| // |
| // buffered_read_stream.hpp |
| // ~~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2008 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/push_options.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| #include <cstddef> |
| #include <cstring> |
| #include <boost/config.hpp> |
| #include <boost/type_traits.hpp> |
| #include "asio/detail/pop_options.hpp" |
| |
| #include "asio/buffered_read_stream_fwd.hpp" |
| #include "asio/buffer.hpp" |
| #include "asio/error.hpp" |
| #include "asio/io_service.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" |
| |
| 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, Sync_Read_Stream, SyncWriteStream. |
| */ |
| template <typename Stream> |
| class buffered_read_stream |
| : private noncopyable |
| { |
| public: |
| /// The type of the next layer. |
| typedef typename boost::remove_reference<Stream>::type next_layer_type; |
| |
| /// The type of the lowest layer. |
| typedef typename next_layer_type::lowest_layer_type lowest_layer_type; |
| |
| #if defined(GENERATING_DOCUMENTATION) |
| /// The default buffer size. |
| static const std::size_t default_buffer_size = implementation_defined; |
| #else |
| BOOST_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(); |
| } |
| |
| /// (Deprecated: use get_io_service().) Get the io_service associated with |
| /// the object. |
| asio::io_service& io_service() |
| { |
| return next_layer_.get_io_service(); |
| } |
| |
| /// Get the io_service associated with the object. |
| asio::io_service& get_io_service() |
| { |
| return next_layer_.get_io_service(); |
| } |
| |
| /// Close the stream. |
| void close() |
| { |
| next_layer_.close(); |
| } |
| |
| /// Close the stream. |
| asio::error_code close(asio::error_code& ec) |
| { |
| return next_layer_.close(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> |
| void async_write_some(const ConstBufferSequence& buffers, |
| WriteHandler handler) |
| { |
| next_layer_.async_write_some(buffers, 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() |
| { |
| detail::buffer_resize_guard<detail::buffered_stream_storage> |
| resize_guard(storage_); |
| std::size_t previous_size = storage_.size(); |
| storage_.resize(storage_.capacity()); |
| storage_.resize(previous_size + next_layer_.read_some(buffer( |
| storage_.data() + previous_size, |
| storage_.size() - previous_size))); |
| resize_guard.commit(); |
| return storage_.size() - previous_size; |
| } |
| |
| /// 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) |
| { |
| detail::buffer_resize_guard<detail::buffered_stream_storage> |
| resize_guard(storage_); |
| std::size_t previous_size = storage_.size(); |
| storage_.resize(storage_.capacity()); |
| storage_.resize(previous_size + next_layer_.read_some(buffer( |
| storage_.data() + previous_size, |
| storage_.size() - previous_size), |
| ec)); |
| resize_guard.commit(); |
| return storage_.size() - previous_size; |
| } |
| |
| template <typename ReadHandler> |
| class fill_handler |
| { |
| public: |
| fill_handler(asio::io_service& io_service, |
| detail::buffered_stream_storage& storage, |
| std::size_t previous_size, ReadHandler handler) |
| : io_service_(io_service), |
| storage_(storage), |
| previous_size_(previous_size), |
| handler_(handler) |
| { |
| } |
| |
| void operator()(const asio::error_code& ec, |
| std::size_t bytes_transferred) |
| { |
| storage_.resize(previous_size_ + bytes_transferred); |
| io_service_.dispatch(detail::bind_handler( |
| handler_, ec, bytes_transferred)); |
| } |
| |
| private: |
| asio::io_service& io_service_; |
| detail::buffered_stream_storage& storage_; |
| std::size_t previous_size_; |
| ReadHandler handler_; |
| }; |
| |
| /// Start an asynchronous fill. |
| template <typename ReadHandler> |
| void async_fill(ReadHandler handler) |
| { |
| std::size_t previous_size = storage_.size(); |
| storage_.resize(storage_.capacity()); |
| next_layer_.async_read_some( |
| buffer( |
| storage_.data() + previous_size, |
| storage_.size() - previous_size), |
| fill_handler<ReadHandler>(get_io_service(), |
| storage_, previous_size, 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) |
| { |
| typename MutableBufferSequence::const_iterator iter = buffers.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers.end(); |
| size_t total_buffer_size = 0; |
| for (; iter != end; ++iter) |
| { |
| asio::mutable_buffer buffer(*iter); |
| total_buffer_size += asio::buffer_size(buffer); |
| } |
| |
| if (total_buffer_size == 0) |
| return 0; |
| |
| if (storage_.empty()) |
| fill(); |
| |
| return copy(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) |
| { |
| ec = asio::error_code(); |
| |
