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1 | // | |
2 | // write_at.hpp | |
3 | // ~~~~~~~~~~~~ | |
4 | // | |
5 | // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com) | |
6 | // | |
7 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
9 | // | |
10 | ||
11 | #ifndef BOOST_ASIO_WRITE_AT_HPP | |
12 | #define BOOST_ASIO_WRITE_AT_HPP | |
13 | ||
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1200) | |
15 | # pragma once | |
16 | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) | |
17 | ||
18 | #include <boost/asio/detail/config.hpp> | |
19 | #include <cstddef> | |
20 | #include <boost/asio/async_result.hpp> | |
21 | #include <boost/asio/basic_streambuf_fwd.hpp> | |
22 | #include <boost/asio/detail/cstdint.hpp> | |
23 | #include <boost/asio/error.hpp> | |
24 | ||
25 | #include <boost/asio/detail/push_options.hpp> | |
26 | ||
27 | namespace boost { | |
28 | namespace asio { | |
29 | ||
30 | /** | |
31 | * @defgroup write_at boost::asio::write_at | |
32 | * | |
33 | * @brief Write a certain amount of data at a specified offset before returning. | |
34 | */ | |
35 | /*@{*/ | |
36 | ||
37 | /// Write all of the supplied data at the specified offset before returning. | |
38 | /** | |
39 | * This function is used to write a certain number of bytes of data to a random | |
40 | * access device at a specified offset. The call will block until one of the | |
41 | * following conditions is true: | |
42 | * | |
43 | * @li All of the data in the supplied buffers has been written. That is, the | |
44 | * bytes transferred is equal to the sum of the buffer sizes. | |
45 | * | |
46 | * @li An error occurred. | |
47 | * | |
48 | * This operation is implemented in terms of zero or more calls to the device's | |
49 | * write_some_at function. | |
50 | * | |
51 | * @param d The device to which the data is to be written. The type must support | |
52 | * the SyncRandomAccessWriteDevice concept. | |
53 | * | |
54 | * @param offset The offset at which the data will be written. | |
55 | * | |
56 | * @param buffers One or more buffers containing the data to be written. The sum | |
57 | * of the buffer sizes indicates the maximum number of bytes to write to the | |
58 | * device. | |
59 | * | |
60 | * @returns The number of bytes transferred. | |
61 | * | |
62 | * @throws boost::system::system_error Thrown on failure. | |
63 | * | |
64 | * @par Example | |
65 | * To write a single data buffer use the @ref buffer function as follows: | |
66 | * @code boost::asio::write_at(d, 42, boost::asio::buffer(data, size)); @endcode | |
67 | * See the @ref buffer documentation for information on writing multiple | |
68 | * buffers in one go, and how to use it with arrays, boost::array or | |
69 | * std::vector. | |
70 | * | |
71 | * @note This overload is equivalent to calling: | |
72 | * @code boost::asio::write_at( | |
73 | * d, offset, buffers, | |
74 | * boost::asio::transfer_all()); @endcode | |
75 | */ | |
76 | template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence> | |
77 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
78 | uint64_t offset, const ConstBufferSequence& buffers); | |
79 | ||
80 | /// Write all of the supplied data at the specified offset before returning. | |
81 | /** | |
82 | * This function is used to write a certain number of bytes of data to a random | |
83 | * access device at a specified offset. The call will block until one of the | |
84 | * following conditions is true: | |
85 | * | |
86 | * @li All of the data in the supplied buffers has been written. That is, the | |
87 | * bytes transferred is equal to the sum of the buffer sizes. | |
88 | * | |
89 | * @li An error occurred. | |
90 | * | |
91 | * This operation is implemented in terms of zero or more calls to the device's | |
92 | * write_some_at function. | |
93 | * | |
94 | * @param d The device to which the data is to be written. The type must support | |
95 | * the SyncRandomAccessWriteDevice concept. | |
96 | * | |
97 | * @param offset The offset at which the data will be written. | |
98 | * | |
99 | * @param buffers One or more buffers containing the data to be written. The sum | |
