libstdc++
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00001 // Pair implementation -*- C++ -*- 00002 00003 // Copyright (C) 2001-2017 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /* 00026 * 00027 * Copyright (c) 1994 00028 * Hewlett-Packard Company 00029 * 00030 * Permission to use, copy, modify, distribute and sell this software 00031 * and its documentation for any purpose is hereby granted without fee, 00032 * provided that the above copyright notice appear in all copies and 00033 * that both that copyright notice and this permission notice appear 00034 * in supporting documentation. Hewlett-Packard Company makes no 00035 * representations about the suitability of this software for any 00036 * purpose. It is provided "as is" without express or implied warranty. 00037 * 00038 * 00039 * Copyright (c) 1996,1997 00040 * Silicon Graphics Computer Systems, Inc. 00041 * 00042 * Permission to use, copy, modify, distribute and sell this software 00043 * and its documentation for any purpose is hereby granted without fee, 00044 * provided that the above copyright notice appear in all copies and 00045 * that both that copyright notice and this permission notice appear 00046 * in supporting documentation. Silicon Graphics makes no 00047 * representations about the suitability of this software for any 00048 * purpose. It is provided "as is" without express or implied warranty. 00049 */ 00050 00051 /** @file bits/stl_pair.h 00052 * This is an internal header file, included by other library headers. 00053 * Do not attempt to use it directly. @headername{utility} 00054 */ 00055 00056 #ifndef _STL_PAIR_H 00057 #define _STL_PAIR_H 1 00058 00059 #include <bits/move.h> // for std::move / std::forward, and std::swap 00060 00061 #if __cplusplus >= 201103L 00062 #include <type_traits> // for std::__decay_and_strip too 00063 #endif 00064 00065 namespace std _GLIBCXX_VISIBILITY(default) 00066 { 00067 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00068 00069 /** 00070 * @addtogroup utilities 00071 * @{ 00072 */ 00073 00074 #if __cplusplus >= 201103L 00075 /// piecewise_construct_t 00076 struct piecewise_construct_t { explicit piecewise_construct_t() = default; }; 00077 00078 /// piecewise_construct 00079 _GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct = 00080 piecewise_construct_t(); 00081 00082 // Forward declarations. 00083 template<typename...> 00084 class tuple; 00085 00086 template<std::size_t...> 00087 struct _Index_tuple; 00088 00089 // Concept utility functions, reused in conditionally-explicit 00090 // constructors. 00091 // See PR 70437, don't look at is_constructible or 00092 // is_convertible if the types are the same to 00093 // avoid querying those properties for incomplete types. 00094 template <bool, typename _T1, typename _T2> 00095 struct _PCC 00096 { 00097 template <typename _U1, typename _U2> 00098 static constexpr bool _ConstructiblePair() 00099 { 00100 return __and_<is_constructible<_T1, const _U1&>, 00101 is_constructible<_T2, const _U2&>>::value; 00102 } 00103 00104 template <typename _U1, typename _U2> 00105 static constexpr bool _ImplicitlyConvertiblePair() 00106 { 00107 return __and_<is_convertible<const _U1&, _T1>, 00108 is_convertible<const _U2&, _T2>>::value; 00109 } 00110 00111 template <typename _U1, typename _U2> 00112 static constexpr bool _MoveConstructiblePair() 00113 { 00114 return __and_<is_constructible<_T1, _U1&&>, 00115 is_constructible<_T2, _U2&&>>::value; 00116 } 00117 00118 template <typename _U1, typename _U2> 00119 static constexpr bool _ImplicitlyMoveConvertiblePair() 00120 { 00121 