text: //
  // impl/buffered_write_stream.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 BOOST_ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
  #define BOOST_ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #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/push_options.hpp>
  
  namespace boost {
  namespace asio {
  
  template <typename Stream>
  std::size_t buffered_write_stream<Stream>::flush()
  {
    std::size_t bytes_written = write(next_layer_,
        buffer(storage_.data(), storage_.size()));
    storage_.consume(bytes_written);
    return bytes_written;
  }
  
  template <typename Stream>
  std::size_t buffered_write_stream<Stream>::flush(boost::system::error_code& ec)
  {
    std::size_t bytes_written = write(next_layer_,
        buffer(storage_.data(), storage_.size()),
        transfer_all(), ec);
    storage_.consume(bytes_written);
    return bytes_written;
  }
  
  namespace detail
  {
    template <typename WriteHandler>
    class buffered_flush_handler
    {
    public:
      buffered_flush_handler(detail::buffered_stream_storage& storage,
          WriteHandler& handler)
        : storage_(storage),
          handler_(handler)
      {
      }
  
  #if defined(BOOST_ASIO_HAS_MOVE)
      buffered_flush_handler(const buffered_flush_handler& other)
        : storage_(other.storage_),
          handler_(other.handler_)
      {
      }
  
      buffered_flush_handler(buffered_flush_handler&& other)
        : storage_(other.storage_),
          handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(other.handler_))
      {
      }
  #endif // defined(BOOST_ASIO_HAS_MOVE)
  
      void operator()(const boost::system::error_code& ec,
          const std::size_t bytes_written)
      {
        storage_.consume(bytes_written);
        handler_(ec, bytes_written);
      }
  
    //private:
      detail::buffered_stream_storage& storage_;
      WriteHandler handler_;
    };
  
    template <typename WriteHandler>
    inline void* asio_handler_allocate(std::size_t size,
        buffered_flush_handler<WriteHandler>* this_handler)
    {
      return boost_asio_handler_alloc_helpers::allocate(
          size, this_handler->handler_);
    }
  
    template <typename WriteHandler>
    inline void asio_handler_deallocate(void* pointer, std::size_t size,
        buffered_flush_handler<WriteHandler>* this_handler)
    {
      boost_asio_handler_alloc_helpers::deallocate(
          pointer, size, this_handler->handler_);
    }
  
    template <typename WriteHandler>
    inline bool asio_handler_is_continuation(
        buffered_flush_handler<WriteHandler>* this_handler)
    {
      return boost_asio_handler_cont_helpers::is_continuation(
            this_handler->handler_);
    }
  
    template <typename Function, typename WriteHandler>
    inline void asio_handler_invoke(Function& function,
        buffered_flush_handler<WriteHandler>* this_handler)
    {
      boost_asio_handler_invoke_helpers::invoke(
          function, this_handler->handler_);
    }
  
    template <typename Function, typename WriteHandler>
    inline void asio_handler_invoke(const Function& function,
        buffered_flush_handler<WriteHandler>* this_handler)
    {
      boost_asio_handler_invoke_helpers::invoke(
          function, this_handler->handler_);
    }
  }
  
  template <typename Stream>
  template <typename WriteHandler>
  BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
      void (boost::system::error_code, std::size_t))
  buffered_write_stream<Stream>::async_flush(
      BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
  {
    // If you get an error on the following line it means that your handler does
    // not meet the documented type requirements for a WriteHandler.
    BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
  
    detail::async_result_init<
      WriteHandler, void (boost::system::error_code, std::size_t)> init(
        BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
  
    async_write(next_layer_, buffer(storage_.data(), storage_.size()),
        detail::buffered_flush_handler<BOOST_ASIO_HANDLER_TYPE(
          WriteHandler, void (boost::system::error_code, std::size_t))>(
          storage_, init.handler));
  
    return init.result.get();
  }
  
  template <typename Stream>
  template <typename ConstBufferSequence>
  std::size_t buffered_write_stream<Stream>::write_some(
      const ConstBufferSequence& buffers)
  {
    if (boost::asio::buffer_size(buffers) == 0)
      return 0;
  
    if (storage_.size() == storage_.capacity())
      this->flush();
  
    return this->copy(buffers);
  }
  
  template <typename Stream>
  template <typename ConstBufferSequence>
  std::size_t buffered_write_stream<Stream>::write_some(
      const ConstBufferSequence& buffers, boost::system::error_code& ec)
  {
    ec = boost::system::error_code();
  
    if (boost::asio::buffer_size(buffers) == 0)
      return 0;
  
    if (storage_.size() == storage_.capacity() && !flush(ec))
      return 0;
  
    return this->copy(buffers);
  }
  
  namespace detail
  {
    template <typename ConstBufferSequence, typename WriteHandler>
    class buffered_write_some_handler
    {
    public:
      buffered_write_some_handler(detail::buffered_stream_storage& storage,
          const ConstBufferSequence& buffers, WriteHandler& handler)
        : storage_(storage),
          buffers_(buffers),
          handler_(handler)
      {
      }
  
