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3 Copyright (C) 2001-2013 GNUnet e.V.
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Affero General Public License for more details.
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16 along with this program. If not, see <http://www.gnu.org/licenses/>.
18 SPDX-License-Identifier: AGPL3.0-or-later
22 * @author Christian Grothoff
25 * Functions related to time
27 * @defgroup time Time library
28 * Time and time calculations.
32 #ifndef GNUNET_TIME_LIB_H
33 #define GNUNET_TIME_LIB_H
38 #if 0 /* keep Emacsens' auto-indent happy */
43 #include "gnunet_common.h"
46 * Time for absolute times used by GNUnet, in microseconds.
48 struct GNUNET_TIME_Absolute
53 uint64_t abs_value_us;
57 * Time for relative time used by GNUnet, in microseconds.
58 * Always positive, so we can only refer to future time.
60 struct GNUNET_TIME_Relative
65 uint64_t rel_value_us;
68 GNUNET_NETWORK_STRUCT_BEGIN
71 * Time for relative time used by GNUnet, in microseconds and in network byte order.
73 struct GNUNET_TIME_RelativeNBO
76 * The actual value (in network byte order).
78 uint64_t rel_value_us__ GNUNET_PACKED;
83 * Time for absolute time used by GNUnet, in microseconds and in network byte order.
85 struct GNUNET_TIME_AbsoluteNBO
88 * The actual value (in network byte order).
90 uint64_t abs_value_us__ GNUNET_PACKED;
92 GNUNET_NETWORK_STRUCT_END
97 #define GNUNET_TIME_UNIT_ZERO GNUNET_TIME_relative_get_zero_()
100 * Absolute time zero.
102 #define GNUNET_TIME_UNIT_ZERO_ABS GNUNET_TIME_absolute_get_zero_()
105 * One microsecond, our basic time unit.
107 #define GNUNET_TIME_UNIT_MICROSECONDS GNUNET_TIME_relative_get_unit_()
112 #define GNUNET_TIME_UNIT_MILLISECONDS GNUNET_TIME_relative_get_millisecond_()
117 #define GNUNET_TIME_UNIT_SECONDS GNUNET_TIME_relative_get_second_()
122 #define GNUNET_TIME_UNIT_MINUTES GNUNET_TIME_relative_get_minute_()
127 #define GNUNET_TIME_UNIT_HOURS GNUNET_TIME_relative_get_hour_()
132 #define GNUNET_TIME_UNIT_DAYS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 24)
137 #define GNUNET_TIME_UNIT_WEEKS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 7)
140 * One month (30 days).
142 #define GNUNET_TIME_UNIT_MONTHS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 30)
145 * One year (365 days).
147 #define GNUNET_TIME_UNIT_YEARS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 365)
150 * Constant used to specify "forever". This constant
151 * will be treated specially in all time operations.
153 #define GNUNET_TIME_UNIT_FOREVER_REL GNUNET_TIME_relative_get_forever_ ()
156 * Constant used to specify "forever". This constant
157 * will be treated specially in all time operations.
159 #define GNUNET_TIME_UNIT_FOREVER_ABS GNUNET_TIME_absolute_get_forever_ ()
164 * Threshold after which exponential backoff should not increase (15 m).
166 #define GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15)
170 * Perform our standard exponential back-off calculation, starting at 1 ms
171 * and then going by a factor of 2 up unto a maximum of 15 m.
173 * @param r current backoff time, initially zero
175 #define GNUNET_TIME_STD_BACKOFF(r) GNUNET_TIME_relative_min (GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD, \
176 GNUNET_TIME_relative_multiply (GNUNET_TIME_relative_max (GNUNET_TIME_UNIT_MILLISECONDS, (r)), 2));
180 * Randomized exponential back-off, starting at 1 ms
181 * and going up by a factor of 2+r, where 0 <= r <= 0.5, up
182 * to a maximum of the given threshold.