return __and_<is_convertible<_U1&&, _T1>, 00122 is_convertible<_U2&&, _T2>>::value; 00123 } 00124 00125 template <bool __implicit, typename _U1, typename _U2> 00126 static constexpr bool _CopyMovePair() 00127 { 00128 using __do_converts = __and_<is_convertible<const _U1&, _T1>, 00129 is_convertible<_U2&&, _T2>>; 00130 using __converts = typename conditional<__implicit, 00131 __do_converts, 00132 __not_<__do_converts>>::type; 00133 return __and_<is_constructible<_T1, const _U1&>, 00134 is_constructible<_T2, _U2&&>, 00135 __converts 00136 >::value; 00137 } 00138 00139 template <bool __implicit, typename _U1, typename _U2> 00140 static constexpr bool _MoveCopyPair() 00141 { 00142 using __do_converts = __and_<is_convertible<_U1&&, _T1>, 00143 is_convertible<const _U2&, _T2>>; 00144 using __converts = typename conditional<__implicit, 00145 __do_converts, 00146 __not_<__do_converts>>::type; 00147 return __and_<is_constructible<_T1, _U1&&>, 00148 is_constructible<_T2, const _U2&&>, 00149 __converts 00150 >::value; 00151 } 00152 }; 00153 00154 template <typename _T1, typename _T2> 00155 struct _PCC<false, _T1, _T2> 00156 { 00157 template <typename _U1, typename _U2> 00158 static constexpr bool _ConstructiblePair() 00159 { 00160 return false; 00161 } 00162 00163 template <typename _U1, typename _U2> 00164 static constexpr bool _ImplicitlyConvertiblePair() 00165 { 00166 return false; 00167 } 00168 00169 template <typename _U1, typename _U2> 00170 static constexpr bool _MoveConstructiblePair() 00171 { 00172 return false; 00173 } 00174 00175 template <typename _U1, typename _U2> 00176 static constexpr bool _ImplicitlyMoveConvertiblePair() 00177 { 00178 return false; 00179 } 00180 }; 00181 00182 // PR libstdc++/79141, a utility type for preventing 00183 // initialization of an argument of a disabled assignment 00184 // operator from a pair of empty braces. 00185 struct __nonesuch_no_braces : std::__nonesuch { 00186 explicit __nonesuch_no_braces(const __nonesuch&) = delete; 00187 }; 00188 00189 #endif 00190 00191 /** 00192 * @brief Struct holding two objects of arbitrary type. 00193 * 00194 * @tparam _T1 Type of first object. 00195 * @tparam _T2 Type of second object. 00196 */ 00197 template<typename _T1, typename _T2> 00198 struct pair 00199 { 00200 typedef _T1 first_type; /// @c first_type is the first bound type 00201 typedef _T2 second_type; /// @c second_type is the second bound type 00202 00203 _T1 first; /// @c first is a copy of the first object 00204 _T2 second; /// @c second is a copy of the second object 00205 00206 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00207 // 265. std::pair::pair() effects overly restrictive 00208 /** The default constructor creates @c first and @c second using their 00209 * respective default constructors. */ 00210 #if __cplusplus >= 201103L 00211 template <typename _U1 = _T1, 00212 typename _U2 = _T2, 00213 typename enable_if<__and_< 00214 __is_implicitly_default_constructible<_U1>, 00215 __is_implicitly_default_constructible<_U2>> 00216 ::value, bool>::type = true> 00217 #endif 00218 _GLIBCXX_CONSTEXPR pair() 00219 : first(), second() { } 00220 00221 #if __cplusplus >= 201103L 00222 template <typename _U1 = _T1, 00223 typename _U2 = _T2, 00224 typename enable_if<__and_< 00225 is_default_constructible<_U1>, 00226 is_default_constructible<_U2>, 00227 __not_< 00228 __and_<__is_implicitly_default_constructible<_U1>, 00229 __is_implicitly_default_constructible<_U2>>>> 00230 ::value, bool>::type = false> 00231 explicit constexpr pair() 00232 : first(), second() { } 00233 #endif 00234 00235 /** Two objects may be passed to a @c pair constructor to be copied. */ 00236 #if __cplusplus < 201103L 00237 pair(const _T1& __a, const _T2& __b) 00238 : first(__a), second(__b) { } 00239 #else 00240 // Shortcut for constraining the templates that don't take pairs. 