libstdc++-v3/include/bits/alloc_traits.h

   1 // Allocator traits -*- C++ -*-
   2
   3 // Copyright (C) 2011-2012 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 bits/alloc_traits.h
  26  *  This is an internal header file, included by other library headers.
  27  *  Do not attempt to use it directly. @headername{memory}
  28  */
  29
  30 #ifndef _ALLOC_TRAITS_H
  31 #define _ALLOC_TRAITS_H 1
  32
  33 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  34
  35 #include <bits/ptr_traits.h>
  36 #include <ext/numeric_traits.h>
  37
  38 namespace std _GLIBCXX_VISIBILITY(default)
  39 {
  40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  41
  42   template<typename _Alloc, typename _Tp>
  43     class __alloctr_rebind_helper
  44     {
  45       template<typename _Alloc2, typename _Tp2>
  46         static constexpr bool
  47         _S_chk(typename _Alloc2::template rebind<_Tp2>::other*)
  48         { return true; }
  49
  50       template<typename, typename>
  51         static constexpr bool
  52         _S_chk(...)
  53         { return false; }
  54
  55     public:
  56       static const bool __value = _S_chk<_Alloc, _Tp>(nullptr);
  57     };
  58
  59   template<typename _Alloc, typename _Tp>
  60     const bool __alloctr_rebind_helper<_Alloc, _Tp>::__value;
  61
  62   template<typename _Alloc, typename _Tp,
  63            bool = __alloctr_rebind_helper<_Alloc, _Tp>::__value>
  64     struct __alloctr_rebind;
  65
  66   template<typename _Alloc, typename _Tp>
  67     struct __alloctr_rebind<_Alloc, _Tp, true>
  68     {
  69       typedef typename _Alloc::template rebind<_Tp>::other __type;
  70     };
  71
  72   template<template<typename, typename...> class _Alloc, typename _Tp,
  73             typename _Up, typename... _Args>
  74     struct __alloctr_rebind<_Alloc<_Up, _Args...>, _Tp, false>
  75     {
  76       typedef _Alloc<_Tp, _Args...> __type;
  77     };
  78
  79   /**
  80    * @brief  Uniform interface to all allocator types.
  81    * @ingroup allocators
  82   */
  83   template<typename _Alloc>
  84     struct allocator_traits
  85     {
  86       /// The allocator type
  87       typedef _Alloc allocator_type;
  88       /// The allocated type
  89       typedef typename _Alloc::value_type value_type;
  90
  91 #define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
  92   private: \
  93   template<typename _Tp> \
  94     static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
  95   static _ALT _S_##_NTYPE##_helper(...); \
  96     typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
  97   public:
  98
  99 _GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer, value_type*)
 100
 101       /**
 102        * @brief   The allocator's pointer type.
 103        *
 104        * @c Alloc::pointer if that type exists, otherwise @c value_type*
 105       */
 106       typedef __pointer pointer;
 107
 108 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer,
 109   typename pointer_traits<pointer>::template rebind<const value_type>)
 110
 111       /**
 112        * @brief   The allocator's const pointer type.
 113        *
 114        * @c Alloc::const_pointer if that type exists, otherwise
 115        * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
 116       */
 117       typedef __const_pointer const_pointer;
 118
 119 _GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer,
 120   typename pointer_traits<pointer>::template rebind<void>)
 121
 122       /**
 123        * @brief   The allocator's void pointer type.
 124        *
 125        * @c Alloc::void_pointer if that type exists, otherwise
 126        * <tt> pointer_traits<pointer>::rebind<void> </tt>
 127       */
 128       typedef __void_pointer void_pointer;
 129
 130 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer,
 131   typename pointer_traits<pointer>::template rebind<const void>)
 132
 133       /**
 134        * @brief   The allocator's const void pointer type.
