1 // Pair implementation -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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) 1996,1997 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_pair.h 53 * This is an internal header file, included by other library headers. 54 * You should not attempt to use it directly. 55 */ 56 57 #ifndef _STL_PAIR_H 58 #define _STL_PAIR_H 1 59 60 #include <bits/move.h> // for std::move / std::forward, std::decay, and 61 // std::swap 62 63 _GLIBCXX_BEGIN_NAMESPACE(std) 64 65 /// pair holds two objects of arbitrary type. 66 template<class _T1, class _T2> 67 struct pair 68 { 69 typedef _T1 first_type; ///< @c first_type is the first bound type 70 typedef _T2 second_type; ///< @c second_type is the second bound type 71 72 _T1 first; ///< @c first is a copy of the first object 73 _T2 second; ///< @c second is a copy of the second object 74 75 // _GLIBCXX_RESOLVE_LIB_DEFECTS 76 // 265. std::pair::pair() effects overly restrictive 77 /** The default constructor creates @c first and @c second using their 78 * respective default constructors. */ 79 pair() 80 : first(), second() { } 81 82 /** Two objects may be passed to a @c pair constructor to be copied. */ 83 pair(const _T1& __a, const _T2& __b) 84 : first(__a), second(__b) { } 85 86 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 87 template<class _U1, class _U2> 88 pair(_U1&& __x, _U2&& __y) 89 : first(std::forward<_U1>(__x)), 90 second(std::forward<_U2>(__y)) { } 91 92 pair(pair&& __p) 93 : first(std::move(__p.first)), 94 second(std::move(__p.second)) { } 95 #endif 96 97 /** There is also a templated copy ctor for the @c pair class itself. */ 98 template<class _U1, class _U2> 99 pair(const pair<_U1, _U2>& __p) 100 : first(__p.first), 101 second(__p.second) { } 102 103 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 104 template<class _U1, class _U2> 105 pair(pair<_U1, _U2>&& __p) 106 : first(std::move(__p.first)), 107 second(std::move(__p.second)) { } 108 109 // http://gcc.gnu.org/ml/libstdc++/2007-08/msg00052.html 110 template<class _U1, class _Arg0, class... _Args> 111 pair(_U1&& __x, _Arg0&& __arg0, _Args&&... __args) 112 : first(std::forward<_U1>(__x)), 113 second(std::forward<_Arg0>(__arg0), 114 std::forward<_Args>(__args)...) { } 115 116 pair& 117 operator=(pair&& __p) 118 { 119 first = std::move(__p.first); 120 second = std::move(__p.second); 121 return *this; 122 } 123 124 template<class _U1, class _U2> 125 pair& 126 operator=(pair<_U1, _U2>&& __p) 127 { 128 first = std::move(__p.first); 129 second = std::move(__p.second); 130 return *this; 131 } 132 133 void 134 swap(pair&& __p) 135 { 136 using std::swap; 137 swap(first, __p.first); 138 swap(second, __p.second); 139 } 140 #endif 141 }; 142 143 /// Two pairs of the same type are equal iff their members are equal. 144 template<class _T1, class _T2> 145 inline bool 146 operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 147 { return __x.first == __y.first && __x.second == __y.second; } 148 149 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> 150 template<class _T1, class _T2> 151 inline bool 152 operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 153 { return __x.first < __y.first 154 || (!(__y.first < __x.first) && __x.second < __y.second); } 155 156 /// Uses @c operator== to find the result. 157 template<class _T1, class _T2> 158 inline bool 159 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 160 { return !(__x == __y); } 161 162 /// Uses @c operator< to find the result. 163 template<class _T1, class _T2> 164 inline bool 165 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 166 { return __y < __x; } 167 168 /// Uses @c operator< to find the result. 169 template<class _T1, class _T2> 170 inline bool 171 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 172 { return !(__y < __x); } 173 174 /// Uses @c operator< to find the result. 175 template<class _T1, class _T2> 176 inline bool 177 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 178 { return !(__x < __y); } 179 180 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 181 /// See std::pair::swap(). 182 // Note: no std::swap overloads in C++03 mode, this has performance 183 // implications, see, eg, libstdc++/38466. 184 template<class _T1, class _T2> 185 inline void 186 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) 187 { __x.swap(__y); } 188 189 template<class _T1, class _T2> 190 inline void 191 swap(pair<_T1, _T2>&& __x, pair<_T1, _T2>& __y) 192 { __x.swap(__y); } 193 194 template<class _T1, class _T2> 195 inline void 196 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>&& __y) 197 { __x.swap(__y); } 198 #endif 199 200 /** 201 * @brief A convenience wrapper for creating a pair from two objects. 202 * @param x The first object. 203 * @param y The second object. 204 * @return A newly-constructed pair<> object of the appropriate type. 205 * 206 * The standard requires that the objects be passed by reference-to-const, 207 * but LWG issue #181 says they should be passed by const value. We follow 208 * the LWG by default. 209 */ 210 // _GLIBCXX_RESOLVE_LIB_DEFECTS 211 // 181. make_pair() unintended behavior 212 #ifndef __GXX_EXPERIMENTAL_CXX0X__ 213 template<class _T1, class _T2> 214 inline pair<_T1, _T2> 215 make_pair(_T1 __x, _T2 __y) 216 { return pair<_T1, _T2>(__x, __y); } 217 #else 218 template<typename _Tp> 219 class reference_wrapper; 220 221 // Helper which adds a reference to a type when given a reference_wrapper 222 template<typename _Tp> 223 struct __strip_reference_wrapper 224 { 225 typedef _Tp __type; 226 }; 227 228 template<typename _Tp> 229 struct __strip_reference_wrapper<reference_wrapper<_Tp> > 230 { 231 typedef _Tp& __type; 232 }; 233 234 template<typename _Tp> 235 struct __strip_reference_wrapper<const reference_wrapper<_Tp> > 236 { 237 typedef _Tp& __type; 238 }; 239 240 template<typename _Tp> 241 struct __decay_and_strip 242 { 243 typedef typename __strip_reference_wrapper< 244 typename decay<_Tp>::type>::__type __type; 245 }; 246 247 // NB: DR 706. 248 template<class _T1, class _T2> 249 inline pair<typename __decay_and_strip<_T1>::__type, 250 typename __decay_and_strip<_T2>::__type> 251 make_pair(_T1&& __x, _T2&& __y) 252 { 253 return pair<typename __decay_and_strip<_T1>::__type, 254 typename __decay_and_strip<_T2>::__type> 255 (std::forward<_T1>(__x), std::forward<_T2>(__y)); 256 } 257 #endif 258 259 _GLIBCXX_END_NAMESPACE 260 261 #endif /* _STL_PAIR_H */ 262
