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657 lines
25 KiB
657 lines
25 KiB
// |
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// read_at.hpp |
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// ~~~~~~~~~~~ |
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// |
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// Copyright (c) 2003-2011 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 BOOST_ASIO_READ_AT_HPP |
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#define BOOST_ASIO_READ_AT_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 <boost/asio/detail/config.hpp> |
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#include <cstddef> |
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#include <boost/cstdint.hpp> |
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#include <boost/asio/basic_streambuf_fwd.hpp> |
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#include <boost/asio/error.hpp> |
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#include <boost/asio/detail/push_options.hpp> |
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namespace boost { |
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namespace asio { |
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/** |
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* @defgroup read_at boost::asio::read_at |
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* |
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* @brief Attempt to read a certain amount of data at the specified offset |
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* before returning. |
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*/ |
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/*@{*/ |
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The supplied buffers are full. That is, the bytes transferred is equal to |
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* the sum of the buffer sizes. |
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* |
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* @li An error occurred. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param buffers One or more buffers into which the data will be read. The sum |
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* of the buffer sizes indicates the maximum number of bytes to read from the |
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* device. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @throws boost::system::system_error Thrown on failure. |
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* |
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* @par Example |
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* To read into a single data buffer use the @ref buffer function as follows: |
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* @code boost::asio::read_at(d, 42, boost::asio::buffer(data, size)); @endcode |
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* See the @ref buffer documentation for information on reading into multiple |
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* buffers in one go, and how to use it with arrays, boost::array or |
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* std::vector. |
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* |
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* @note This overload is equivalent to calling: |
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* @code boost::asio::read_at( |
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* d, 42, buffers, |
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* boost::asio::transfer_all()); @endcode |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, const MutableBufferSequence& buffers); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The supplied buffers are full. That is, the bytes transferred is equal to |
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* the sum of the buffer sizes. |
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* |
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* @li An error occurred. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param buffers One or more buffers into which the data will be read. The sum |
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* of the buffer sizes indicates the maximum number of bytes to read from the |
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* device. |
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* |
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* @param ec Set to indicate what error occurred, if any. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @par Example |
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* To read into a single data buffer use the @ref buffer function as follows: |
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* @code boost::asio::read_at(d, 42, |
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* boost::asio::buffer(data, size), ec); @endcode |
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* See the @ref buffer documentation for information on reading into multiple |
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* buffers in one go, and how to use it with arrays, boost::array or |
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* std::vector. |
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* |
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* @note This overload is equivalent to calling: |
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* @code boost::asio::read_at( |
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* d, 42, buffers, |
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* boost::asio::transfer_all(), ec); @endcode |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, const MutableBufferSequence& buffers, |
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boost::system::error_code& ec); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The supplied buffers are full. That is, the bytes transferred is equal to |
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* the sum of the buffer sizes. |
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* |
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* @li The completion_condition function object returns 0. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param buffers One or more buffers into which the data will be read. The sum |
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* of the buffer sizes indicates the maximum number of bytes to read from the |
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* device. |
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* |
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* @param completion_condition The function object to be called to determine |
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* whether the read operation is complete. The signature of the function object |
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* must be: |
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* @code std::size_t completion_condition( |
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* // Result of latest read_some_at operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes transferred so far. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* A return value of 0 indicates that the read operation is complete. A non-zero |
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* return value indicates the maximum number of bytes to be read on the next |
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* call to the device's read_some_at function. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @throws boost::system::system_error Thrown on failure. |
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* |
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* @par Example |
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* To read into a single data buffer use the @ref buffer function as follows: |
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* @code boost::asio::read_at(d, 42, boost::asio::buffer(data, size), |
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* boost::asio::transfer_at_least(32)); @endcode |
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* See the @ref buffer documentation for information on reading into multiple |
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* buffers in one go, and how to use it with arrays, boost::array or |
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* std::vector. |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, |