 135        *
 136        * @c Alloc::const_void_pointer if that type exists, otherwise
 137        * <tt> pointer_traits<pointer>::rebind<const void> </tt>
 138       */
 139       typedef __const_void_pointer const_void_pointer;
 140
 141 _GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type,
 142                               typename pointer_traits<pointer>::difference_type)
 143
 144       /**
 145        * @brief   The allocator's difference type
 146        *
 147        * @c Alloc::difference_type if that type exists, otherwise
 148        * <tt> pointer_traits<pointer>::difference_type </tt>
 149       */
 150       typedef __difference_type difference_type;
 151
 152 _GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type,
 153                               typename make_unsigned<difference_type>::type)
 154
 155       /**
 156        * @brief   The allocator's size type
 157        *
 158        * @c Alloc::size_type if that type exists, otherwise
 159        * <tt> make_unsigned<difference_type>::type </tt>
 160       */
 161       typedef __size_type size_type;
 162
 163 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment,
 164                               false_type)
 165
 166       /**
 167        * @brief   How the allocator is propagated on copy assignment
 168        *
 169        * @c Alloc::propagate_on_container_copy_assignment if that type exists,
 170        * otherwise @c false_type
 171       */
 172       typedef __propagate_on_container_copy_assignment
 173         propagate_on_container_copy_assignment;
 174
 175 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment,
 176                               false_type)
 177
 178       /**
 179        * @brief   How the allocator is propagated on move assignment
 180        *
 181        * @c Alloc::propagate_on_container_move_assignment if that type exists,
 182        * otherwise @c false_type
 183       */
 184       typedef __propagate_on_container_move_assignment
 185         propagate_on_container_move_assignment;
 186
 187 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap,
 188                               false_type)
 189
 190       /**
 191        * @brief   How the allocator is propagated on swap
 192        *
 193        * @c Alloc::propagate_on_container_swap if that type exists,
 194        * otherwise @c false_type
 195       */
 196       typedef __propagate_on_container_swap propagate_on_container_swap;
 197
 198 #undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
 199
 200       template<typename _Tp>
 201         using rebind_alloc = typename __alloctr_rebind<_Alloc, _Tp>::__type;
 202       template<typename _Tp>
 203         using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
 204
 205     private:
 206       template<typename _Alloc2>
 207         struct __allocate_helper
 208         {
 209           template<typename _Alloc3,
 210             typename = decltype(std::declval<_Alloc3*>()->allocate(
 211                   std::declval<size_type>(),
 212                   std::declval<const_void_pointer>()))>
 213             static true_type __test(int);
 214
 215           template<typename>
 216             static false_type __test(...);
 217
 218           typedef decltype(__test<_Alloc>(0)) type;
 219           static const bool value = type::value;
 220         };
 221
 222       template<typename _Alloc2>
 223         static typename
 224         enable_if<__allocate_helper<_Alloc2>::value, pointer>::type
 225         _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint)
 226         { return __a.allocate(__n, __hint); }
 227
 228       template<typename _Alloc2>
 229         static typename
 230         enable_if<!__allocate_helper<_Alloc2>::value, pointer>::type
 231         _S_allocate(_Alloc2& __a, size_type __n, ...)
 232         { return __a.allocate(__n); }
 233
 234       template<typename _Tp, typename... _Args>
 235         struct __construct_helper
 236         {
 237           template<typename _Alloc2,
 238             typename = decltype(std::declval<_Alloc2*>()->construct(
 239                   std::declval<_Tp*>(), std::declval<_Args>()...))>
 240             static true_type __test(int);
 241
 242           template<typename>
 243             static false_type __test(...);
 244
 245           typedef decltype(__test<_Alloc>(0)) type;
 246           static const bool value = type::value;
 247         };
 248
 249       template<typename _Tp, typename... _Args>
 250         static typename
 251         enable_if<__construct_helper<_Tp, _Args...>::value, void>::type
 252         _S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
 253         { __a.construct(__p, std::forward<_Args>(__args)...); }
 254
 255       template<typename _Tp, typename... _Args>
 256         static typename
 257         enable_if<!__construct_helper<_Tp, _Args...>::value, void>::type
 258         _S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
 259         { ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
 260
 261       template<typename _Tp>
 262         struct __destroy_helper
 263         {
 264           template<typename _Alloc2,
 265             typename = decltype(std::declval<_Alloc2*>()->destroy(
 266                   std::declval<_Tp*>()))>
 267             static true_type __test(int);
 268
