1 // Pair implementation -*- C++ -*- 2 3 // Copyright (C) 2001-2013 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /* 26 * 27 * Copyright (c) 1994 28 * Hewlett-Packard Company 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Hewlett-Packard Company makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 * 38 * 39 * Copyright (c) 1996,1997 40 * Silicon Graphics Computer Systems, Inc. 41 * 42 * Permission to use, copy, modify, distribute and sell this software 43 * and its documentation for any purpose is hereby granted without fee, 44 * provided that the above copyright notice appear in all copies and 45 * that both that copyright notice and this permission notice appear 46 * in supporting documentation. Silicon Graphics makes no 47 * representations about the suitability of this software for any 48 * purpose. It is provided "as is" without express or implied warranty. 49 */ 50 51 /** @file bits/stl_pair.h 52 * This is an internal header file, included by other library headers. 53 * Do not attempt to use it directly. @headername{utility} 54 */ 55 56 #ifndef _STL_PAIR_H 57 #define _STL_PAIR_H 1 58 59 #include <bits/move.h> // for std::move / std::forward, and std::swap 60 61 #if __cplusplus >= 201103L 62 #include <type_traits> // for std::__decay_and_strip too 63 #endif 64 65 namespace std _GLIBCXX_VISIBILITY(default) 66 { 67 _GLIBCXX_BEGIN_NAMESPACE_VERSION 68 69 /** 70 * @addtogroup utilities 71 * @{ 72 */ 73 74 #if __cplusplus >= 201103L 75 /// piecewise_construct_t 76 struct piecewise_construct_t { }; 77 78 /// piecewise_construct 79 constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t(); 80 81 // Forward declarations. 82 template<typename...> 83 class tuple; 84 85 template<std::size_t...> 86 struct _Index_tuple; 87 #endif 88 89 /** 90 * @brief Struct holding two objects of arbitrary type. 91 * 92 * @tparam _T1 Type of first object. 93 * @tparam _T2 Type of second object. 94 */ 95 template<class _T1, class _T2> 96 struct pair 97 { 98 typedef _T1 first_type; /// @c first_type is the first bound type 99 typedef _T2 second_type; /// @c second_type is the second bound type 100 101 _T1 first; /// @c first is a copy of the first object 102 _T2 second; /// @c second is a copy of the second object 103 104 // _GLIBCXX_RESOLVE_LIB_DEFECTS 105 // 265. std::pair::pair() effects overly restrictive 106 /** The default constructor creates @c first and @c second using their 107 * respective default constructors. */ 108 _GLIBCXX_CONSTEXPR pair() 109 : first(), second() { } 110 111 /** Two objects may be passed to a @c pair constructor to be copied. */ 112 _GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b) 113 : first(__a), second(__b) { } 114 115 /** There is also a templated copy ctor for the @c pair class itself. */ 116 #if __cplusplus < 201103L 117 template<class _U1, class _U2> 118 pair(const pair<_U1, _U2>& __p) 119 : first(__p.first), second(__p.second) { } 120 #else 121 template<class _U1, class _U2, class = typename 122 enable_if<__and_<is_convertible<const _U1&, _T1>, 123 is_convertible<const _U2&, _T2>>::value>::type> 124 constexpr pair(const pair<_U1, _U2>& __p) 125 : first(__p.first), second(__p.second) { } 126 127 constexpr pair(const pair&) = default; 128 constexpr pair(pair&&) = default; 129 130 // DR 811. 131 template<class _U1, class = typename 132 enable_if<is_convertible<_U1, _T1>::value>::type> 133 constexpr pair(_U1&& __x, const _T2& __y) 134 : first(std::forward<_U1>(__x)), second(__y) { } 135 136 template<class _U2, class = typename 137 enable_if<is_convertible<_U2, _T2>::value>::type> 138 constexpr pair(const _T1& __x, _U2&& __y) 139 : first(__x), second(std::forward<_U2>(__y)) { } 140 141 template<class _U1, class _U2, class = typename 142 enable_if<__and_<is_convertible<_U1, _T1>, 143 is_convertible<_U2, _T2>>::value>::type> 144 constexpr pair(_U1&& __x, _U2&& __y) 145 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } 146 147 template<class _U1, class _U2, class = typename 148 enable_if<__and_<is_convertible<_U1, _T1>, 149 is_convertible<_U2, _T2>>::value>::type> 150 constexpr pair(pair<_U1, _U2>&& __p) 151 : first(std::forward<_U1>(__p.first)), 152 second(std::forward<_U2>(__p.second)) { } 