100 | * of the buffer sizes indicates the maximum number of bytes to write to the | |
101 | * device. | |
102 | * | |
103 | * @param ec Set to indicate what error occurred, if any. | |
104 | * | |
105 | * @returns The number of bytes transferred. | |
106 | * | |
107 | * @par Example | |
108 | * To write a single data buffer use the @ref buffer function as follows: | |
109 | * @code boost::asio::write_at(d, 42, | |
110 | * boost::asio::buffer(data, size), ec); @endcode | |
111 | * See the @ref buffer documentation for information on writing multiple | |
112 | * buffers in one go, and how to use it with arrays, boost::array or | |
113 | * std::vector. | |
114 | * | |
115 | * @note This overload is equivalent to calling: | |
116 | * @code boost::asio::write_at( | |
117 | * d, offset, buffers, | |
118 | * boost::asio::transfer_all(), ec); @endcode | |
119 | */ | |
120 | template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence> | |
121 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
122 | uint64_t offset, const ConstBufferSequence& buffers, | |
123 | boost::system::error_code& ec); | |
124 | ||
125 | /// Write a certain amount of data at a specified offset before returning. | |
126 | /** | |
127 | * This function is used to write a certain number of bytes of data to a random | |
128 | * access device at a specified offset. The call will block until one of the | |
129 | * following conditions is true: | |
130 | * | |
131 | * @li All of the data in the supplied buffers has been written. That is, the | |
132 | * bytes transferred is equal to the sum of the buffer sizes. | |
133 | * | |
134 | * @li The completion_condition function object returns 0. | |
135 | * | |
136 | * This operation is implemented in terms of zero or more calls to the device's | |
137 | * write_some_at function. | |
138 | * | |
139 | * @param d The device to which the data is to be written. The type must support | |
140 | * the SyncRandomAccessWriteDevice concept. | |
141 | * | |
142 | * @param offset The offset at which the data will be written. | |
143 | * | |
144 | * @param buffers One or more buffers containing the data to be written. The sum | |
145 | * of the buffer sizes indicates the maximum number of bytes to write to the | |
146 | * device. | |
147 | * | |
148 | * @param completion_condition The function object to be called to determine | |
149 | * whether the write operation is complete. The signature of the function object | |
150 | * must be: | |
151 | * @code std::size_t completion_condition( | |
152 | * // Result of latest write_some_at operation. | |
153 | * const boost::system::error_code& error, | |
154 | * | |
155 | * // Number of bytes transferred so far. | |
156 | * std::size_t bytes_transferred | |
157 | * ); @endcode | |
158 | * A return value of 0 indicates that the write operation is complete. A | |
159 | * non-zero return value indicates the maximum number of bytes to be written on | |
160 | * the next call to the device's write_some_at function. | |
161 | * | |
162 | * @returns The number of bytes transferred. | |
163 | * | |
164 | * @throws boost::system::system_error Thrown on failure. | |
165 | * | |
166 | * @par Example | |
167 | * To write a single data buffer use the @ref buffer function as follows: | |
168 | * @code boost::asio::write_at(d, 42, boost::asio::buffer(data, size), | |
169 | * boost::asio::transfer_at_least(32)); @endcode | |
170 | * See the @ref buffer documentation for information on writing multiple | |
171 | * buffers in one go, and how to use it with arrays, boost::array or | |
172 | * std::vector. | |
173 | */ | |
174 | template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence, | |
175 | typename CompletionCondition> | |
176 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
177 | uint64_t offset, const ConstBufferSequence& buffers, | |
178 | CompletionCondition completion_condition); | |
179 | ||
180 | /// Write a certain amount of data at a specified offset before returning. | |
181 | /** | |
182 | * This function is used to write a certain number of bytes of data to a random | |
183 | * access device at a specified offset. The call will block until one of the | |
184 | * following conditions is true: | |
185 | * | |
