Where Online Learning is simpler!
The C and C++ Include Header Files
cat -n /usr/include/c++/15/scoped_allocator
1 // <scoped_allocator> -*- C++ -*- 2 3 // Copyright (C) 2011-2025 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 /** @file include/scoped_allocator 26 * This is a Standard C++ Library header. 27 */ 28 29 #ifndef _SCOPED_ALLOCATOR 30 #define _SCOPED_ALLOCATOR 1 31 32 #ifdef _GLIBCXX_SYSHDR 33 #pragma GCC system_header 34 #endif 35 36 #if __cplusplus < 201103L 37 # include <bits/c++0x_warning.h> 38 #else 39 40 #include <tuple> 41 #include <bits/alloc_traits.h> 42 #include <bits/stl_pair.h> 43 #include <bits/uses_allocator.h> 44 #if __cplusplus > 201703L 45 # include <bits/uses_allocator_args.h> 46 #endif 47 48 #define __glibcxx_want_allocator_traits_is_always_equal 49 #include <bits/version.h> 50 51 namespace std _GLIBCXX_VISIBILITY(default) 52 { 53 _GLIBCXX_BEGIN_NAMESPACE_VERSION 54 55 /** 56 * @addtogroup allocators 57 * @{ 58 */ 59 60 template<typename _OuterAlloc, typename... _InnerAllocs> 61 class scoped_allocator_adaptor; 62 63 /// @cond undocumented 64 65 template<typename _Alloc> 66 using __outer_allocator_t 67 = decltype(std::declval<_Alloc>().outer_allocator()); 68 69 template<typename _Alloc, typename = void> 70 struct __outermost_type 71 { 72 using type = _Alloc; 73 static type& _S_outermost(_Alloc& __a) noexcept { return __a; } 74 }; 75 76 template<typename _Alloc> 77 struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>> 78 : __outermost_type< 79 typename remove_reference<__outer_allocator_t<_Alloc>>::type 80 > 81 { 82 using __base = __outermost_type< 83 typename remove_reference<__outer_allocator_t<_Alloc>>::type 84 >; 85 86 static typename __base::type& 87 _S_outermost(_Alloc& __a) noexcept 88 { return __base::_S_outermost(__a.outer_allocator()); } 89 }; 90 91 // Implementation of the OUTERMOST pseudofunction 92 template<typename _Alloc> 93 inline typename __outermost_type<_Alloc>::type& 94 __outermost(_Alloc& __a) 95 { return __outermost_type<_Alloc>::_S_outermost(__a); } 96 97 template<typename...> 98 struct __inner_type_impl; 99 100 template<typename _Outer> 101 struct __inner_type_impl<_Outer> 102 { 103 typedef scoped_allocator_adaptor<_Outer> __type; 104 105 __inner_type_impl() = default; 106 __inner_type_impl(const __inner_type_impl&) = default; 107 __inner_type_impl(__inner_type_impl&&) = default; 108 __inner_type_impl& operator=(const __inner_type_impl&) = default; 109 __inner_type_impl& operator=(__inner_type_impl&&) = default; 110 111 template<typename _Alloc> 112 __inner_type_impl(const __inner_type_impl<_Alloc>&) noexcept 113 { } 114 115 template<typename _Alloc> 116 __inner_type_impl(__inner_type_impl<_Alloc>&&) noexcept 117 { } 118 119 __type& 120 _M_get(__type* __p) noexcept { return *__p; } 121 122 const __type& 123 _M_get(const __type* __p) const noexcept { return *__p; } 124 125 tuple<> 126 _M_tie() const noexcept { return tuple<>(); } 127 128 bool 129 operator==(const __inner_type_impl&) const noexcept 130 { return true; } 131 }; 132 133 template<typename _Outer, typename _InnerHead, typename... _InnerTail> 134 struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...> 135 { 136 typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type; 137 138 __inner_type_impl() = default; 139 __inner_type_impl(const __inner_type_impl&) = default; 140 __inner_type_impl(__inner_type_impl&&) = default; 141 __inner_type_impl& operator=(const __inner_type_impl&) = default; 142 __inner_type_impl& operator=(__inner_type_impl&&) = default; 143 144 template<typename... _Allocs> 145 __inner_type_impl(const __inner_type_impl<_Allocs...>& __other) noexcept 146 : _M_inner(__other._M_inner) { } 147 148 template<typename... _Allocs> 149 __inner_type_impl(__inner_type_impl<_Allocs...>&& __other) noexcept 150 : _M_inner(std::move(__other._M_inner)) { } 151 152 template<typename... _Args> 153 explicit 154 __inner_type_impl(_Args&&... __args) noexcept 155 : _M_inner(std::forward<_Args>(__args)...) { } 156 157 __type& 158 _M_get(void*) noexcept { return _M_inner; } 159 160 const __type& 161 _M_get(const void*) const noexcept { return _M_inner; } 162 163 tuple<const _InnerHead&, const _InnerTail&...