boost/asio/impl/write_at.hpp

   1 //
   2 // impl/write_at.hpp
   3 // ~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_IMPL_WRITE_AT_HPP
  12 #define BOOST_ASIO_IMPL_WRITE_AT_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/associated_allocator.hpp>
  19 #include <boost/asio/associated_executor.hpp>
  20 #include <boost/asio/buffer.hpp>
  21 #include <boost/asio/completion_condition.hpp>
  22 #include <boost/asio/detail/array_fwd.hpp>
  23 #include <boost/asio/detail/base_from_completion_cond.hpp>
  24 #include <boost/asio/detail/bind_handler.hpp>
  25 #include <boost/asio/detail/consuming_buffers.hpp>
  26 #include <boost/asio/detail/dependent_type.hpp>
  27 #include <boost/asio/detail/handler_alloc_helpers.hpp>
  28 #include <boost/asio/detail/handler_cont_helpers.hpp>
  29 #include <boost/asio/detail/handler_invoke_helpers.hpp>
  30 #include <boost/asio/detail/handler_type_requirements.hpp>
  31 #include <boost/asio/detail/non_const_lvalue.hpp>
  32 #include <boost/asio/detail/throw_error.hpp>
  33
  34 #include <boost/asio/detail/push_options.hpp>
  35
  36 namespace boost {
  37 namespace asio {
  38
  39 namespace detail
  40 {
  41   template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
  42       typename ConstBufferIterator, typename CompletionCondition>
  43   std::size_t write_at_buffer_sequence(SyncRandomAccessWriteDevice& d,
  44       uint64_t offset, const ConstBufferSequence& buffers,
  45       const ConstBufferIterator&, CompletionCondition completion_condition,
  46       boost::system::error_code& ec)
  47   {
  48     ec = boost::system::error_code();
  49     boost::asio::detail::consuming_buffers<const_buffer,
  50         ConstBufferSequence, ConstBufferIterator> tmp(buffers);
  51     while (!tmp.empty())
  52     {
  53       if (std::size_t max_size = detail::adapt_completion_condition_result(
  54             completion_condition(ec, tmp.total_consumed())))
  55       {
  56         tmp.consume(d.write_some_at(offset + tmp.total_consumed(),
  57               tmp.prepare(max_size), ec));
  58       }
  59       else
  60         break;
  61     }
  62     return tmp.total_consumed();;
  63   }
  64 } // namespace detail
  65
  66 template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
  67     typename CompletionCondition>
  68 std::size_t write_at(SyncRandomAccessWriteDevice& d,
  69     uint64_t offset, const ConstBufferSequence& buffers,
  70     CompletionCondition completion_condition, boost::system::error_code& ec)
  71 {
  72   return detail::write_at_buffer_sequence(d, offset, buffers,
  73       boost::asio::buffer_sequence_begin(buffers),
  74       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition), ec);
  75 }
  76
  77 template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
  78 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
  79     uint64_t offset, const ConstBufferSequence& buffers)
  80 {
  81   boost::system::error_code ec;
  82   std::size_t bytes_transferred = write_at(
  83       d, offset, buffers, transfer_all(), ec);
  84   boost::asio::detail::throw_error(ec, "write_at");
  85   return bytes_transferred;
  86 }
  87
  88 template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
  89 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
  90     uint64_t offset, const ConstBufferSequence& buffers,
  91     boost::system::error_code& ec)
  92 {
  93   return write_at(d, offset, buffers, transfer_all(), ec);
  94 }
  95
  96 template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
  97     typename CompletionCondition>
  98 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
  99     uint64_t offset, const ConstBufferSequence& buffers,
 100     CompletionCondition completion_condition)
 101 {
 102   boost::system::error_code ec;
 103   std::size_t bytes_transferred = write_at(d, offset, buffers,
 104       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition), ec);
 105   boost::asio::detail::throw_error(ec, "write_at");
 106   return bytes_transferred;
 107 }
 108
 109 #if !defined(BOOST_ASIO_NO_EXTENSIONS)
 110 #if !defined(BOOST_ASIO_NO_IOSTREAM)
 111
 112 template <typename SyncRandomAccessWriteDevice, typename Allocator,
 113     typename CompletionCondition>
 114 std::size_t write_at(SyncRandomAccessWriteDevice& d,
 115     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
 116     CompletionCondition completion_condition, boost::system::error_code& ec)
 117 {
 118   std::size_t bytes_transferred = write_at(d, offset, b.data(),
