libstdc++-v3/include/std/scoped_allocator

   1 // <scoped_allocator> -*- C++ -*-
   2
   3 // Copyright (C) 2011-2018 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 #pragma GCC system_header
  33
  34 #if __cplusplus < 201103L
  35 # include <bits/c++0x_warning.h>
  36 #else
  37
  38 #include <utility>
  39 #include <tuple>
  40 #include <bits/alloc_traits.h>
  41
  42 namespace std _GLIBCXX_VISIBILITY(default)
  43 {
  44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  45
  46   /**
  47    * @addtogroup allocators
  48    * @{
  49    */
  50
  51   template<typename _Alloc>
  52     using __outer_allocator_t
  53       = decltype(std::declval<_Alloc>().outer_allocator());
  54
  55   template<typename _Alloc, typename = void>
  56     struct __outermost_type
  57     {
  58       using type = _Alloc;
  59       static type& _S_outermost(_Alloc& __a) { return __a; }
  60     };
  61
  62   template<typename _Alloc>
  63     struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>>
  64     : __outermost_type<
  65       typename remove_reference<__outer_allocator_t<_Alloc>>::type
  66     >
  67     {
  68       using __base = __outermost_type<
  69         typename remove_reference<__outer_allocator_t<_Alloc>>::type
  70       >;
  71
  72       static typename __base::type&
  73       _S_outermost(_Alloc& __a)
  74       { return __base::_S_outermost(__a.outer_allocator()); }
  75     };
  76
  77   template<typename _Alloc>
  78     inline typename __outermost_type<_Alloc>::type&
  79     __outermost(_Alloc& __a)
  80     { return __outermost_type<_Alloc>::_S_outermost(__a); }
  81
  82   template<typename _OuterAlloc, typename... _InnerAllocs>
  83     class scoped_allocator_adaptor;
  84
  85   template<typename...>
  86     struct __inner_type_impl;
  87
  88   template<typename _Outer>
  89     struct __inner_type_impl<_Outer>
  90     {
  91       typedef scoped_allocator_adaptor<_Outer> __type;
  92
  93       __inner_type_impl() = default;
  94       __inner_type_impl(const __inner_type_impl&) = default;
  95       __inner_type_impl(__inner_type_impl&&) = default;
  96       __inner_type_impl& operator=(const __inner_type_impl&) = default;
  97       __inner_type_impl& operator=(__inner_type_impl&&) = default;
  98
  99       template<typename _Alloc>
 100       __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
 101       { }
 102
 103       template<typename _Alloc>
 104       __inner_type_impl(__inner_type_impl<_Alloc>&& __other)
 105       { }
 106
 107       __type&
 108       _M_get(__type* __p) noexcept { return *__p; }
 109
 110       const __type&
 111       _M_get(const __type* __p) const noexcept { return *__p; }
 112
 113       tuple<>
 114       _M_tie() const noexcept { return tuple<>(); }
 115
 116       bool
 117       operator==(const __inner_type_impl&) const noexcept
 118       { return true; }
 119     };
 120
 121   template<typename _Outer, typename _InnerHead, typename... _InnerTail>
 122     struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...>
 123     {
 124       typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type;
 125
 126       __inner_type_impl() = default;
 127       __inner_type_impl(const __inner_type_impl&) = default;
 128       __inner_type_impl(__inner_type_impl&&) = default;
 129       __inner_type_impl& operator=(const __inner_type_impl&) = default;
 130       __inner_type_impl& operator=(__inner_type_impl&&) = default;
 131
 132       template<typename... _Allocs>
 133       __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
 134       : _M_inner(__other._M_inner) { }
 135
 136       template<typename... _Allocs>
 137       __inner_type_impl(__inner_type_impl<_Allocs...>&& __other)
 138       : _M_inner(std::move(__other._M_inner)) { }
 139
 140     template<typename... _Args>
 141       explicit
 142       __inner_type_impl(_Args&&... __args)
 143       : _M_inner(std::forward<_Args>(__args)...) { }
 144
 145       __type&
 146       _M_get(void*) noexcept { return _M_inner; }
 147
 148       const __type&
 149       _M_get(const void*) const noexcept { return _M_inner; }
 150
 151       tuple<const _InnerHead&, const _InnerTail&...>
 152       _M_tie() const noexcept
 153       { return _M_inner._M_tie(); }
 154
 155       bool
 156       operator==(const __inner_type_impl& __other) const noexcept
 157       { return _M_inner == __other._M_inner; }
 158
 159     private:
 160       template<typename...> friend class __inner_type_impl;
 161       template<typename, typename...> friend class scoped_allocator_adaptor;
 162
 163       __type _M_inner;
 164     };
 165
 166   /// Primary class template.