00241 using _PCCP = _PCC<true, _T1, _T2>; 00242 00243 template<typename _U1 = _T1, typename _U2=_T2, typename 00244 enable_if<_PCCP::template 00245 _ConstructiblePair<_U1, _U2>() 00246 && _PCCP::template 00247 _ImplicitlyConvertiblePair<_U1, _U2>(), 00248 bool>::type=true> 00249 constexpr pair(const _T1& __a, const _T2& __b) 00250 : first(__a), second(__b) { } 00251 00252 template<typename _U1 = _T1, typename _U2=_T2, typename 00253 enable_if<_PCCP::template 00254 _ConstructiblePair<_U1, _U2>() 00255 && !_PCCP::template 00256 _ImplicitlyConvertiblePair<_U1, _U2>(), 00257 bool>::type=false> 00258 explicit constexpr pair(const _T1& __a, const _T2& __b) 00259 : first(__a), second(__b) { } 00260 #endif 00261 00262 /** There is also a templated copy ctor for the @c pair class itself. */ 00263 #if __cplusplus < 201103L 00264 template<typename _U1, typename _U2> 00265 pair(const pair<_U1, _U2>& __p) 00266 : first(__p.first), second(__p.second) { } 00267 #else 00268 // Shortcut for constraining the templates that take pairs. 00269 template <typename _U1, typename _U2> 00270 using _PCCFP = _PCC<!is_same<_T1, _U1>::value 00271 || !is_same<_T2, _U2>::value, 00272 _T1, _T2>; 00273 00274 template<typename _U1, typename _U2, typename 00275 enable_if<_PCCFP<_U1, _U2>::template 00276 _ConstructiblePair<_U1, _U2>() 00277 && _PCCFP<_U1, _U2>::template 00278 _ImplicitlyConvertiblePair<_U1, _U2>(), 00279 bool>::type=true> 00280 constexpr pair(const pair<_U1, _U2>& __p) 00281 : first(__p.first), second(__p.second) { } 00282 00283 template<typename _U1, typename _U2, typename 00284 enable_if<_PCCFP<_U1, _U2>::template 00285 _ConstructiblePair<_U1, _U2>() 00286 && !_PCCFP<_U1, _U2>::template 00287 _ImplicitlyConvertiblePair<_U1, _U2>(), 00288 bool>::type=false> 00289 explicit constexpr pair(const pair<_U1, _U2>& __p) 00290 : first(__p.first), second(__p.second) { } 00291 00292 constexpr pair(const pair&) = default; 00293 constexpr pair(pair&&) = default; 00294 00295 // DR 811. 00296 template<typename _U1, typename 00297 enable_if<_PCCP::template 00298 _MoveCopyPair<true, _U1, _T2>(), 00299 bool>::type=true> 00300 constexpr pair(_U1&& __x, const _T2& __y) 00301 : first(std::forward<_U1>(__x)), second(__y) { } 00302 00303 template<typename _U1, typename 00304 enable_if<_PCCP::template 00305 _MoveCopyPair<false, _U1, _T2>(), 00306 bool>::type=false> 00307 explicit constexpr pair(_U1&& __x, const _T2& __y) 00308 : first(std::forward<_U1>(__x)), second(__y) { } 00309 00310 template<typename _U2, typename 00311 enable_if<_PCCP::template 00312 _CopyMovePair<true, _T1, _U2>(), 00313 bool>::type=true> 00314 constexpr pair(const _T1& __x, _U2&& __y) 00315 : first(__x), second(std::forward<_U2>(__y)) { } 00316 00317 template<typename _U2, typename 00318 enable_if<_PCCP::template 00319 _CopyMovePair<false, _T1, _U2>(), 00320 bool>::type=false> 00321 explicit pair(const _T1& __x, _U2&& __y) 00322 : first(__x), second(std::forward<_U2>(__y)) { } 00323 00324 template<typename _U1, typename _U2, typename 00325 enable_if<_PCCP::template 00326 _MoveConstructiblePair<_U1, _U2>() 00327 && _PCCP::template 00328 _ImplicitlyMoveConvertiblePair<_U1, _U2>(), 00329 bool>::type=true> 00330 constexpr pair(_U1&& __x, _U2&& __y) 00331 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } 00332 00333 template<typename _U1, typename _U2, typename 00334 enable_if<_PCCP::template 00335 _MoveConstructiblePair<_U1, _U2>() 00336 && !