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3 Copyright (C) 2001-2013 GNUnet e.V.
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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/>.
20 * @author Christian Grothoff
23 * Functions related to time
25 * @defgroup time Time library
26 * Time and time calculations.
30 #ifndef GNUNET_TIME_LIB_H
31 #define GNUNET_TIME_LIB_H
36 #if 0 /* keep Emacsens' auto-indent happy */
41 #include "gnunet_common.h"
44 * Time for absolute times used by GNUnet, in microseconds.
46 struct GNUNET_TIME_Absolute
51 uint64_t abs_value_us;
55 * Time for relative time used by GNUnet, in microseconds.
56 * Always positive, so we can only refer to future time.
58 struct GNUNET_TIME_Relative
63 uint64_t rel_value_us;
66 GNUNET_NETWORK_STRUCT_BEGIN
69 * Time for relative time used by GNUnet, in microseconds and in network byte order.
71 struct GNUNET_TIME_RelativeNBO
74 * The actual value (in network byte order).
76 uint64_t rel_value_us__ GNUNET_PACKED;
81 * Time for absolute time used by GNUnet, in microseconds and in network byte order.
83 struct GNUNET_TIME_AbsoluteNBO
86 * The actual value (in network byte order).
88 uint64_t abs_value_us__ GNUNET_PACKED;
90 GNUNET_NETWORK_STRUCT_END
95 #define GNUNET_TIME_UNIT_ZERO GNUNET_TIME_relative_get_zero_()
100 #define GNUNET_TIME_UNIT_ZERO_ABS GNUNET_TIME_absolute_get_zero_()
103 * One microsecond, our basic time unit.
105 #define GNUNET_TIME_UNIT_MICROSECONDS GNUNET_TIME_relative_get_unit_()
110 #define GNUNET_TIME_UNIT_MILLISECONDS GNUNET_TIME_relative_get_millisecond_()
115 #define GNUNET_TIME_UNIT_SECONDS GNUNET_TIME_relative_get_second_()
120 #define GNUNET_TIME_UNIT_MINUTES GNUNET_TIME_relative_get_minute_()
125 #define GNUNET_TIME_UNIT_HOURS GNUNET_TIME_relative_get_hour_()
130 #define GNUNET_TIME_UNIT_DAYS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 24)
135 #define GNUNET_TIME_UNIT_WEEKS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 7)
138 * One month (30 days).
140 #define GNUNET_TIME_UNIT_MONTHS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 30)
143 * One year (365 days).
145 #define GNUNET_TIME_UNIT_YEARS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS, 365)
148 * Constant used to specify "forever". This constant
149 * will be treated specially in all time operations.
151 #define GNUNET_TIME_UNIT_FOREVER_REL GNUNET_TIME_relative_get_forever_ ()
154 * Constant used to specify "forever". This constant
155 * will be treated specially in all time operations.
157 #define GNUNET_TIME_UNIT_FOREVER_ABS GNUNET_TIME_absolute_get_forever_ ()
162 * Threshold after which exponential backoff should not increase (15 m).
164 #define GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15)
168 * Perform our standard exponential back-off calculation, starting at 1 ms
169 * and then going by a factor of 2 up unto a maximum of 15 m.
171 * @param r current backoff time, initially zero
173 #define GNUNET_TIME_STD_BACKOFF(r) GNUNET_TIME_relative_min (GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD, \
174 GNUNET_TIME_relative_multiply (GNUNET_TIME_relative_max (GNUNET_TIME_UNIT_MILLISECONDS, (r)), 2));
177 * Return relative time of 0ms.
179 struct GNUNET_TIME_Relative
180 GNUNET_TIME_relative_get_zero_ (void);
184 * Return absolute time of 0ms.
186 struct GNUNET_TIME_Absolute
187 GNUNET_TIME_absolute_get_zero_ (void);
191 * Return relative time of 1 microsecond.
193 struct GNUNET_TIME_Relative
194 GNUNET_TIME_relative_get_unit_ (void);
198 * Return relative time of 1ms.
200 struct GNUNET_TIME_Relative
201 GNUNET_TIME_relative_get_millisecond_ (void);
205 * Return relative time of 1s.
207 struct GNUNET_TIME_Relative
208 GNUNET_TIME_relative_get_second_ (void);
212 * Return relative time of 1 minute.
214 struct GNUNET_TIME_Relative
215 GNUNET_TIME_relative_get_minute_ (void);
219 * Return relative time of 1 hour.
