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1 | // | |
2 | // buffered_read_stream.hpp | |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~~ | |
4 | // | |
5 | // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com) | |
6 | // | |
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) | |
9 | // | |
10 | ||
11 | #ifndef BOOST_ASIO_BUFFERED_READ_STREAM_HPP | |
12 | #define BOOST_ASIO_BUFFERED_READ_STREAM_HPP | |
13 | ||
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1200) | |
15 | # pragma once | |
16 | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) | |
17 | ||
18 | #include <boost/asio/detail/config.hpp> | |
19 | #include <cstddef> | |
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> | |
29 | #include <boost/asio/io_service.hpp> | |
30 | ||
31 | #include <boost/asio/detail/push_options.hpp> | |
32 | ||
33 | namespace boost { | |
34 | namespace asio { | |
35 | ||
36 | /// Adds buffering to the read-related operations of a stream. | |
37 | /** | |
38 | * The buffered_read_stream class template can be used to add buffering to the | |
39 | * synchronous and asynchronous read operations of a stream. | |
40 | * | |
41 | * @par Thread Safety | |
42 | * @e Distinct @e objects: Safe.@n | |
43 | * @e Shared @e objects: Unsafe. | |
44 | * | |
45 | * @par Concepts: | |
46 | * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream. | |
47 | */ | |
48 | template <typename Stream> | |
49 | class buffered_read_stream | |
50 | : private noncopyable | |
51 | { | |
52 | public: | |
53 | /// The type of the next layer. | |
54 | typedef typename remove_reference<Stream>::type next_layer_type; | |
55 | ||
56 | /// The type of the lowest layer. | |
57 | typedef typename next_layer_type::lowest_layer_type lowest_layer_type; | |
58 | ||
59 | #if defined(GENERATING_DOCUMENTATION) | |
60 | /// The default buffer size. | |
61 | static const std::size_t default_buffer_size = implementation_defined; | |
62 | #else | |
63 | BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024); | |
64 | #endif | |
65 | ||
66 | /// Construct, passing the specified argument to initialise the next layer. | |
67 | template <typename Arg> | |
68 | explicit buffered_read_stream(Arg& a) | |
69 | : next_layer_(a), | |
70 | storage_(default_buffer_size) | |
71 | { | |
72 | } | |
73 | ||
74 | /// Construct, passing the specified argument to initialise the next layer. | |
75 | template <typename Arg> | |
76 | buffered_read_stream(Arg& a, std::size_t buffer_size) | |
77 | : next_layer_(a), | |
78 | storage_(buffer_size) | |
79 | { | |
80 | } | |
81 | ||
82 | /// Get a reference to the next layer. | |
83 | next_layer_type& next_layer() | |
84 | { | |
85 | return next_layer_; | |
86 | } | |
87 | ||
88 | /// Get a reference to the lowest layer. | |
89 | lowest_layer_type& lowest_layer() | |
90 | { | |
91 | return next_layer_.lowest_layer(); | |
92 | } | |
93 | ||
94 | /// Get a const reference to the lowest layer. | |
95 | const lowest_layer_type& lowest_layer() const | |
96 | { | |
97 | return next_layer_.lowest_layer(); | |
98 | } | |
99 | ||
100 | /// Get the io_service associated with the object. | |
101 | boost::asio::io_service& get_io_service() | |
102 | { | |
103 | return next_layer_.get_io_service(); | |
104 | } | |
105 | ||
106 | /// Close the stream. | |
107 | void close() | |
108 | { | |
109 | next_layer_.close(); | |
110 | } | |
111 | ||
112 | /// Close the stream. | |
113 | boost::system::error_code close(boost::system::error_code& ec) | |
114 | { | |
115 | return next_layer_.close(ec); | |
116 | } | |
117 | ||
118 | /// Write the given data to the stream. Returns the number of bytes written. | |
119 | /// Throws an exception on failure. | |
120 | template <typename ConstBufferSequence> | |
121 | std::size_t write_some(const ConstBufferSequence& buffers) | |
122 | { | |
123 | return next_layer_.write_some(buffers); | |
124 | } | |
125 | ||
126 | /// Write the given data to the stream. Returns the number of bytes written, | |
127 | /// or 0 if an error occurred. | |
128 | template <typename ConstBufferSequence> | |
129 | std::size_t write_some(const ConstBufferSequence& buffers, | |
130 | boost::system::error_code& ec) | |
131 | { | |
132 | return next_layer_.write_some(buffers, ec); | |
133 | } | |
134 | ||
135 | /// Start an asynchronous write. The data being written must be valid for the | |
136 | /// lifetime of the asynchronous operation. | |
137 | template <typename ConstBufferSequence, typename WriteHandler> | |