184 * @param rt current backoff time, initially zero
185 * @param threshold maximum value for backoff
186 * @return the next backoff time
188 struct GNUNET_TIME_Relative
189 GNUNET_TIME_randomized_backoff(struct GNUNET_TIME_Relative rt, struct GNUNET_TIME_Relative threshold);
193 * Return a random time value between 0.5*r and 1.5*r.
195 * @param r input time for scaling
196 * @return randomized time
198 struct GNUNET_TIME_Relative
199 GNUNET_TIME_randomize(struct GNUNET_TIME_Relative r);
203 * Return relative time of 0ms.
205 struct GNUNET_TIME_Relative
206 GNUNET_TIME_relative_get_zero_ (void);
210 * Return absolute time of 0ms.
212 struct GNUNET_TIME_Absolute
213 GNUNET_TIME_absolute_get_zero_ (void);
217 * Return relative time of 1 microsecond.
219 struct GNUNET_TIME_Relative
220 GNUNET_TIME_relative_get_unit_ (void);
224 * Return relative time of 1ms.
226 struct GNUNET_TIME_Relative
227 GNUNET_TIME_relative_get_millisecond_ (void);
231 * Return relative time of 1s.
233 struct GNUNET_TIME_Relative
234 GNUNET_TIME_relative_get_second_ (void);
238 * Return relative time of 1 minute.
240 struct GNUNET_TIME_Relative
241 GNUNET_TIME_relative_get_minute_ (void);
245 * Return relative time of 1 hour.
247 struct GNUNET_TIME_Relative
248 GNUNET_TIME_relative_get_hour_ (void);
254 struct GNUNET_TIME_Relative
255 GNUNET_TIME_relative_get_forever_ (void);
261 struct GNUNET_TIME_Absolute
262 GNUNET_TIME_absolute_get_forever_ (void);
266 * Get the current time.
268 * @return the current time
270 struct GNUNET_TIME_Absolute
271 GNUNET_TIME_absolute_get (void);
275 * Convert relative time to an absolute time in the
278 * @param rel relative time to convert
279 * @return timestamp that is "rel" in the future, or FOREVER if rel==FOREVER (or if we would overflow)
281 struct GNUNET_TIME_Absolute
282 GNUNET_TIME_relative_to_absolute (struct GNUNET_TIME_Relative rel);
286 * Round a time value so that it is suitable for transmission
287 * via JSON encodings.
289 * @param at time to round
290 * @return #GNUNET_OK if time was already rounded, #GNUNET_NO if
291 * it was just now rounded
294 GNUNET_TIME_round_abs (struct GNUNET_TIME_Absolute *at);
298 * Round a time value so that it is suitable for transmission
299 * via JSON encodings.
301 * @param rt time to round
302 * @return #GNUNET_OK if time was already rounded, #GNUNET_NO if
303 * it was just now rounded
306 GNUNET_TIME_round_rel (struct GNUNET_TIME_Relative *rt);
310 * Return the minimum of two relative time values.
312 * @param t1 first timestamp
313 * @param t2 other timestamp
314 * @return timestamp that is smaller
316 struct GNUNET_TIME_Relative
317 GNUNET_TIME_relative_min (struct GNUNET_TIME_Relative t1,
318 struct GNUNET_TIME_Relative t2);
323 * Return the maximum of two relative time values.
325 * @param t1 first timestamp
326 * @param t2 other timestamp
327 * @return timestamp that is larger
329 struct GNUNET_TIME_Relative
330 GNUNET_TIME_relative_max (struct GNUNET_TIME_Relative t1,
331 struct GNUNET_TIME_Relative t2);
335 * Return the minimum of two absolute time values.
337 * @param t1 first timestamp
338 * @param t2 other timestamp
339 * @return timestamp that is smaller
341 struct GNUNET_TIME_Absolute
342 GNUNET_TIME_absolute_min (struct GNUNET_TIME_Absolute t1,
343 struct GNUNET_TIME_Absolute t2);
347 * Return the maximum of two absolute time values.
