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- //
- // buffered_read_stream.hpp
- // ~~~~~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 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_BUFFERED_READ_STREAM_HPP
- #define ASIO_BUFFERED_READ_STREAM_HPP
-
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
-
- #include "asio/detail/config.hpp"
- #include <cstddef>
- #include "asio/async_result.hpp"
- #include "asio/buffered_read_stream_fwd.hpp"
- #include "asio/buffer.hpp"
- #include "asio/detail/bind_handler.hpp"
- #include "asio/detail/buffer_resize_guard.hpp"
- #include "asio/detail/buffered_stream_storage.hpp"
- #include "asio/detail/noncopyable.hpp"
- #include "asio/detail/type_traits.hpp"
- #include "asio/error.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- 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
- 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() ASIO_NOEXCEPT
- {
- return next_layer_.lowest_layer().get_executor();
- }
-
- /// Close the stream.
- void close()
- {
- next_layer_.close();
- }
-
- /// Close the stream.
- ASIO_SYNC_OP_VOID close(asio::error_code& ec)
- {
- next_layer_.close(ec);
- 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,
- asio::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, typename WriteHandler>
- ASIO_INITFN_RESULT_TYPE(WriteHandler,
- void (asio::error_code, std::size_t))
- async_write_some(const ConstBufferSequence& buffers,
- ASIO_MOVE_ARG(WriteHandler) handler)
- {
- return next_layer_.async_write_some(buffers,
- 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(asio::error_code& ec);
-
- /// Start an asynchronous fill.
- template <typename ReadHandler>
- ASIO_INITFN_RESULT_TYPE(ReadHandler,
- void (asio::error_code, std::size_t))
- async_fill(ASIO_MOVE_ARG(ReadHandler) handler);
-
- /// 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,
- asio::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, typename ReadHandler>
- ASIO_INITFN_RESULT_TYPE(ReadHandler,
- void (asio::error_code, std::size_t))
- async_read_some(const MutableBufferSequence& buffers,
- ASIO_MOVE_ARG(ReadHandler) handler);
-
- /// 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,
- asio::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(asio::error_code& ec)
- {
- ec = asio::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 = 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 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
-
- #include "asio/detail/pop_options.hpp"
-
- #include "asio/impl/buffered_read_stream.hpp"
-
- #endif // ASIO_BUFFERED_READ_STREAM_HPP
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