boost/asio/buffered_read_stream.hpp
//
// buffered_read_stream.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 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_BUFFERED_READ_STREAM_HPP
#define BOOST_ASIO_BUFFERED_READ_STREAM_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/config.hpp>
#include <cstddef>
#include <boost/asio/async_result.hpp>
#include <boost/asio/buffered_read_stream_fwd.hpp>
#include <boost/asio/buffer.hpp>
#include <boost/asio/detail/bind_handler.hpp>
#include <boost/asio/detail/buffer_resize_guard.hpp>
#include <boost/asio/detail/buffered_stream_storage.hpp>
#include <boost/asio/detail/noncopyable.hpp>
#include <boost/asio/detail/type_traits.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
/// Adds buffering to the read-related operations of a stream.
/**
* The buffered_read_stream class template can be used to add buffering to the
* synchronous and asynchronous read operations of a stream.
*
* @par Thread Safety
* @e Distinct @e objects: Safe.@n
* @e Shared @e objects: Unsafe.
*
* @par Concepts:
* AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
*/
template <typename Stream>
class buffered_read_stream
: private noncopyable
{
public:
/// The type of the next layer.
typedef typename remove_reference<Stream>::type next_layer_type;
/// The type of the lowest layer.
typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
/// The type of the executor associated with the object.
typedef typename lowest_layer_type::executor_type executor_type;
#if defined(GENERATING_DOCUMENTATION)
/// The default buffer size.
static const std::size_t default_buffer_size = implementation_defined;
#else
BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
#endif
/// Construct, passing the specified argument to initialise the next layer.
template <typename Arg>
explicit buffered_read_stream(Arg& a)
: next_layer_(a),
storage_(default_buffer_size)
{
}
/// Construct, passing the specified argument to initialise the next layer.
template <typename Arg>
buffered_read_stream(Arg& a, std::size_t buffer_size)
: next_layer_(a),
storage_(buffer_size)
{
}
/// Get a reference to the next layer.
next_layer_type& next_layer()
{
return next_layer_;
}
/// Get a reference to the lowest layer.
lowest_layer_type& lowest_layer()
{
return next_layer_.lowest_layer();
}
/// Get a const reference to the lowest layer.
const lowest_layer_type& lowest_layer() const
{
return next_layer_.lowest_layer();
}
/// Get the executor associated with the object.
executor_type get_executor() BOOST_ASIO_NOEXCEPT
{
return next_layer_.lowest_layer().get_executor();
}
/// Close the stream.
void close()
{
next_layer_.close();
}
/// Close the stream.
BOOST_ASIO_SYNC_OP_VOID close(boost::system::error_code& ec)
{
next_layer_.close(ec);
BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Write the given data to the stream. Returns the number of bytes written.
/// Throws an exception on failure.
template <typename ConstBufferSequence>
std::size_t write_some(const ConstBufferSequence& buffers)
{
return next_layer_.write_some(buffers);
}
/// Write the given data to the stream. Returns the number of bytes written,
/// or 0 if an error occurred.
template <typename ConstBufferSequence>
std::size_t write_some(const ConstBufferSequence& buffers,
boost::system::error_code& ec)
{
return next_layer_.write_some(buffers, ec);
}
/// Start an asynchronous write. The data being written must be valid for the
/// lifetime of the asynchronous operation.
template <typename ConstBufferSequence,
BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
std::size_t)) WriteHandler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
void (boost::system::error_code, std::size_t))
async_write_some(const ConstBufferSequence& buffers,
BOOST_ASIO_MOVE_ARG(WriteHandler) handler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
{
return next_layer_.async_write_some(buffers,
BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
}
/// Fill the buffer with some data. Returns the number of bytes placed in the
/// buffer as a result of the operation. Throws an exception on failure.
std::size_t fill();
/// Fill the buffer with some data. Returns the number of bytes placed in the
/// buffer as a result of the operation, or 0 if an error occurred.
std::size_t fill(boost::system::error_code& ec);
/// Start an asynchronous fill.
template <
BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
std::size_t)) ReadHandler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
void (boost::system::error_code, std::size_t))
async_fill(
BOOST_ASIO_MOVE_ARG(ReadHandler) handler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
/// Read some data from the stream. Returns the number of bytes read. Throws
/// an exception on failure.
template <typename MutableBufferSequence>
std::size_t read_some(const MutableBufferSequence& buffers);
/// Read some data from the stream. Returns the number of bytes read or 0 if
/// an error occurred.
template <typename MutableBufferSequence>
std::size_t read_some(const MutableBufferSequence& buffers,
boost::system::error_code& ec);
/// Start an asynchronous read. The buffer into which the data will be read
/// must be valid for the lifetime of the asynchronous operation.
template <typename MutableBufferSequence,
BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
std::size_t)) ReadHandler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
void (boost::system::error_code, std::size_t))
async_read_some(const MutableBufferSequence& buffers,
BOOST_ASIO_MOVE_ARG(ReadHandler) handler
BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
/// Peek at the incoming data on the stream. Returns the number of bytes read.
/// Throws an exception on failure.
template <typename MutableBufferSequence>
std::size_t peek(const MutableBufferSequence& buffers);
/// Peek at the incoming data on the stream. Returns the number of bytes read,
/// or 0 if an error occurred.
template <typename MutableBufferSequence>
std::size_t peek(const MutableBufferSequence& buffers,
boost::system::error_code& ec);
/// Determine the amount of data that may be read without blocking.
std::size_t in_avail()
{
return storage_.size();
}
/// Determine the amount of data that may be read without blocking.
std::size_t in_avail(boost::system::error_code& ec)
{
ec = boost::system::error_code();
return storage_.size();
}
private:
/// Copy data out of the internal buffer to the specified target buffer.
/// Returns the number of bytes copied.
template <typename MutableBufferSequence>
std::size_t copy(const MutableBufferSequence& buffers)
{
std::size_t bytes_copied = boost::asio::buffer_copy(
buffers, storage_.data(), storage_.size());
storage_.consume(bytes_copied);
return bytes_copied;
}
/// Copy data from the internal buffer to the specified target buffer, without
/// removing the data from the internal buffer. Returns the number of bytes
/// copied.
template <typename MutableBufferSequence>
std::size_t peek_copy(const MutableBufferSequence& buffers)
{
return boost::asio::buffer_copy(buffers, storage_.data(), storage_.size());
}
/// The next layer.
Stream next_layer_;
// The data in the buffer.
detail::buffered_stream_storage storage_;
};
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#include <boost/asio/impl/buffered_read_stream.hpp>
#endif // BOOST_ASIO_BUFFERED_READ_STREAM_HPP