libstdc++
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00001 // <utility> -*- C++ -*- 00002 00003 // Copyright (C) 2001-2019 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 include/utility 00052 * This is a Standard C++ Library header. 00053 */ 00054 00055 #ifndef _GLIBCXX_UTILITY 00056 #define _GLIBCXX_UTILITY 1 00057 00058 #pragma GCC system_header 00059 00060 /** 00061 * @defgroup utilities Utilities 00062 * 00063 * Components deemed generally useful. Includes pair, tuple, 00064 * forward/move helpers, ratio, function object, metaprogramming and 00065 * type traits, time, date, and memory functions. 00066 */ 00067 00068 #include <bits/c++config.h> 00069 #include <bits/stl_relops.h> 00070 #include <bits/stl_pair.h> 00071 00072 #if __cplusplus >= 201103L 00073 00074 #include <type_traits> 00075 #include <bits/move.h> 00076 #include <initializer_list> 00077 00078 namespace std _GLIBCXX_VISIBILITY(default) 00079 { 00080 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00081 00082 /// Finds the size of a given tuple type. 00083 template<typename _Tp> 00084 struct tuple_size; 00085 00086 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00087 // 2313. tuple_size should always derive from integral_constant<size_t, N> 00088 // 2770. tuple_size<const T> specialization is not SFINAE compatible 00089 00090 template<typename _Tp, 00091 typename _Up = typename remove_cv<_Tp>::type, 00092 typename = typename enable_if<is_same<_Tp, _Up>::value>::type, 00093 size_t = tuple_size<_Tp>::value> 00094 using __enable_if_has_tuple_size = _Tp; 00095 00096 template<typename _Tp> 00097 struct tuple_size<const __enable_if_has_tuple_size<_Tp>> 00098 : public tuple_size<_Tp> { }; 00099 00100 template<typename _Tp> 00101 struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>> 00102 : public tuple_size<_Tp> { }; 00103 00104 template<typename _Tp> 00105 struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>> 00106 : public tuple_size<_Tp> { }; 00107 00108 /// Gives the type of the ith element of a given tuple type. 00109 template<std::size_t __i, typename _Tp> 00110 struct tuple_element; 00111 00112 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode 00113 template<std::size_t __i, typename _Tp> 00114 using __tuple_element_t = typename tuple_element<__i, _Tp>::type; 00115 00116 template<std::size_t __i, typename _Tp> 00117 struct tuple_element<__i, const _Tp> 00118 { 00119 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type; 00120 }; 00121 00122 template<std::size_t __i, typename _Tp> 00123 struct tuple_element<__i, volatile _Tp> 00124 { 00125 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type; 00126 }; 00127 00128 template<std::size_t __i, typename _Tp> 00129 struct tuple_element<__i, const volatile _Tp> 00130 { 00131 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type; 00132 }; 00133 00134 #if __cplusplus >= 201402L 00135 // The standard says this macro and alias template should be in <tuple> 00136 // but we define them here, to be available when the partial specializations 00137 // of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined. 00138 #define __cpp_lib_tuple_element_t 201402L 00139 00140 template<std::size_t __i, typename _Tp> 00141 using tuple_element_t = typename tuple_element<__i, _Tp>::type; 00142 #endif 00143 00144 // Various functions which give std::pair a tuple-like interface. 