 119       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition), ec);
 120   b.consume(bytes_transferred);
 121   return bytes_transferred;
 122 }
 123
 124 template <typename SyncRandomAccessWriteDevice, typename Allocator>
 125 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
 126     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b)
 127 {
 128   boost::system::error_code ec;
 129   std::size_t bytes_transferred = write_at(d, offset, b, transfer_all(), ec);
 130   boost::asio::detail::throw_error(ec, "write_at");
 131   return bytes_transferred;
 132 }
 133
 134 template <typename SyncRandomAccessWriteDevice, typename Allocator>
 135 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
 136     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
 137     boost::system::error_code& ec)
 138 {
 139   return write_at(d, offset, b, transfer_all(), ec);
 140 }
 141
 142 template <typename SyncRandomAccessWriteDevice, typename Allocator,
 143     typename CompletionCondition>
 144 inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
 145     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
 146     CompletionCondition completion_condition)
 147 {
 148   boost::system::error_code ec;
 149   std::size_t bytes_transferred = write_at(d, offset, b,
 150       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition), ec);
 151   boost::asio::detail::throw_error(ec, "write_at");
 152   return bytes_transferred;
 153 }
 154
 155 #endif // !defined(BOOST_ASIO_NO_IOSTREAM)
 156 #endif // !defined(BOOST_ASIO_NO_EXTENSIONS)
 157
 158 namespace detail
 159 {
 160   template <typename AsyncRandomAccessWriteDevice,
 161       typename ConstBufferSequence, typename ConstBufferIterator,
 162       typename CompletionCondition, typename WriteHandler>
 163   class write_at_op
 164     : detail::base_from_completion_cond<CompletionCondition>
 165   {
 166   public:
 167     write_at_op(AsyncRandomAccessWriteDevice& device,
 168         uint64_t offset, const ConstBufferSequence& buffers,
 169         CompletionCondition& completion_condition, WriteHandler& handler)
 170       : detail::base_from_completion_cond<
 171           CompletionCondition>(completion_condition),
 172         device_(device),
 173         offset_(offset),
 174         buffers_(buffers),
 175         start_(0),
 176         handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(handler))
 177     {
 178     }
 179
 180 #if defined(BOOST_ASIO_HAS_MOVE)
 181     write_at_op(const write_at_op& other)
 182       : detail::base_from_completion_cond<CompletionCondition>(other),
 183         device_(other.device_),
 184         offset_(other.offset_),
 185         buffers_(other.buffers_),
 186         start_(other.start_),
 187         handler_(other.handler_)
 188     {
 189     }
 190
 191     write_at_op(write_at_op&& other)
 192       : detail::base_from_completion_cond<CompletionCondition>(
 193           BOOST_ASIO_MOVE_CAST(detail::base_from_completion_cond<
 194             CompletionCondition>)(other)),
 195         device_(other.device_),
 196         offset_(other.offset_),
 197         buffers_(BOOST_ASIO_MOVE_CAST(buffers_type)(other.buffers_)),
 198         start_(other.start_),
 199         handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(other.handler_))
 200     {
 201     }
 202 #endif // defined(BOOST_ASIO_HAS_MOVE)
 203
 204     void operator()(const boost::system::error_code& ec,
 205         std::size_t bytes_transferred, int start = 0)
 206     {
 207       std::size_t max_size;
 208       switch (start_ = start)
 209       {
 210         case 1:
 211         max_size = this->check_for_completion(ec, buffers_.total_consumed());
 212         do
 213         {
 214           device_.async_write_some_at(
 215               offset_ + buffers_.total_consumed(), buffers_.prepare(max_size),
 216               BOOST_ASIO_MOVE_CAST(write_at_op)(*this));
 217           return; default:
 218           buffers_.consume(bytes_transferred);
 219           if ((!ec && bytes_transferred == 0) || buffers_.empty())
 220             break;
 221           max_size = this->check_for_completion(ec, buffers_.total_consumed());
 222         } while (max_size > 0);
 223
 224         handler_(ec, buffers_.total_consumed());
 225       }
 226     }
 227
 228   //private:
 229     typedef boost::asio::detail::consuming_buffers<const_buffer,
 230         ConstBufferSequence, ConstBufferIterator> buffers_type;
 231
 232     AsyncRandomAccessWriteDevice& device_;