> 164 _M_tie() const noexcept 165 { return _M_inner._M_tie(); } 166 167 bool 168 operator==(const __inner_type_impl& __other) const noexcept 169 { return _M_inner == __other._M_inner; } 170 171 private: 172 template<typename...> friend struct __inner_type_impl; 173 template<typename, typename...> friend class scoped_allocator_adaptor; 174 175 __type _M_inner; 176 }; 177 178 /// @endcond 179 180 /// An adaptor to recursively pass an allocator to the objects it constructs 181 template<typename _OuterAlloc, typename... _InnerAllocs> 182 class scoped_allocator_adaptor 183 : public _OuterAlloc 184 { 185 typedef allocator_traits<_OuterAlloc> __traits; 186 187 typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type; 188 __inner_type _M_inner; 189 190 template<typename _Outer, typename... _Inner> 191 friend class scoped_allocator_adaptor; 192 193 template<typename...> 194 friend struct __inner_type_impl; 195 196 tuple<const _OuterAlloc&, const _InnerAllocs&...> 197 _M_tie() const noexcept 198 { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); } 199 200 template<typename _Alloc> 201 using __outermost_alloc_traits 202 = allocator_traits<typename __outermost_type<_Alloc>::type>; 203 204 #if ! __glibcxx_make_obj_using_allocator 205 template<typename _Tp, typename... _Args> 206 void 207 _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args) 208 { 209 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 210 _O_traits::construct(__outermost(*this), __p, 211 std::forward<_Args>(__args)...); 212 } 213 214 typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_; 215 typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_; 216 217 template<typename _Tp, typename... _Args> 218 void 219 _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args) 220 { 221 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 222 _O_traits::construct(__outermost(*this), __p, 223 allocator_arg, inner_allocator(), 224 std::forward<_Args>(__args)...); 225 } 226 227 template<typename _Tp, typename... _Args> 228 void 229 _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args) 230 { 231 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 232 _O_traits::construct(__outermost(*this), __p, 233 std::forward<_Args>(__args)..., 234 inner_allocator()); 235 } 236 #endif // ! make_obj_using_allocator 237 238 template<typename _Alloc> 239 static _Alloc 240 _S_select_on_copy(const _Alloc& __a) 241 { 242 typedef allocator_traits<_Alloc> __a_traits; 243 return __a_traits::select_on_container_copy_construction(__a); 244 } 245 246 template<std::size_t... _Indices> 247 scoped_allocator_adaptor(tuple<const _OuterAlloc&, 248 const _InnerAllocs&...> __refs, 249 _Index_tuple<_Indices...>) 250 : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))), 251 _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...) 252 { } 253 254 // Used to constrain constructors to disallow invalid conversions. 255 template<typename _Alloc> 256 using _Constructible = typename enable_if< 257 is_constructible<_OuterAlloc, _Alloc>::value 258 >::type; 259 260 // _GLIBCXX_RESOLVE_LIB_DEFECTS 261 // 2975. Missing case for pair construction in scoped [...] allocators 262 template<typename _Tp> 263 struct __not_pair { using type = void; }; 264 265 template<typename _Tp, typename _Up> 266 struct __not_pair<pair<_Tp, _Up>> { }; 267 268 public: 269 typedef _OuterAlloc outer_allocator_type; 270 typedef typename __inner_type::__type inner_allocator_type; 271 272 typedef typename __traits::value_type value_type; 273 typedef typename __traits::size_type size_type; 274 typedef typename __traits::difference_type difference_type; 275 typedef typename __traits::pointer pointer; 276 typedef typename __traits::const_pointer const_pointer; 277 typedef typename __traits::void_pointer void_pointer; 278 typedef typename __traits::const_void_pointer const_void_pointer; 279 280 typedef typename __or_< 281 typename __traits::propagate_on_container_copy_assignment, 282 typename allocator_traits<_InnerAllocs>:: 283 propagate_on_container_copy_assignment...