221 struct GNUNET_TIME_Relative
222 GNUNET_TIME_relative_get_hour_ (void);
228 struct GNUNET_TIME_Relative
229 GNUNET_TIME_relative_get_forever_ (void);
235 struct GNUNET_TIME_Absolute
236 GNUNET_TIME_absolute_get_forever_ (void);
240 * Get the current time.
242 * @return the current time
244 struct GNUNET_TIME_Absolute
245 GNUNET_TIME_absolute_get (void);
249 * Convert relative time to an absolute time in the
252 * @param rel relative time to convert
253 * @return timestamp that is "rel" in the future, or FOREVER if rel==FOREVER (or if we would overflow)
255 struct GNUNET_TIME_Absolute
256 GNUNET_TIME_relative_to_absolute (struct GNUNET_TIME_Relative rel);
260 * Round a time value so that it is suitable for transmission
261 * via JSON encodings.
263 * @param at time to round
264 * @return #GNUNET_OK if time was already rounded, #GNUNET_NO if
265 * it was just now rounded
268 GNUNET_TIME_round_abs (struct GNUNET_TIME_Absolute *at);
272 * Round a time value so that it is suitable for transmission
273 * via JSON encodings.
275 * @param rt time to round
276 * @return #GNUNET_OK if time was already rounded, #GNUNET_NO if
277 * it was just now rounded
280 GNUNET_TIME_round_rel (struct GNUNET_TIME_Relative *rt);
284 * Return the minimum of two relative time values.
286 * @param t1 first timestamp
287 * @param t2 other timestamp
288 * @return timestamp that is smaller
290 struct GNUNET_TIME_Relative
291 GNUNET_TIME_relative_min (struct GNUNET_TIME_Relative t1,
292 struct GNUNET_TIME_Relative t2);
297 * Return the maximum of two relative time values.
299 * @param t1 first timestamp
300 * @param t2 other timestamp
301 * @return timestamp that is larger
303 struct GNUNET_TIME_Relative
304 GNUNET_TIME_relative_max (struct GNUNET_TIME_Relative t1,
305 struct GNUNET_TIME_Relative t2);
309 * Return the minimum of two absolute time values.
311 * @param t1 first timestamp
312 * @param t2 other timestamp
313 * @return timestamp that is smaller
315 struct GNUNET_TIME_Absolute
316 GNUNET_TIME_absolute_min (struct GNUNET_TIME_Absolute t1,
317 struct GNUNET_TIME_Absolute t2);
321 * Return the maximum of two absolute time values.
323 * @param t1 first timestamp
324 * @param t2 other timestamp
325 * @return timestamp that is smaller
327 struct GNUNET_TIME_Absolute
328 GNUNET_TIME_absolute_max (struct GNUNET_TIME_Absolute t1,
329 struct GNUNET_TIME_Absolute t2);
333 * Given a timestamp in the future, how much time
334 * remains until then?
336 * @param future some absolute time, typically in the future
337 * @return future - now, or 0 if now >= future, or FOREVER if future==FOREVER.
339 struct GNUNET_TIME_Relative
340 GNUNET_TIME_absolute_get_remaining (struct GNUNET_TIME_Absolute future);
344 * Calculate the estimate time of arrival/completion
347 * @param start when did the operation start?
348 * @param finished how much has been done?
349 * @param total how much must be done overall (same unit as for "finished")
350 * @return remaining duration for the operation,
351 * assuming it continues at the same speed
353 struct GNUNET_TIME_Relative
354 GNUNET_TIME_calculate_eta (struct GNUNET_TIME_Absolute start, uint64_t finished,
359 * Compute the time difference between the given start and end times.
360 * Use this function instead of actual subtraction to ensure that
361 * "FOREVER" and overflows are handeled correctly.
363 * @param start some absolute time
364 * @param end some absolute time (typically larger or equal to start)
365 * @return 0 if start >= end; FOREVER if end==FOREVER; otherwise end - start
367 struct GNUNET_TIME_Relative
368 GNUNET_TIME_absolute_get_difference (struct GNUNET_TIME_Absolute start,
369 struct GNUNET_TIME_Absolute end);
373 * Get the duration of an operation as the
374 * difference of the current time and the given start time "hence".
376 * @param whence some absolute time, typically in the past
377 * @return 0 if hence > now, otherwise now-hence.
