254 lines
7.8 KiB
C++
254 lines
7.8 KiB
C++
//
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// buffered_read_stream.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_BUFFERED_READ_STREAM_HPP
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#define ASIO_BUFFERED_READ_STREAM_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include <cstddef>
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#include "asio/async_result.hpp"
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#include "asio/buffered_read_stream_fwd.hpp"
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#include "asio/buffer.hpp"
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#include "asio/detail/bind_handler.hpp"
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#include "asio/detail/buffer_resize_guard.hpp"
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#include "asio/detail/buffered_stream_storage.hpp"
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#include "asio/detail/noncopyable.hpp"
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#include "asio/detail/type_traits.hpp"
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#include "asio/error.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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/// Adds buffering to the read-related operations of a stream.
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/**
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* The buffered_read_stream class template can be used to add buffering to the
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* synchronous and asynchronous read operations of a stream.
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*
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* @par Thread Safety
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* @e Distinct @e objects: Safe.@n
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* @e Shared @e objects: Unsafe.
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*
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* @par Concepts:
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* AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
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*/
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template <typename Stream>
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class buffered_read_stream
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: private noncopyable
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{
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public:
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/// The type of the next layer.
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typedef typename remove_reference<Stream>::type next_layer_type;
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/// The type of the lowest layer.
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typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
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/// The type of the executor associated with the object.
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typedef typename lowest_layer_type::executor_type executor_type;
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#if defined(GENERATING_DOCUMENTATION)
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/// The default buffer size.
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static const std::size_t default_buffer_size = implementation_defined;
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#else
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ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
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#endif
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/// Construct, passing the specified argument to initialise the next layer.
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template <typename Arg>
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explicit buffered_read_stream(Arg& a)
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: next_layer_(a),
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storage_(default_buffer_size)
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{
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}
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/// Construct, passing the specified argument to initialise the next layer.
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template <typename Arg>
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buffered_read_stream(Arg& a, std::size_t buffer_size)
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: next_layer_(a),
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storage_(buffer_size)
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{
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}
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/// Get a reference to the next layer.
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next_layer_type& next_layer()
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{
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return next_layer_;
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}
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/// Get a reference to the lowest layer.
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lowest_layer_type& lowest_layer()
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{
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return next_layer_.lowest_layer();
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}
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/// Get a const reference to the lowest layer.
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const lowest_layer_type& lowest_layer() const
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{
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return next_layer_.lowest_layer();
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}
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/// Get the executor associated with the object.
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executor_type get_executor() ASIO_NOEXCEPT
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{
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return next_layer_.lowest_layer().get_executor();
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}
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/// Close the stream.
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void close()
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{
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next_layer_.close();
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}
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/// Close the stream.
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ASIO_SYNC_OP_VOID close(asio::error_code& ec)
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{
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next_layer_.close(ec);
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ASIO_SYNC_OP_VOID_RETURN(ec);
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}
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/// Write the given data to the stream. Returns the number of bytes written.
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/// Throws an exception on failure.
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template <typename ConstBufferSequence>
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std::size_t write_some(const ConstBufferSequence& buffers)
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{
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return next_layer_.write_some(buffers);
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}
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/// Write the given data to the stream. Returns the number of bytes written,
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/// or 0 if an error occurred.
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template <typename ConstBufferSequence>
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std::size_t write_some(const ConstBufferSequence& buffers,
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asio::error_code& ec)
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{
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return next_layer_.write_some(buffers, ec);
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}
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/// Start an asynchronous write. The data being written must be valid for the
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/// lifetime of the asynchronous operation.
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template <typename ConstBufferSequence,
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ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
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std::size_t)) WriteHandler
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ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
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ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
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void (asio::error_code, std::size_t))
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async_write_some(const ConstBufferSequence& buffers,
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ASIO_MOVE_ARG(WriteHandler) handler
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ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
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{
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return next_layer_.async_write_some(buffers,
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ASIO_MOVE_CAST(WriteHandler)(handler));
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}
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/// Fill the buffer with some data. Returns the number of bytes placed in the
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/// buffer as a result of the operation. Throws an exception on failure.
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std::size_t fill();
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/// Fill the buffer with some data. Returns the number of bytes placed in the
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/// buffer as a result of the operation, or 0 if an error occurred.
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std::size_t fill(asio::error_code& ec);
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/// Start an asynchronous fill.
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template <
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ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
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std::size_t)) ReadHandler
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ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
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ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
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void (asio::error_code, std::size_t))
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async_fill(
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ASIO_MOVE_ARG(ReadHandler) handler
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ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
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/// Read some data from the stream. Returns the number of bytes read. Throws
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/// an exception on failure.
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template <typename MutableBufferSequence>
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std::size_t read_some(const MutableBufferSequence& buffers);
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/// Read some data from the stream. Returns the number of bytes read or 0 if
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/// an error occurred.
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template <typename MutableBufferSequence>
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std::size_t read_some(const MutableBufferSequence& buffers,
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asio::error_code& ec);
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/// Start an asynchronous read. The buffer into which the data will be read
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/// must be valid for the lifetime of the asynchronous operation.
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template <typename MutableBufferSequence,
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ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
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std::size_t)) ReadHandler
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ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
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ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
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void (asio::error_code, std::size_t))
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async_read_some(const MutableBufferSequence& buffers,
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ASIO_MOVE_ARG(ReadHandler) handler
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ASIO_DEFAULT_COMPLETION_TOKEN(executor_type));
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/// Peek at the incoming data on the stream. Returns the number of bytes read.
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/// Throws an exception on failure.
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template <typename MutableBufferSequence>
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std::size_t peek(const MutableBufferSequence& buffers);
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/// Peek at the incoming data on the stream. Returns the number of bytes read,
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/// or 0 if an error occurred.
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template <typename MutableBufferSequence>
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std::size_t peek(const MutableBufferSequence& buffers,
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asio::error_code& ec);
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/// Determine the amount of data that may be read without blocking.
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std::size_t in_avail()
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{
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return storage_.size();
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}
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/// Determine the amount of data that may be read without blocking.
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std::size_t in_avail(asio::error_code& ec)
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{
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ec = asio::error_code();
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return storage_.size();
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}
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private:
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/// Copy data out of the internal buffer to the specified target buffer.
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/// Returns the number of bytes copied.
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template <typename MutableBufferSequence>
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std::size_t copy(const MutableBufferSequence& buffers)
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{
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std::size_t bytes_copied = asio::buffer_copy(
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buffers, storage_.data(), storage_.size());
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storage_.consume(bytes_copied);
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return bytes_copied;
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}
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/// Copy data from the internal buffer to the specified target buffer, without
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/// removing the data from the internal buffer. Returns the number of bytes
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/// copied.
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template <typename MutableBufferSequence>
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std::size_t peek_copy(const MutableBufferSequence& buffers)
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{
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return asio::buffer_copy(buffers, storage_.data(), storage_.size());
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}
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/// The next layer.
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Stream next_layer_;
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// The data in the buffer.
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detail::buffered_stream_storage storage_;
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};
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#include "asio/impl/buffered_read_stream.hpp"
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#endif // ASIO_BUFFERED_READ_STREAM_HPP
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