00001 // Types used in iterator implementation -*- C++ -*- 00002 00003 // Copyright (C) 2001, 2002 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 2, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // You should have received a copy of the GNU General Public License along 00017 // with this library; see the file COPYING. If not, write to the Free 00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 00019 // USA. 00020 00021 // As a special exception, you may use this file as part of a free software 00022 // library without restriction. Specifically, if other files instantiate 00023 // templates or use macros or inline functions from this file, or you compile 00024 // this file and link it with other files to produce an executable, this 00025 // file does not by itself cause the resulting executable to be covered by 00026 // the GNU General Public License. This exception does not however 00027 // invalidate any other reasons why the executable file might be covered by 00028 // the GNU General Public License. 00029 00030 /* 00031 * 00032 * Copyright (c) 1994 00033 * Hewlett-Packard Company 00034 * 00035 * Permission to use, copy, modify, distribute and sell this software 00036 * and its documentation for any purpose is hereby granted without fee, 00037 * provided that the above copyright notice appear in all copies and 00038 * that both that copyright notice and this permission notice appear 00039 * in supporting documentation. Hewlett-Packard Company makes no 00040 * representations about the suitability of this software for any 00041 * purpose. It is provided "as is" without express or implied warranty. 00042 * 00043 * 00044 * Copyright (c) 1996-1998 00045 * Silicon Graphics Computer Systems, Inc. 00046 * 00047 * Permission to use, copy, modify, distribute and sell this software 00048 * and its documentation for any purpose is hereby granted without fee, 00049 * provided that the above copyright notice appear in all copies and 00050 * that both that copyright notice and this permission notice appear 00051 * in supporting documentation. Silicon Graphics makes no 00052 * representations about the suitability of this software for any 00053 * purpose. It is provided "as is" without express or implied warranty. 00054 */ 00055 00056 /** @file stl_iterator_base_types.h 00057 * This is an internal header file, included by other library headers. 00058 * You should not attempt to use it directly. 00059 * 00060 * This file contains all of the general iterator-related utility types, 00061 * such as iterator_traits and struct iterator. 00062 */ 00063 00064 #ifndef __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H 00065 #define __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H 00066 00067 #pragma GCC system_header 00068 00069 namespace std 00070 { 00071 //@{ 00072 /** 00073 * @defgroup iterator_tags Iterator Tags 00074 * These are empty types, used to distinguish different iterators. The 00075 * distinction is not made by what they contain, but simply by what they 00076 * are. Different underlying algorithms can then be used based on the 00077 * different operations supporetd by different iterator types. 00078 */ 00079 /// Marking input iterators. 00080 struct input_iterator_tag {}; 00081 /// Marking output iterators. 00082 struct output_iterator_tag {}; 00083 /// Forward iterators support a superset of input iterator operations. 00084 struct forward_iterator_tag : public input_iterator_tag {}; 00085 /// Bidirectional iterators support a superset of forward iterator operations. 00086 struct bidirectional_iterator_tag : public forward_iterator_tag {}; 00087 /// Random-access iterators support a superset of bidirectional iterator operations. 00088 struct random_access_iterator_tag : public bidirectional_iterator_tag {}; 00089 //@} 00090 00091 00092 /** 00093 * @brief Common %iterator class. 00094 * 00095 * This class does nothing but define nested typedefs. %Iterator classes 00096 * can inherit from this class to save some work. The typedefs are then 00097 * used in specializations and overloading. 00098 * 00099 * In particular, there are no default implementations of requirements 00100 * such as @c operator++ and the like. (How could there be?) 00101 */ 00102 template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, 00103 typename _Pointer = _Tp*, typename _Reference = _Tp&> 00104 struct iterator 00105 { 00106 /// One of the @link iterator_tags tag types@endlink. 00107 typedef _Category iterator_category; 00108 /// The type "pointed to" by the iterator. 00109 typedef _Tp value_type; 00110 /// Distance between iterators is represented as this type. 00111 typedef _Distance difference_type; 00112 /// This type represents a pointer-to-value_type. 00113 typedef _Pointer pointer; 00114 /// This type represents a reference-to-value_type. 00115 typedef _Reference reference; 00116 }; 00117 00118 /** 00119 * This class does nothing but define nested typedefs. The general 00120 * version simply "forwards" the nested typedefs from the Iterator 00121 * argument. Specialized versions for pointers and pointers-to-const 00122 * provide tighter, more correct semantics. 00123 */ 00124 template<typename _Iterator> 00125 struct iterator_traits { 00126 typedef typename _Iterator::iterator_category iterator_category; 00127 typedef typename _Iterator::value_type value_type; 00128 typedef typename _Iterator::difference_type difference_type; 00129 typedef typename _Iterator::pointer pointer; 00130 typedef typename _Iterator::reference reference; 00131 }; 00132 00133 template<typename _Tp> 00134 struct iterator_traits<_Tp*> { 00135 typedef random_access_iterator_tag iterator_category; 00136 typedef _Tp value_type; 00137 typedef ptrdiff_t difference_type; 00138 typedef _Tp* pointer; 00139 typedef _Tp& reference; 00140 }; 00141 00142 template<typename _Tp> 00143 struct iterator_traits<const _Tp*> { 00144 typedef random_access_iterator_tag iterator_category; 00145 typedef _Tp value_type; 00146 typedef ptrdiff_t difference_type; 00147 typedef const _Tp* pointer; 00148 typedef const _Tp& reference; 00149 }; 00150 00151 /** 00152 * @if maint 00153 * This function is not a part of the C++ standard but is syntactic 00154 * sugar for internal library use only. 00155 * @endif 00156 */ 00157 template<typename _Iter> 00158 inline typename iterator_traits<_Iter>::iterator_category 00159 __iterator_category(const _Iter&) 00160 { return typename iterator_traits<_Iter>::iterator_category(); } 00161 00162 } // namespace std 00163 00164 #endif /* __GLIBCPP_INTERNAL_ITERATOR_BASE_TYPES_H */ 00165