186 | * @li All of the data in the supplied buffers has been written. That is, the | |
187 | * bytes transferred is equal to the sum of the buffer sizes. | |
188 | * | |
189 | * @li The completion_condition function object returns 0. | |
190 | * | |
191 | * This operation is implemented in terms of zero or more calls to the device's | |
192 | * write_some_at function. | |
193 | * | |
194 | * @param d The device to which the data is to be written. The type must support | |
195 | * the SyncRandomAccessWriteDevice concept. | |
196 | * | |
197 | * @param offset The offset at which the data will be written. | |
198 | * | |
199 | * @param buffers One or more buffers containing the data to be written. The sum | |
200 | * of the buffer sizes indicates the maximum number of bytes to write to the | |
201 | * device. | |
202 | * | |
203 | * @param completion_condition The function object to be called to determine | |
204 | * whether the write operation is complete. The signature of the function object | |
205 | * must be: | |
206 | * @code std::size_t completion_condition( | |
207 | * // Result of latest write_some_at operation. | |
208 | * const boost::system::error_code& error, | |
209 | * | |
210 | * // Number of bytes transferred so far. | |
211 | * std::size_t bytes_transferred | |
212 | * ); @endcode | |
213 | * A return value of 0 indicates that the write operation is complete. A | |
214 | * non-zero return value indicates the maximum number of bytes to be written on | |
215 | * the next call to the device's write_some_at function. | |
216 | * | |
217 | * @param ec Set to indicate what error occurred, if any. | |
218 | * | |
219 | * @returns The number of bytes written. If an error occurs, returns the total | |
220 | * number of bytes successfully transferred prior to the error. | |
221 | */ | |
222 | template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence, | |
223 | typename CompletionCondition> | |
224 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
225 | uint64_t offset, const ConstBufferSequence& buffers, | |
226 | CompletionCondition completion_condition, boost::system::error_code& ec); | |
227 | ||
228 | #if !defined(BOOST_ASIO_NO_IOSTREAM) | |
229 | ||
230 | /// Write all of the supplied data at the specified offset before returning. | |
231 | /** | |
232 | * This function is used to write a certain number of bytes of data to a random | |
233 | * access device at a specified offset. The call will block until one of the | |
234 | * following conditions is true: | |
235 | * | |
236 | * @li All of the data in the supplied basic_streambuf has been written. | |
237 | * | |
238 | * @li An error occurred. | |
239 | * | |
240 | * This operation is implemented in terms of zero or more calls to the device's | |
241 | * write_some_at function. | |
242 | * | |
243 | * @param d The device to which the data is to be written. The type must support | |
244 | * the SyncRandomAccessWriteDevice concept. | |
245 | * | |
246 | * @param offset The offset at which the data will be written. | |
247 | * | |
248 | * @param b The basic_streambuf object from which data will be written. | |
249 | * | |
250 | * @returns The number of bytes transferred. | |
251 | * | |
252 | * @throws boost::system::system_error Thrown on failure. | |
253 | * | |
254 | * @note This overload is equivalent to calling: | |
255 | * @code boost::asio::write_at( | |
256 | * d, 42, b, | |
257 | * boost::asio::transfer_all()); @endcode | |
258 | */ | |
259 | template <typename SyncRandomAccessWriteDevice, typename Allocator> | |
260 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
261 | uint64_t offset, basic_streambuf<Allocator>& b); | |
262 | ||
263 | /// Write all of the supplied data at the specified offset before returning. | |
264 | /** | |
265 | * This function is used to write a certain number of bytes of data to a random | |
266 | * access device at a specified offset. The call will block until one of the | |
267 | * following conditions is true: | |
268 | * | |
269 | * @li All of the data in the supplied basic_streambuf has been written. | |
270 | * | |
271 | * @li An error occurred. | |
272 | * | |