 269           template<typename>
 270             static false_type __test(...);
 271
 272           typedef decltype(__test<_Alloc>(0)) type;
 273           static const bool value = type::value;
 274         };
 275
 276       template<typename _Tp>
 277         static typename enable_if<__destroy_helper<_Tp>::value, void>::type
 278         _S_destroy(_Alloc& __a, _Tp* __p)
 279         { __a.destroy(__p); }
 280
 281       template<typename _Tp>
 282         static typename enable_if<!__destroy_helper<_Tp>::value, void>::type
 283         _S_destroy(_Alloc&, _Tp* __p)
 284         { __p->~_Tp(); }
 285
 286       template<typename _Alloc2>
 287         struct __maxsize_helper
 288         {
 289           template<typename _Alloc3,
 290             typename = decltype(std::declval<_Alloc3*>()->max_size())>
 291             static true_type __test(int);
 292
 293           template<typename>
 294             static false_type __test(...);
 295
 296           typedef decltype(__test<_Alloc2>(0)) type;
 297           static const bool value = type::value;
 298         };
 299
 300       template<typename _Alloc2>
 301         static typename
 302         enable_if<__maxsize_helper<_Alloc2>::value, size_type>::type
 303         _S_max_size(_Alloc2& __a)
 304         { return __a.max_size(); }
 305
 306       template<typename _Alloc2>
 307         static typename
 308         enable_if<!__maxsize_helper<_Alloc2>::value, size_type>::type
 309         _S_max_size(_Alloc2&)
 310         { return __gnu_cxx::__numeric_traits<size_type>::__max; }
 311
 312       template<typename _Alloc2>
 313         struct __select_helper
 314         {
 315           template<typename _Alloc3, typename
 316             = decltype(std::declval<_Alloc3*>()
 317                 ->select_on_container_copy_construction())>
 318             static true_type __test(int);
 319
 320           template<typename>
 321             static false_type __test(...);
 322
 323           typedef decltype(__test<_Alloc2>(0)) type;
 324           static const bool value = type::value;
 325         };
 326       template<typename _Alloc2>
 327         static typename
 328         enable_if<__select_helper<_Alloc2>::value, _Alloc2>::type
 329         _S_select(_Alloc2& __a)
 330         { return __a.select_on_container_copy_construction(); }
 331
 332       template<typename _Alloc2>
 333         static typename
 334         enable_if<!__select_helper<_Alloc2>::value, _Alloc2>::type
 335         _S_select(_Alloc2& __a)
 336         { return __a; }
 337
 338     public:
 339
 340       /**
 341        *  @brief  Allocate memory.
 342        *  @param  __a  An allocator.
 343        *  @param  __n  The number of objects to allocate space for.
 344        *
 345        *  Calls @c a.allocate(n)
 346       */
 347       static pointer
 348       allocate(_Alloc& __a, size_type __n)
 349       { return __a.allocate(__n); }
 350
 351       /**
 352        *  @brief  Allocate memory.
 353        *  @param  __a  An allocator.
 354        *  @param  __n  The number of objects to allocate space for.
 355        *  @param  __hint Aid to locality.
 356        *  @return Memory of suitable size and alignment for @a n objects
 357        *          of type @c value_type
 358        *
 359        *  Returns <tt> a.allocate(n, hint) </tt> if that expression is
 360        *  well-formed, otherwise returns @c a.allocate(n)
 361       */
 362       static pointer
 363       allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
 364       { return _S_allocate(__a, __n, __hint); }
 365
 366       /**
 367        *  @brief  Deallocate memory.
 368        *  @param  __a  An allocator.
 369        *  @param  __p  Pointer to the memory to deallocate.
 370        *  @param  __n  The number of objects space was allocated for.
 371        *
 372        *  Calls <tt> a.deallocate(p, n) </tt>
 373       */
 374       static void deallocate(_Alloc& __a, pointer __p, size_type __n)
 375       { __a.deallocate(__p, __n); }
 376
 377       /**
 378        *  @brief  Construct an object of type @a _Tp
 379        *  @param  __a  An allocator.
 380        *  @param  __p  Pointer to memory of suitable size and alignment for Tp
 381        *  @param  __args Constructor arguments.
 382        *
 383        *  Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
 384        *  if that expression is well-formed, otherwise uses placement-new
 385        *  to construct an object of type @a _Tp at location @a __p from the
 386        *  arguments @a __args...
 387       */
 388       template<typename _Tp, typename... _Args>
 389         static void construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
 390         { _S_construct(__a, __p, std::forward<_Args>(__args)...); }
 391
 392       /**
 393        *  @brief  Destroy an object of type @a _Tp
 394        *  @param  __a  An allocator.
 395        *  @param  __p  Pointer to the object to destroy
 396        *
 397        *  Calls @c __a.destroy(__p) if that expression is well-formed,
 398        *  otherwise calls @c __p->~_Tp()
 399       */
 400       template <class _Tp>
 401         static void destroy(_Alloc& __a, _Tp* __p)
 402         { _S_destroy(__a, __p); }
 403
 404       /**
 405        *  @brief  The maximum supported allocation size
 406        *  @param  __a  An allocator.
