00001 // Types used in iterator implementation -*- C++ -*- 00002 00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 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 2, 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 // You should have received a copy of the GNU General Public License along 00018 // with this library; see the file COPYING. If not, write to the Free 00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 00020 // USA. 00021 00022 // As a special exception, you may use this file as part of a free software 00023 // library without restriction. Specifically, if other files instantiate 00024 // templates or use macros or inline functions from this file, or you compile 00025 // this file and link it with other files to produce an executable, this 00026 // file does not by itself cause the resulting executable to be covered by 00027 // the GNU General Public License. This exception does not however 00028 // invalidate any other reasons why the executable file might be covered by 00029 // the GNU General Public License. 00030 00031 /* 00032 * 00033 * Copyright (c) 1994 00034 * Hewlett-Packard Company 00035 * 00036 * Permission to use, copy, modify, distribute and sell this software 00037 * and its documentation for any purpose is hereby granted without fee, 00038 * provided that the above copyright notice appear in all copies and 00039 * that both that copyright notice and this permission notice appear 00040 * in supporting documentation. Hewlett-Packard Company makes no 00041 * representations about the suitability of this software for any 00042 * purpose. It is provided "as is" without express or implied warranty. 00043 * 00044 * 00045 * Copyright (c) 1996-1998 00046 * Silicon Graphics Computer Systems, Inc. 00047 * 00048 * Permission to use, copy, modify, distribute and sell this software 00049 * and its documentation for any purpose is hereby granted without fee, 00050 * provided that the above copyright notice appear in all copies and 00051 * that both that copyright notice and this permission notice appear 00052 * in supporting documentation. Silicon Graphics makes no 00053 * representations about the suitability of this software for any 00054 * purpose. It is provided "as is" without express or implied warranty. 00055 */ 00056 00057 /** @file stl_iterator_base_types.h 00058 * This is an internal header file, included by other library headers. 00059 * You should not attempt to use it directly. 00060 * 00061 * This file contains all of the general iterator-related utility types, 00062 * such as iterator_traits and struct iterator. 00063 */ 00064 00065 #ifndef _STL_ITERATOR_BASE_TYPES_H 00066 #define _STL_ITERATOR_BASE_TYPES_H 1 00067 00068 #pragma GCC system_header 00069 00070 #include <bits/c++config.h> 00071 #include <cstddef> 00072 00073 _GLIBCXX_BEGIN_NAMESPACE(std) 00074 00075 //@{ 00076 /** 00077 * @defgroup iterator_tags Iterator Tags 00078 * These are empty types, used to distinguish different iterators. The 00079 * distinction is not made by what they contain, but simply by what they 00080 * are. Different underlying algorithms can then be used based on the 00081 * different operations supported by different iterator types. 00082 */ 00083 /// Marking input iterators. 00084 struct input_iterator_tag {}; 00085 /// Marking output iterators. 00086 struct output_iterator_tag {}; 00087 /// Forward iterators support a superset of input iterator operations. 00088 struct forward_iterator_tag : public input_iterator_tag {}; 00089 /// Bidirectional iterators support a superset of forward iterator 00090 /// operations. 00091 struct bidirectional_iterator_tag : public forward_iterator_tag {}; 00092 /// Random-access iterators support a superset of bidirectional iterator 00093 /// operations. 00094 struct random_access_iterator_tag : public bidirectional_iterator_tag {}; 00095 //@} 00096 00097 00098 /** 00099 * @brief Common %iterator class. 00100 * 00101 * This class does nothing but define nested typedefs. %Iterator classes 00102 * can inherit from this class to save some work. The typedefs are then 00103 * used in specializations and overloading. 00104 * 00105 * In particular, there are no default implementations of requirements 00106 * such as @c operator++ and the like. (How could there be?) 00107 */ 00108 template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t, 00109 typename _Pointer = _Tp*, typename _Reference = _Tp&> 00110 struct iterator 00111 { 00112 /// One of the @link iterator_tags tag types@endlink. 00113 typedef _Category iterator_category; 00114 /// The type "pointed to" by the iterator. 00115 typedef _Tp value_type; 00116 /// Distance between iterators is represented as this type. 00117 typedef _Distance difference_type; 00118 /// This type represents a pointer-to-value_type. 00119 typedef _Pointer pointer; 00120 /// This type represents a reference-to-value_type. 00121 typedef _Reference reference; 00122 }; 00123 00124 /** 00125 * This class does nothing but define nested typedefs. The general 00126 * version simply "forwards" the nested typedefs from the Iterator 00127 * argument. Specialized versions for pointers and pointers-to-const 00128 * provide tighter, more correct semantics. 00129 */ 00130 template<typename _Iterator> 00131 struct iterator_traits 00132 { 00133 typedef typename _Iterator::iterator_category iterator_category; 00134 typedef typename _Iterator::value_type value_type; 00135 typedef typename _Iterator::difference_type difference_type; 00136 typedef typename _Iterator::pointer pointer; 00137 typedef typename _Iterator::reference reference; 00138 }; 00139 00140 template<typename _Tp> 00141 struct iterator_traits<_Tp*> 00142 { 00143 typedef random_access_iterator_tag iterator_category; 00144 typedef _Tp value_type; 00145 typedef ptrdiff_t difference_type; 00146 typedef _Tp* pointer; 00147 typedef _Tp& reference; 00148 }; 00149 00150 template<typename _Tp> 00151 struct iterator_traits<const _Tp*> 00152 { 00153 typedef random_access_iterator_tag iterator_category; 00154 typedef _Tp value_type; 00155 typedef ptrdiff_t difference_type; 00156 typedef const _Tp* pointer; 00157 typedef const _Tp& reference; 00158 }; 00159 00160 /** 00161 * This function is not a part of the C++ standard but is syntactic 00162 * sugar for internal library use only. 00163 */ 00164 template<typename _Iter> 00165 inline typename iterator_traits<_Iter>::iterator_category 00166 __iterator_category(const _Iter&) 00167 { return typename iterator_traits<_Iter>::iterator_category(); } 00168 00169 _GLIBCXX_END_NAMESPACE 00170 00171 #endif /* _STL_ITERATOR_BASE_TYPES_H */ 00172