138 | BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler, | |
139 | void (boost::system::error_code, std::size_t)) | |
140 | async_write_some(const ConstBufferSequence& buffers, | |
141 | BOOST_ASIO_MOVE_ARG(WriteHandler) handler) | |
142 | { | |
143 | detail::async_result_init< | |
144 | WriteHandler, void (boost::system::error_code, std::size_t)> init( | |
145 | BOOST_ASIO_MOVE_CAST(WriteHandler)(handler)); | |
146 | ||
147 | next_layer_.async_write_some(buffers, | |
148 | BOOST_ASIO_MOVE_CAST(BOOST_ASIO_HANDLER_TYPE(WriteHandler, | |
149 | void (boost::system::error_code, std::size_t)))(init.handler)); | |
150 | ||
151 | return init.result.get(); | |
152 | } | |
153 | ||
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. | |
156 | std::size_t fill(); | |
157 | ||
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); | |
161 | ||
162 | /// Start an asynchronous fill. | |
163 | template <typename ReadHandler> | |
164 | BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, | |
165 | void (boost::system::error_code, std::size_t)) | |
166 | async_fill(BOOST_ASIO_MOVE_ARG(ReadHandler) handler); | |
167 | ||
168 | /// Read some data from the stream. Returns the number of bytes read. Throws | |
169 | /// an exception on failure. | |
170 | template <typename MutableBufferSequence> | |
171 | std::size_t read_some(const MutableBufferSequence& buffers); | |
172 | ||
173 | /// Read some data from the stream. Returns the number of bytes read or 0 if | |
174 | /// an error occurred. | |
175 | template <typename MutableBufferSequence> | |
176 | std::size_t read_some(const MutableBufferSequence& buffers, | |
177 | boost::system::error_code& ec); | |
178 | ||
179 | /// Start an asynchronous read. The buffer into which the data will be read | |
180 | /// must be valid for the lifetime of the asynchronous operation. | |
181 | template <typename MutableBufferSequence, typename ReadHandler> | |
182 | BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, | |
183 | void (boost::system::error_code, std::size_t)) | |
184 | async_read_some(const MutableBufferSequence& buffers, | |
185 | BOOST_ASIO_MOVE_ARG(ReadHandler) handler); | |
186 | ||
187 | /// Peek at the incoming data on the stream. Returns the number of bytes read. | |
188 | /// Throws an exception on failure. | |
189 | template <typename MutableBufferSequence> | |
190 | std::size_t peek(const MutableBufferSequence& buffers); | |
191 | ||
192 | /// Peek at the incoming data on the stream. Returns the number of bytes read, | |
193 | /// or 0 if an error occurred. | |
194 | template <typename MutableBufferSequence> | |
195 | std::size_t peek(const MutableBufferSequence& buffers, | |
196 | boost::system::error_code& ec); | |
197 | ||
198 | /// Determine the amount of data that may be read without blocking. | |
199 | std::size_t in_avail() | |
200 | { | |
201 | return storage_.size(); | |
202 | } | |
203 | ||
204 | /// Determine the amount of data that may be read without blocking. | |
205 | std::size_t in_avail(boost::system::error_code& ec) | |
206 | { | |
207 | ec = boost::system::error_code(); | |
208 | return storage_.size(); | |
209 | } | |
210 | ||
211 | private: | |
212 | /// Copy data out of the internal buffer to the specified target buffer. | |
213 | /// Returns the number of bytes copied. | |
214 | template <typename MutableBufferSequence> | |
215 | std::size_t copy(const MutableBufferSequence& buffers) | |
216 | { | |
217 | std::size_t bytes_copied = boost::asio::buffer_copy( | |
218 | buffers, storage_.data(), storage_.size()); | |
219 | storage_.consume(bytes_copied); | |
220 | return bytes_copied; | |
221 | } | |
222 | ||
223 | /// Copy data from the internal buffer to the specified target buffer, without | |
224 | /// removing the data from the internal buffer. Returns the number of bytes | |
225 | /// copied. | |
226 | template <typename MutableBufferSequence> | |
227 | std::size_t peek_copy(const MutableBufferSequence& buffers) | |
228 | { | |
229 | return boost::asio::buffer_copy(buffers, storage_.data(), storage_.size()); | |
230 | } | |
231 | ||
232 | /// The next layer. | |
233 | Stream next_layer_; | |
234 | ||
235 | // The data in the buffer. | |
236 | detail::buffered_stream_storage storage_; | |
237 | }; | |
238 | ||
239 | } // namespace asio | |
240 | } // namespace boost | |
241 | ||
242 | #include <boost/asio/detail/pop_options.hpp> | |
243 | ||
244 | #include <boost/asio/impl/buffered_read_stream.hpp> | |
245 | ||
246 | #endif // BOOST_ASIO_BUFFERED_READ_STREAM_HPP |