// | |
// read_at.hpp | |
// ~~~~~~~~~~~ | |
// | |
// Copyright (c) 2003-2011 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_READ_AT_HPP | |
#define BOOST_ASIO_READ_AT_HPP | |
#if defined(_MSC_VER) && (_MSC_VER >= 1200) | |
# pragma once | |
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) | |
#include <boost/asio/detail/config.hpp> | |
#include <cstddef> | |
#include <boost/cstdint.hpp> | |
#include <boost/asio/basic_streambuf_fwd.hpp> | |
#include <boost/asio/error.hpp> | |
#include <boost/asio/detail/push_options.hpp> | |
namespace boost { | |
namespace asio { | |
/** | |
* @defgroup read_at boost::asio::read_at | |
* | |
* @brief Attempt to read a certain amount of data at the specified offset | |
* before returning. | |
*/ | |
/*@{*/ | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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 An error occurred. | |
* | |
* This operation is implemented in terms of zero or more calls to the device's | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice 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. | |
* | |
* @returns The number of bytes transferred. | |
* | |
* @throws boost::system::system_error Thrown on failure. | |
* | |
* @par Example | |
* To read into a single data buffer use the @ref buffer function as follows: | |
* @code boost::asio::read_at(d, 42, boost::asio::buffer(data, size)); @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. | |
* | |
* @note This overload is equivalent to calling: | |
* @code boost::asio::read_at( | |
* d, 42, buffers, | |
* boost::asio::transfer_all()); @endcode | |
*/ | |
template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, const MutableBufferSequence& buffers); | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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. | |
* | |
* This operation is implemented in terms of zero or more calls to the device's | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice 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. | |
* | |
* @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 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 read_some_at function. | |
* | |
* @returns The number of bytes transferred. | |
* | |
* @throws boost::system::system_error Thrown on failure. | |
* | |
* @par Example | |
* To read into a single data buffer use the @ref buffer function as follows: | |
* @code boost::asio::read_at(d, 42, boost::asio::buffer(data, size), | |
* boost::asio::transfer_at_least(32)); @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 SyncRandomAccessReadDevice, typename MutableBufferSequence, | |
typename CompletionCondition> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, const MutableBufferSequence& buffers, | |
CompletionCondition completion_condition); | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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. | |
* | |
* This operation is implemented in terms of zero or more calls to the device's | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice 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. | |
* | |
* @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 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 read_some_at function. | |
* | |
* @param ec Set to indicate what error occurred, if any. | |
* | |
* @returns The number of bytes read. If an error occurs, returns the total | |
* number of bytes successfully transferred prior to the error. | |
*/ | |
template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence, | |
typename CompletionCondition> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, const MutableBufferSequence& buffers, | |
CompletionCondition completion_condition, boost::system::error_code& ec); | |
#if !defined(BOOST_NO_IOSTREAM) | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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 | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice concept. | |
* | |
* @param offset The offset at which the data will be read. | |
* | |
* @param b The basic_streambuf object into which the data will be read. | |
* | |
* @returns The number of bytes transferred. | |
* | |
* @throws boost::system::system_error Thrown on failure. | |
* | |
* @note This overload is equivalent to calling: | |
* @code boost::asio::read_at( | |
* d, 42, b, | |
* boost::asio::transfer_all()); @endcode | |
*/ | |
template <typename SyncRandomAccessReadDevice, typename Allocator> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, basic_streambuf<Allocator>& b); | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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 | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice concept. | |
* | |
* @param offset The offset at which the data will be read. | |
* | |
* @param b The basic_streambuf object into which the data will be read. | |
* | |
* @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 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 read_some_at function. | |
* | |
* @returns The number of bytes transferred. | |
* | |
* @throws boost::system::system_error Thrown on failure. | |
*/ | |
template <typename SyncRandomAccessReadDevice, typename Allocator, | |
typename CompletionCondition> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, basic_streambuf<Allocator>& b, | |
CompletionCondition completion_condition); | |
/// Attempt to read a certain amount of data at the specified offset before | |
/// returning. | |
/** | |
* This function is used to read a certain number of bytes of data from a | |
* random access device at the specified offset. The call will block 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 | |
* read_some_at function. | |
* | |
* @param d The device from which the data is to be read. The type must support | |
* the SyncRandomAccessReadDevice concept. | |
* | |
* @param offset The offset at which the data will be read. | |
* | |
* @param b The basic_streambuf object into which the data will be read. | |
* | |
* @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 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 read_some_at function. | |
* | |
* @param ec Set to indicate what error occurred, if any. | |
* | |
* @returns The number of bytes read. If an error occurs, returns the total | |
* number of bytes successfully transferred prior to the error. | |
*/ | |
template <typename SyncRandomAccessReadDevice, typename Allocator, | |
typename CompletionCondition> | |
std::size_t read_at(SyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, basic_streambuf<Allocator>& b, | |
CompletionCondition completion_condition, boost::system::error_code& ec); | |
#endif // !defined(BOOST_NO_IOSTREAM) | |
/*@}*/ | |
/** | |
* @defgroup async_read_at boost::asio::async_read_at | |
* | |
* @brief Start an asynchronous operation to read a certain amount of data at | |
* the specified offset. | |
*/ | |
/*@{*/ | |
/// 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 supplied buffers are full. That is, the bytes transferred is equal to | |
* the sum of the buffer sizes. | |
* | |
* @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 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 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(). | |
* | |
* @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), 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. | |
* | |
* @note This overload is equivalent to calling: | |
* @code boost::asio::async_read_at( | |
* d, 42, buffers, | |
* boost::asio::transfer_all(), | |
* handler); @endcode | |
*/ | |
template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, | |
typename ReadHandler> | |
void async_read_at(AsyncRandomAccessReadDevice& d, boost::uint64_t offset, | |
const MutableBufferSequence& buffers, 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 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( | |
* // 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(). | |
* | |
* @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, | |
typename CompletionCondition, typename ReadHandler> | |
void async_read_at(AsyncRandomAccessReadDevice& d, | |
boost::uint64_t offset, const MutableBufferSequence& buffers, | |
CompletionCondition completion_condition, ReadHandler handler); | |
#if !defined(BOOST_NO_IOSTREAM) | |
/// 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, 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, 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 |