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typename CompletionCondition> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, const MutableBufferSequence& buffers, |
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CompletionCondition completion_condition); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The supplied buffers are full. That is, the bytes transferred is equal to |
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* the sum of the buffer sizes. |
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* |
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* @li The completion_condition function object returns 0. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param buffers One or more buffers into which the data will be read. The sum |
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* of the buffer sizes indicates the maximum number of bytes to read from the |
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* device. |
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* |
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* @param completion_condition The function object to be called to determine |
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* whether the read operation is complete. The signature of the function object |
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* must be: |
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* @code std::size_t completion_condition( |
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* // Result of latest read_some_at operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes transferred so far. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* A return value of 0 indicates that the read operation is complete. A non-zero |
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* return value indicates the maximum number of bytes to be read on the next |
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* call to the device's read_some_at function. |
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* |
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* @param ec Set to indicate what error occurred, if any. |
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* |
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* @returns The number of bytes read. If an error occurs, returns the total |
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* number of bytes successfully transferred prior to the error. |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, |
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typename CompletionCondition> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, const MutableBufferSequence& buffers, |
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CompletionCondition completion_condition, boost::system::error_code& ec); |
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#if !defined(BOOST_NO_IOSTREAM) |
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li An error occurred. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param b The basic_streambuf object into which the data will be read. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @throws boost::system::system_error Thrown on failure. |
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* |
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* @note This overload is equivalent to calling: |
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* @code boost::asio::read_at( |
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* d, 42, b, |
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* boost::asio::transfer_all()); @endcode |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename Allocator> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, basic_streambuf<Allocator>& b); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li An error occurred. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param b The basic_streambuf object into which the data will be read. |
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* |
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* @param ec Set to indicate what error occurred, if any. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @note This overload is equivalent to calling: |
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* @code boost::asio::read_at( |
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* d, 42, b, |
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* boost::asio::transfer_all(), ec); @endcode |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename Allocator> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, basic_streambuf<Allocator>& b, |
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boost::system::error_code& ec); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The completion_condition function object returns 0. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param b The basic_streambuf object into which the data will be read. |
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* |
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* @param completion_condition The function object to be called to determine |
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* whether the read operation is complete. The signature of the function object |
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* must be: |
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* @code std::size_t completion_condition( |
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* // Result of latest read_some_at operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes transferred so far. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* A return value of 0 indicates that the read operation is complete. A non-zero |
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* return value indicates the maximum number of bytes to be read on the next |
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* call to the device's read_some_at function. |
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* |
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* @returns The number of bytes transferred. |
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* |
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* @throws boost::system::system_error Thrown on failure. |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename Allocator, |
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typename CompletionCondition> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, basic_streambuf<Allocator>& b, |
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CompletionCondition completion_condition); |
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|
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/// Attempt to read a certain amount of data at the specified offset before |
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/// returning. |
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/** |
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* This function is used to read a certain number of bytes of data from a |
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* random access device at the specified offset. The call will block until one |
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* of the following conditions is true: |
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* |
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* @li The completion_condition function object returns 0. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the SyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param b The basic_streambuf object into which the data will be read. |
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* |
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* @param completion_condition The function object to be called to determine |
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* whether the read operation is complete. The signature of the function object |
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* must be: |
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* @code std::size_t completion_condition( |
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* // Result of latest read_some_at operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes transferred so far. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* A return value of 0 indicates that the read operation is complete. A non-zero |
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* return value indicates the maximum number of bytes to be read on the next |
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* call to the device's read_some_at function. |