 167   template<typename _OuterAlloc, typename... _InnerAllocs>
 168     class scoped_allocator_adaptor
 169     : public _OuterAlloc
 170     {
 171       typedef allocator_traits<_OuterAlloc> __traits;
 172
 173       typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type;
 174       __inner_type _M_inner;
 175
 176       template<typename _Outer, typename... _Inner>
 177         friend class scoped_allocator_adaptor;
 178
 179       template<typename...>
 180         friend class __inner_type_impl;
 181
 182       tuple<const _OuterAlloc&, const _InnerAllocs&...>
 183       _M_tie() const noexcept
 184       { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); }
 185
 186       template<typename _Alloc>
 187         using __outermost_alloc_traits
 188           = allocator_traits<typename __outermost_type<_Alloc>::type>;
 189
 190       template<typename _Tp, typename... _Args>
 191         void
 192         _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
 193         {
 194           typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
 195           _O_traits::construct(__outermost(*this), __p,
 196                                std::forward<_Args>(__args)...);
 197         }
 198
 199       typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_;
 200       typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_;
 201
 202       template<typename _Tp, typename... _Args>
 203         void
 204         _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args)
 205         {
 206           typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
 207           _O_traits::construct(__outermost(*this), __p,
 208                                allocator_arg, inner_allocator(),
 209                                std::forward<_Args>(__args)...);
 210         }
 211
 212       template<typename _Tp, typename... _Args>
 213         void
 214         _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args)
 215         {
 216           typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
 217           _O_traits::construct(__outermost(*this), __p,
 218                                std::forward<_Args>(__args)...,
 219                                inner_allocator());
 220         }
 221
 222       template<typename _Alloc>
 223         static _Alloc
 224         _S_select_on_copy(const _Alloc& __a)
 225         {
 226           typedef allocator_traits<_Alloc> __a_traits;
 227           return __a_traits::select_on_container_copy_construction(__a);
 228         }
 229
 230       template<std::size_t... _Indices>
 231         scoped_allocator_adaptor(tuple<const _OuterAlloc&,
 232                                        const _InnerAllocs&...> __refs,
 233                                  _Index_tuple<_Indices...>)
 234         : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))),
 235           _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...)
 236         { }
 237
 238       // Used to constrain constructors to disallow invalid conversions.
