George Burgess IV | 33581f7 | 2019-01-23 13:26:47 -0800 | [diff] [blame] | 1 | // Types used in iterator implementation -*- C++ -*- |
| 2 | |
| 3 | // Copyright (C) 2001-2013 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 3, 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 | // Under Section 7 of GPL version 3, you are granted additional |
| 17 | // permissions described in the GCC Runtime Library Exception, version |
| 18 | // 3.1, as published by the Free Software Foundation. |
| 19 | |
| 20 | // You should have received a copy of the GNU General Public License and |
| 21 | // a copy of the GCC Runtime Library Exception along with this program; |
| 22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| 23 | // <http://www.gnu.org/licenses/>. |
| 24 | |
| 25 | /* |
| 26 | * |
| 27 | * Copyright (c) 1994 |
| 28 | * Hewlett-Packard Company |
| 29 | * |
| 30 | * Permission to use, copy, modify, distribute and sell this software |
| 31 | * and its documentation for any purpose is hereby granted without fee, |
| 32 | * provided that the above copyright notice appear in all copies and |
| 33 | * that both that copyright notice and this permission notice appear |
| 34 | * in supporting documentation. Hewlett-Packard Company makes no |
| 35 | * representations about the suitability of this software for any |
| 36 | * purpose. It is provided "as is" without express or implied warranty. |
| 37 | * |
| 38 | * |
| 39 | * Copyright (c) 1996-1998 |
| 40 | * Silicon Graphics Computer Systems, Inc. |
| 41 | * |
| 42 | * Permission to use, copy, modify, distribute and sell this software |
| 43 | * and its documentation for any purpose is hereby granted without fee, |
| 44 | * provided that the above copyright notice appear in all copies and |
| 45 | * that both that copyright notice and this permission notice appear |
| 46 | * in supporting documentation. Silicon Graphics makes no |
| 47 | * representations about the suitability of this software for any |
| 48 | * purpose. It is provided "as is" without express or implied warranty. |
| 49 | */ |
| 50 | |
| 51 | /** @file bits/stl_iterator_base_types.h |
| 52 | * This is an internal header file, included by other library headers. |
| 53 | * Do not attempt to use it directly. @headername{iterator} |
| 54 | * |
| 55 | * This file contains all of the general iterator-related utility types, |
| 56 | * such as iterator_traits and struct iterator. |
| 57 | */ |
| 58 | |
| 59 | #ifndef _STL_ITERATOR_BASE_TYPES_H |
| 60 | #define _STL_ITERATOR_BASE_TYPES_H 1 |
| 61 | |
| 62 | #pragma GCC system_header |
| 63 | |
| 64 | #include <bits/c++config.h> |
| 65 | |
| 66 | #if __cplusplus >= 201103L |
| 67 | # include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE, is_convertible |
| 68 | #endif |
| 69 | |
| 70 | namespace std _GLIBCXX_VISIBILITY(default) |
| 71 | { |
| 72 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| 73 | |
| 74 | /** |
| 75 | * @defgroup iterators Iterators |
| 76 | * Abstractions for uniform iterating through various underlying types. |
| 77 | */ |
| 78 | //@{ |
| 79 | |
| 80 | /** |
| 81 | * @defgroup iterator_tags Iterator Tags |
| 82 | * These are empty types, used to distinguish different iterators. The |
| 83 | * distinction is not made by what they contain, but simply by what they |
| 84 | * are. Different underlying algorithms can then be used based on the |
| 85 | * different operations supported by different iterator types. |
| 86 | */ |
| 87 | //@{ |
| 88 | /// Marking input iterators. |
| 89 | struct input_iterator_tag { }; |
| 90 | |
| 91 | /// Marking output iterators. |
| 92 | struct output_iterator_tag { }; |
| 93 | |
| 94 | /// Forward iterators support a superset of input iterator operations. |
| 95 | struct forward_iterator_tag : public input_iterator_tag { }; |
| 96 | |
| 97 | /// Bidirectional iterators support a superset of forward iterator |
| 98 | /// operations. |
| 99 | struct bidirectional_iterator_tag : public forward_iterator_tag { }; |
| 100 | |
| 101 | /// Random-access iterators support a superset of bidirectional |
| 102 | /// iterator operations. |
| 103 | struct random_access_iterator_tag : public bidirectional_iterator_tag { }; |
| 104 | //@} |
| 105 | |
| 106 | /** |
| 107 | * @brief Common %iterator class. |
| 108 | * |
| 109 | * This class does nothing but define nested typedefs. %Iterator classes |
| 110 | * can inherit from this class to save some work. The typedefs are then |
| 111 | * used in specializations and overloading. |
| 112 | * |
| 113 | * In particular, there are no default implementations of requirements |
