00001 // Types used in iterator implementation -*- C++ -*- 00002 00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 3, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // Under Section 7 of GPL version 3, you are granted additional 00018 // permissions described in the GCC Runtime Library Exception, version 00019 // 3.1, as published by the Free Software Foundation. 00020 00021 // You should have received a copy of the GNU General Public License and 00022 // a copy of the GCC Runtime Library Exception along with this program; 00023 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00024 // <http://www.gnu.org/licenses/>. 00025 00026 /* 00027 * 00028 * Copyright (c) 1994 00029 * Hewlett-Packard Company 00030 * 00031 * Permission to use, copy, modify, distribute and sell this software 00032 * and its documentation for any purpose is hereby granted without fee, 00033 * provided that the above copyright notice appear in all copies and 00034 * that both that copyright notice and this permission notice appear 00035 * in supporting documentation. Hewlett-Packard Company makes no 00036 * representations about the suitability of this software for any 00037 * purpose. It is provided "as is" without express or implied warranty. 00038 * 00039 * 00040 * Copyright (c) 1996-1998 00041 * Silicon Graphics Computer Systems, Inc. 00042 * 00043 * Permission to use, copy, modify, distribute and sell this software 00044 * and its documentation for any purpose is hereby granted without fee, 00045 * provided that the above copyright notice appear in all copies and 00046 * that both that copyright notice and this permission notice appear 00047 * in supporting documentation. Silicon Graphics makes no 00048 * representations about the suitability of this software for any 00049 * purpose. It is provided "as is" without express or implied warranty. 00050 */ 00051 00052 /** @file stl_iterator_base_types.h 00053 * This is an internal header file, included by other library headers. 00054 * You should not attempt to use it directly. 00055 * 00056 * This file contains all of the general iterator-related utility types, 00057 * such as iterator_traits and struct iterator. 00058 */ 00059 00060 #ifndef _STL_ITERATOR_BASE_TYPES_H 00061 #define _STL_ITERATOR_BASE_TYPES_H 1 00062 00063 #pragma GCC system_header 00064 00065 #include <bits/c++config.h> 00066 00067 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00068 # include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE 00069 #endif 00070 00071 _GLIBCXX_BEGIN_NAMESPACE(std) 00072 00073 /** 00074 * @defgroup iterators Iterators 00075 * Abstractions for uniform iterating through various underlying types. 00076 */ 00077 //@{ 00078 00079 /** 00080 * @defgroup iterator_tags Iterator Tags 00081 * These are empty types, used to distinguish different iterators. The 00082 * distinction is not made by what they contain, but simply by what they 00083 * are. Different underlying algorithms can then be used based on the 00084 * different operations supported by different iterator types. 00085 */ 00086 //@{ 00087 /// Marking input iterators. 00088 struct input_iterator_tag { }; 00089 00090 /// Marking output iterators. 00091 struct output_iterator_tag { }; 00092 00093 /// Forward iterators support a superset of input iterator operations. 00094 struct forward_iterator_tag : public input_iterator_tag { }; 00095 00096 /// Bidirectional iterators support a superset of forward iterator 00097 /// operations. 00098 struct bidirectional_iterator_tag : public forward_iterator_tag { }; 00099 00100 /// Random-access iterators support a superset of bidirectional 00101 /// iterator operations. 00102 struct random_access_iterator_tag : public bidirectional_iterator_tag { }; 00103 //@} 00104 00105 /** 00106 * @brief Common %iterator class. 00107 * 00108 * This class does nothing but define nested typedefs. %Iterator classes 00109 * can inherit from this class to save some work. The typedefs are then 00110 * used in specializations and overloading. 