 239       template<typename _Alloc>
 240         using _Constructible = typename enable_if<
 241             is_constructible<_OuterAlloc, _Alloc>::value
 242           >::type;
 243
 244     public:
 245       typedef _OuterAlloc                       outer_allocator_type;
 246       typedef typename __inner_type::__type     inner_allocator_type;
 247
 248       typedef typename __traits::value_type             value_type;
 249       typedef typename __traits::size_type              size_type;
 250       typedef typename __traits::difference_type        difference_type;
 251       typedef typename __traits::pointer                pointer;
 252       typedef typename __traits::const_pointer          const_pointer;
 253       typedef typename __traits::void_pointer           void_pointer;
 254       typedef typename __traits::const_void_pointer     const_void_pointer;
 255
 256       typedef typename __or_<
 257         typename __traits::propagate_on_container_copy_assignment,
 258         typename allocator_traits<_InnerAllocs>::
 259           propagate_on_container_copy_assignment...>::type
 260           propagate_on_container_copy_assignment;
 261
 262       typedef typename __or_<
 263         typename __traits::propagate_on_container_move_assignment,
 264         typename allocator_traits<_InnerAllocs>::
 265           propagate_on_container_move_assignment...>::type
 266           propagate_on_container_move_assignment;
 267
 268       typedef typename __or_<
 269         typename __traits::propagate_on_container_swap,
 270         typename allocator_traits<_InnerAllocs>::
 271           propagate_on_container_swap...>::type
 272           propagate_on_container_swap;
 273
 274       typedef typename __and_<
 275         typename __traits::is_always_equal,
 276         typename allocator_traits<_InnerAllocs>::is_always_equal...>::type
 277           is_always_equal;
 278
 279       template <class _Tp>
 280         struct rebind
 281         {
 282           typedef scoped_allocator_adaptor<
 283             typename __traits::template rebind_alloc<_Tp>,
 284             _InnerAllocs...> other;
 285         };
 286
 287       scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { }
 288
 289       template<typename _Outer2, typename = _Constructible<_Outer2>>
 290         scoped_allocator_adaptor(_Outer2&& __outer,
 291                                  const _InnerAllocs&... __inner)
 292         : _OuterAlloc(std::forward<_Outer2>(__outer)),
 293           _M_inner(__inner...)
 294         { }
 295
 296       scoped_allocator_adaptor(const scoped_allocator_adaptor& __other)
 297       : _OuterAlloc(__other.outer_allocator()),
 298         _M_inner(__other._M_inner)
 299       { }
 300
 301       scoped_allocator_adaptor(scoped_allocator_adaptor&& __other)
 302       : _OuterAlloc(std::move(__other.outer_allocator())),
 303         _M_inner(std::move(__other._M_inner))
 304       { }
 305
 306       template<typename _Outer2, typename = _Constructible<const _Outer2&>>
 307         scoped_allocator_adaptor(
 308             const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other)
 309         : _OuterAlloc(__other.outer_allocator()),
 310           _M_inner(__other._M_inner)
 311         { }
 312
 313       template<typename _Outer2, typename = _Constructible<_Outer2>>
 314         scoped_allocator_adaptor(
 315             scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other)
 316         : _OuterAlloc(std::move(__other.outer_allocator())),
 317           _M_inner(std::move(__other._M_inner))
 318         { }
 319
 320       scoped_allocator_adaptor&
 321       operator=(const scoped_allocator_adaptor&) = default;
 322
 323       scoped_allocator_adaptor&
 324       operator=(scoped_allocator_adaptor&&) = default;
 325
 326       inner_allocator_type& inner_allocator() noexcept
 327       { return _M_inner._M_get(this); }
 328
 329       const inner_allocator_type& inner_allocator() const noexcept
 330       { return _M_inner._M_get(this); }
 331
 332       outer_allocator_type& outer_allocator() noexcept
 333       { return static_cast<_OuterAlloc&>(*this); }
 334
 335       const outer_allocator_type& outer_allocator() const noexcept
 336       { return static_cast<const _OuterAlloc&>(*this); }
 337
 338       pointer allocate(size_type __n)
 339       { return __traits::allocate(outer_allocator(), __n); }
 340
 341       pointer allocate(size_type __n, const_void_pointer __hint)
 342       { return __traits::allocate(outer_allocator(), __n, __hint); }
 343
 344       void deallocate(pointer __p, size_type __n)
 345       { return __traits::deallocate(outer_allocator(), __p, __n); }
 346
 347       size_type max_size() const
 348       { return __traits::max_size(outer_allocator()); }
 349
 350       template<typename _Tp, typename... _Args>
 351         void construct(_Tp* __p, _Args&&... __args)
 352         {
 353           auto& __inner = inner_allocator();
 354           auto __use_tag
 355             = __use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
 356           _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
