text: //
  // windows/random_access_handle_service.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2015 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 ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
  #define ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include "asio/detail/config.hpp"
  
  #if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
    || defined(GENERATING_DOCUMENTATION)
  
  #include <cstddef>
  #include "asio/async_result.hpp"
  #include "asio/detail/cstdint.hpp"
  #include "asio/detail/win_iocp_handle_service.hpp"
  #include "asio/error.hpp"
  #include "asio/io_context.hpp"
  
  #include "asio/detail/push_options.hpp"
  
  namespace asio {
  namespace windows {
  
  /// Default service implementation for a random-access handle.
  class random_access_handle_service
  #if defined(GENERATING_DOCUMENTATION)
    : public asio::io_context::service
  #else
    : public asio::detail::service_base<random_access_handle_service>
  #endif
  {
  public:
  #if defined(GENERATING_DOCUMENTATION)
    /// The unique service identifier.
    static asio::io_context::id id;
  #endif
  
  private:
    // The type of the platform-specific implementation.
    typedef detail::win_iocp_handle_service service_impl_type;
  
  public:
    /// The type of a random-access handle implementation.
  #if defined(GENERATING_DOCUMENTATION)
    typedef implementation_defined implementation_type;
  #else
    typedef service_impl_type::implementation_type implementation_type;
  #endif
  
    /// The native handle type.
  #if defined(GENERATING_DOCUMENTATION)
    typedef implementation_defined native_handle_type;
  #else
    typedef service_impl_type::native_handle_type native_handle_type;
  #endif
  
    /// Construct a new random-access handle service for the specified io_context.
    explicit random_access_handle_service(asio::io_context& io_context)
      : asio::detail::service_base<
          random_access_handle_service>(io_context),
        service_impl_(io_context)
    {
    }
  
    /// Construct a new random-access handle implementation.
    void construct(implementation_type& impl)
    {
      service_impl_.construct(impl);
    }
  
  #if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
    /// Move-construct a new random-access handle implementation.
    void move_construct(implementation_type& impl,
        implementation_type& other_impl)
    {
      service_impl_.move_construct(impl, other_impl);
    }
  
    /// Move-assign from another random-access handle implementation.
    void move_assign(implementation_type& impl,
        random_access_handle_service& other_service,
        implementation_type& other_impl)
    {
      service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
    }
  #endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
  
    /// Destroy a random-access handle implementation.
    void destroy(implementation_type& impl)
    {
      service_impl_.destroy(impl);
    }
  
    /// Assign an existing native handle to a random-access handle.
    asio::error_code assign(implementation_type& impl,
        const native_handle_type& handle, asio::error_code& ec)
    {
      return service_impl_.assign(impl, handle, ec);
    }
  
    /// Determine whether the handle is open.
    bool is_open(const implementation_type& impl) const
    {
      return service_impl_.is_open(impl);
    }
  
    /// Close a random-access handle implementation.
    asio::error_code close(implementation_type& impl,
        asio::error_code& ec)
    {
      return service_impl_.close(impl, ec);
    }
  
    /// Get the native handle implementation.
    native_handle_type native_handle(implementation_type& impl)
    {
      return service_impl_.native_handle(impl);
    }
  
    /// Cancel all asynchronous operations associated with the handle.
    asio::error_code cancel(implementation_type& impl,
        asio::error_code& ec)
    {
      return service_impl_.cancel(impl, ec);
    }
  
    /// Write the given data at the specified offset.
    template <typename ConstBufferSequence>
    std::size_t write_some_at(implementation_type& impl, uint64_t offset,
        const ConstBufferSequence& buffers, asio::error_code& ec)
    {
      return service_impl_.write_some_at(impl, offset, buffers, ec);
    }
  
    /// Start an asynchronous write at the specified offset.
    template <typename ConstBufferSequence, typename WriteHandler>
    ASIO_INITFN_RESULT_TYPE(WriteHandler,
        void (asio::error_code, std::size_t))
    async_write_some_at(implementation_type& impl,
        uint64_t offset, const ConstBufferSequence& buffers,
        ASIO_MOVE_ARG(WriteHandler) handler)
    {
      asio::async_completion<WriteHandler,
        void (asio::error_code, std::size_t)> init(handler);
  
      service_impl_.async_write_some_at(impl, offset, buffers, init.handler);
  
      return init.result.get();
    }
  
    /// Read some data from the specified offset.
    template <typename MutableBufferSequence>
    std::size_t read_some_at(implementation_type& impl, uint64_t offset,
        const MutableBufferSequence& buffers, asio::error_code& ec)
    {
      return service_impl_.read_some_at(impl, offset, buffers, ec);
    }
  
    /// Start an asynchronous read at the specified offset.
    template <typename MutableBufferSequence, typename ReadHandler>
    ASIO_INITFN_RESULT_TYPE(ReadHandler,
        void (asio::error_code, std::size_t))
    async_read_some_at(implementation_type& impl,
        uint64_t offset, const MutableBufferSequence& buffers,
        ASIO_MOVE_ARG(ReadHandler) handler)
    {
      asio::async_completion<ReadHandler,
        void (asio::error_code, std::size_t)> init(handler);
  
      service_impl_.async_read_some_at(impl, offset, buffers, init.handler);
  
      return init.result.get();
    }
  
  private:
    // Destroy all user-defined handler objects owned by the service.
    void shutdown()
    {
      service_impl_.shutdown();
    }
  
    // The platform-specific implementation.
    service_impl_type service_impl_;
  };
  
  } // namespace windows
  } // namespace asio
  
  #include "asio/detail/pop_options.hpp"
  
  #endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
         //   || defined(GENERATING_DOCUMENTATION)
  
  #endif // ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
  