1 // Pair implementation -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 4 // 2010, 2011, 2012 5 // Free Software Foundation, Inc. 6 // 7 // This file is part of the GNU ISO C++ Library. This library is free 8 // software; you can redistribute it and/or modify it under the 9 // terms of the GNU General Public License as published by the 10 // Free Software Foundation; either version 3, or (at your option) 11 // any later version. 12 13 // This library is distributed in the hope that it will be useful, 14 // but WITHOUT ANY WARRANTY; without even the implied warranty of 15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 // GNU General Public License for more details. 17 18 // Under Section 7 of GPL version 3, you are granted additional 19 // permissions described in the GCC Runtime Library Exception, version 20 // 3.1, as published by the Free Software Foundation. 21 22 // You should have received a copy of the GNU General Public License and 23 // a copy of the GCC Runtime Library Exception along with this program; 24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 25 // <http://www.gnu.org/licenses/>. 26 27 /* 28 * 29 * Copyright (c) 1994 30 * Hewlett-Packard Company 31 * 32 * Permission to use, copy, modify, distribute and sell this software 33 * and its documentation for any purpose is hereby granted without fee, 34 * provided that the above copyright notice appear in all copies and 35 * that both that copyright notice and this permission notice appear 36 * in supporting documentation. Hewlett-Packard Company makes no 37 * representations about the suitability of this software for any 38 * purpose. It is provided "as is" without express or implied warranty. 39 * 40 * 41 * Copyright (c) 1996,1997 42 * Silicon Graphics Computer Systems, Inc. 43 * 44 * Permission to use, copy, modify, distribute and sell this software 45 * and its documentation for any purpose is hereby granted without fee, 46 * provided that the above copyright notice appear in all copies and 47 * that both that copyright notice and this permission notice appear 48 * in supporting documentation. Silicon Graphics makes no 49 * representations about the suitability of this software for any 50 * purpose. It is provided "as is" without express or implied warranty. 51 */ 52 53 /** @file bits/stl_pair.h 54 * This is an internal header file, included by other library headers. 55 * Do not attempt to use it directly. @headername{utility} 56 */ 57 58 #ifndef _STL_PAIR_H 59 #define _STL_PAIR_H 1 60 61 #include <bits/move.h> // for std::move / std::forward, and std::swap 62 63 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 64 #include <type_traits> // for std::__decay_and_strip too 65 #endif 66 67 namespace std _GLIBCXX_VISIBILITY(default) 68 { 69 _GLIBCXX_BEGIN_NAMESPACE_VERSION 70 71 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 72 /// piecewise_construct_t 73 struct piecewise_construct_t { }; 74 75 /// piecewise_construct 76 constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t(); 77 78 // Forward declarations. 79 template<typename...> 80 class tuple; 81 82 template<std::size_t...> 83 struct _Index_tuple; 84 #endif 85 86 /// Struct holding two objects of arbitrary type. 87 template<class _T1, class _T2> 88 struct pair 89 { 90 typedef _T1 first_type; /// @c first_type is the first bound type 91 typedef _T2 second_type; /// @c second_type is the second bound type 92 93 _T1 first; /// @c first is a copy of the first object 94 _T2 second; /// @c second is a copy of the second object 95 96 // _GLIBCXX_RESOLVE_LIB_DEFECTS 97 // 265. std::pair::pair() effects overly restrictive 98 /** The default constructor creates @c first and @c second using their 99 * respective default constructors. */ 100 _GLIBCXX_CONSTEXPR pair() 101 : first(), second() { } 102 103 /** Two objects may be passed to a @c pair constructor to be copied. */ 104 _GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b) 105 : first(__a), second(__b) { } 106 107 /** There is also a templated copy ctor for the @c pair class itself. */ 108 #ifndef __GXX_EXPERIMENTAL_CXX0X__ 109 template<class _U1, class _U2> 110 pair(const pair<_U1, _U2>& __p) 111 : first(__p.first), second(__p.second) { } 112 #else 113 template<class _U1, class _U2, class = typename 114 enable_if<__and_<is_convertible<const _U1&, _T1>, 115 is_convertible<const _U2&, _T2>>::value>::type> 116 constexpr pair(const pair<_U1, _U2>& __p) 117 : first(__p.first), second(__p.second) { } 118 119 constexpr pair(const pair&) = default; 120 constexpr pair(pair&&) = default; 121 122 // DR 811. 