00145 00146 /// Partial specialization for std::pair 00147 template<typename _T1, typename _T2> 00148 struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type 00149 { }; 00150 00151 /// Partial specialization for std::pair 00152 template<class _Tp1, class _Tp2> 00153 struct tuple_size<std::pair<_Tp1, _Tp2>> 00154 : public integral_constant<std::size_t, 2> { }; 00155 00156 /// Partial specialization for std::pair 00157 template<class _Tp1, class _Tp2> 00158 struct tuple_element<0, std::pair<_Tp1, _Tp2>> 00159 { typedef _Tp1 type; }; 00160 00161 /// Partial specialization for std::pair 00162 template<class _Tp1, class _Tp2> 00163 struct tuple_element<1, std::pair<_Tp1, _Tp2>> 00164 { typedef _Tp2 type; }; 00165 00166 template<std::size_t _Int> 00167 struct __pair_get; 00168 00169 template<> 00170 struct __pair_get<0> 00171 { 00172 template<typename _Tp1, typename _Tp2> 00173 static constexpr _Tp1& 00174 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept 00175 { return __pair.first; } 00176 00177 template<typename _Tp1, typename _Tp2> 00178 static constexpr _Tp1&& 00179 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept 00180 { return std::forward<_Tp1>(__pair.first); } 00181 00182 template<typename _Tp1, typename _Tp2> 00183 static constexpr const _Tp1& 00184 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept 00185 { return __pair.first; } 00186 00187 template<typename _Tp1, typename _Tp2> 00188 static constexpr const _Tp1&& 00189 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept 00190 { return std::forward<const _Tp1>(__pair.first); } 00191 }; 00192 00193 template<> 00194 struct __pair_get<1> 00195 { 00196 template<typename _Tp1, typename _Tp2> 00197 static constexpr _Tp2& 00198 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept 00199 { return __pair.second; } 00200 00201 template<typename _Tp1, typename _Tp2> 00202 static constexpr _Tp2&& 00203 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept 00204 { return std::forward<_Tp2>(__pair.second); } 00205 00206 template<typename _Tp1, typename _Tp2> 00207 static constexpr const _Tp2& 00208 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept 00209 { return __pair.second; } 00210 00211 template<typename _Tp1, typename _Tp2> 00212 static constexpr const _Tp2&& 00213 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept 00214 { return std::forward<const _Tp2>(__pair.second); } 00215 }; 00216 00217 template<std::size_t _Int, class _Tp1, class _Tp2> 00218 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type& 00219 get(std::pair<_Tp1, _Tp2>& __in) noexcept 00220 { return __pair_get<_Int>::__get(__in); } 00221 00222 template<std::size_t _Int, class _Tp1, class _Tp2> 00223 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&& 00224 get(std::pair<_Tp1, _Tp2>&& __in) noexcept 00225 { return __pair_get<_Int>::__move_get(std::move(__in)); } 00226 00227 template<std::size_t _Int, class _Tp1, class _Tp2> 00228 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type& 00229 get(const std::pair<_Tp1, _Tp2>& __in) noexcept 00230 { return __pair_get<_Int>::__const_get(__in); } 00231 00232 template<std::size_t _Int, class _Tp1, class _Tp2> 00233 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&& 00234 get(const std::pair<_Tp1, _Tp2>&& __in) noexcept 00235 { return __pair_get<_Int>::__const_move_get(std::move(__in)); } 00236 00237 #if __cplusplus > 201103L 00238 00239 #define __cpp_lib_tuples_by_type 201304 00240 00241 template <typename _Tp, typename _Up> 00242 constexpr _Tp& 00243 get(pair<_Tp, _Up>& __p) noexcept 00244 { return __p.first; } 00245 00246 template <typename _Tp, typename _Up> 00247 constexpr const _Tp& 00248 get(const pair<_Tp, _Up>& __p) noexcept 00249 { return __p.first; } 00250 00251 template <typename _Tp, typename _Up> 00252 constexpr _Tp&& 00253 get(pair<_Tp, _Up>&& __p) noexcept 00254 { return std::move(__p.first); } 00255 00256 template <typename _Tp, typename _Up> 00257 constexpr const _Tp&& 00258 get(const pair<_Tp, _Up>&& __p) noexcept 00259 { return std::move(__p.first); } 00260 00261 template <typename _Tp, typename _Up> 00262 constexpr _Tp& 00263 get(pair<_Up, _Tp>& __p) noexcept 00264 { return __p.second; } 00265 00266 template <typename _Tp, typename _Up> 00267 constexpr const _Tp& 00268 get(const pair<_Up, _Tp>& __p) noexcept 00269 { return __p.second; } 00270 00271 template <typename _Tp, typename _Up> 00272 constexpr _Tp&& 00273 get(pair<_Up, _Tp>&& __p) noexcept 00274 { return std::move(__p.second); } 00275 00276 template <typename _Tp, typename _Up> 00277 constexpr const _Tp&& 00278 get(const pair<_Up, _Tp>&& __p) noexcept 00279 { return std::move(__p.second); } 00280 00281 #define __cpp_lib_exchange_function 201304 00282 00283 /// Assign @p __new_val to @p __obj and return its previous value. 