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* |
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* @param ec Set to indicate what error occurred, if any. |
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* |
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* @returns The number of bytes read. If an error occurs, returns the total |
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* number of bytes successfully transferred prior to the error. |
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*/ |
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template <typename SyncRandomAccessReadDevice, typename Allocator, |
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typename CompletionCondition> |
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std::size_t read_at(SyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, basic_streambuf<Allocator>& b, |
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CompletionCondition completion_condition, boost::system::error_code& ec); |
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#endif // !defined(BOOST_NO_IOSTREAM) |
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/*@}*/ |
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/** |
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* @defgroup async_read_at boost::asio::async_read_at |
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* |
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* @brief Start an asynchronous operation to read a certain amount of data at |
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* the specified offset. |
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*/ |
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/*@{*/ |
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|
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/// Start an asynchronous operation to read a certain amount of data at the |
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/// specified offset. |
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/** |
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* This function is used to asynchronously read a certain number of bytes of |
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* data from a random access device at the specified offset. The function call |
|
* always returns immediately. The asynchronous operation will continue until |
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* one of the following conditions is true: |
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* |
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* @li The supplied buffers are full. That is, the bytes transferred is equal to |
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* the sum of the buffer sizes. |
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* |
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* @li An error occurred. |
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* |
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* This operation is implemented in terms of zero or more calls to the device's |
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* async_read_some_at function. |
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* |
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* @param d The device from which the data is to be read. The type must support |
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* the AsyncRandomAccessReadDevice concept. |
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* |
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* @param offset The offset at which the data will be read. |
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* |
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* @param buffers One or more buffers into which the data will be read. The sum |
|
* of the buffer sizes indicates the maximum number of bytes to read from the |
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* device. Although the buffers object may be copied as necessary, ownership of |
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* the underlying memory blocks is retained by the caller, which must guarantee |
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* that they remain valid until the handler is called. |
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* |
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* @param handler The handler to be called when the read operation completes. |
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* Copies will be made of the handler as required. The function signature of the |
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* handler must be: |
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* @code void handler( |
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* // Result of operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes copied into the buffers. If an error |
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* // occurred, this will be the number of bytes successfully |
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* // transferred prior to the error. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* Regardless of whether the asynchronous operation completes immediately or |
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* not, the handler will not be invoked from within this function. Invocation of |
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* the handler will be performed in a manner equivalent to using |
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* boost::asio::io_service::post(). |
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* |
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* @par Example |
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* To read into a single data buffer use the @ref buffer function as follows: |
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* @code |
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* boost::asio::async_read_at(d, 42, boost::asio::buffer(data, size), handler); |
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* @endcode |
|
* See the @ref buffer documentation for information on reading into multiple |
|
* buffers in one go, and how to use it with arrays, boost::array or |
|
* std::vector. |
|
* |
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* @note This overload is equivalent to calling: |
|
* @code boost::asio::async_read_at( |
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* d, 42, buffers, |
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* boost::asio::transfer_all(), |
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* handler); @endcode |
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*/ |
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template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, |
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typename ReadHandler> |
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void async_read_at(AsyncRandomAccessReadDevice& d, boost::uint64_t offset, |
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const MutableBufferSequence& buffers, |
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BOOST_ASIO_MOVE_ARG(ReadHandler) handler); |
|
|
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/// Start an asynchronous operation to read a certain amount of data at the |
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/// specified offset. |
|
/** |
|
* This function is used to asynchronously read a certain number of bytes of |
|
* data from a random access device at the specified offset. The function call |
|
* always returns immediately. The asynchronous operation will continue until |
|
* one of the following conditions is true: |
|
* |
|
* @li The supplied buffers are full. That is, the bytes transferred is equal to |
|
* the sum of the buffer sizes. |
|
* |
|
* @li The completion_condition function object returns 0. |
|
* |
|
* @param d The device from which the data is to be read. The type must support |
|
* the AsyncRandomAccessReadDevice concept. |
|
* |
|
* @param offset The offset at which the data will be read. |
|
* |
|
* @param buffers One or more buffers into which the data will be read. The sum |
|
* of the buffer sizes indicates the maximum number of bytes to read from the |
|
* device. Although the buffers object may be copied as necessary, ownership of |
|
* the underlying memory blocks is retained by the caller, which must guarantee |
|
* that they remain valid until the handler is called. |
|
* |
|
* @param completion_condition The function object to be called to determine |
