comparison DEPENDENCIES/generic/include/boost/asio/impl/read_at.hpp @ 16:2665513ce2d3

Add boost headers

+//
+// impl/read_at.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BOOST_ASIO_IMPL_READ_AT_HPP
+#define BOOST_ASIO_IMPL_READ_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <algorithm>
+#include <boost/asio/buffer.hpp>
+#include <boost/asio/completion_condition.hpp>
+#include <boost/asio/detail/array_fwd.hpp>
+#include <boost/asio/detail/base_from_completion_cond.hpp>
+#include <boost/asio/detail/bind_handler.hpp>
+#include <boost/asio/detail/consuming_buffers.hpp>
+#include <boost/asio/detail/dependent_type.hpp>
+#include <boost/asio/detail/handler_alloc_helpers.hpp>
+#include <boost/asio/detail/handler_cont_helpers.hpp>
+#include <boost/asio/detail/handler_invoke_helpers.hpp>
+#include <boost/asio/detail/handler_type_requirements.hpp>
+#include <boost/asio/detail/throw_error.hpp>
+#include <boost/asio/error.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition, boost::system::error_code& ec)
+{
+  ec = boost::system::error_code();
+  boost::asio::detail::consuming_buffers<
+    mutable_buffer, MutableBufferSequence> tmp(buffers);
+  std::size_t total_transferred = 0;
+  tmp.prepare(detail::adapt_completion_condition_result(
+        completion_condition(ec, total_transferred)));
+  while (tmp.begin() != tmp.end())
+  {
+    std::size_t bytes_transferred = d.read_some_at(
+        offset + total_transferred, tmp, ec);
+    tmp.consume(bytes_transferred);
+    total_transferred += bytes_transferred;
+    tmp.prepare(detail::adapt_completion_condition_result(
+          completion_condition(ec, total_transferred)));
+  }
+  return total_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers)
+{
+  boost::system::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, buffers, transfer_all(), ec);
+  boost::asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    boost::system::error_code& ec)
+{
+  return read_at(d, offset, buffers, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition)
+{
+  boost::system::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, buffers, completion_condition, ec);
+  boost::asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+#if !defined(BOOST_ASIO_NO_IOSTREAM)
+
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, boost::system::error_code& ec)
+{
+  ec = boost::system::error_code();
+  std::size_t total_transferred = 0;
+  std::size_t max_size = detail::adapt_completion_condition_result(
+        completion_condition(ec, total_transferred));
+  std::size_t bytes_available = read_size_helper(b, max_size);
+  while (bytes_available > 0)
+  {
+    std::size_t bytes_transferred = d.read_some_at(
+        offset + total_transferred, b.prepare(bytes_available), ec);
+    b.commit(bytes_transferred);
+    total_transferred += bytes_transferred;
+    max_size = detail::adapt_completion_condition_result(
+          completion_condition(ec, total_transferred));
+    bytes_available = read_size_helper(b, max_size);
+  }
+  return total_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b)
+{
+  boost::system::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, b, transfer_all(), ec);
+  boost::asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
+    boost::system::error_code& ec)
+{
+  return read_at(d, offset, b, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition)
+{
+  boost::system::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, b, completion_condition, ec);
+  boost::asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+#endif // !defined(BOOST_ASIO_NO_IOSTREAM)
+
+namespace detail
+{
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  class read_at_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, const MutableBufferSequence& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffers_(buffers),
+        start_(0),
+        total_transferred_(0),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+    read_at_op(const read_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_op(read_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+
+    void operator()(const boost::system::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      switch (start_ = start)
+      {
+        case 1:
+        buffers_.prepare(this->check_for_completion(ec, total_transferred_));
+        for (;;)
+        {
+          device_.async_read_some_at(offset_ + total_transferred_,
+              buffers_, BOOST_ASIO_MOVE_CAST(read_at_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          buffers_.consume(bytes_transferred);
+          buffers_.prepare(this->check_for_completion(ec, total_transferred_));
+          if ((!ec && bytes_transferred == 0)
+              || buffers_.begin() == buffers_.end())
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    boost::asio::detail::consuming_buffers<
+      mutable_buffer, MutableBufferSequence> buffers_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_op<AsyncRandomAccessReadDevice,
+      boost::asio::mutable_buffers_1, CompletionCondition, ReadHandler>
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, const boost::asio::mutable_buffers_1& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffer_(buffers),
+        start_(0),