 233     uint64_t offset_;
 234     buffers_type buffers_;
 235     int start_;
 236     WriteHandler handler_;
 237   };
 238
 239   template <typename AsyncRandomAccessWriteDevice,
 240       typename ConstBufferSequence, typename ConstBufferIterator,
 241       typename CompletionCondition, typename WriteHandler>
 242   inline void* asio_handler_allocate(std::size_t size,
 243       write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 244         ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
 245   {
 246     return boost_asio_handler_alloc_helpers::allocate(
 247         size, this_handler->handler_);
 248   }
 249
 250   template <typename AsyncRandomAccessWriteDevice,
 251       typename ConstBufferSequence, typename ConstBufferIterator,
 252       typename CompletionCondition, typename WriteHandler>
 253   inline void asio_handler_deallocate(void* pointer, std::size_t size,
 254       write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 255         ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
 256   {
 257     boost_asio_handler_alloc_helpers::deallocate(
 258         pointer, size, this_handler->handler_);
 259   }
 260
 261   template <typename AsyncRandomAccessWriteDevice,
 262       typename ConstBufferSequence, typename ConstBufferIterator,
 263       typename CompletionCondition, typename WriteHandler>
 264   inline bool asio_handler_is_continuation(
 265       write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 266         ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
 267   {
 268     return this_handler->start_ == 0 ? true
 269       : boost_asio_handler_cont_helpers::is_continuation(
 270           this_handler->handler_);
 271   }
 272
 273   template <typename Function, typename AsyncRandomAccessWriteDevice,
 274       typename ConstBufferSequence, typename ConstBufferIterator,
 275       typename CompletionCondition, typename WriteHandler>
 276   inline void asio_handler_invoke(Function& function,
 277       write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 278         ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
 279   {
 280     boost_asio_handler_invoke_helpers::invoke(
 281         function, this_handler->handler_);
 282   }
 283
 284   template <typename Function, typename AsyncRandomAccessWriteDevice,
 285       typename ConstBufferSequence, typename ConstBufferIterator,
 286       typename CompletionCondition, typename WriteHandler>
 287   inline void asio_handler_invoke(const Function& function,
 288       write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 289         ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
 290   {
 291     boost_asio_handler_invoke_helpers::invoke(
 292         function, this_handler->handler_);
 293   }
 294
 295   template <typename AsyncRandomAccessWriteDevice,
 296       typename ConstBufferSequence, typename ConstBufferIterator,
 297       typename CompletionCondition, typename WriteHandler>
 298   inline void start_write_at_buffer_sequence_op(AsyncRandomAccessWriteDevice& d,
 299       uint64_t offset, const ConstBufferSequence& buffers,
 300       const ConstBufferIterator&, CompletionCondition& completion_condition,
 301       WriteHandler& handler)
 302   {
 303     detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 304       ConstBufferIterator, CompletionCondition, WriteHandler>(
 305         d, offset, buffers, completion_condition, handler)(
 306           boost::system::error_code(), 0, 1);
 307   }
 308
 309   template <typename AsyncRandomAccessWriteDevice>
 310   class initiate_async_write_at_buffer_sequence
 311   {
 312   public:
 313     typedef typename AsyncRandomAccessWriteDevice::executor_type executor_type;
 314
 315     explicit initiate_async_write_at_buffer_sequence(
 316         AsyncRandomAccessWriteDevice& device)
 317       : device_(device)
 318     {
 319     }
 320
 321     executor_type get_executor() const BOOST_ASIO_NOEXCEPT
 322     {
 323       return device_.get_executor();
 324     }
 325
 326     template <typename WriteHandler, typename ConstBufferSequence,
 327         typename CompletionCondition>
 328     void operator()(BOOST_ASIO_MOVE_ARG(WriteHandler) handler,
 329         uint64_t offset, const ConstBufferSequence& buffers,
 330         BOOST_ASIO_MOVE_ARG(CompletionCondition) completion_cond) const
 331     {
 332       // If you get an error on the following line it means that your handler
 333       // does not meet the documented type requirements for a WriteHandler.