273 | * This operation is implemented in terms of zero or more calls to the device's | |
274 | * write_some_at function. | |
275 | * | |
276 | * @param d The device to which the data is to be written. The type must support | |
277 | * the SyncRandomAccessWriteDevice concept. | |
278 | * | |
279 | * @param offset The offset at which the data will be written. | |
280 | * | |
281 | * @param b The basic_streambuf object from which data will be written. | |
282 | * | |
283 | * @param ec Set to indicate what error occurred, if any. | |
284 | * | |
285 | * @returns The number of bytes transferred. | |
286 | * | |
287 | * @note This overload is equivalent to calling: | |
288 | * @code boost::asio::write_at( | |
289 | * d, 42, b, | |
290 | * boost::asio::transfer_all(), ec); @endcode | |
291 | */ | |
292 | template <typename SyncRandomAccessWriteDevice, typename Allocator> | |
293 | std::size_t write_at(SyncRandomAccessWriteDevice& d, | |
294 | uint64_t offset, basic_streambuf<Allocator>& b, | |
295 | boost::system::error_code& ec); | |
296 | ||
297 | /// Write a certain amount of data at a specified offset before returning. | |
298 | /** | |
299 | * This function is used to write a certain number of bytes of data to a random | |
300 | * access device at a specified offset. The call will block until one of the | |
301 | * following conditions is true: | |
302 | * | |
303 | * @li All of the data in the supplied basic_streambuf has been written. | |
304 | * | |
305 | * @li The completion_condition function object returns 0. | |
306 | * | |
307 | * This operation is implemented in terms of zero or more calls to the device's | |
308 | * write_some_at function. | |
309 | * | |
310 | * @param d The device to which the data is to be written. The type must support | |
311 | * the SyncRandomAccessWriteDevice concept. | |
312 | * | |
313 | * @param offset The offset at which the data will be written. | |
314 | * | |
315 | * @param b The basic_streambuf object from which data will be written. | |
316 | * | |
317 | * @param completion_condition The function object to be called to determine | |
318 | * whether the write operation is complete. The signature of the function object | |
319 | * must be: | |
320 | * @code std::size_t completion_condition( | |
321 | * // Result of latest write_some_at operation. | |
322 | * const boost::system::error_code& error, | |
323 | * | |
324 | * // Number of bytes transferred so far. | |
325 | * std::size_t bytes_transferred | |
326 | * ); @endcode | |
327 | * A return value of 0 indicates that the write operation is complete. A | |
328 | * non-zero return value indicates the maximum number of bytes to be written on | |
329 | * the next call to the device's write_some_at function. | |
330 | * | |
331 | * @returns The number of bytes transferred. | |
332 | * | |
333 | * @throws boost::system::system_error Thrown on failure. | |
334 | */ | |
335 | template <typename SyncRandomAccessWriteDevice, typename Allocator, | |
336 | typename CompletionCondition> | |
337 | std::size_t write_at(SyncRandomAccessWriteDevice& d, uint64_t offset, | |
338 | basic_streambuf<Allocator>& b, CompletionCondition completion_condition); | |
339 | ||
340 | /// Write a certain amount of data at a specified offset before returning. | |
341 | /** | |
342 | * This function is used to write a certain number of bytes of data to a random | |
343 | * access device at a specified offset. The call will block until one of the | |
344 | * following conditions is true: | |
345 | * | |
346 | * @li All of the data in the supplied basic_streambuf has been written. | |
347 | * | |
348 | * @li The completion_condition function object returns 0. | |
349 | * | |
350 | * This operation is implemented in terms of zero or more calls to the device's | |
351 | * write_some_at function. | |
352 | * | |
353 | * @param d The device to which the data is to be written. The type must support | |
354 | * the SyncRandomAccessWriteDevice concept. | |
355 | * | |
356 | * @param offset The offset at which the data will be written. | |
357 | * | |
358 | * @param b The basic_streambuf object from which data will be written. | |
359 | * | |
360 | * @param completion_condition The function object to be called to determine | |