>::type 284 propagate_on_container_copy_assignment; 285 286 typedef typename __or_< 287 typename __traits::propagate_on_container_move_assignment, 288 typename allocator_traits<_InnerAllocs>:: 289 propagate_on_container_move_assignment...>::type 290 propagate_on_container_move_assignment; 291 292 typedef typename __or_< 293 typename __traits::propagate_on_container_swap, 294 typename allocator_traits<_InnerAllocs>:: 295 propagate_on_container_swap...>::type 296 propagate_on_container_swap; 297 298 typedef typename __and_< 299 typename __traits::is_always_equal, 300 typename allocator_traits<_InnerAllocs>::is_always_equal...>::type 301 is_always_equal; 302 303 template <class _Tp> 304 struct rebind 305 { 306 typedef scoped_allocator_adaptor< 307 typename __traits::template rebind_alloc<_Tp>, 308 _InnerAllocs...> other; 309 }; 310 311 scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { } 312 313 template<typename _Outer2, typename = _Constructible<_Outer2>> 314 scoped_allocator_adaptor(_Outer2&& __outer, 315 const _InnerAllocs&... __inner) noexcept 316 : _OuterAlloc(std::forward<_Outer2>(__outer)), 317 _M_inner(__inner...) 318 { } 319 320 scoped_allocator_adaptor(const scoped_allocator_adaptor& __other) noexcept 321 : _OuterAlloc(__other.outer_allocator()), 322 _M_inner(__other._M_inner) 323 { } 324 325 scoped_allocator_adaptor(scoped_allocator_adaptor&& __other) noexcept 326 : _OuterAlloc(std::move(__other.outer_allocator())), 327 _M_inner(std::move(__other._M_inner)) 328 { } 329 330 template<typename _Outer2, typename = _Constructible<const _Outer2&>> 331 scoped_allocator_adaptor( 332 const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other 333 ) noexcept 334 : _OuterAlloc(__other.outer_allocator()), 335 _M_inner(__other._M_inner) 336 { } 337 338 template<typename _Outer2, typename = _Constructible<_Outer2>> 339 scoped_allocator_adaptor( 340 scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other) noexcept 341 : _OuterAlloc(std::move(__other.outer_allocator())), 342 _M_inner(std::move(__other._M_inner)) 343 { } 344 345 scoped_allocator_adaptor& 346 operator=(const scoped_allocator_adaptor&) = default; 347 348 scoped_allocator_adaptor& 349 operator=(scoped_allocator_adaptor&&) = default; 350 351 inner_allocator_type& 352 inner_allocator() noexcept 353 { return _M_inner._M_get(this); } 354 355 const inner_allocator_type& 356 inner_allocator() const noexcept 357 { return _M_inner._M_get(this); } 358 359 outer_allocator_type& 360 outer_allocator() noexcept 361 { return static_cast<_OuterAlloc&>(*this); } 362 363 const outer_allocator_type& 364 outer_allocator() const noexcept 365 { return static_cast<const _OuterAlloc&>(*this); } 366 367 _GLIBCXX_NODISCARD pointer 368 allocate(size_type __n) 369 { return __traits::allocate(outer_allocator(), __n); } 370 371 _GLIBCXX_NODISCARD pointer 372 allocate(size_type __n, const_void_pointer __hint) 373 { return __traits::allocate(outer_allocator(), __n, __hint); } 374 375 void deallocate(pointer __p, size_type __n) noexcept 376 { return __traits::deallocate(outer_allocator(), __p, __n); } 377 378 size_type max_size() const 379 { return __traits::max_size(outer_allocator()); } 380 381 #if ! __glibcxx_make_obj_using_allocator 382 template<typename _Tp, typename... _Args> 383 typename __not_pair<_Tp>::type 384 construct(_Tp* __p, _Args&&... __args) 385 { 386 auto& __inner = inner_allocator(); 387 auto __use_tag 388 = std::__use_alloc<_Tp, inner_allocator_type, _Args...>(__inner); 389 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...); 390 } 391 392 template<typename _T1, typename _T2, typename... _Args1, 393 typename... _Args2> 394 void 395 construct(pair<_T1, _T2>* __p, piecewise_construct_t, 396 tuple<_Args1...> __x, tuple<_Args2...> __y) 397 { 398 // _GLIBCXX_RESOLVE_LIB_DEFECTS 399 // 2203. wrong argument types for piecewise construction 400 auto& __inner = inner_allocator(); 401 auto __x_use_tag 402 = std::__use_alloc<_T1, inner_allocator_type, _Args1...>(__inner); 403 auto __y_use_tag 404 = std::__use_alloc<_T2, inner_allocator_type, _Args2...