 334       BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
 335
 336       non_const_lvalue<WriteHandler> handler2(handler);
 337       non_const_lvalue<CompletionCondition> completion_cond2(completion_cond);
 338       start_write_at_buffer_sequence_op(device_, offset, buffers,
 339           boost::asio::buffer_sequence_begin(buffers),
 340           completion_cond2.value, handler2.value);
 341     }
 342
 343   private:
 344     AsyncRandomAccessWriteDevice& device_;
 345   };
 346 } // namespace detail
 347
 348 #if !defined(GENERATING_DOCUMENTATION)
 349
 350 template <typename AsyncRandomAccessWriteDevice,
 351     typename ConstBufferSequence, typename ConstBufferIterator,
 352     typename CompletionCondition, typename WriteHandler, typename Allocator>
 353 struct associated_allocator<
 354     detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 355       ConstBufferIterator, CompletionCondition, WriteHandler>,
 356     Allocator>
 357 {
 358   typedef typename associated_allocator<WriteHandler, Allocator>::type type;
 359
 360   static type get(
 361       const detail::write_at_op<AsyncRandomAccessWriteDevice,
 362         ConstBufferSequence, ConstBufferIterator,
 363         CompletionCondition, WriteHandler>& h,
 364       const Allocator& a = Allocator()) BOOST_ASIO_NOEXCEPT
 365   {
 366     return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
 367   }
 368 };
 369
 370 template <typename AsyncRandomAccessWriteDevice,
 371     typename ConstBufferSequence, typename ConstBufferIterator,
 372     typename CompletionCondition, typename WriteHandler, typename Executor>
 373 struct associated_executor<
 374     detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
 375       ConstBufferIterator, CompletionCondition, WriteHandler>,
 376     Executor>
 377 {
 378   typedef typename associated_executor<WriteHandler, Executor>::type type;
 379
 380   static type get(
 381       const detail::write_at_op<AsyncRandomAccessWriteDevice,
 382         ConstBufferSequence, ConstBufferIterator,
 383         CompletionCondition, WriteHandler>& h,
 384       const Executor& ex = Executor()) BOOST_ASIO_NOEXCEPT
 385   {
 386     return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
 387   }
 388 };
 389
 390 #endif // !defined(GENERATING_DOCUMENTATION)
 391
 392 template <typename AsyncRandomAccessWriteDevice,
 393     typename ConstBufferSequence, typename CompletionCondition,
 394     BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
 395       std::size_t)) WriteHandler>
 396 inline BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
 397     void (boost::system::error_code, std::size_t))
 398 async_write_at(AsyncRandomAccessWriteDevice& d,
 399     uint64_t offset, const ConstBufferSequence& buffers,
 400     CompletionCondition completion_condition,
 401     BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
 402 {
 403   return async_initiate<WriteHandler,
 404     void (boost::system::error_code, std::size_t)>(
 405       detail::initiate_async_write_at_buffer_sequence<
 406         AsyncRandomAccessWriteDevice>(d),
 407       handler, offset, buffers,
 408       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition));
 409 }
 410
 411 template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
 412     BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
 413       std::size_t)) WriteHandler>
 414 inline BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
 415     void (boost::system::error_code, std::size_t))
 416 async_write_at(AsyncRandomAccessWriteDevice& d,
 417     uint64_t offset, const ConstBufferSequence& buffers,
 418     BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
 419 {
 420   return async_initiate<WriteHandler,
 421     void (boost::system::error_code, std::size_t)>(
 422       detail::initiate_async_write_at_buffer_sequence<
 423         AsyncRandomAccessWriteDevice>(d),
 424       handler, offset, buffers, transfer_all());
 425 }