361 | * whether the write operation is complete. The signature of the function object | |
362 | * must be: | |
363 | * @code std::size_t completion_condition( | |
364 | * // Result of latest write_some_at operation. | |
365 | * const boost::system::error_code& error, | |
366 | * | |
367 | * // Number of bytes transferred so far. | |
368 | * std::size_t bytes_transferred | |
369 | * ); @endcode | |
370 | * A return value of 0 indicates that the write operation is complete. A | |
371 | * non-zero return value indicates the maximum number of bytes to be written on | |
372 | * the next call to the device's write_some_at function. | |
373 | * | |
374 | * @param ec Set to indicate what error occurred, if any. | |
375 | * | |
376 | * @returns The number of bytes written. If an error occurs, returns the total | |
377 | * number of bytes successfully transferred prior to the error. | |
378 | */ | |
379 | template <typename SyncRandomAccessWriteDevice, typename Allocator, | |
380 | typename CompletionCondition> | |
381 | std::size_t write_at(SyncRandomAccessWriteDevice& d, uint64_t offset, | |
382 | basic_streambuf<Allocator>& b, CompletionCondition completion_condition, | |
383 | boost::system::error_code& ec); | |
384 | ||
385 | #endif // !defined(BOOST_ASIO_NO_IOSTREAM) | |
386 | ||
387 | /*@}*/ | |
388 | /** | |
389 | * @defgroup async_write_at boost::asio::async_write_at | |
390 | * | |
391 | * @brief Start an asynchronous operation to write a certain amount of data at | |
392 | * the specified offset. | |
393 | */ | |
394 | /*@{*/ | |
395 | ||
396 | /// Start an asynchronous operation to write all of the supplied data at the | |
397 | /// specified offset. | |
398 | /** | |
399 | * This function is used to asynchronously write a certain number of bytes of | |
400 | * data to a random access device at a specified offset. The function call | |
401 | * always returns immediately. The asynchronous operation will continue until | |
402 | * one of the following conditions is true: | |
403 | * | |
404 | * @li All of the data in the supplied buffers has been written. That is, the | |
405 | * bytes transferred is equal to the sum of the buffer sizes. | |
406 | * | |
407 | * @li An error occurred. | |
408 | * | |
409 | * This operation is implemented in terms of zero or more calls to the device's | |
410 | * async_write_some_at function, and is known as a <em>composed operation</em>. | |
411 | * The program must ensure that the device performs no <em>overlapping</em> | |
412 | * write operations (such as async_write_at, the device's async_write_some_at | |
413 | * function, or any other composed operations that perform writes) until this | |
414 | * operation completes. Operations are overlapping if the regions defined by | |
415 | * their offsets, and the numbers of bytes to write, intersect. | |
416 | * | |
417 | * @param d The device to which the data is to be written. The type must support | |
418 | * the AsyncRandomAccessWriteDevice concept. | |
419 | * | |
420 | * @param offset The offset at which the data will be written. | |
421 | * | |
422 | * @param buffers One or more buffers containing the data to be written. | |
423 | * Although the buffers object may be copied as necessary, ownership of the | |
424 | * underlying memory blocks is retained by the caller, which must guarantee | |
425 | * that they remain valid until the handler is called. | |
426 | * | |
427 | * @param handler The handler to be called when the write operation completes. | |
428 | * Copies will be made of the handler as required. The function signature of | |
429 | * the handler must be: | |
430 | * @code void handler( | |
431 | * // Result of operation. | |
432 | * const boost::system::error_code& error, | |
433 | * | |
434 | * // Number of bytes written from the buffers. If an error | |
435 | * // occurred, this will be less than the sum of the buffer sizes. | |
436 | * std::size_t bytes_transferred | |
437 | * ); @endcode | |
438 | * Regardless of whether the asynchronous operation completes immediately or | |
439 | * not, the handler will not be invoked from within this function. Invocation of | |
