * used in specializations and overloading. 108 * 109 * In particular, there are no default implementations of requirements 110 * such as @c operator++ and the like. (How could there be?) 111 */ 112 template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, 113 typename _Pointer = _Tp*, typename _Reference = _Tp&> 114 struct iterator 115 { 116 /// One of the @link iterator_tags tag types@endlink. 117 typedef _Category iterator_category; 118 /// The type "pointed to" by the iterator. 119 typedef _Tp value_type; 120 /// Distance between iterators is represented as this type. 121 typedef _Distance difference_type; 122 /// This type represents a pointer-to-value_type. 123 typedef _Pointer pointer; 124 /// This type represents a reference-to-value_type. 125 typedef _Reference reference; 126 }; 127 128 /** 129 * @brief Traits class for iterators. 130 * 131 * This class does nothing but define nested typedefs. The general 132 * version simply @a forwards the nested typedefs from the Iterator 133 * argument. Specialized versions for pointers and pointers-to-const 134 * provide tighter, more correct semantics. 135 */ 136 template<typename _Iterator> 137 struct iterator_traits 138 { 139 typedef typename _Iterator::iterator_category iterator_category; 140 typedef typename _Iterator::value_type value_type; 141 typedef typename _Iterator::difference_type difference_type; 142 typedef typename _Iterator::pointer pointer; 143 typedef typename _Iterator::reference reference; 144 }; 145 146 /// Partial specialization for pointer types. 147 template<typename _Tp> 148 struct iterator_traits<_Tp*> 149 { 150 typedef random_access_iterator_tag iterator_category; 151 typedef _Tp value_type; 152 typedef ptrdiff_t difference_type; 153 typedef _Tp* pointer; 154 typedef _Tp& reference; 155 }; 156 157 /// Partial specialization for const pointer types. 158 template<typename _Tp> 159 struct iterator_traits<const _Tp*> 160 { 161 typedef random_access_iterator_tag iterator_category; 162 typedef _Tp value_type; 163 typedef ptrdiff_t difference_type; 164 typedef const _Tp* pointer; 165 typedef const _Tp& reference; 166 }; 167 168 /** 169 * This function is not a part of the C++ standard but is syntactic 170 * sugar for internal library use only. 171 */ 172 template<typename _Iter> 173 inline typename iterator_traits<_Iter>::iterator_category 174 __iterator_category(const _Iter&) 175 { return typename iterator_traits<_Iter>::iterator_category(); } 176 177 //@} 178 179_GLIBCXX_END_NAMESPACE 180 181#endif /* _STL_ITERATOR_BASE_TYPES_H */ 182 183