349 * @param t1 first timestamp
350 * @param t2 other timestamp
351 * @return timestamp that is smaller
353 struct GNUNET_TIME_Absolute
354 GNUNET_TIME_absolute_max (struct GNUNET_TIME_Absolute t1,
355 struct GNUNET_TIME_Absolute t2);
359 * Given a timestamp in the future, how much time
360 * remains until then?
362 * @param future some absolute time, typically in the future
363 * @return future - now, or 0 if now >= future, or FOREVER if future==FOREVER.
365 struct GNUNET_TIME_Relative
366 GNUNET_TIME_absolute_get_remaining (struct GNUNET_TIME_Absolute future);
370 * Calculate the estimate time of arrival/completion
373 * @param start when did the operation start?
374 * @param finished how much has been done?
375 * @param total how much must be done overall (same unit as for "finished")
376 * @return remaining duration for the operation,
377 * assuming it continues at the same speed
379 struct GNUNET_TIME_Relative
380 GNUNET_TIME_calculate_eta (struct GNUNET_TIME_Absolute start,
386 * Compute the time difference between the given start and end times.
387 * Use this function instead of actual subtraction to ensure that
388 * "FOREVER" and overflows are handeled correctly.
390 * @param start some absolute time
391 * @param end some absolute time (typically larger or equal to start)
392 * @return 0 if start >= end; FOREVER if end==FOREVER; otherwise end - start
394 struct GNUNET_TIME_Relative
395 GNUNET_TIME_absolute_get_difference (struct GNUNET_TIME_Absolute start,
396 struct GNUNET_TIME_Absolute end);
400 * Get the duration of an operation as the
401 * difference of the current time and the given start time "hence".
403 * @param whence some absolute time, typically in the past
404 * @return 0 if hence > now, otherwise now-hence.
406 struct GNUNET_TIME_Relative
407 GNUNET_TIME_absolute_get_duration (struct GNUNET_TIME_Absolute whence);
411 * Add a given relative duration to the
414 * @param start some absolute time
415 * @param duration some relative time to add
416 * @return FOREVER if either argument is FOREVER or on overflow; start+duration otherwise
418 struct GNUNET_TIME_Absolute
419 GNUNET_TIME_absolute_add (struct GNUNET_TIME_Absolute start,
420 struct GNUNET_TIME_Relative duration);
424 * Subtract a given relative duration from the
427 * @param start some absolute time
428 * @param duration some relative time to subtract
429 * @return ZERO if start <= duration, or FOREVER if start time is FOREVER; start-duration otherwise
431 struct GNUNET_TIME_Absolute
432 GNUNET_TIME_absolute_subtract (struct GNUNET_TIME_Absolute start,
433 struct GNUNET_TIME_Relative duration);
437 * Multiply relative time by a given factor.
439 * @param rel some duration
440 * @param factor integer to multiply with
441 * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
443 struct GNUNET_TIME_Relative
444 GNUNET_TIME_relative_multiply (struct GNUNET_TIME_Relative rel,
445 unsigned long long factor);
449 * Saturating multiply relative time by a given factor.
451 * @param rel some duration
452 * @param factor integer to multiply with
453 * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
455 struct GNUNET_TIME_Relative
456 GNUNET_TIME_relative_saturating_multiply (struct GNUNET_TIME_Relative rel,
457 unsigned long long factor);
461 * Divide relative time by a given factor.
463 * @param rel some duration
464 * @param factor integer to divide by
465 * @return FOREVER if rel=FOREVER or factor==0; otherwise rel/factor
467 struct GNUNET_TIME_Relative
468 GNUNET_TIME_relative_divide (struct GNUNET_TIME_Relative rel,
469 unsigned long long factor);
473 * Add relative times together.