  #if defined(BOOST_ASIO_HAS_MOVE)
        buffered_write_some_handler(const buffered_write_some_handler& other)
          : storage_(other.storage_),
            buffers_(other.buffers_),
            handler_(other.handler_)
        {
        }
  
        buffered_write_some_handler(buffered_write_some_handler&& other)
          : storage_(other.storage_),
            buffers_(other.buffers_),
            handler_(BOOST_ASIO_MOVE_CAST(WriteHandler)(other.handler_))
        {
        }
  #endif // defined(BOOST_ASIO_HAS_MOVE)
  
      void operator()(const boost::system::error_code& ec, std::size_t)
      {
        if (ec)
        {
          const std::size_t length = 0;
          handler_(ec, length);
        }
        else
        {
          std::size_t orig_size = storage_.size();
          std::size_t space_avail = storage_.capacity() - orig_size;
          std::size_t bytes_avail = boost::asio::buffer_size(buffers_);
          std::size_t length = bytes_avail < space_avail
            ? bytes_avail : space_avail;
          storage_.resize(orig_size + length);
          const std::size_t bytes_copied = boost::asio::buffer_copy(
              storage_.data() + orig_size, buffers_, length);
          handler_(ec, bytes_copied);
        }
      }
  
    //private:
      detail::buffered_stream_storage& storage_;
      ConstBufferSequence buffers_;
      WriteHandler handler_;
    };
  
    template <typename ConstBufferSequence, typename WriteHandler>
    inline void* asio_handler_allocate(std::size_t size,
        buffered_write_some_handler<
          ConstBufferSequence, WriteHandler>* this_handler)
    {
      return boost_asio_handler_alloc_helpers::allocate(
          size, this_handler->handler_);
    }
  
    template <typename ConstBufferSequence, typename WriteHandler>
    inline void asio_handler_deallocate(void* pointer, std::size_t size,
        buffered_write_some_handler<
          ConstBufferSequence, WriteHandler>* this_handler)
    {
      boost_asio_handler_alloc_helpers::deallocate(
          pointer, size, this_handler->handler_);
    }
  
    template <typename ConstBufferSequence, typename WriteHandler>
    inline bool asio_handler_is_continuation(
        buffered_write_some_handler<
          ConstBufferSequence, WriteHandler>* this_handler)
    {
      return boost_asio_handler_cont_helpers::is_continuation(
            this_handler->handler_);
    }
  
    template <typename Function, typename ConstBufferSequence,
        typename WriteHandler>
    inline void asio_handler_invoke(Function& function,
        buffered_write_some_handler<
          ConstBufferSequence, WriteHandler>* this_handler)
    {
      boost_asio_handler_invoke_helpers::invoke(
          function, this_handler->handler_);
    }
  
    template <typename Function, typename ConstBufferSequence,
        typename WriteHandler>
    inline void asio_handler_invoke(const Function& function,
        buffered_write_some_handler<
          ConstBufferSequence, WriteHandler>* this_handler)
    {
      boost_asio_handler_invoke_helpers::invoke(
          function, this_handler->handler_);
    }
  } // namespace detail
  
  template <typename Stream>
  template <typename ConstBufferSequence, typename WriteHandler>
  BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
      void (boost::system::error_code, std::size_t))
  buffered_write_stream<Stream>::async_write_some(
      const ConstBufferSequence& buffers,
      BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
  {
    // If you get an error on the following line it means that your handler does
    // not meet the documented type requirements for a WriteHandler.
    BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
  
    detail::async_result_init<
      WriteHandler, void (boost::system::error_code, std::size_t)> init(
        BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
  
    if (boost::asio::buffer_size(buffers) == 0
        || storage_.size() < storage_.capacity())
    {
      next_layer_.async_write_some(boost::asio::const_buffers_1(0, 0),
          detail::buffered_write_some_handler<
            ConstBufferSequence, BOOST_ASIO_HANDLER_TYPE(
              WriteHandler, void (boost::system::error_code, std::size_t))>(
              storage_, buffers, init.handler));
    }
    else
    {
      this->async_flush(detail::buffered_write_some_handler<
            ConstBufferSequence, BOOST_ASIO_HANDLER_TYPE(
              WriteHandler, void (boost::system::error_code, std::size_t))>(
              storage_, buffers, init.handler));
    }
  
    return init.result.get();
  }
  
  template <typename Stream>
  template <typename ConstBufferSequence>
  std::size_t buffered_write_stream<Stream>::copy(
      const ConstBufferSequence& buffers)
  {
    std::size_t orig_size = storage_.size();
    std::size_t space_avail = storage_.capacity() - orig_size;
    std::size_t bytes_avail = boost::asio::buffer_size(buffers);
    std::size_t length = bytes_avail < space_avail ? bytes_avail : space_avail;
    storage_.resize(orig_size + length);
    return boost::asio::buffer_copy(
        storage_.data() + orig_size, buffers, length);
  }
  
  } // namespace asio
  } // namespace boost
  
  #include <boost/asio/detail/pop_options.hpp>
  
  #endif // BOOST_ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
  