440 | * the handler will be performed in a manner equivalent to using | |
441 | * boost::asio::io_service::post(). | |
442 | * | |
443 | * @par Example | |
444 | * To write a single data buffer use the @ref buffer function as follows: | |
445 | * @code | |
446 | * boost::asio::async_write_at(d, 42, boost::asio::buffer(data, size), handler); | |
447 | * @endcode | |
448 | * See the @ref buffer documentation for information on writing multiple | |
449 | * buffers in one go, and how to use it with arrays, boost::array or | |
450 | * std::vector. | |
451 | */ | |
452 | template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence, | |
453 | typename WriteHandler> | |
454 | BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler, | |
455 | void (boost::system::error_code, std::size_t)) | |
456 | async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset, | |
457 | const ConstBufferSequence& buffers, | |
458 | BOOST_ASIO_MOVE_ARG(WriteHandler) handler); | |
459 | ||
460 | /// Start an asynchronous operation to write a certain amount of data at the | |
461 | /// specified offset. | |
462 | /** | |
463 | * This function is used to asynchronously write a certain number of bytes of | |
464 | * data to a random access device at a specified offset. The function call | |
465 | * always returns immediately. The asynchronous operation will continue until | |
466 | * one of the following conditions is true: | |
467 | * | |
468 | * @li All of the data in the supplied buffers has been written. That is, the | |
469 | * bytes transferred is equal to the sum of the buffer sizes. | |
470 | * | |
471 | * @li The completion_condition function object returns 0. | |
472 | * | |
473 | * This operation is implemented in terms of zero or more calls to the device's | |
474 | * async_write_some_at function, and is known as a <em>composed operation</em>. | |
475 | * The program must ensure that the device performs no <em>overlapping</em> | |
476 | * write operations (such as async_write_at, the device's async_write_some_at | |
477 | * function, or any other composed operations that perform writes) until this | |
478 | * operation completes. Operations are overlapping if the regions defined by | |
479 | * their offsets, and the numbers of bytes to write, intersect. | |
480 | * | |
481 | * @param d The device to which the data is to be written. The type must support | |
482 | * the AsyncRandomAccessWriteDevice concept. | |
483 | * | |
484 | * @param offset The offset at which the data will be written. | |
485 | * | |
486 | * @param buffers One or more buffers containing the data to be written. | |
487 | * Although the buffers object may be copied as necessary, ownership of the | |
488 | * underlying memory blocks is retained by the caller, which must guarantee | |
489 | * that they remain valid until the handler is called. | |
490 | * | |
491 | * @param completion_condition The function object to be called to determine | |
492 | * whether the write operation is complete. The signature of the function object | |
493 | * must be: | |
494 | * @code std::size_t completion_condition( | |
495 | * // Result of latest async_write_some_at operation. | |
496 | * const boost::system::error_code& error, | |
497 | * | |
498 | * // Number of bytes transferred so far. | |
499 | * std::size_t bytes_transferred | |
500 | * ); @endcode | |
501 | * A return value of 0 indicates that the write operation is complete. A | |
502 | * non-zero return value indicates the maximum number of bytes to be written on | |
503 | * the next call to the device's async_write_some_at function. | |
504 | * | |
505 | * @param handler The handler to be called when the write operation completes. | |
506 | * Copies will be made of the handler as required. The function signature of the | |
507 | * handler must be: | |
508 | * @code void handler( | |
509 | * // Result of operation. | |
510 | * const boost::system::error_code& error, | |
511 | * | |
512 | * // Number of bytes written from the buffers. If an error | |
513 | * // occurred, this will be less than the sum of the buffer sizes. | |
514 | * std::size_t bytes_transferred | |
515 | * ); @endcode | |
516 | * Regardless of whether the asynchronous operation completes immediately or | |