_PCCP::template 00337 _ImplicitlyMoveConvertiblePair<_U1, _U2>(), 00338 bool>::type=false> 00339 explicit constexpr pair(_U1&& __x, _U2&& __y) 00340 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } 00341 00342 00343 template<typename _U1, typename _U2, typename 00344 enable_if<_PCCFP<_U1, _U2>::template 00345 _MoveConstructiblePair<_U1, _U2>() 00346 && _PCCFP<_U1, _U2>::template 00347 _ImplicitlyMoveConvertiblePair<_U1, _U2>(), 00348 bool>::type=true> 00349 constexpr pair(pair<_U1, _U2>&& __p) 00350 : first(std::forward<_U1>(__p.first)), 00351 second(std::forward<_U2>(__p.second)) { } 00352 00353 template<typename _U1, typename _U2, typename 00354 enable_if<_PCCFP<_U1, _U2>::template 00355 _MoveConstructiblePair<_U1, _U2>() 00356 && !_PCCFP<_U1, _U2>::template 00357 _ImplicitlyMoveConvertiblePair<_U1, _U2>(), 00358 bool>::type=false> 00359 explicit constexpr pair(pair<_U1, _U2>&& __p) 00360 : first(std::forward<_U1>(__p.first)), 00361 second(std::forward<_U2>(__p.second)) { } 00362 00363 template<typename... _Args1, typename... _Args2> 00364 pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); 00365 00366 pair& 00367 operator=(typename conditional< 00368 __and_<is_copy_assignable<_T1>, 00369 is_copy_assignable<_T2>>::value, 00370 const pair&, const __nonesuch_no_braces&>::type __p) 00371 { 00372 first = __p.first; 00373 second = __p.second; 00374 return *this; 00375 } 00376 00377 pair& 00378 operator=(typename conditional< 00379 __not_<__and_<is_copy_assignable<_T1>, 00380 is_copy_assignable<_T2>>>::value, 00381 const pair&, const __nonesuch_no_braces&>::type __p) = delete; 00382 00383 pair& 00384 operator=(typename conditional< 00385 __and_<is_move_assignable<_T1>, 00386 is_move_assignable<_T2>>::value, 00387 pair&&, __nonesuch_no_braces&&>::type __p) 00388 noexcept(__and_<is_nothrow_move_assignable<_T1>, 00389 is_nothrow_move_assignable<_T2>>::value) 00390 { 00391 first = std::forward<first_type>(__p.first); 00392 second = std::forward<second_type>(__p.second); 00393 return *this; 00394 } 00395 00396 template<typename _U1, typename _U2> 00397 typename enable_if<__and_<is_assignable<_T1&, const _U1&>, 00398 is_assignable<_T2&, const _U2&>>::value, 00399 pair&>::type 00400 operator=(const pair<_U1, _U2>& __p) 00401 { 00402 first = __p.first; 00403 second = __p.second; 00404 return *this; 00405 } 00406 00407 template<typename _U1, typename _U2> 00408 typename enable_if<__and_<is_assignable<_T1&, _U1&&>, 00409 is_assignable<_T2&, _U2&&>>::value, 00410 pair&>::type 00411 operator=(pair<_U1, _U2>&& __p) 00412 { 00413 first = std::forward<_U1>(__p.first); 00414 second = std::forward<_U2>(__p.second); 00415 return *this; 00416 } 00417 00418 void 00419 swap(pair& __p) 00420 noexcept(__and_<__is_nothrow_swappable<_T1>, 00421 __is_nothrow_swappable<_T2>>::value) 00422 { 00423 using std::swap; 00424 swap(first, __p.first); 00425 swap(second, __p.second); 00426 } 00427 00428 private: 00429 template<typename... _Args1, std::size_t... _Indexes1, 00430 typename... _Args2, std::size_t... _Indexes2> 00431 pair(tuple<_Args1...>&, tuple<_Args2...>&, 00432 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); 00433 #endif 00434 }; 00435 00436 #if __cpp_deduction_guides >= 201606 00437 template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>; 00438 #endif 00439 00440 /// Two pairs of the same type are equal iff their members are equal. 