379 struct GNUNET_TIME_Relative
380 GNUNET_TIME_absolute_get_duration (struct GNUNET_TIME_Absolute whence);
384 * Add a given relative duration to the
387 * @param start some absolute time
388 * @param duration some relative time to add
389 * @return FOREVER if either argument is FOREVER or on overflow; start+duration otherwise
391 struct GNUNET_TIME_Absolute
392 GNUNET_TIME_absolute_add (struct GNUNET_TIME_Absolute start,
393 struct GNUNET_TIME_Relative duration);
397 * Subtract a given relative duration from the
400 * @param start some absolute time
401 * @param duration some relative time to subtract
402 * @return ZERO if start <= duration, or FOREVER if start time is FOREVER; start-duration otherwise
404 struct GNUNET_TIME_Absolute
405 GNUNET_TIME_absolute_subtract (struct GNUNET_TIME_Absolute start,
406 struct GNUNET_TIME_Relative duration);
410 * Multiply relative time by a given factor.
412 * @param rel some duration
413 * @param factor integer to multiply with
414 * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
416 struct GNUNET_TIME_Relative
417 GNUNET_TIME_relative_multiply (struct GNUNET_TIME_Relative rel,
418 unsigned long long factor);
422 * Saturating multiply relative time by a given factor.
424 * @param rel some duration
425 * @param factor integer to multiply with
426 * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
428 struct GNUNET_TIME_Relative
429 GNUNET_TIME_relative_saturating_multiply (struct GNUNET_TIME_Relative rel,
430 unsigned long long factor);
434 * Divide relative time by a given factor.
436 * @param rel some duration
437 * @param factor integer to divide by
438 * @return FOREVER if rel=FOREVER or factor==0; otherwise rel/factor
440 struct GNUNET_TIME_Relative
441 GNUNET_TIME_relative_divide (struct GNUNET_TIME_Relative rel,
442 unsigned long long factor);
446 * Add relative times together.
448 * @param a1 some relative time
449 * @param a2 some other relative time
450 * @return FOREVER if either argument is FOREVER or on overflow; a1+a2 otherwise
452 struct GNUNET_TIME_Relative
453 GNUNET_TIME_relative_add (struct GNUNET_TIME_Relative a1,
454 struct GNUNET_TIME_Relative a2);
458 * Subtract relative timestamp from the other.
460 * @param a1 first timestamp
461 * @param a2 second timestamp
462 * @return ZERO if a2>=a1 (including both FOREVER), FOREVER if a1 is FOREVER, a1-a2 otherwise
464 struct GNUNET_TIME_Relative
465 GNUNET_TIME_relative_subtract (struct GNUNET_TIME_Relative a1,
466 struct GNUNET_TIME_Relative a2);
470 * Convert relative time to network byte order.
472 * @param a time to convert
473 * @return converted time value
475 struct GNUNET_TIME_RelativeNBO
476 GNUNET_TIME_relative_hton (struct GNUNET_TIME_Relative a);
480 * Convert relative time from network byte order.
482 * @param a time to convert
483 * @return converted time value
485 struct GNUNET_TIME_Relative
486 GNUNET_TIME_relative_ntoh (struct GNUNET_TIME_RelativeNBO a);
490 * Convert absolute time to network byte order.
492 * @param a time to convert
493 * @return converted time value
495 struct GNUNET_TIME_AbsoluteNBO
496 GNUNET_TIME_absolute_hton (struct GNUNET_TIME_Absolute a);
500 * Convert absolute time from network byte order.
502 * @param a time to convert
503 * @return converted time value
505 struct GNUNET_TIME_Absolute
506 GNUNET_TIME_absolute_ntoh (struct GNUNET_TIME_AbsoluteNBO a);
510 * Set the timestamp offset for this instance.
512 * @param offset the offset to skew the locale time by
515 GNUNET_TIME_set_offset (long long offset);
519 * Get the timestamp offset for this instance.
521 * @return the offset we currently skew the locale time by
524 GNUNET_TIME_get_offset (void);
528 * Return the current year (i.e. '2011').
531 GNUNET_TIME_get_current_year (void);
535 * Convert a year to an expiration time of January 1st of that year.
537 * @param year a year (after 1970, please ;-)).
538 * @return absolute time for January 1st of that year.
540 struct GNUNET_TIME_Absolute
541 GNUNET_TIME_year_to_time (unsigned int year);
545 * Convert an expiration time to the respective year (rounds)
547 * @param at absolute time
548 * @return year a year (after 1970), 0 on error
551 GNUNET_TIME_time_to_year (struct GNUNET_TIME_Absolute at);
554 #if 0 /* keep Emacsens' auto-indent happy */
561 /* ifndef GNUNET_TIME_LIB_H */
564 /** @} */ /* end of group time */
566 /* end of gnunet_time_lib.h */