boost/asio/impl/read_at.hpp
// // impl/read_at.hpp // ~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2018 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 BOOST_ASIO_IMPL_READ_AT_HPP #define BOOST_ASIO_IMPL_READ_AT_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <algorithm> #include <boost/asio/associated_allocator.hpp> #include <boost/asio/associated_executor.hpp> #include <boost/asio/buffer.hpp> #include <boost/asio/completion_condition.hpp> #include <boost/asio/detail/array_fwd.hpp> #include <boost/asio/detail/base_from_completion_cond.hpp> #include <boost/asio/detail/bind_handler.hpp> #include <boost/asio/detail/consuming_buffers.hpp> #include <boost/asio/detail/dependent_type.hpp> #include <boost/asio/detail/handler_alloc_helpers.hpp> #include <boost/asio/detail/handler_cont_helpers.hpp> #include <boost/asio/detail/handler_invoke_helpers.hpp> #include <boost/asio/detail/handler_type_requirements.hpp> #include <boost/asio/detail/throw_error.hpp> #include <boost/asio/error.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace detail { template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition> std::size_t read_at_buffer_sequence(SyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, const MutableBufferIterator&, CompletionCondition completion_condition, boost::system::error_code& ec) { ec = boost::system::error_code(); boost::asio::detail::consuming_buffers<mutable_buffer, MutableBufferSequence, MutableBufferIterator> tmp(buffers); while (!tmp.empty()) { if (std::size_t max_size = detail::adapt_completion_condition_result( completion_condition(ec, tmp.total_consumed()))) { tmp.consume(d.read_some_at(offset + tmp.total_consumed(), tmp.prepare(max_size), ec)); } else break; } return tmp.total_consumed();; } } // namespace detail template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, typename CompletionCondition> std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, CompletionCondition completion_condition, boost::system::error_code& ec) { return detail::read_at_buffer_sequence(d, offset, buffers, boost::asio::buffer_sequence_begin(buffers), completion_condition, ec); } template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers) { boost::system::error_code ec; std::size_t bytes_transferred = read_at( d, offset, buffers, transfer_all(), ec); boost::asio::detail::throw_error(ec, "read_at"); return bytes_transferred; } template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, boost::system::error_code& ec) { return read_at(d, offset, buffers, transfer_all(), ec); } template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, typename CompletionCondition> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, CompletionCondition completion_condition) { boost::system::error_code ec; std::size_t bytes_transferred = read_at( d, offset, buffers, completion_condition, ec); boost::asio::detail::throw_error(ec, "read_at"); return bytes_transferred; } #if !defined(BOOST_ASIO_NO_EXTENSIONS) #if !defined(BOOST_ASIO_NO_IOSTREAM) template <typename SyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition> std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b, CompletionCondition completion_condition, boost::system::error_code& ec) { ec = boost::system::error_code(); std::size_t total_transferred = 0; std::size_t max_size = detail::adapt_completion_condition_result( completion_condition(ec, total_transferred)); std::size_t bytes_available = read_size_helper(b, max_size); while (bytes_available > 0) { std::size_t bytes_transferred = d.read_some_at( offset + total_transferred, b.prepare(bytes_available), ec); b.commit(bytes_transferred); total_transferred += bytes_transferred; max_size = detail::adapt_completion_condition_result( completion_condition(ec, total_transferred)); bytes_available = read_size_helper(b, max_size); } return total_transferred; } template <typename SyncRandomAccessReadDevice, typename Allocator> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b) { boost::system::error_code ec; std::size_t bytes_transferred = read_at( d, offset, b, transfer_all(), ec); boost::asio::detail::throw_error(ec, "read_at"); return bytes_transferred; } template <typename SyncRandomAccessReadDevice, typename Allocator> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b, boost::system::error_code& ec) { return read_at(d, offset, b, transfer_all(), ec); } template <typename SyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition> inline std::size_t read_at(SyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b, CompletionCondition completion_condition) { boost::system::error_code ec; std::size_t bytes_transferred = read_at( d, offset, b, completion_condition, ec); boost::asio::detail::throw_error(ec, "read_at"); return bytes_transferred; } #endif // !defined(BOOST_ASIO_NO_IOSTREAM) #endif // !defined(BOOST_ASIO_NO_EXTENSIONS) namespace detail { template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> class read_at_op : detail::base_from_completion_cond<CompletionCondition> { public: read_at_op(AsyncRandomAccessReadDevice& device, uint64_t offset, const MutableBufferSequence& buffers, CompletionCondition completion_condition, ReadHandler& handler) : detail::base_from_completion_cond< CompletionCondition>(completion_condition), device_(device), offset_(offset), buffers_(buffers), start_(0), handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler)) { } #if defined(BOOST_ASIO_HAS_MOVE) read_at_op(const read_at_op& other) : detail::base_from_completion_cond<CompletionCondition>(other), device_(other.device_), offset_(other.offset_), buffers_(other.buffers_), start_(other.start_), handler_(other.handler_) { } read_at_op(read_at_op&& other) : detail::base_from_completion_cond<CompletionCondition>(other), device_(other.device_), offset_(other.offset_), buffers_(other.buffers_), start_(other.start_), handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_)) { } #endif // defined(BOOST_ASIO_HAS_MOVE) void