00284 template <typename _Tp, typename _Up = _Tp> 00285 inline _Tp 00286 exchange(_Tp& __obj, _Up&& __new_val) 00287 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); } 00288 #endif 00289 00290 // Stores a tuple of indices. Used by tuple and pair, and by bind() to 00291 // extract the elements in a tuple. 00292 template<size_t... _Indexes> struct _Index_tuple { }; 00293 00294 #ifdef __has_builtin 00295 # if __has_builtin(__make_integer_seq) 00296 # define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1 00297 # endif 00298 #endif 00299 00300 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>. 00301 template<size_t _Num> 00302 struct _Build_index_tuple 00303 { 00304 #if _GLIBCXX_USE_MAKE_INTEGER_SEQ 00305 template<typename, size_t... _Indices> 00306 using _IdxTuple = _Index_tuple<_Indices...>; 00307 00308 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>; 00309 #else 00310 using __type = _Index_tuple<__integer_pack(_Num)...>; 00311 #endif 00312 }; 00313 00314 #if __cplusplus > 201103L 00315 00316 #define __cpp_lib_integer_sequence 201304 00317 00318 /// Class template integer_sequence 00319 template<typename _Tp, _Tp... _Idx> 00320 struct integer_sequence 00321 { 00322 typedef _Tp value_type; 00323 static constexpr size_t size() noexcept { return sizeof...(_Idx); } 00324 }; 00325 00326 /// Alias template make_integer_sequence 00327 template<typename _Tp, _Tp _Num> 00328 using make_integer_sequence 00329 #if _GLIBCXX_USE_MAKE_INTEGER_SEQ 00330 = __make_integer_seq<integer_sequence, _Tp, _Num>; 00331 #else 00332 = integer_sequence<_Tp, __integer_pack(_Num)...>; 00333 #endif 00334 00335 #undef _GLIBCXX_USE_MAKE_INTEGER_SEQ 00336 00337 /// Alias template index_sequence 00338 template<size_t... _Idx> 00339 using index_sequence = integer_sequence<size_t, _Idx...>; 00340 00341 /// Alias template make_index_sequence 00342 template<size_t _Num> 00343 using make_index_sequence = make_integer_sequence<size_t, _Num>; 00344 00345 /// Alias template index_sequence_for 00346 template<typename... _Types> 00347 using index_sequence_for = make_index_sequence<sizeof...(_Types)>; 00348 #endif 00349 00350 #if __cplusplus > 201402L 00351 00352 struct in_place_t { 00353 explicit in_place_t() = default; 00354 }; 00355 00356 inline constexpr in_place_t in_place{}; 00357 00358 template<typename _Tp> struct in_place_type_t 00359 { 00360 explicit in_place_type_t() = default; 00361 }; 00362 00363 template<typename _Tp> 00364 inline constexpr in_place_type_t<_Tp> in_place_type{}; 00365 00366 template<size_t _Idx> struct in_place_index_t 00367 { 00368 explicit in_place_index_t() = default; 00369 }; 00370 00371 template<size_t _Idx> 00372 inline constexpr in_place_index_t<_Idx> in_place_index{}; 00373 00374 template<typename> 00375 struct __is_in_place_type_impl : false_type 00376 { }; 00377 00378 template<typename _Tp> 00379 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type 00380 { }; 00381 00382 template<typename _Tp> 00383 struct __is_in_place_type 00384 : public __is_in_place_type_impl<_Tp> 00385 { }; 00386 00387 #define __cpp_lib_as_const 201510 00388 template<typename _Tp> 00389 constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; } 00390 00391 template<typename _Tp> 00392 void as_const(const _Tp&&) = delete; 00393 00394 #endif // C++17 00395 00396 _GLIBCXX_END_NAMESPACE_VERSION 00397 } // namespace 00398 00399 #endif 00400 00401 #endif /* _GLIBCXX_UTILITY */