517 | * not, the handler will not be invoked from within this function. Invocation of | |
518 | * the handler will be performed in a manner equivalent to using | |
519 | * boost::asio::io_service::post(). | |
520 | * | |
521 | * @par Example | |
522 | * To write a single data buffer use the @ref buffer function as follows: | |
523 | * @code boost::asio::async_write_at(d, 42, | |
524 | * boost::asio::buffer(data, size), | |
525 | * boost::asio::transfer_at_least(32), | |
526 | * handler); @endcode | |
527 | * See the @ref buffer documentation for information on writing multiple | |
528 | * buffers in one go, and how to use it with arrays, boost::array or | |
529 | * std::vector. | |
530 | */ | |
531 | template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence, | |
532 | typename CompletionCondition, typename WriteHandler> | |
533 | BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler, | |
534 | void (boost::system::error_code, std::size_t)) | |
535 | async_write_at(AsyncRandomAccessWriteDevice& d, | |
536 | uint64_t offset, const ConstBufferSequence& buffers, | |
537 | CompletionCondition completion_condition, | |
538 | BOOST_ASIO_MOVE_ARG(WriteHandler) handler); | |
539 | ||
540 | #if !defined(BOOST_ASIO_NO_IOSTREAM) | |
541 | ||
542 | /// Start an asynchronous operation to write all of the supplied data at the | |
543 | /// specified offset. | |
544 | /** | |
545 | * This function is used to asynchronously write a certain number of bytes of | |
546 | * data to a random access device at a specified offset. The function call | |
547 | * always returns immediately. The asynchronous operation will continue until | |
548 | * one of the following conditions is true: | |
549 | * | |
550 | * @li All of the data in the supplied basic_streambuf has been written. | |
551 | * | |
552 | * @li An error occurred. | |
553 | * | |
554 | * This operation is implemented in terms of zero or more calls to the device's | |
555 | * async_write_some_at function, and is known as a <em>composed operation</em>. | |
556 | * The program must ensure that the device performs no <em>overlapping</em> | |
557 | * write operations (such as async_write_at, the device's async_write_some_at | |
558 | * function, or any other composed operations that perform writes) until this | |
559 | * operation completes. Operations are overlapping if the regions defined by | |
560 | * their offsets, and the numbers of bytes to write, intersect. | |
561 | * | |
562 | * @param d The device to which the data is to be written. The type must support | |
563 | * the AsyncRandomAccessWriteDevice concept. | |
564 | * | |
565 | * @param offset The offset at which the data will be written. | |
566 | * | |
567 | * @param b A basic_streambuf object from which data will be written. Ownership | |
568 | * of the streambuf is retained by the caller, which must guarantee that it | |
569 | * remains valid until the handler is called. | |
570 | * | |
571 | * @param handler The handler to be called when the write operation completes. | |
572 | * Copies will be made of the handler as required. The function signature of the | |
573 | * handler must be: | |
574 | * @code void handler( | |
575 | * // Result of operation. | |
576 | * const boost::system::error_code& error, | |
577 | * | |
578 | * // Number of bytes written from the buffers. If an error | |
579 | * // occurred, this will be less than the sum of the buffer sizes. | |
580 | * std::size_t bytes_transferred | |
581 | * ); @endcode | |
582 | * Regardless of whether the asynchronous operation completes immediately or | |
583 | * not, the handler will not be invoked from within this function. Invocation of | |
584 | * the handler will be performed in a manner equivalent to using | |
585 | * boost::asio::io_service::post(). | |
586 | */ | |
587 | template <typename AsyncRandomAccessWriteDevice, typename Allocator, | |
588 | typename WriteHandler> | |
589 | BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler, | |
590 | void (boost::system::error_code, std::size_t)) | |
591 | async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset, | |