123 template<class _U1, class = typename 124 enable_if<is_convertible<_U1, _T1>::value>::type> 125 constexpr pair(_U1&& __x, const _T2& __y) 126 : first(std::forward<_U1>(__x)), second(__y) { } 127 128 template<class _U2, class = typename 129 enable_if<is_convertible<_U2, _T2>::value>::type> 130 constexpr pair(const _T1& __x, _U2&& __y) 131 : first(__x), second(std::forward<_U2>(__y)) { } 132 133 template<class _U1, class _U2, class = typename 134 enable_if<__and_<is_convertible<_U1, _T1>, 135 is_convertible<_U2, _T2>>::value>::type> 136 constexpr pair(_U1&& __x, _U2&& __y) 137 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } 138 139 template<class _U1, class _U2, class = typename 140 enable_if<__and_<is_convertible<_U1, _T1>, 141 is_convertible<_U2, _T2>>::value>::type> 142 constexpr pair(pair<_U1, _U2>&& __p) 143 : first(std::forward<_U1>(__p.first)), 144 second(std::forward<_U2>(__p.second)) { } 145 146 template<typename... _Args1, typename... _Args2> 147 pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); 148 149 pair& 150 operator=(const pair& __p) 151 { 152 first = __p.first; 153 second = __p.second; 154 return *this; 155 } 156 157 pair& 158 operator=(pair&& __p) 159 noexcept(__and_<is_nothrow_move_assignable<_T1>, 160 is_nothrow_move_assignable<_T2>>::value) 161 { 162 first = std::forward<first_type>(__p.first); 163 second = std::forward<second_type>(__p.second); 164 return *this; 165 } 166 167 template<class _U1, class _U2> 168 pair& 169 operator=(const pair<_U1, _U2>& __p) 170 { 171 first = __p.first; 172 second = __p.second; 173 return *this; 174 } 175 176 template<class _U1, class _U2> 177 pair& 178 operator=(pair<_U1, _U2>&& __p) 179 { 180 first = std::forward<_U1>(__p.first); 181 second = std::forward<_U2>(__p.second); 182 return *this; 183 } 184 185 void 186 swap(pair& __p) 187 noexcept(noexcept(swap(first, __p.first)) 188 && noexcept(swap(second, __p.second))) 189 { 190 using std::swap; 191 swap(first, __p.first); 192 swap(second, __p.second); 193 } 194 195 private: 196 template<typename... _Args1, std::size_t... _Indexes1, 197 typename... _Args2, std::size_t... _Indexes2> 198 pair(tuple<_Args1...>&, tuple<_Args2...>&, 199 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); 200 #endif 201 }; 202 203 /// Two pairs of the same type are equal iff their members are equal. 204 template<class _T1, class _T2> 205 inline _GLIBCXX_CONSTEXPR bool 206 operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 207 { return __x.first == __y.first && __x.second == __y.second; } 208 209 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> 210 template<class _T1, class _T2> 211 inline _GLIBCXX_CONSTEXPR bool 212 operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 213 { return __x.first < __y.first 214 || (!(__y.first < __x.first) && __x.second < __y.second); } 215 216 /// Uses @c operator== to find the result. 217 template<class _T1, class _T2> 218 inline _GLIBCXX_CONSTEXPR bool 219 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 220 { return !(__x == __y); } 221 222 /// Uses @c operator< to find the result. 223 template<class _T1, class _T2> 224 inline _GLIBCXX_CONSTEXPR bool 225 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 226 { return __y < __x; } 227 228 /// Uses @c operator< to find the result. 229 template<class _T1, class _T2> 230 inline _GLIBCXX_CONSTEXPR bool 231 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 232 { return !(__y < __x); } 233 234 /// Uses @c operator< to find the result. 235 template<class _T1, class _T2> 236 inline _GLIBCXX_CONSTEXPR bool 237 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 238 { return !(__x < __y); } 239 240 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 241 /// See std::pair::swap(). 242 // Note: no std::swap overloads in C++03 mode, this has performance 243 // implications, see, eg, libstdc++/38466. 244 template<class _T1, class _T2> 245 inline void 246 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) 247 noexcept(noexcept(__x.swap(__y))) 248 { __x.swap(__y); } 249 #endif 250 251 /** 252 * @brief A convenience wrapper for creating a pair from two objects. 253 * @param __x The first object. 254 * @param __y The second object. 255 * @return A newly-constructed pair<> object of the appropriate type. 256 * 257 * The standard requires that the objects be passed by reference-to-const, 258 * but LWG issue #181 says they should be passed by const value. We follow 259 * the LWG by default. 260 */ 261 // _GLIBCXX_RESOLVE_LIB_DEFECTS 262 // 181. make_pair() unintended behavior 263 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 264 // NB: DR 706. 265 template<class _T1, class _T2> 266 constexpr pair<typename __decay_and_strip<_T1>::__type, 267 typename __decay_and_strip<_T2>::__type> 268 make_pair(_T1&& __x, _T2&& __y) 269 { 270 typedef typename __decay_and_strip<_T1>::__type __ds_type1; 271 typedef typename __decay_and_strip<_T2>::__type __ds_type2; 272 typedef pair<__ds_type1, __ds_type2> __pair_type; 273 return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); 274 } 275 #else 276 template<class _T1, class _T2> 277 inline pair<_T1, _T2> 278 make_pair(_T1 __x, _T2 __y) 279 { return pair<_T1, _T2>(__x, __y); } 280 #endif 281 282 _GLIBCXX_END_NAMESPACE_VERSION 283 } // namespace 284 285 #endif /* _STL_PAIR_H */ 286