+        total_transferred_(0),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+    read_at_op(const read_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffer_(other.buffer_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_op(read_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffer_(other.buffer_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+
+    void operator()(const boost::system::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t n = 0;
+      switch (start_ = start)
+      {
+        case 1:
+        n = this->check_for_completion(ec, total_transferred_);
+        for (;;)
+        {
+          device_.async_read_some_at(offset_ + total_transferred_,
+              boost::asio::buffer(buffer_ + total_transferred_, n),
+              BOOST_ASIO_MOVE_CAST(read_at_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          if ((!ec && bytes_transferred == 0)
+              || (n = this->check_for_completion(ec, total_transferred_)) == 0
+              || total_transferred_ == boost::asio::buffer_size(buffer_))
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    boost::asio::mutable_buffer buffer_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessReadDevice, typename Elem,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_op<AsyncRandomAccessReadDevice, boost::array<Elem, 2>,
+      CompletionCondition, ReadHandler>
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, const boost::array<Elem, 2>& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffers_(buffers),
+        start_(0),
+        total_transferred_(0),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+    read_at_op(const read_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_op(read_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+
+    void operator()(const boost::system::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      typename boost::asio::detail::dependent_type<Elem,
+          boost::array<boost::asio::mutable_buffer, 2> >::type bufs = {{
+        boost::asio::mutable_buffer(buffers_[0]),
+        boost::asio::mutable_buffer(buffers_[1]) }};
+      std::size_t buffer_size0 = boost::asio::buffer_size(bufs[0]);
+      std::size_t buffer_size1 = boost::asio::buffer_size(bufs[1]);
+      std::size_t n = 0;
+      switch (start_ = start)
+      {
+        case 1:
+        n = this->check_for_completion(ec, total_transferred_);
+        for (;;)
+        {
+          bufs[0] = boost::asio::buffer(bufs[0] + total_transferred_, n);
+          bufs[1] = boost::asio::buffer(
+              bufs[1] + (total_transferred_ < buffer_size0
+                ? 0 : total_transferred_ - buffer_size0),
+              n - boost::asio::buffer_size(bufs[0]));
+          device_.async_read_some_at(offset_ + total_transferred_,
+              bufs, BOOST_ASIO_MOVE_CAST(read_at_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          if ((!ec && bytes_transferred == 0)
+              || (n = this->check_for_completion(ec, total_transferred_)) == 0
+              || total_transferred_ == buffer_size0 + buffer_size1)
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    boost::array<Elem, 2> buffers_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+#if defined(BOOST_ASIO_HAS_STD_ARRAY)
+
+  template <typename AsyncRandomAccessReadDevice, typename Elem,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_op<AsyncRandomAccessReadDevice, std::array<Elem, 2>,
+      CompletionCondition, ReadHandler>
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, const std::array<Elem, 2>& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffers_(buffers),
+        start_(0),
+        total_transferred_(0),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+    read_at_op(const read_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_op(read_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+
+    void operator()(const boost::system::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      typename boost::asio::detail::dependent_type<Elem,
+          std::array<boost::asio::mutable_buffer, 2> >::type bufs = {{
+        boost::asio::mutable_buffer(buffers_[0]),
+        boost::asio::mutable_buffer(buffers_[1]) }};
+      std::size_t buffer_size0 = boost::asio::buffer_size(bufs[0]);
+      std::size_t buffer_size1 = boost::asio::buffer_size(bufs[1]);
+      std::size_t n = 0;
+      switch (start_ = start)
+      {
+        case 1:
+        n = this->check_for_completion(ec, total_transferred_);
+        for (;;)
+        {
+          bufs[0] = boost::asio::buffer(bufs[0] + total_transferred_, n);
+          bufs[1] = boost::asio::buffer(
+              bufs[1] + (total_transferred_ < buffer_size0
+                ? 0 : total_transferred_ - buffer_size0),
+              n - boost::asio::buffer_size(bufs[0]));
+          device_.async_read_some_at(offset_ + total_transferred_,
+              bufs, BOOST_ASIO_MOVE_CAST(read_at_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          if ((!ec && bytes_transferred == 0)
+              || (n = this->check_for_completion(ec, total_transferred_)) == 0
+              || total_transferred_ == buffer_size0 + buffer_size1)
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    std::array<Elem, 2> buffers_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+#endif // defined(BOOST_ASIO_HAS_STD_ARRAY)
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return boost_asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : boost_asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename CompletionCondition,