00441 template<typename _T1, typename _T2> 00442 inline _GLIBCXX_CONSTEXPR bool 00443 operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00444 { return __x.first == __y.first && __x.second == __y.second; } 00445 00446 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> 00447 template<typename _T1, typename _T2> 00448 inline _GLIBCXX_CONSTEXPR bool 00449 operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00450 { return __x.first < __y.first 00451 || (!(__y.first < __x.first) && __x.second < __y.second); } 00452 00453 /// Uses @c operator== to find the result. 00454 template<typename _T1, typename _T2> 00455 inline _GLIBCXX_CONSTEXPR bool 00456 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00457 { return !(__x == __y); } 00458 00459 /// Uses @c operator< to find the result. 00460 template<typename _T1, typename _T2> 00461 inline _GLIBCXX_CONSTEXPR bool 00462 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00463 { return __y < __x; } 00464 00465 /// Uses @c operator< to find the result. 00466 template<typename _T1, typename _T2> 00467 inline _GLIBCXX_CONSTEXPR bool 00468 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00469 { return !(__y < __x); } 00470 00471 /// Uses @c operator< to find the result. 00472 template<typename _T1, typename _T2> 00473 inline _GLIBCXX_CONSTEXPR bool 00474 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) 00475 { return !(__x < __y); } 00476 00477 #if __cplusplus >= 201103L 00478 /// See std::pair::swap(). 00479 // Note: no std::swap overloads in C++03 mode, this has performance 00480 // implications, see, eg, libstdc++/38466. 00481 template<typename _T1, typename _T2> 00482 inline 00483 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 00484 // Constrained free swap overload, see p0185r1 00485 typename enable_if<__and_<__is_swappable<_T1>, 00486 __is_swappable<_T2>>::value>::type 00487 #else 00488 void 00489 #endif 00490 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) 00491 noexcept(noexcept(__x.swap(__y))) 00492 { __x.swap(__y); } 00493 00494 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 00495 template<typename _T1, typename _T2> 00496 typename enable_if<!__and_<__is_swappable<_T1>, 00497 __is_swappable<_T2>>::value>::type 00498 swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete; 00499 #endif 00500 #endif // __cplusplus >= 201103L 00501 00502 /** 00503 * @brief A convenience wrapper for creating a pair from two objects. 00504 * @param __x The first object. 00505 * @param __y The second object. 00506 * @return A newly-constructed pair<> object of the appropriate type. 00507 * 00508 * The standard requires that the objects be passed by reference-to-const, 00509 * but LWG issue #181 says they should be passed by const value. We follow 00510 * the LWG by default. 00511 */ 00512 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00513 // 181. make_pair() unintended behavior 00514 #if __cplusplus >= 201103L 00515 // NB: DR 706. 00516 template<typename _T1, typename _T2> 00517 constexpr pair<typename __decay_and_strip<_T1>::__type, 00518 typename __decay_and_strip<_T2>::__type> 00519 make_pair(_T1&& __x, _T2&& __y) 00520 { 00521 typedef typename __decay_and_strip<_T1>::__type __ds_type1; 00522 typedef typename __decay_and_strip<_T2>::__type __ds_type2; 00523 typedef pair<__ds_type1, __ds_type2> __pair_type; 00524 return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); 00525 } 00526 #else 00527 template<typename _T1, typename _T2> 00528 inline pair<_T1, _T2> 00529 make_pair(_T1 __x, _T2 __y) 00530 { return pair<_T1, _T2>(__x, __y); } 00531 #endif 00532 00533 /// @} 00534 00535 _GLIBCXX_END_NAMESPACE_VERSION 00536 } // namespace std 00537 00538 #endif /* _STL_PAIR_H */