|
* whether the read operation is complete. The signature of the function object |
|
* must be: |
|
* @code std::size_t completion_condition( |
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* // Result of latest async_read_some_at operation. |
|
* const boost::system::error_code& error, |
|
* |
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* // Number of bytes transferred so far. |
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* std::size_t bytes_transferred |
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* ); @endcode |
|
* A return value of 0 indicates that the read operation is complete. A non-zero |
|
* return value indicates the maximum number of bytes to be read on the next |
|
* call to the device's async_read_some_at function. |
|
* |
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* @param handler The handler to be called when the read operation completes. |
|
* Copies will be made of the handler as required. The function signature of the |
|
* handler must be: |
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* @code void handler( |
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* // Result of operation. |
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* const boost::system::error_code& error, |
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* |
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* // Number of bytes copied into the buffers. If an error |
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* // occurred, this will be the number of bytes successfully |
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* // transferred prior to the error. |
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* std::size_t bytes_transferred |
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* ); @endcode |
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* Regardless of whether the asynchronous operation completes immediately or |
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* not, the handler will not be invoked from within this function. Invocation of |
|
* the handler will be performed in a manner equivalent to using |
|
* boost::asio::io_service::post(). |
|
* |
|
* @par Example |
|
* To read into a single data buffer use the @ref buffer function as follows: |
|
* @code boost::asio::async_read_at(d, 42, |
|
* boost::asio::buffer(data, size), |
|
* boost::asio::transfer_at_least(32), |
|
* handler); @endcode |
|
* See the @ref buffer documentation for information on reading into multiple |
|
* buffers in one go, and how to use it with arrays, boost::array or |
|
* std::vector. |
|
*/ |
|
template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, |
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typename CompletionCondition, typename ReadHandler> |
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void async_read_at(AsyncRandomAccessReadDevice& d, |
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boost::uint64_t offset, const MutableBufferSequence& buffers, |
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CompletionCondition completion_condition, |
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BOOST_ASIO_MOVE_ARG(ReadHandler) handler); |
|
|
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#if !defined(BOOST_NO_IOSTREAM) |
|
|
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/// Start an asynchronous operation to read a certain amount of data at the |
|
/// specified offset. |
|
/** |
|
* This function is used to asynchronously read a certain number of bytes of |
|
* data from a random access device at the specified offset. The function call |
|
* always returns immediately. The asynchronous operation will continue until |
|
* one of the following conditions is true: |
|
* |
|
* @li An error occurred. |
|
* |
|
* This operation is implemented in terms of zero or more calls to the device's |
|
* async_read_some_at function. |
|
* |
|
* @param d The device from which the data is to be read. The type must support |
|
* the AsyncRandomAccessReadDevice concept. |
|
* |
|
* @param offset The offset at which the data will be read. |
|
* |
|
* @param b A basic_streambuf object into which the data will be read. Ownership |
|
* of the streambuf is retained by the caller, which must guarantee that it |
|
* remains valid until the handler is called. |
|
* |
|
* @param handler The handler to be called when the read operation completes. |
|
* Copies will be made of the handler as required. The function signature of the |
|
* handler must be: |
|
* @code void handler( |
|
* // Result of operation. |
|
* const boost::system::error_code& error, |
|
* |
|
* // Number of bytes copied into the buffers. If an error |
|
* // occurred, this will be the number of bytes successfully |
|
* // transferred prior to the error. |
|
* std::size_t bytes_transferred |
|
* ); @endcode |
|
* Regardless of whether the asynchronous operation completes immediately or |
|
* not, the handler will not be invoked from within this function. Invocation of |
|
* the handler will be performed in a manner equivalent to using |
|
* boost::asio::io_service::post(). |
|
* |
|
* @note This overload is equivalent to calling: |
|
* @code boost::asio::async_read_at( |
|
* d, 42, b, |
|
* boost::asio::transfer_all(), |
|
* handler); @endcode |
|
*/ |
|
template <typename AsyncRandomAccessReadDevice, typename Allocator, |
|
typename ReadHandler> |
|
void async_read_at(AsyncRandomAccessReadDevice& d, boost::uint64_t offset, |
|
basic_streambuf<Allocator>& b, BOOST_ASIO_MOVE_ARG(ReadHandler) handler); |
|
|
|
/// Start an asynchronous operation to read a certain amount of data at the |
|
/// specified offset. |
|
/** |
|
* This function is used to asynchronously read a certain number of bytes of |
|
* data from a random access device at the specified offset. The function call |
|
* always returns immediately. The asynchronous operation will continue until |
|
* one of the following conditions is true: |
|
* |
|
* @li The completion_condition function object returns 0. |
|
* |
|
* This operation is implemented in terms of zero or more calls to the device's |
|
* async_read_some_at function. |
|
* |
|
* @param d The device from which the data is to be read. The type must support |
|
* the AsyncRandomAccessReadDevice concept. |
|
* |
|
* @param offset The offset at which the data will be read. |
|
* |
|
* @param b A basic_streambuf object into which the data will be read. Ownership |
|
* of the streambuf is retained by the caller, which must guarantee that it |
|
* remains valid until the handler is called. |
|
* |
|
* @param completion_condition The function object to be called to determine |
|
* whether the read operation is complete. The signature of the function object |
|
* must be: |
|
* @code std::size_t completion_condition( |
|
* // Result of latest async_read_some_at operation. |
|
* const boost::system::error_code& error, |
|
* |
|
* // Number of bytes transferred so far. |
|
* std::size_t bytes_transferred |
|
* ); @endcode |
|
* A return value of 0 indicates that the read operation is complete. A non-zero |
|
* return value indicates the maximum number of bytes to be read on the next |
|
* call to the device's async_read_some_at function. |
|
* |
|
* @param handler The handler to be called when the read operation completes. |
|
* Copies will be made of the handler as required. The function signature of the |
|
* handler must be: |
|
* @code void handler( |
|
* // Result of operation. |
|
* const boost::system::error_code& error, |
|
* |
|
* // Number of bytes copied into the buffers. If an error |
|
* // occurred, this will be the number of bytes successfully |
|
* // transferred prior to the error. |
|
* std::size_t bytes_transferred |
|
* ); @endcode |
|
* Regardless of whether the asynchronous operation completes immediately or |
|
* not, the handler will not be invoked from within this function. Invocation of |
|
* the handler will be performed in a manner equivalent to using |
|
* boost::asio::io_service::post(). |
|
*/ |
|
template <typename AsyncRandomAccessReadDevice, typename Allocator, |
|
typename CompletionCondition, typename ReadHandler> |
|
void async_read_at(AsyncRandomAccessReadDevice& d, |
|
boost::uint64_t offset, basic_streambuf<Allocator>& b, |
|
CompletionCondition completion_condition, |
|
BOOST_ASIO_MOVE_ARG(ReadHandler) handler); |
|
|
|
#endif // !defined(BOOST_NO_IOSTREAM) |
|
|
|
/*@}*/ |
|
|
|
} // namespace asio |
|
} // namespace boost |
|
|
|
#include <boost/asio/detail/pop_options.hpp> |
|
|
|
#include <boost/asio/impl/read_at.hpp> |
|
|
|
#endif // BOOST_ASIO_READ_AT_HPP
|
|
|