+      typename ReadHandler>
+  inline read_at_op<AsyncRandomAccessReadDevice,
+      MutableBufferSequence, CompletionCondition, ReadHandler>
+  make_read_at_op(AsyncRandomAccessReadDevice& d,
+      uint64_t offset, const MutableBufferSequence& buffers,
+      CompletionCondition completion_condition, ReadHandler handler)
+  {
+    return read_at_op<AsyncRandomAccessReadDevice,
+      MutableBufferSequence, CompletionCondition, ReadHandler>(
+        d, offset, buffers, completion_condition, handler);
+  }
+} // namespace detail
+
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition, typename ReadHandler>
+inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (boost::system::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  detail::async_result_init<
+    ReadHandler, void (boost::system::error_code, std::size_t)> init(
+      BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
+
+  detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+    CompletionCondition, BOOST_ASIO_HANDLER_TYPE(ReadHandler,
+      void (boost::system::error_code, std::size_t))>(
+        d, offset, buffers, completion_condition, init.handler)(
+          boost::system::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename ReadHandler>
+inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (boost::system::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  detail::async_result_init<
+    ReadHandler, void (boost::system::error_code, std::size_t)> init(
+      BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
+
+  detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+    detail::transfer_all_t, BOOST_ASIO_HANDLER_TYPE(ReadHandler,
+      void (boost::system::error_code, std::size_t))>(
+        d, offset, buffers, transfer_all(), init.handler)(
+          boost::system::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#if !defined(BOOST_ASIO_NO_IOSTREAM)
+
+namespace detail
+{
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_streambuf_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_streambuf_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, basic_streambuf<Allocator>& streambuf,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        streambuf_(streambuf),
+        start_(0),
+        total_transferred_(0),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+    read_at_streambuf_op(const read_at_streambuf_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        streambuf_(other.streambuf_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_streambuf_op(read_at_streambuf_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        streambuf_(other.streambuf_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+
+    void operator()(const boost::system::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size, bytes_available;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, total_transferred_);
+        bytes_available = read_size_helper(streambuf_, max_size);
+        for (;;)
+        {
+          device_.async_read_some_at(offset_ + total_transferred_,
+              streambuf_.prepare(bytes_available),
+              BOOST_ASIO_MOVE_CAST(read_at_streambuf_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          streambuf_.commit(bytes_transferred);
+          max_size = this->check_for_completion(ec, total_transferred_);
+          bytes_available = read_size_helper(streambuf_, max_size);
+          if ((!ec && bytes_transferred == 0) || bytes_available == 0)
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    boost::asio::basic_streambuf<Allocator>& streambuf_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return boost_asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : boost_asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename Allocator, typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename Allocator, typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    boost_asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition, typename ReadHandler>
+inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (boost::system::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  detail::async_result_init<
+    ReadHandler, void (boost::system::error_code, std::size_t)> init(
+      BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
+
+  detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+    CompletionCondition, BOOST_ASIO_HANDLER_TYPE(ReadHandler,
+      void (boost::system::error_code, std::size_t))>(
+        d, offset, b, completion_condition, init.handler)(
+          boost::system::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename ReadHandler>
+inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (boost::system::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
+    BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  detail::async_result_init<
+    ReadHandler, void (boost::system::error_code, std::size_t)> init(
+      BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
+
+  detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+    detail::transfer_all_t, BOOST_ASIO_HANDLER_TYPE(ReadHandler,
+      void (boost::system::error_code, std::size_t))>(
+        d, offset, b, transfer_all(), init.handler)(
+          boost::system::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#endif // !defined(BOOST_ASIO_NO_IOSTREAM)
+
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_IMPL_READ_AT_HPP