2 // buffered_read_stream.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~
5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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)
11 #ifndef BOOST_ASIO_BUFFERED_READ_STREAM_HPP
12 #define BOOST_ASIO_BUFFERED_READ_STREAM_HPP
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
18 #include <boost/asio/detail/config.hpp>
20 #include <boost/asio/async_result.hpp>
21 #include <boost/asio/buffered_read_stream_fwd.hpp>
22 #include <boost/asio/buffer.hpp>
23 #include <boost/asio/detail/bind_handler.hpp>
24 #include <boost/asio/detail/buffer_resize_guard.hpp>
25 #include <boost/asio/detail/buffered_stream_storage.hpp>
26 #include <boost/asio/detail/noncopyable.hpp>
27 #include <boost/asio/detail/type_traits.hpp>
28 #include <boost/asio/error.hpp>
30 #include <boost/asio/detail/push_options.hpp>
35 /// Adds buffering to the read-related operations of a stream.
37 * The buffered_read_stream class template can be used to add buffering to the
38 * synchronous and asynchronous read operations of a stream.
41 * @e Distinct @e objects: Safe.@n
42 * @e Shared @e objects: Unsafe.
45 * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
47 template <typename Stream>
48 class buffered_read_stream
52 /// The type of the next layer.
53 typedef typename remove_reference<Stream>::type next_layer_type;
55 /// The type of the lowest layer.
56 typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
58 /// The type of the executor associated with the object.
59 typedef typename lowest_layer_type::executor_type executor_type;
61 #if defined(GENERATING_DOCUMENTATION)
62 /// The default buffer size.
63 static const std::size_t default_buffer_size = implementation_defined;
65 BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
68 /// Construct, passing the specified argument to initialise the next layer.
69 template <typename Arg>
70 explicit buffered_read_stream(Arg& a)
72 storage_(default_buffer_size)
76 /// Construct, passing the specified argument to initialise the next layer.
77 template <typename Arg>
78 buffered_read_stream(Arg& a, std::size_t buffer_size)
84 /// Get a reference to the next layer.
85 next_layer_type& next_layer()
90 /// Get a reference to the lowest layer.
91 lowest_layer_type& lowest_layer()
93 return next_layer_.lowest_layer();
96 /// Get a const reference to the lowest layer.
97 const lowest_layer_type& lowest_layer() const
99 return next_layer_.lowest_layer();
102 /// Get the executor associated with the object.
103 executor_type get_executor() BOOST_ASIO_NOEXCEPT
105 return next_layer_.lowest_layer().get_executor();
108 /// Close the stream.
114 /// Close the stream.
115 BOOST_ASIO_SYNC_OP_VOID close(boost::system::error_code& ec)
117 next_layer_.close(ec);
118 BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
121 /// Write the given data to the stream. Returns the number of bytes written.
122 /// Throws an exception on failure.
123 template <typename ConstBufferSequence>
124 std::size_t write_some(const ConstBufferSequence& buffers)
126 return next_layer_.write_some(buffers);
129 /// Write the given data to the stream. Returns the number of bytes written,
130 /// or 0 if an error occurred.
131 template <typename ConstBufferSequence>
132 std::size_t write_some(const ConstBufferSequence& buffers,
133 boost::system::error_code& ec)
135 return next_layer_.write_some(buffers, ec);
138 /// Start an asynchronous write. The data being written must be valid for the
139 /// lifetime of the asynchronous operation.
140 template <typename ConstBufferSequence,
141 BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
142 std::size_t)) WriteHandler
143 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
144 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
145 void (boost::system::error_code, std::size_t))
146 async_write_some(const ConstBufferSequence& buffers,
147 BOOST_ASIO_MOVE_ARG(WriteHandler) handler
148 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
150 return next_layer_.async_write_some(buffers,
151 BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
154 /// Fill the buffer with some data. Returns the number of bytes placed in the
155 /// buffer as a result of the operation. Throws an exception on failure.
158 /// Fill the buffer with some data. Returns the number of bytes placed in the
159 /// buffer as a result of the operation, or 0 if an error occurred.
160 std::size_t fill(boost::system::error_code& ec);
162 /// Start an asynchronous fill.
164 BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
165 std::size_t)) ReadHandler
166 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
167 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
168 void (boost::system::error_code, std::size_t))
170 BOOST_ASIO_MOVE_ARG(ReadHandler) handler
171 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
173 /// Read some data from the stream. Returns the number of bytes read. Throws
174 /// an exception on failure.
175 template <typename MutableBufferSequence>
176 std::size_t read_some(const MutableBufferSequence& buffers);
178 /// Read some data from the stream. Returns the number of bytes read or 0 if
179 /// an error occurred.
180 template <typename MutableBufferSequence>
181 std::size_t read_some(const MutableBufferSequence& buffers,
182 boost::system::error_code& ec);
184 /// Start an asynchronous read. The buffer into which the data will be read
185 /// must be valid for the lifetime of the asynchronous operation.
186 template <typename MutableBufferSequence,
187 BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code,
188 std::size_t)) ReadHandler
189 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
190 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
191 void (boost::system::error_code, std::size_t))
192 async_read_some(const MutableBufferSequence& buffers,
193 BOOST_ASIO_MOVE_ARG(ReadHandler) handler
194 BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
196 /// Peek at the incoming data on the stream. Returns the number of bytes read.
197 /// Throws an exception on failure.
198 template <typename MutableBufferSequence>
199 std::size_t peek(const MutableBufferSequence& buffers);
201 /// Peek at the incoming data on the stream. Returns the number of bytes read,
202 /// or 0 if an error occurred.
203 template <typename MutableBufferSequence>
204 std::size_t peek(const MutableBufferSequence& buffers,
205 boost::system::error_code& ec);
207 /// Determine the amount of data that may be read without blocking.
208 std::size_t in_avail()
210 return storage_.size();
213 /// Determine the amount of data that may be read without blocking.
214 std::size_t in_avail(boost::system::error_code& ec)
216 ec = boost::system::error_code();
217 return storage_.size();
221 /// Copy data out of the internal buffer to the specified target buffer.
222 /// Returns the number of bytes copied.
223 template <typename MutableBufferSequence>
224 std::size_t copy(const MutableBufferSequence& buffers)
226 std::size_t bytes_copied = boost::asio::buffer_copy(
227 buffers, storage_.data(), storage_.size());
228 storage_.consume(bytes_copied);
232 /// Copy data from the internal buffer to the specified target buffer, without
233 /// removing the data from the internal buffer. Returns the number of bytes
235 template <typename MutableBufferSequence>
236 std::size_t peek_copy(const MutableBufferSequence& buffers)
238 return boost::asio::buffer_copy(buffers, storage_.data(), storage_.size());
244 // The data in the buffer.
245 detail::buffered_stream_storage storage_;
251 #include <boost/asio/detail/pop_options.hpp>
253 #include <boost/asio/impl/buffered_read_stream.hpp>
255 #endif // BOOST_ASIO_BUFFERED_READ_STREAM_HPP