| 114 | * such as @c operator++ and the like. (How could there be?) |
| 115 | */ |
| 116 | template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, |
| 117 | typename _Pointer = _Tp*, typename _Reference = _Tp&> |
| 118 | struct iterator |
| 119 | { |
| 120 | /// One of the @link iterator_tags tag types@endlink. |
| 121 | typedef _Category iterator_category; |
| 122 | /// The type "pointed to" by the iterator. |
| 123 | typedef _Tp value_type; |
| 124 | /// Distance between iterators is represented as this type. |
| 125 | typedef _Distance difference_type; |
| 126 | /// This type represents a pointer-to-value_type. |
| 127 | typedef _Pointer pointer; |
| 128 | /// This type represents a reference-to-value_type. |
| 129 | typedef _Reference reference; |
| 130 | }; |
| 131 | |
| 132 | /** |
| 133 | * @brief Traits class for iterators. |
| 134 | * |
| 135 | * This class does nothing but define nested typedefs. The general |
| 136 | * version simply @a forwards the nested typedefs from the Iterator |
| 137 | * argument. Specialized versions for pointers and pointers-to-const |
| 138 | * provide tighter, more correct semantics. |
| 139 | */ |
| 140 | #if __cplusplus >= 201103L |
| 141 | |
| 142 | _GLIBCXX_HAS_NESTED_TYPE(iterator_category) |
| 143 | |
| 144 | template<typename _Iterator, |
| 145 | bool = __has_iterator_category<_Iterator>::value> |
| 146 | struct __iterator_traits { }; |
| 147 | |
| 148 | template<typename _Iterator> |
| 149 | struct __iterator_traits<_Iterator, true> |
| 150 | { |
| 151 | typedef typename _Iterator::iterator_category iterator_category; |
| 152 | typedef typename _Iterator::value_type value_type; |
| 153 | typedef typename _Iterator::difference_type difference_type; |
| 154 | typedef typename _Iterator::pointer pointer; |
| 155 | typedef typename _Iterator::reference reference; |
| 156 | }; |
| 157 | |
| 158 | template<typename _Iterator> |
| 159 | struct iterator_traits |
| 160 | : public __iterator_traits<_Iterator> { }; |
| 161 | #else |
| 162 | template<typename _Iterator> |
| 163 | struct iterator_traits |
| 164 | { |
| 165 | typedef typename _Iterator::iterator_category iterator_category; |
| 166 | typedef typename _Iterator::value_type value_type; |
| 167 | typedef typename _Iterator::difference_type difference_type; |
| 168 | typedef typename _Iterator::pointer pointer; |
| 169 | typedef typename _Iterator::reference reference; |
| 170 | }; |
| 171 | #endif |
| 172 | |
| 173 | /// Partial specialization for pointer types. |
| 174 | template<typename _Tp> |
| 175 | struct iterator_traits<_Tp*> |
| 176 | { |
| 177 | typedef random_access_iterator_tag iterator_category; |
| 178 | typedef _Tp value_type; |
| 179 | typedef ptrdiff_t difference_type; |
| 180 | typedef _Tp* pointer; |
| 181 | typedef _Tp& reference; |
| 182 | }; |
| 183 | |
| 184 | /// Partial specialization for const pointer types. |
| 185 | template<typename _Tp> |
| 186 | struct iterator_traits<const _Tp*> |
| 187 | { |
| 188 | typedef random_access_iterator_tag iterator_category; |
| 189 | typedef _Tp value_type; |
| 190 | typedef ptrdiff_t difference_type; |
| 191 | typedef const _Tp* pointer; |
| 192 | typedef const _Tp& reference; |
| 193 | }; |
| 194 | |
| 195 | /** |
| 196 | * This function is not a part of the C++ standard but is syntactic |
| 197 | * sugar for internal library use only. |
| 198 | */ |
| 199 | template<typename _Iter> |
| 200 | inline typename iterator_traits<_Iter>::iterator_category |
| 201 | __iterator_category(const _Iter&) |
| 202 | { return typename iterator_traits<_Iter>::iterator_category(); } |
| 203 | |
| 204 | //@} |
| 205 | |
| 206 | // If _Iterator has a base returns it otherwise _Iterator is returned |
| 207 | // untouched |
| 208 | template<typename _Iterator, bool _HasBase> |
| 209 | struct _Iter_base |
| 210 | { |
| 211 | typedef _Iterator iterator_type; |
| 212 | static iterator_type _S_base(_Iterator __it) |
| 213 | { return __it; } |
| 214 | }; |
| 215 | |
| 216 | template<typename _Iterator> |
| 217 | struct _Iter_base<_Iterator, true> |
| 218 | { |
| 219 | typedef typename _Iterator::iterator_type iterator_type; |
| 220 | static iterator_type _S_base(_Iterator __it) |
| 221 | { return __it.base(); } |
| 222 | }; |
| 223 | |
| 224 | #if __cplusplus >= 201103L |
| 225 | template<typename _InIter> |
| 226 | using _RequireInputIter = typename |
| 227 | enable_if<is_convertible<typename |
| 228 | iterator_traits<_InIter>::iterator_category, |
| 229 | input_iterator_tag>::value>::type; |
| 230 | #endif |
| 231 | |
| 232 | _GLIBCXX_END_NAMESPACE_VERSION |
| 233 | } // namespace |
| 234 | |
| 235 | #endif /* _STL_ITERATOR_BASE_TYPES_H */ |
| 236 | |