592 | basic_streambuf<Allocator>& b, BOOST_ASIO_MOVE_ARG(WriteHandler) handler); | |
593 | ||
594 | /// Start an asynchronous operation to write a certain amount of data at the | |
595 | /// specified offset. | |
596 | /** | |
597 | * This function is used to asynchronously write a certain number of bytes of | |
598 | * data to a random access device at a specified offset. The function call | |
599 | * always returns immediately. The asynchronous operation will continue until | |
600 | * one of the following conditions is true: | |
601 | * | |
602 | * @li All of the data in the supplied basic_streambuf has been written. | |
603 | * | |
604 | * @li The completion_condition function object returns 0. | |
605 | * | |
606 | * This operation is implemented in terms of zero or more calls to the device's | |
607 | * async_write_some_at function, and is known as a <em>composed operation</em>. | |
608 | * The program must ensure that the device performs no <em>overlapping</em> | |
609 | * write operations (such as async_write_at, the device's async_write_some_at | |
610 | * function, or any other composed operations that perform writes) until this | |
611 | * operation completes. Operations are overlapping if the regions defined by | |
612 | * their offsets, and the numbers of bytes to write, intersect. | |
613 | * | |
614 | * @param d The device to which the data is to be written. The type must support | |
615 | * the AsyncRandomAccessWriteDevice concept. | |
616 | * | |
617 | * @param offset The offset at which the data will be written. | |
618 | * | |
619 | * @param b A basic_streambuf object from which data will be written. Ownership | |
620 | * of the streambuf is retained by the caller, which must guarantee that it | |
621 | * remains valid until the handler is called. | |
622 | * | |
623 | * @param completion_condition The function object to be called to determine | |
624 | * whether the write operation is complete. The signature of the function object | |
625 | * must be: | |
626 | * @code std::size_t completion_condition( | |
627 | * // Result of latest async_write_some_at operation. | |
628 | * const boost::system::error_code& error, | |
629 | * | |
630 | * // Number of bytes transferred so far. | |
631 | * std::size_t bytes_transferred | |
632 | * ); @endcode | |
633 | * A return value of 0 indicates that the write operation is complete. A | |
634 | * non-zero return value indicates the maximum number of bytes to be written on | |
635 | * the next call to the device's async_write_some_at function. | |
636 | * | |
637 | * @param handler The handler to be called when the write operation completes. | |
638 | * Copies will be made of the handler as required. The function signature of the | |
639 | * handler must be: | |
640 | * @code void handler( | |
641 | * // Result of operation. | |
642 | * const boost::system::error_code& error, | |
643 | * | |
644 | * // Number of bytes written from the buffers. If an error | |
645 | * // occurred, this will be less than the sum of the buffer sizes. | |
646 | * std::size_t bytes_transferred | |
647 | * ); @endcode | |
648 | * Regardless of whether the asynchronous operation completes immediately or | |
649 | * not, the handler will not be invoked from within this function. Invocation of | |
650 | * the handler will be performed in a manner equivalent to using | |
651 | * boost::asio::io_service::post(). | |
652 | */ | |
653 | template <typename AsyncRandomAccessWriteDevice, typename Allocator, | |
654 | typename CompletionCondition, typename WriteHandler> | |
655 | BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler, | |
656 | void (boost::system::error_code, std::size_t)) | |
657 | async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset, | |
658 | basic_streambuf<Allocator>& b, CompletionCondition completion_condition, | |
659 | BOOST_ASIO_MOVE_ARG(WriteHandler) handler); | |
660 | ||
661 | #endif // !defined(BOOST_ASIO_NO_IOSTREAM) | |
662 | ||
663 | /*@}*/ | |
664 | ||
665 | } // namespace asio | |
666 | } // namespace boost | |
667 | ||
668 | #include <boost/asio/detail/pop_options.hpp> | |
669 | ||
670 | #include <boost/asio/impl/write_at.hpp> | |
671 | ||
672 | #endif // BOOST_ASIO_WRITE_AT_HPP |