153 154 template<typename... _Args1, typename... _Args2> 155 pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); 156 157 pair& 158 operator=(const pair& __p) 159 { 160 first = __p.first; 161 second = __p.second; 162 return *this; 163 } 164 165 pair& 166 operator=(pair&& __p) 167 noexcept(__and_<is_nothrow_move_assignable<_T1>, 168 is_nothrow_move_assignable<_T2>>::value) 169 { 170 first = std::forward<first_type>(__p.first); 171 second = std::forward<second_type>(__p.second); 172 return *this; 173 } 174 175 template<class _U1, class _U2> 176 pair& 177 operator=(const pair<_U1, _U2>& __p) 178 { 179 first = __p.first; 180 second = __p.second; 181 return *this; 182 } 183 184 template<class _U1, class _U2> 185 pair& 186 operator=(pair<_U1, _U2>&& __p) 187 { 188 first = std::forward<_U1>(__p.first); 189 second = std::forward<_U2>(__p.second); 190 return *this; 191 } 192 193 void 194 swap(pair& __p) 195 noexcept(noexcept(swap(first, __p.first)) 196 && noexcept(swap(second, __p.second))) 197 { 198 using std::swap; 199 swap(first, __p.first); 200 swap(second, __p.second); 201 } 202 203 private: 204 template<typename... _Args1, std::size_t... _Indexes1, 205 typename... _Args2, std::size_t... _Indexes2> 206 pair(tuple<_Args1...>&, tuple<_Args2...>&, 207 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); 208 #endif 209 }; 210 211 /// Two pairs of the same type are equal iff their members are equal. 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.first == __y.first && __x.second == __y.second; } 216 217 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> 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 __x.first < __y.first 222 || (!(__y.first < __x.first) && __x.second < __y.second); } 223 224 /// Uses @c operator== to find the result. 225 template<class _T1, class _T2> 226 inline _GLIBCXX_CONSTEXPR bool 227 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 228 { return !(__x == __y); } 229 230 /// Uses @c operator< to find the result. 231 template<class _T1, class _T2> 232 inline _GLIBCXX_CONSTEXPR bool 233 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 234 { return __y < __x; } 235 236 /// Uses @c operator< to find the result. 237 template<class _T1, class _T2> 238 inline _GLIBCXX_CONSTEXPR bool 239 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 240 { return !(__y < __x); } 241 242 /// Uses @c operator< to find the result. 243 template<class _T1, class _T2> 244 inline _GLIBCXX_CONSTEXPR bool 245 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 246 { return !(__x < __y); } 247 248 #if __cplusplus >= 201103L 249 /// See std::pair::swap(). 250 // Note: no std::swap overloads in C++03 mode, this has performance 251 // implications, see, eg, libstdc++/38466. 252 template<class _T1, class _T2> 253 inline void 254 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) 255 noexcept(noexcept(__x.swap(__y))) 256 { __x.swap(__y); } 257 #endif 258 259 /** 260 * @brief A convenience wrapper for creating a pair from two objects. 261 * @param __x The first object. 262 * @param __y The second object. 263 * @return A newly-constructed pair<> object of the appropriate type. 264 * 265 * The standard requires that the objects be passed by reference-to-const, 266 * but LWG issue #181 says they should be passed by const value. We follow 267 * the LWG by default. 268 */ 269 // _GLIBCXX_RESOLVE_LIB_DEFECTS 270 // 181. make_pair() unintended behavior 271 #if __cplusplus >= 201103L 272 // NB: DR 706. 273 template<class _T1, class _T2> 274 constexpr pair<typename __decay_and_strip<_T1>::__type, 275 typename __decay_and_strip<_T2>::__type> 276 make_pair(_T1&& __x, _T2&& __y) 277 { 278 typedef typename __decay_and_strip<_T1>::__type __ds_type1; 279 typedef typename __decay_and_strip<_T2>::__type __ds_type2; 280 typedef pair<__ds_type1, __ds_type2> __pair_type; 281 return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); 282 } 283 #else 284 template<class _T1, class _T2> 285 inline pair<_T1, _T2> 286 make_pair(_T1 __x, _T2 __y) 287 { return pair<_T1, _T2>(__x, __y); } 288 #endif 289 290 /// @} 291 292 _GLIBCXX_END_NAMESPACE_VERSION 293 } // namespace std 294 295 #endif /* _STL_PAIR_H */ 296