 426
 427 #if !defined(BOOST_ASIO_NO_EXTENSIONS)
 428 #if !defined(BOOST_ASIO_NO_IOSTREAM)
 429
 430 namespace detail
 431 {
 432   template <typename Allocator, typename WriteHandler>
 433   class write_at_streambuf_op
 434   {
 435   public:
 436     write_at_streambuf_op(
 437         boost::asio::basic_streambuf<Allocator>& streambuf,
 438         WriteHandler& handler)
 439       : streambuf_(streambuf),
 440         handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(handler))
 441     {
 442     }
 443
 444 #if defined(BOOST_ASIO_HAS_MOVE)
 445     write_at_streambuf_op(const write_at_streambuf_op& other)
 446       : streambuf_(other.streambuf_),
 447         handler_(other.handler_)
 448     {
 449     }
 450
 451     write_at_streambuf_op(write_at_streambuf_op&& other)
 452       : streambuf_(other.streambuf_),
 453         handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(other.handler_))
 454     {
 455     }
 456 #endif // defined(BOOST_ASIO_HAS_MOVE)
 457
 458     void operator()(const boost::system::error_code& ec,
 459         const std::size_t bytes_transferred)
 460     {
 461       streambuf_.consume(bytes_transferred);
 462       handler_(ec, bytes_transferred);
 463     }
 464
 465   //private:
 466     boost::asio::basic_streambuf<Allocator>& streambuf_;
 467     WriteHandler handler_;
 468   };
 469
 470   template <typename Allocator, typename WriteHandler>
 471   inline void* asio_handler_allocate(std::size_t size,
 472       write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
 473   {
 474     return boost_asio_handler_alloc_helpers::allocate(
 475         size, this_handler->handler_);
 476   }
 477
 478   template <typename Allocator, typename WriteHandler>
 479   inline void asio_handler_deallocate(void* pointer, std::size_t size,
 480       write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
 481   {
 482     boost_asio_handler_alloc_helpers::deallocate(
 483         pointer, size, this_handler->handler_);
 484   }
 485
 486   template <typename Allocator, typename WriteHandler>
 487   inline bool asio_handler_is_continuation(
 488       write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
 489   {
 490     return boost_asio_handler_cont_helpers::is_continuation(
 491         this_handler->handler_);
 492   }
 493
 494   template <typename Function, typename Allocator, typename WriteHandler>
 495   inline void asio_handler_invoke(Function& function,
 496       write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
 497   {
 498     boost_asio_handler_invoke_helpers::invoke(
 499         function, this_handler->handler_);
 500   }
 501
 502   template <typename Function, typename Allocator, typename WriteHandler>
 503   inline void asio_handler_invoke(const Function& function,
 504       write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
 505   {
 506     boost_asio_handler_invoke_helpers::invoke(
 507         function, this_handler->handler_);
 508   }
 509
 510   template <typename AsyncRandomAccessWriteDevice>
 511   class initiate_async_write_at_streambuf
 512   {
 513   public:
 514     typedef typename AsyncRandomAccessWriteDevice::executor_type executor_type;
 515
 516     explicit initiate_async_write_at_streambuf(
 517         AsyncRandomAccessWriteDevice& device)
 518       : device_(device)
 519     {
 520     }
 521
 522     executor_type get_executor() const BOOST_ASIO_NOEXCEPT
 523     {
 524       return device_.get_executor();
 525     }
 526
 527     template <typename WriteHandler,
 528         typename Allocator, typename CompletionCondition>
 529     void operator()(BOOST_ASIO_MOVE_ARG(WriteHandler) handler,
 530         uint64_t offset, basic_streambuf<Allocator>* b,
 531         BOOST_ASIO_MOVE_ARG(CompletionCondition) completion_condition) const
 532     {
 533       // If you get an error on the following line it means that your handler
 534       // does not meet the documented type requirements for a WriteHandler.