>(__inner); 405 typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices; 406 typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices; 407 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 408 _O_traits::construct(__outermost(*this), __p, piecewise_construct, 409 _M_construct_p(__x_use_tag, __x_indices, __x), 410 _M_construct_p(__y_use_tag, __y_indices, __y)); 411 } 412 413 template<typename _T1, typename _T2> 414 void 415 construct(pair<_T1, _T2>* __p) 416 { construct(__p, piecewise_construct, tuple<>(), tuple<>()); } 417 418 template<typename _T1, typename _T2, typename _Up, typename _Vp> 419 void 420 construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v) 421 { 422 construct(__p, piecewise_construct, 423 std::forward_as_tuple(std::forward<_Up>(__u)), 424 std::forward_as_tuple(std::forward<_Vp>(__v))); 425 } 426 427 template<typename _T1, typename _T2, typename _Up, typename _Vp> 428 void 429 construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x) 430 { 431 construct(__p, piecewise_construct, 432 std::forward_as_tuple(__x.first), 433 std::forward_as_tuple(__x.second)); 434 } 435 436 template<typename _T1, typename _T2, typename _Up, typename _Vp> 437 void 438 construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x) 439 { 440 construct(__p, piecewise_construct, 441 std::forward_as_tuple(std::forward<_Up>(__x.first)), 442 std::forward_as_tuple(std::forward<_Vp>(__x.second))); 443 } 444 #else // make_obj_using_allocator 445 template<typename _Tp, typename... _Args> 446 __attribute__((__nonnull__)) 447 void 448 construct(_Tp* __p, _Args&&... __args) 449 { 450 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 451 std::apply([__p, this](auto&&... __newargs) { 452 _O_traits::construct(__outermost(*this), __p, 453 std::forward<decltype(__newargs)>(__newargs)...); 454 }, 455 uses_allocator_construction_args<_Tp>(inner_allocator(), 456 std::forward<_Args>(__args)...)); 457 } 458 #endif 459 460 template<typename _Tp> 461 void destroy(_Tp* __p) 462 { 463 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits; 464 _O_traits::destroy(__outermost(*this), __p); 465 } 466 467 scoped_allocator_adaptor 468 select_on_container_copy_construction() const 469 { 470 typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type 471 _Indices; 472 return scoped_allocator_adaptor(_M_tie(), _Indices()); 473 } 474 475 template <typename _OutA1, typename _OutA2, typename... _InA> 476 friend bool 477 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a, 478 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept; 479 480 private: 481 #if ! __glibcxx_make_obj_using_allocator 482 template<typename _Ind, typename... _Args> 483 tuple<_Args&&...> 484 _M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t) 485 { return std::move(__t); } 486 487 template<size_t... _Ind, typename... _Args> 488 tuple<allocator_arg_t, inner_allocator_type&, _Args&&...> 489 _M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>, 490 tuple<_Args...>& __t) 491 { 492 return { allocator_arg, inner_allocator(), 493 std::get<_Ind>(std::move(__t))... 494 }; 495 } 496 497 template<size_t... _Ind, typename... _Args> 498 tuple<_Args&&..., inner_allocator_type&> 499 _M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>, 500 tuple<_Args...>& __t) 501 { 502 return { std::get<_Ind>(std::move(__t))..., inner_allocator() }; 503 } 504 #endif // ! make_obj_using_allocator 505 }; 506 507 /// @related std::scoped_allocator_adaptor 508 template <typename _OutA1, typename _OutA2, typename... _InA> 509 inline bool 510 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a, 511 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept 512 { 513 return __a.outer_allocator() == __b.outer_allocator() 514 && __a._M_inner == __b._M_inner; 515 } 516 517 #if __cpp_impl_three_way_comparison < 201907L 518 /// @related std::scoped_allocator_adaptor 519 template <typename _OutA1, typename _OutA2, typename... _InA> 520 inline bool 521 operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a, 522 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept 523 { return !(__a == __b); } 524 #endif 525 526 /// @} 527 528 _GLIBCXX_END_NAMESPACE_VERSION 529 } // namespace 530 531 #endif // C++11 532 533 #endif // _SCOPED_ALLOCATOR