 407        *  @return @c __a.max_size() or @c numeric_limits<size_type>::max()
 408        *
 409        *  Returns @c __a.max_size() if that expression is well-formed,
 410        *  otherwise returns @c numeric_limits<size_type>::max()
 411       */
 412       static size_type max_size(const _Alloc& __a)
 413       { return _S_max_size(__a); }
 414
 415       /**
 416        *  @brief  Obtain an allocator to use when copying a container.
 417        *  @param  __rhs  An allocator.
 418        *  @return @c __rhs.select_on_container_copy_construction() or @a __rhs
 419        *
 420        *  Returns @c __rhs.select_on_container_copy_construction() if that
 421        *  expression is well-formed, otherwise returns @a __rhs
 422       */
 423       static _Alloc
 424       select_on_container_copy_construction(const _Alloc& __rhs)
 425       { return _S_select(__rhs); }
 426     };
 427
 428   template<typename _Alloc>
 429   template<typename _Alloc2>
 430     const bool allocator_traits<_Alloc>::__allocate_helper<_Alloc2>::value;
 431
 432   template<typename _Alloc>
 433   template<typename _Tp, typename... _Args>
 434     const bool
 435     allocator_traits<_Alloc>::__construct_helper<_Tp, _Args...>::value;
 436
 437   template<typename _Alloc>
 438   template<typename _Tp>
 439     const bool allocator_traits<_Alloc>::__destroy_helper<_Tp>::value;
 440
 441   template<typename _Alloc>
 442   template<typename _Alloc2>
 443     const bool allocator_traits<_Alloc>::__maxsize_helper<_Alloc2>::value;
 444
 445   template<typename _Alloc>
 446   template<typename _Alloc2>
 447     const bool allocator_traits<_Alloc>::__select_helper<_Alloc2>::value;
 448
 449   template<typename _Alloc>
 450     inline void
 451     __do_alloc_on_copy(_Alloc& __one, const _Alloc& __two, true_type)
 452     { __one = __two; }
 453
 454   template<typename _Alloc>
 455     inline void
 456     __do_alloc_on_copy(_Alloc&, const _Alloc&, false_type)
 457     { }
 458
 459   template<typename _Alloc>
 460     inline void __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
 461     {
 462       typedef allocator_traits<_Alloc> __traits;
 463       typedef typename __traits::propagate_on_container_copy_assignment __pocca;
 464       __do_alloc_on_copy(__one, __two, __pocca());
 465     }
 466
 467   template<typename _Alloc>
 468     inline _Alloc __alloc_on_copy(const _Alloc& __a)
 469     {
 470       typedef allocator_traits<_Alloc> __traits;
 471       return __traits::select_on_container_copy_construction(__a);
 472     }
 473
 474   template<typename _Alloc>
 475     inline void __do_alloc_on_move(_Alloc& __one, _Alloc& __two, true_type)
 476     { __one = std::move(__two); }
 477
 478   template<typename _Alloc>
 479     inline void __do_alloc_on_move(_Alloc&, _Alloc&, false_type)
 480     { }
 481
 482   template<typename _Alloc>
 483     inline void __alloc_on_move(_Alloc& __one, _Alloc& __two)
 484     {
 485       typedef allocator_traits<_Alloc> __traits;
 486       typedef typename __traits::propagate_on_container_move_assignment __pocma;
 487       __do_alloc_on_move(__one, __two, __pocma());
 488     }
 489
 490   template<typename _Alloc>
 491     inline void __do_alloc_on_swap(_Alloc& __one, _Alloc& __two, true_type)
 492     {
 493       using std::swap;
 494       swap(__one, __two);
 495     }
 496
 497   template<typename _Alloc>
 498     inline void __do_alloc_on_swap(_Alloc&, _Alloc&, false_type)
 499     { }
 500
 501   template<typename _Alloc>
 502     inline void __alloc_on_swap(_Alloc& __one, _Alloc& __two)
 503     {
 504       typedef allocator_traits<_Alloc> __traits;
 505       typedef typename __traits::propagate_on_container_swap __pocs;
 506       __do_alloc_on_swap(__one, __two, __pocs());
 507     }
 508
 509 _GLIBCXX_END_NAMESPACE_VERSION
 510 } // namespace std
 511
 512 #endif
 513 #endif