00111 * 00112 * In particular, there are no default implementations of requirements 00113 * such as @c operator++ and the like. (How could there be?) 00114 */ 00115 template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, 00116 typename _Pointer = _Tp*, typename _Reference = _Tp&> 00117 struct iterator 00118 { 00119 /// One of the @link iterator_tags tag types@endlink. 00120 typedef _Category iterator_category; 00121 /// The type "pointed to" by the iterator. 00122 typedef _Tp value_type; 00123 /// Distance between iterators is represented as this type. 00124 typedef _Distance difference_type; 00125 /// This type represents a pointer-to-value_type. 00126 typedef _Pointer pointer; 00127 /// This type represents a reference-to-value_type. 00128 typedef _Reference reference; 00129 }; 00130 00131 /** 00132 * @brief Traits class for iterators. 00133 * 00134 * This class does nothing but define nested typedefs. The general 00135 * version simply @a forwards the nested typedefs from the Iterator 00136 * argument. Specialized versions for pointers and pointers-to-const 00137 * provide tighter, more correct semantics. 00138 */ 00139 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00140 00141 _GLIBCXX_HAS_NESTED_TYPE(iterator_category) 00142 00143 template<typename _Iterator, 00144 bool = __has_iterator_category<_Iterator>::value> 00145 struct __iterator_traits { }; 00146 00147 template<typename _Iterator> 00148 struct __iterator_traits<_Iterator, true> 00149 { 00150 typedef typename _Iterator::iterator_category iterator_category; 00151 typedef typename _Iterator::value_type value_type; 00152 typedef typename _Iterator::difference_type difference_type; 00153 typedef typename _Iterator::pointer pointer; 00154 typedef typename _Iterator::reference reference; 00155 }; 00156 00157 template<typename _Iterator> 00158 struct iterator_traits 00159 : public __iterator_traits<_Iterator> { }; 00160 #else 00161 template<typename _Iterator> 00162 struct iterator_traits 00163 { 00164 typedef typename _Iterator::iterator_category iterator_category; 00165 typedef typename _Iterator::value_type value_type; 00166 typedef typename _Iterator::difference_type difference_type; 00167 typedef typename _Iterator::pointer pointer; 00168 typedef typename _Iterator::reference reference; 00169 }; 00170 #endif 00171 00172 /// Partial specialization for pointer types. 00173 template<typename _Tp> 00174 struct iterator_traits<_Tp*> 00175 { 00176 typedef random_access_iterator_tag iterator_category; 00177 typedef _Tp value_type; 00178 typedef ptrdiff_t difference_type; 00179 typedef _Tp* pointer; 00180 typedef _Tp& reference; 00181 }; 00182 00183 /// Partial specialization for const pointer types. 00184 template<typename _Tp> 00185 struct iterator_traits<const _Tp*> 00186 { 00187 typedef random_access_iterator_tag iterator_category; 00188 typedef _Tp value_type; 00189 typedef ptrdiff_t difference_type; 00190 typedef const _Tp* pointer; 00191 typedef const _Tp& reference; 00192 }; 00193 00194 /** 00195 * This function is not a part of the C++ standard but is syntactic 00196 * sugar for internal library use only. 00197 */ 00198 template<typename _Iter> 00199 inline typename iterator_traits<_Iter>::iterator_category 00200 __iterator_category(const _Iter&) 00201 { return typename iterator_traits<_Iter>::iterator_category(); } 00202 00203 //@} 00204 00205 // If _Iterator has a base returns it otherwise _Iterator is returned 00206 // untouched 00207 template<typename _Iterator, bool _HasBase> 00208 struct _Iter_base 00209 { 00210 typedef _Iterator iterator_type; 00211 static iterator_type _S_base(_Iterator __it) 00212 { return __it; } 00213 }; 00214 00215 template<typename _Iterator> 00216 struct _Iter_base<_Iterator, true> 00217 { 00218 typedef typename _Iterator::iterator_type iterator_type; 00219 static iterator_type _S_base(_Iterator __it) 00220 { return __it.base(); } 00221 }; 00222 00223 _GLIBCXX_END_NAMESPACE 00224 00225 #endif /* _STL_ITERATOR_BASE_TYPES_H */ 00226