1 // Pair implementation -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 bits/stl_pair.h 53 * This is an internal header file, included by other library headers. 54 * Do not attempt to use it directly. @headername{utility} 55 */ 56 57 #ifndef _STL_PAIR_H 58 #define _STL_PAIR_H 1 59 60 #include <bits/move.h> // for std::move / std::forward, and std::swap 61 62 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 63 #include <type_traits> // for std::__decay_and_strip too 64 #endif 65 66 namespace std _GLIBCXX_VISIBILITY(default) 67 { 68 _GLIBCXX_BEGIN_NAMESPACE_VERSION 69 70 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 71 /// piecewise_construct_t 72 struct piecewise_construct_t { }; 73 74 /// piecewise_construct 75 constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t(); 76 77 // Forward declarations. 78 template<typename...> 79 class tuple; 80 81 template<int...> 82 struct _Index_tuple; 83 #endif 84 85 /// Struct holding two objects of arbitrary type. 86 template<class _T1, class _T2> 87 struct pair 88 { 89 typedef _T1 first_type; /// @c first_type is the first bound type 90 typedef _T2 second_type; /// @c second_type is the second bound type 91 92 _T1 first; /// @c first is a copy of the first object 93 _T2 second; /// @c second is a copy of the second object 94 95 // _GLIBCXX_RESOLVE_LIB_DEFECTS 96 // 265. std::pair::pair() effects overly restrictive 97 /** The default constructor creates @c first and @c second using their 98 * respective default constructors. */ 99 _GLIBCXX_CONSTEXPR pair() 100 : first(), second() { } 101 102 /** Two objects may be passed to a @c pair constructor to be copied. */ 103 _GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b) 104 : first(__a), second(__b) { } 105 106 /** There is also a templated copy ctor for the @c pair class itself. */ 107 template<class _U1, class _U2> 108 _GLIBCXX_CONSTEXPR pair(const pair<_U1, _U2>& __p) 109 : first(__p.first), second(__p.second) { } 110 111 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 112 constexpr pair(const pair&) = default; 113 114 // Implicit. 115 // pair(pair&&) = default; 116 117 // DR 811. 118 template<class _U1, class = typename 119 std::enable_if<std::is_convertible<_U1, _T1>::value>::type> 120 pair(_U1&& __x, const _T2& __y) 121 : first(std::forward<_U1>(__x)), second(__y) { } 122 123 template<class _U2, class = typename 124 std::enable_if<std::is_convertible<_U2, _T2>::value>::type> 125 pair(const _T1& __x, _U2&& __y) 126 : first(__x), second(std::forward<_U2>(__y)) { } 127 128 template<class _U1, class _U2, class = typename 129 std::enable_if<std::is_convertible<_U1, _T1>::value 130 && std::is_convertible<_U2, _T2>::value>::type> 131 pair(_U1&& __x, _U2&& __y) 132 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } 133 134 template<class _U1, class _U2> 135 pair(pair<_U1, _U2>&& __p) 136 : first(std::forward<_U1>(__p.first)), 137 second(std::forward<_U2>(__p.second)) { } 138 139 template<class... _Args1, class... _Args2> 140 pair(piecewise_construct_t, 141 tuple<_Args1...> __first, tuple<_Args2...> __second) 142 : first(__cons<first_type>(std::move(__first))), 143 second(__cons<second_type>(std::move(__second))) { } 144 145 pair& 146 operator=(const pair& __p) 147 { 148 first = __p.first; 149 second = __p.second; 150 return *this; 151 } 152 153 pair& 154 operator=(pair&& __p) 155 { 156 first = std::move(__p.first); 157 second = std::move(__p.second); 158 return *this; 159 } 160 161 template<class _U1, class _U2> 162 pair& 163 operator=(const pair<_U1, _U2>& __p) 164 { 165 first = __p.first; 166 second = __p.second; 167 return *this; 168 } 169 170 template<class _U1, class _U2> 171 pair& 172 operator=(pair<_U1, _U2>&& __p) 173 { 174 first = std::move(__p.first); 175 second = std::move(__p.second); 176 return *this; 177 } 178 179 void 180 swap(pair& __p) 181 { 182 using std::swap; 183 swap(first, __p.first); 184 swap(second, __p.second); 185 } 186 187 private: 188 template<typename _Tp, typename... _Args> 189 static _Tp 190 __cons(tuple<_Args...>&&); 191 192 template<typename _Tp, typename... _Args, int... _Indexes> 193 static _Tp 194 __do_cons(tuple<_Args...>&&, const _Index_tuple<_Indexes...>&); 195 #endif 196 }; 197 198 /// Two pairs of the same type are equal iff their members are equal. 199 template<class _T1, class _T2> 200 inline _GLIBCXX_CONSTEXPR bool 201 operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 202 { return __x.first == __y.first && __x.second == __y.second; } 203 204 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> 205 template<class _T1, class _T2> 206 inline _GLIBCXX_CONSTEXPR bool 207 operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 208 { return __x.first < __y.first 209 || (!(__y.first < __x.first) && __x.second < __y.second); } 210 211 /// Uses @c operator== to find the result. 212 template<class _T1, class _T2> 213 inline _GLIBCXX_CONSTEXPR bool 214 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 215 { return !(__x == __y); } 216 217 /// Uses @c operator< to find the result. 218 template<class _T1, class _T2> 219 inline _GLIBCXX_CONSTEXPR bool 220 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 221 { return __y < __x; } 222 223 /// Uses @c operator< to find the result. 224 template<class _T1, class _T2> 225 inline _GLIBCXX_CONSTEXPR bool 226 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 227 { return !(__y < __x); } 228 229 /// Uses @c operator< to find the result. 230 template<class _T1, class _T2> 231 inline _GLIBCXX_CONSTEXPR bool 232 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 233 { return !(__x < __y); } 234 235 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 236 /// See std::pair::swap(). 237 // Note: no std::swap overloads in C++03 mode, this has performance 238 // implications, see, eg, libstdc++/38466. 239 template<class _T1, class _T2> 240 inline void 241 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) 242 { __x.swap(__y); } 243 #endif 244 245 /** 246 * @brief A convenience wrapper for creating a pair from two objects. 247 * @param x The first object. 248 * @param y The second object. 249 * @return A newly-constructed pair<> object of the appropriate type. 250 * 251 * The standard requires that the objects be passed by reference-to-const, 252 * but LWG issue #181 says they should be passed by const value. We follow 253 * the LWG by default. 254 */ 255 // _GLIBCXX_RESOLVE_LIB_DEFECTS 256 // 181. make_pair() unintended behavior 257 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 258 // NB: DR 706. 259 template<class _T1, class _T2> 260 inline pair<typename __decay_and_strip<_T1>::__type, 261 typename __decay_and_strip<_T2>::__type> 262 make_pair(_T1&& __x, _T2&& __y) 263 { 264 typedef typename __decay_and_strip<_T1>::__type __ds_type1; 265 typedef typename __decay_and_strip<_T2>::__type __ds_type2; 266 typedef pair<__ds_type1, __ds_type2> __pair_type; 267 return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); 268 } 269 #else 270 template<class _T1, class _T2> 271 inline pair<_T1, _T2> 272 make_pair(_T1 __x, _T2 __y) 273 { return pair<_T1, _T2>(__x, __y); } 274 #endif 275 276 _GLIBCXX_END_NAMESPACE_VERSION 277 } // namespace 278 279 #endif /* _STL_PAIR_H */ 280