| typename MutableBufferSequence::const_iterator iter = buffers.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers.end(); |
| size_t total_buffer_size = 0; |
| for (; iter != end; ++iter) |
| { |
| asio::mutable_buffer buffer(*iter); |
| total_buffer_size += asio::buffer_size(buffer); |
| } |
| |
| if (total_buffer_size == 0) |
| return 0; |
| |
| if (storage_.empty() && !fill(ec)) |
| return 0; |
| |
| return copy(buffers); |
| } |
| |
| template <typename MutableBufferSequence, typename ReadHandler> |
| class read_some_handler |
| { |
| public: |
| read_some_handler(asio::io_service& io_service, |
| detail::buffered_stream_storage& storage, |
| const MutableBufferSequence& buffers, ReadHandler handler) |
| : io_service_(io_service), |
| storage_(storage), |
| buffers_(buffers), |
| handler_(handler) |
| { |
| } |
| |
| void operator()(const asio::error_code& ec, std::size_t) |
| { |
| if (ec || storage_.empty()) |
| { |
| std::size_t length = 0; |
| io_service_.dispatch(detail::bind_handler(handler_, ec, length)); |
| } |
| else |
| { |
| using namespace std; // For memcpy. |
| |
| std::size_t bytes_avail = storage_.size(); |
| std::size_t bytes_copied = 0; |
| |
| typename MutableBufferSequence::const_iterator iter = buffers_.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers_.end(); |
| for (; iter != end && bytes_avail > 0; ++iter) |
| { |
| std::size_t max_length = buffer_size(*iter); |
| std::size_t length = (max_length < bytes_avail) |
| ? max_length : bytes_avail; |
| memcpy(buffer_cast<void*>(*iter), |
| storage_.data() + bytes_copied, length); |
| bytes_copied += length; |
| bytes_avail -= length; |
| } |
| |
| storage_.consume(bytes_copied); |
| io_service_.dispatch(detail::bind_handler(handler_, ec, bytes_copied)); |
| } |
| } |
| |
| private: |
| asio::io_service& io_service_; |
| detail::buffered_stream_storage& storage_; |
| MutableBufferSequence buffers_; |
| ReadHandler handler_; |
| }; |
| |
| /// 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> |
| void async_read_some(const MutableBufferSequence& buffers, |
| ReadHandler handler) |
| { |
| typename MutableBufferSequence::const_iterator iter = buffers.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers.end(); |
| size_t total_buffer_size = 0; |
| for (; iter != end; ++iter) |
| { |
| asio::mutable_buffer buffer(*iter); |
| total_buffer_size += asio::buffer_size(buffer); |
| } |
| |
| if (total_buffer_size == 0) |
| { |
| get_io_service().post(detail::bind_handler( |
| handler, asio::error_code(), 0)); |
| } |
| else if (storage_.empty()) |
| { |
| async_fill(read_some_handler<MutableBufferSequence, ReadHandler>( |
| get_io_service(), storage_, buffers, handler)); |
| } |
| else |
| { |
| std::size_t length = copy(buffers); |
| get_io_service().post(detail::bind_handler( |
| handler, asio::error_code(), length)); |
| } |
| } |
| |
| /// 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) |
| { |
| if (storage_.empty()) |
| fill(); |
| return peek_copy(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) |
| { |
| ec = asio::error_code(); |
| if (storage_.empty() && !fill(ec)) |
| return 0; |
| return peek_copy(buffers); |
| } |
| |
| /// 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) |
| { |
| using namespace std; // For memcpy. |
| |
| std::size_t bytes_avail = storage_.size(); |
| std::size_t bytes_copied = 0; |
| |
| typename MutableBufferSequence::const_iterator iter = buffers.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers.end(); |
| for (; iter != end && bytes_avail > 0; ++iter) |
| { |
| std::size_t max_length = buffer_size(*iter); |
| std::size_t length = (max_length < bytes_avail) |
| ? max_length : bytes_avail; |
| memcpy(buffer_cast<void*>(*iter), storage_.data() + bytes_copied, length); |
| bytes_copied += length; |
| bytes_avail -= length; |
| } |
| |
| 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) |
| { |
| using namespace std; // For memcpy. |
| |
| std::size_t bytes_avail = storage_.size(); |
| std::size_t bytes_copied = 0; |
| |
| typename MutableBufferSequence::const_iterator iter = buffers.begin(); |
| typename MutableBufferSequence::const_iterator end = buffers.end(); |
| for (; iter != end && bytes_avail > 0; ++iter) |
| { |
| std::size_t max_length = buffer_size(*iter); |
| std::size_t length = (max_length < bytes_avail) |
| ? max_length : bytes_avail; |
| memcpy(buffer_cast<void*>(*iter), storage_.data() + bytes_copied, length); |
| bytes_copied += length; |
| bytes_avail -= length; |
| } |
| |
| return bytes_copied; |
| } |
| |
| /// The next layer. |
| Stream next_layer_; |
| |
| // The data in the buffer. |
| detail::buffered_stream_storage storage_; |
| }; |
| |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #endif // ASIO_BUFFERED_READ_STREAM_HPP |