 357         }
 358
 359       template<typename _T1, typename _T2, typename... _Args1,
 360                typename... _Args2>
 361         void
 362         construct(pair<_T1, _T2>* __p, piecewise_construct_t,
 363                   tuple<_Args1...> __x, tuple<_Args2...> __y)
 364         {
 365           // _GLIBCXX_RESOLVE_LIB_DEFECTS
 366           // 2203.  wrong argument types for piecewise construction
 367           auto& __inner = inner_allocator();
 368           auto __x_use_tag
 369             = __use_alloc<_T1, inner_allocator_type, _Args1...>(__inner);
 370           auto __y_use_tag
 371             = __use_alloc<_T2, inner_allocator_type, _Args2...>(__inner);
 372           typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices;
 373           typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices;
 374           typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
 375           _O_traits::construct(__outermost(*this), __p, piecewise_construct,
 376                                _M_construct_p(__x_use_tag, __x_indices, __x),
 377                                _M_construct_p(__y_use_tag, __y_indices, __y));
 378         }
 379
 380       template<typename _T1, typename _T2>
 381         void
 382         construct(pair<_T1, _T2>* __p)
 383         { construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
 384
 385       template<typename _T1, typename _T2, typename _Up, typename _Vp>
 386         void
 387         construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v)
 388         {
 389           construct(__p, piecewise_construct,
 390                     std::forward_as_tuple(std::forward<_Up>(__u)),
 391                     std::forward_as_tuple(std::forward<_Vp>(__v)));
 392         }
 393
 394       template<typename _T1, typename _T2, typename _Up, typename _Vp>
 395         void
 396         construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x)
 397         {
 398           construct(__p, piecewise_construct,
 399                     std::forward_as_tuple(__x.first),
 400                     std::forward_as_tuple(__x.second));
 401         }
 402
 403       template<typename _T1, typename _T2, typename _Up, typename _Vp>
 404         void
 405         construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x)
 406         {
 407           construct(__p, piecewise_construct,
 408                     std::forward_as_tuple(std::forward<_Up>(__x.first)),
 409                     std::forward_as_tuple(std::forward<_Vp>(__x.second)));
 410         }
 411
 412       template<typename _Tp>
 413         void destroy(_Tp* __p)
 414         {
 415           typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
 416           _O_traits::destroy(__outermost(*this), __p);
 417         }
 418
 419       scoped_allocator_adaptor
 420       select_on_container_copy_construction() const
 421       {
 422         typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type
 423             _Indices;
 424         return scoped_allocator_adaptor(_M_tie(), _Indices());
 425       }
 426
 427       template <typename _OutA1, typename _OutA2, typename... _InA>
 428       friend bool
 429       operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
 430                  const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
 431
 432     private:
 433       template<typename _Ind, typename... _Args>
 434         tuple<_Args&&...>
 435         _M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
 436         { return std::move(__t); }
 437
 438       template<size_t... _Ind, typename... _Args>
 439         tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
 440         _M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>,
 441                        tuple<_Args...>& __t)
 442         {
 443           return { allocator_arg, inner_allocator(),
 444               std::get<_Ind>(std::move(__t))...
 445           };
 446         }
 447
 448       template<size_t... _Ind, typename... _Args>
 449         tuple<_Args&&..., inner_allocator_type&>
 450         _M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>,
 451                        tuple<_Args...>& __t)
 452         {
 453           return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
 454         }
 455     };
 456
 457   template <typename _OutA1, typename _OutA2, typename... _InA>
 458     inline bool
 459     operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
 460                const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
 461     {
 462       return __a.outer_allocator() == __b.outer_allocator()
 463           && __a._M_inner == __b._M_inner;
 464     }
 465
 466   template <typename _OutA1, typename _OutA2, typename... _InA>
 467     inline bool
 468     operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
 469                const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
 470     { return !(__a == __b); }
 471
 472   /// @}
 473
 474 _GLIBCXX_END_NAMESPACE_VERSION
 475 } // namespace
 476
 477 #endif // C++11
 478
 479 #endif // _SCOPED_ALLOCATOR