operator()(const boost::system::error_code& ec, std::size_t bytes_transferred, int start = 0) { std::size_t max_size; switch (start_ = start) { case 1: max_size = this->check_for_completion(ec, buffers_.total_consumed()); do { device_.async_read_some_at( offset_ + buffers_.total_consumed(), buffers_.prepare(max_size), BOOST_ASIO_MOVE_CAST(read_at_op)(*this)); return; default: buffers_.consume(bytes_transferred); if ((!ec && bytes_transferred == 0) || buffers_.empty()) break; max_size = this->check_for_completion(ec, buffers_.total_consumed()); } while (max_size > 0); handler_(ec, buffers_.total_consumed()); } } //private: AsyncRandomAccessReadDevice& device_; uint64_t offset_; boost::asio::detail::consuming_buffers<mutable_buffer, MutableBufferSequence, MutableBufferIterator> buffers_; int start_; ReadHandler handler_; }; template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline void* asio_handler_allocate(std::size_t size, read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler) { return boost_asio_handler_alloc_helpers::allocate( size, this_handler->handler_); } template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_deallocate(void* pointer, std::size_t size, read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_alloc_helpers::deallocate( pointer, size, this_handler->handler_); } template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline bool asio_handler_is_continuation( read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler) { return this_handler->start_ == 0 ? true : boost_asio_handler_cont_helpers::is_continuation( this_handler->handler_); } template <typename Function, typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_invoke(Function& function, read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); } template <typename Function, typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_invoke(const Function& function, read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); } template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler> inline void start_read_at_buffer_sequence_op(AsyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, const MutableBufferIterator&, CompletionCondition completion_condition, ReadHandler& handler) { detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>( d, offset, buffers, completion_condition, handler)( boost::system::error_code(), 0, 1); } } // namespace detail #if !defined(GENERATING_DOCUMENTATION) template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler, typename Allocator> struct associated_allocator< detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>, Allocator> { typedef typename associated_allocator<ReadHandler, Allocator>::type type; static type get( const detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>& h, const Allocator& a = Allocator()) BOOST_ASIO_NOEXCEPT { return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a); } }; template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename MutableBufferIterator, typename CompletionCondition, typename ReadHandler, typename Executor> struct associated_executor< detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>, Executor> { typedef typename associated_executor<ReadHandler, Executor>::type type; static type get( const detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence, MutableBufferIterator, CompletionCondition, ReadHandler>& h, const Executor& ex = Executor()) BOOST_ASIO_NOEXCEPT { return associated_executor<ReadHandler, Executor>::get(h.handler_, ex); } }; #endif // !defined(GENERATING_DOCUMENTATION) template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename CompletionCondition, typename ReadHandler> inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, void (boost::system::error_code, std::size_t)) async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, CompletionCondition completion_condition, BOOST_ASIO_MOVE_ARG(ReadHandler) handler) { // If you get an error on the following line it means that your handler does // not meet the documented type requirements for a ReadHandler. BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; async_completion<ReadHandler, void (boost::system::error_code, std::size_t)> init(handler); detail::start_read_at_buffer_sequence_op(d, offset, buffers, boost::asio::buffer_sequence_begin(buffers), completion_condition, init.completion_handler); return init.result.get(); } template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename ReadHandler> inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, void (boost::system::error_code, std::size_t)) async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, const MutableBufferSequence& buffers, BOOST_ASIO_MOVE_ARG(ReadHandler) handler) { // If you get an error on the following line it means that your handler does // not meet the documented type requirements for a ReadHandler. BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; async_completion<ReadHandler, void (boost::system::error_code, std::size_t)> init(handler); detail::start_read_at_buffer_sequence_op(d, offset, buffers, boost::asio::buffer_sequence_begin(buffers), transfer_all(), init.completion_handler); return init.result.get(); } #if !defined(BOOST_ASIO_NO_EXTENSIONS) #if !defined(BOOST_ASIO_NO_IOSTREAM) namespace detail { template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> class read_at_streambuf_op : detail::base_from_completion_cond<CompletionCondition> { public: read_at_streambuf_op(AsyncRandomAccessReadDevice& device, uint64_t offset, basic_streambuf<Allocator>& streambuf, CompletionCondition completion_condition, ReadHandler& handler) : detail::base_from_completion_cond< CompletionCondition>(completion_condition), device_(device), offset_(offset), streambuf_(streambuf), start_(0), total_transferred_(0), handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(handler)) { } #if defined(BOOST_ASIO_HAS_MOVE) read_at_streambuf_op(const