 535       BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
 536
 537       non_const_lvalue<WriteHandler> handler2(handler);
 538       async_write_at(device_, offset, b->data(),
 539           BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition),
 540           write_at_streambuf_op<Allocator, typename decay<WriteHandler>::type>(
 541             *b, handler2.value));
 542     }
 543
 544   private:
 545     AsyncRandomAccessWriteDevice& device_;
 546   };
 547 } // namespace detail
 548
 549 #if !defined(GENERATING_DOCUMENTATION)
 550
 551 template <typename Allocator, typename WriteHandler, typename Allocator1>
 552 struct associated_allocator<
 553     detail::write_at_streambuf_op<Allocator, WriteHandler>,
 554     Allocator1>
 555 {
 556   typedef typename associated_allocator<WriteHandler, Allocator1>::type type;
 557
 558   static type get(
 559       const detail::write_at_streambuf_op<Allocator, WriteHandler>& h,
 560       const Allocator1& a = Allocator1()) BOOST_ASIO_NOEXCEPT
 561   {
 562     return associated_allocator<WriteHandler, Allocator1>::get(h.handler_, a);
 563   }
 564 };
 565
 566 template <typename Executor, typename WriteHandler, typename Executor1>
 567 struct associated_executor<
 568     detail::write_at_streambuf_op<Executor, WriteHandler>,
 569     Executor1>
 570 {
 571   typedef typename associated_executor<WriteHandler, Executor1>::type type;
 572
 573   static type get(
 574       const detail::write_at_streambuf_op<Executor, WriteHandler>& h,
 575       const Executor1& ex = Executor1()) BOOST_ASIO_NOEXCEPT
 576   {
 577     return associated_executor<WriteHandler, Executor1>::get(h.handler_, ex);
 578   }
 579 };
 580
 581 #endif // !defined(GENERATING_DOCUMENTATION)
 582
 583 template <typename AsyncRandomAccessWriteDevice,
 584     typename Allocator, typename CompletionCondition,
 585     BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
 586       std::size_t)) WriteHandler>
 587 inline BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
 588     void (boost::system::error_code, std::size_t))
 589 async_write_at(AsyncRandomAccessWriteDevice& d,
 590     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
 591     CompletionCondition completion_condition,
 592     BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
 593 {
 594   return async_initiate<WriteHandler,
 595     void (boost::system::error_code, std::size_t)>(
 596       detail::initiate_async_write_at_streambuf<
 597         AsyncRandomAccessWriteDevice>(d),
 598       handler, offset, &b,
 599       BOOST_ASIO_MOVE_CAST(CompletionCondition)(completion_condition));
 600 }
 601
 602 template <typename AsyncRandomAccessWriteDevice, typename Allocator,
 603     BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
 604       std::size_t)) WriteHandler>
 605 inline BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
 606     void (boost::system::error_code, std::size_t))
 607 async_write_at(AsyncRandomAccessWriteDevice& d,
 608     uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
 609     BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
 610 {
 611   return async_initiate<WriteHandler,
 612     void (boost::system::error_code, std::size_t)>(
 613       detail::initiate_async_write_at_streambuf<
 614         AsyncRandomAccessWriteDevice>(d),
 615       handler, offset, &b, transfer_all());
 616 }
 617
 618 #endif // !defined(BOOST_ASIO_NO_IOSTREAM)
 619 #endif // !defined(BOOST_ASIO_NO_EXTENSIONS)
 620
 621 } // namespace asio
 622 } // namespace boost
 623
 624 #include <boost/asio/detail/pop_options.hpp>
 625
 626 #endif // BOOST_ASIO_IMPL_WRITE_AT_HPP