diff options
Diffstat (limited to 'lib/asio/read_at.hpp')
| -rw-r--r-- | lib/asio/read_at.hpp | 671 |
1 files changed, 671 insertions, 0 deletions
diff --git a/lib/asio/read_at.hpp b/lib/asio/read_at.hpp new file mode 100644 index 0000000..df2c628 --- /dev/null +++ b/lib/asio/read_at.hpp @@ -0,0 +1,671 @@ +// +// 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 ASIO_READ_AT_HPP +#define ASIO_READ_AT_HPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" +#include <cstddef> +#include "asio/async_result.hpp" +#include "asio/detail/cstdint.hpp" +#include "asio/error.hpp" + +#if !defined(ASIO_NO_EXTENSIONS) +# include "asio/basic_streambuf_fwd.hpp" +#endif // !defined(ASIO_NO_EXTENSIONS) + +#include "asio/detail/push_options.hpp" + +namespace asio { + +/** + * @defgroup read_at 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 asio::system_error Thrown on failure. + * + * @par Example + * To read into a single data buffer use the @ref buffer function as follows: + * @code asio::read_at(d, 42, 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 asio::read_at( + * d, 42, buffers, + * asio::transfer_all()); @endcode + */ +template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> +std::size_t read_at(SyncRandomAccessReadDevice& d, + 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 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. + * + * @param ec Set to indicate what error occurred, if any. + * + * @returns The number of bytes transferred. + * + * @par Example + * To read into a single data buffer use the @ref buffer function as follows: + * @code asio::read_at(d, 42, + * asio::buffer(data, size), ec); @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 asio::read_at( + * d, 42, buffers, + * asio::transfer_all(), ec); @endcode + */ +template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence> +std::size_t read_at(SyncRandomAccessReadDevice& d, + uint64_t offset, const MutableBufferSequence& buffers, + asio::error_code& ec); + +/// 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 asio::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 asio::system_error Thrown on failure. + * + * @par Example + * To read into a single data buffer use the @ref buffer function as follows: + * @code asio::read_at(d, 42, asio::buffer(data, size), + * 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, + 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 asio::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, + uint64_t offset, const MutableBufferSequence& buffers, + CompletionCondition completion_condition, asio::error_code& ec); + +#if !defined(ASIO_NO_EXTENSIONS) +#if !defined(ASIO_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 asio::system_error Thrown on failure. + * + * @note This overload is equivalent to calling: + * @code asio::read_at( + * d, 42, b, + * asio::transfer_all()); @endcode + */ +template <typename SyncRandomAccessReadDevice, typename Allocator> +std::size_t read_at(SyncRandomAccessReadDevice& d, + 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 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. + * + * @param ec Set to indicate what error occurred, if any. + * + * @returns The number of bytes transferred. + * + * @note This overload is equivalent to calling: + * @code asio::read_at( + * d, 42, b, + * asio::transfer_all(), ec); @endcode + */ +template <typename SyncRandomAccessReadDevice, typename Allocator> +std::size_t read_at(SyncRandomAccessReadDevice& d, + uint64_t offset, basic_streambuf<Allocator>& b, + asio::error_code& ec); + +/// 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 asio::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 asio::system_error Thrown on failure. + */ +template <typename SyncRandomAccessReadDevice, typename Allocator, + typename CompletionCondition> +std::size_t read_at(SyncRandomAccessReadDevice& d, + 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 asio::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, + uint64_t offset, basic_streambuf<Allocator>& b, + CompletionCondition completion_condition, asio::error_code& ec); + +#endif // !defined(ASIO_NO_IOSTREAM) +#endif // !defined(ASIO_NO_EXTENSIONS) + +/*@}*/ +/** + * @defgroup async_read_at 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 asio::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 + * asio::io_context::post(). + * + * @par Example + * To read into a single data buffer use the @ref buffer function as follows: + * @code + * asio::async_read_at(d, 42, 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 asio::async_read_at( + * d, 42, buffers, + * asio::transfer_all(), + * handler); @endcode + */ +template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, + typename ReadHandler> +ASIO_INITFN_RESULT_TYPE(ReadHandler, + void (asio::error_code, std::size_t)) +async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, + const MutableBufferSequence& buffers, + 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 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 asio::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 asio::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 + * asio::io_context::post(). + * + * @par Example + * To read into a single data buffer use the @ref buffer function as follows: + * @code asio::async_read_at(d, 42, + * asio::buffer(data, size), + * 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> +ASIO_INITFN_RESULT_TYPE(ReadHandler, + void (asio::error_code, std::size_t)) +async_read_at(AsyncRandomAccessReadDevice& d, + uint64_t offset, const MutableBufferSequence& buffers, + CompletionCondition completion_condition, + ASIO_MOVE_ARG(ReadHandler) handler); + +#if !defined(ASIO_NO_EXTENSIONS) +#if !defined(ASIO_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 asio::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 + * asio::io_context::post(). + * + * @note This overload is equivalent to calling: + * @code asio::async_read_at( + * d, 42, b, + * asio::transfer_all(), + * handler); @endcode + */ +template <typename AsyncRandomAccessReadDevice, typename Allocator, + typename ReadHandler> +ASIO_INITFN_RESULT_TYPE(ReadHandler, + void (asio::error_code, std::size_t)) +async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset, + basic_streambuf<Allocator>& b, 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 asio::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 asio::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 + * asio::io_context::post(). + */ +template <typename AsyncRandomAccessReadDevice, typename Allocator, + typename CompletionCondition, typename ReadHandler> +ASIO_INITFN_RESULT_TYPE(ReadHandler, + void (asio::error_code, std::size_t)) +async_read_at(AsyncRandomAccessReadDevice& d, + uint64_t offset, basic_streambuf<Allocator>& b, + CompletionCondition completion_condition, + ASIO_MOVE_ARG(ReadHandler) handler); + +#endif // !defined(ASIO_NO_IOSTREAM) +#endif // !defined(ASIO_NO_EXTENSIONS) + +/*@}*/ + +} // namespace asio + +#include "asio/detail/pop_options.hpp" + +#include "asio/impl/read_at.hpp" + +#endif // ASIO_READ_AT_HPP |