475 * @param a1 some relative time
476 * @param a2 some other relative time
477 * @return FOREVER if either argument is FOREVER or on overflow; a1+a2 otherwise
479 struct GNUNET_TIME_Relative
480 GNUNET_TIME_relative_add (struct GNUNET_TIME_Relative a1,
481 struct GNUNET_TIME_Relative a2);
485 * Subtract relative timestamp from the other.
487 * @param a1 first timestamp
488 * @param a2 second timestamp
489 * @return ZERO if a2>=a1 (including both FOREVER), FOREVER if a1 is FOREVER, a1-a2 otherwise
491 struct GNUNET_TIME_Relative
492 GNUNET_TIME_relative_subtract (struct GNUNET_TIME_Relative a1,
493 struct GNUNET_TIME_Relative a2);
497 * Convert relative time to network byte order.
499 * @param a time to convert
500 * @return converted time value
502 struct GNUNET_TIME_RelativeNBO
503 GNUNET_TIME_relative_hton (struct GNUNET_TIME_Relative a);
507 * Convert relative time from network byte order.
509 * @param a time to convert
510 * @return converted time value
512 struct GNUNET_TIME_Relative
513 GNUNET_TIME_relative_ntoh (struct GNUNET_TIME_RelativeNBO a);
517 * Convert absolute time to network byte order.
519 * @param a time to convert
520 * @return converted time value
522 struct GNUNET_TIME_AbsoluteNBO
523 GNUNET_TIME_absolute_hton (struct GNUNET_TIME_Absolute a);
527 * Convert absolute time from network byte order.
529 * @param a time to convert
530 * @return converted time value
532 struct GNUNET_TIME_Absolute
533 GNUNET_TIME_absolute_ntoh (struct GNUNET_TIME_AbsoluteNBO a);
537 * Set the timestamp offset for this instance.
539 * @param offset the offset to skew the locale time by
542 GNUNET_TIME_set_offset (long long offset);
546 * Get the timestamp offset for this instance.
548 * @return the offset we currently skew the locale time by
551 GNUNET_TIME_get_offset (void);
555 * Return the current year (i.e. '2011').
558 GNUNET_TIME_get_current_year (void);
562 * Convert a year to an expiration time of January 1st of that year.
564 * @param year a year (after 1970, please ;-)).
565 * @return absolute time for January 1st of that year.
567 struct GNUNET_TIME_Absolute
568 GNUNET_TIME_year_to_time (unsigned int year);
572 * Convert an expiration time to the respective year (rounds)
574 * @param at absolute time
575 * @return year a year (after 1970), 0 on error
578 GNUNET_TIME_time_to_year (struct GNUNET_TIME_Absolute at);
582 * A configuration object.
584 struct GNUNET_CONFIGURATION_Handle;
588 * Obtain the current time and make sure it is monotonically
589 * increasing. Guards against systems without an RTC or
590 * clocks running backwards and other nasty surprises. Does
591 * not guarantee that the returned time is near the current
592 * time returned by #GNUNET_TIME_absolute_get(). Two
593 * subsequent calls (within a short time period) may return the
594 * same value. Persists the last returned time on disk to
595 * ensure that time never goes backwards. As a result, the
596 * resulting value can be used to check if a message is the
597 * "most recent" value and replays of older messages (from
598 * the same origin) would be discarded.
600 * @param cfg configuration, used to determine where to
601 * store the time; user can also insist RTC is working
602 * nicely and disable the feature
603 * @return monotonically increasing time
605 struct GNUNET_TIME_Absolute
606 GNUNET_TIME_absolute_get_monotonic (const struct GNUNET_CONFIGURATION_Handle *cfg);
609 #if 0 /* keep Emacsens' auto-indent happy */
616 /* ifndef GNUNET_TIME_LIB_H */
619 /** @} */ /* end of group time */
621 /* end of gnunet_time_lib.h */