read_at_streambuf_op& other) : detail::base_from_completion_cond<CompletionCondition>(other), device_(other.device_), offset_(other.offset_), streambuf_(other.streambuf_), start_(other.start_), total_transferred_(other.total_transferred_), handler_(other.handler_) { } read_at_streambuf_op(read_at_streambuf_op&& other) : detail::base_from_completion_cond<CompletionCondition>(other), device_(other.device_), offset_(other.offset_), streambuf_(other.streambuf_), start_(other.start_), total_transferred_(other.total_transferred_), handler_(BOOST_ASIO_MOVE_CAST(ReadHandler)(other.handler_)) { } #endif // defined(BOOST_ASIO_HAS_MOVE) void operator()(const boost::system::error_code& ec, std::size_t bytes_transferred, int start = 0) { std::size_t max_size, bytes_available; switch (start_ = start) { case 1: max_size = this->check_for_completion(ec, total_transferred_); bytes_available = read_size_helper(streambuf_, max_size); for (;;) { device_.async_read_some_at(offset_ + total_transferred_, streambuf_.prepare(bytes_available), BOOST_ASIO_MOVE_CAST(read_at_streambuf_op)(*this)); return; default: total_transferred_ += bytes_transferred; streambuf_.commit(bytes_transferred); max_size = this->check_for_completion(ec, total_transferred_); bytes_available = read_size_helper(streambuf_, max_size); if ((!ec && bytes_transferred == 0) || bytes_available == 0) break; } handler_(ec, static_cast<const std::size_t&>(total_transferred_)); } } //private: AsyncRandomAccessReadDevice& device_; uint64_t offset_; boost::asio::basic_streambuf<Allocator>& streambuf_; int start_; std::size_t total_transferred_; ReadHandler handler_; }; template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline void* asio_handler_allocate(std::size_t size, read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>* this_handler) { return boost_asio_handler_alloc_helpers::allocate( size, this_handler->handler_); } template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_deallocate(void* pointer, std::size_t size, read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_alloc_helpers::deallocate( pointer, size, this_handler->handler_); } template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline bool asio_handler_is_continuation( read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>* this_handler) { return this_handler->start_ == 0 ? true : boost_asio_handler_cont_helpers::is_continuation( this_handler->handler_); } template <typename Function, typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_invoke(Function& function, read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); } template <typename Function, typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline void asio_handler_invoke(const Function& function, read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); } } // namespace detail #if !defined(GENERATING_DOCUMENTATION) template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler, typename Allocator1> struct associated_allocator< detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>, Allocator1> { typedef typename associated_allocator<ReadHandler, Allocator1>::type type; static type get( const detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, ReadHandler>& h, const Allocator1& a = Allocator1()) BOOST_ASIO_NOEXCEPT { return associated_allocator<ReadHandler, Allocator1>::get(h.handler_, a); } }; template <typename AsyncRandomAccessReadDevice, typename Executor, typename CompletionCondition, typename ReadHandler, typename Executor1> struct associated_executor< detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Executor, CompletionCondition, ReadHandler>, Executor1> { typedef typename associated_executor<ReadHandler, Executor1>::type type; static type get( const detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Executor, CompletionCondition, ReadHandler>& h, const Executor1& ex = Executor1()) BOOST_ASIO_NOEXCEPT { return associated_executor<ReadHandler, Executor1>::get(h.handler_, ex); } }; #endif // !defined(GENERATING_DOCUMENTATION) template <typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadHandler> inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, void (boost::system::error_code, std::size_t)) async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b, CompletionCondition completion_condition, BOOST_ASIO_MOVE_ARG(ReadHandler) handler) { // If you get an error on the following line it means that your handler does // not meet the documented type requirements for a ReadHandler. BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; async_completion<ReadHandler, void (boost::system::error_code, std::size_t)> init(handler); detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, CompletionCondition, BOOST_ASIO_HANDLER_TYPE(ReadHandler, void (boost::system::error_code, std::size_t))>( d, offset, b, completion_condition, init.completion_handler)( boost::system::error_code(), 0, 1); return init.result.get(); } template <typename AsyncRandomAccessReadDevice, typename Allocator, typename ReadHandler> inline BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler, void (boost::system::error_code, std::size_t)) async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, boost::asio::basic_streambuf<Allocator>& b, BOOST_ASIO_MOVE_ARG(ReadHandler) handler) { // If you get an error on the following line it means that your handler does // not meet the documented type requirements for a ReadHandler. BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; async_completion<ReadHandler, void (boost::system::error_code, std::size_t)> init(handler); detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator, detail::transfer_all_t, BOOST_ASIO_HANDLER_TYPE(ReadHandler, void (boost::system::error_code, std::size_t))>( d, offset, b, transfer_all(), init.completion_handler)( boost::system::error_code(), 0, 1); return init.result.get(); } #endif // !defined(BOOST_ASIO_NO_IOSTREAM) #endif // !defined(BOOST_ASIO_NO_EXTENSIONS) } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_IMPL_READ_AT_HPP