Documentation/describe: improve one-line summary
[git.git] / date.c
blob3eba2dfe8841cee28850e2f1f4177e1e32f1c8a8
1 /*
2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
5 */
7 #include "cache.h"
9 /*
10 * This is like mktime, but without normalization of tm_wday and tm_yday.
12 static time_t tm_to_time_t(const struct tm *tm)
14 static const int mdays[] = {
15 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
17 int year = tm->tm_year - 70;
18 int month = tm->tm_mon;
19 int day = tm->tm_mday;
21 if (year < 0 || year > 129) /* algo only works for 1970-2099 */
22 return -1;
23 if (month < 0 || month > 11) /* array bounds */
24 return -1;
25 if (month < 2 || (year + 2) % 4)
26 day--;
27 if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_sec < 0)
28 return -1;
29 return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
30 tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
33 static const char *month_names[] = {
34 "January", "February", "March", "April", "May", "June",
35 "July", "August", "September", "October", "November", "December"
38 static const char *weekday_names[] = {
39 "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
42 static time_t gm_time_t(unsigned long time, int tz)
44 int minutes;
46 minutes = tz < 0 ? -tz : tz;
47 minutes = (minutes / 100)*60 + (minutes % 100);
48 minutes = tz < 0 ? -minutes : minutes;
49 return time + minutes * 60;
53 * The "tz" thing is passed in as this strange "decimal parse of tz"
54 * thing, which means that tz -0100 is passed in as the integer -100,
55 * even though it means "sixty minutes off"
57 static struct tm *time_to_tm(unsigned long time, int tz)
59 time_t t = gm_time_t(time, tz);
60 return gmtime(&t);
64 * What value of "tz" was in effect back then at "time" in the
65 * local timezone?
67 static int local_tzoffset(unsigned long time)
69 time_t t, t_local;
70 struct tm tm;
71 int offset, eastwest;
73 t = time;
74 localtime_r(&t, &tm);
75 t_local = tm_to_time_t(&tm);
77 if (t_local < t) {
78 eastwest = -1;
79 offset = t - t_local;
80 } else {
81 eastwest = 1;
82 offset = t_local - t;
84 offset /= 60; /* in minutes */
85 offset = (offset % 60) + ((offset / 60) * 100);
86 return offset * eastwest;
89 void show_date_relative(unsigned long time, int tz,
90 const struct timeval *now,
91 struct strbuf *timebuf)
93 unsigned long diff;
94 if (now->tv_sec < time) {
95 strbuf_addstr(timebuf, _("in the future"));
96 return;
98 diff = now->tv_sec - time;
99 if (diff < 90) {
100 strbuf_addf(timebuf,
101 Q_("%lu second ago", "%lu seconds ago", diff), diff);
102 return;
104 /* Turn it into minutes */
105 diff = (diff + 30) / 60;
106 if (diff < 90) {
107 strbuf_addf(timebuf,
108 Q_("%lu minute ago", "%lu minutes ago", diff), diff);
109 return;
111 /* Turn it into hours */
112 diff = (diff + 30) / 60;
113 if (diff < 36) {
114 strbuf_addf(timebuf,
115 Q_("%lu hour ago", "%lu hours ago", diff), diff);
116 return;
118 /* We deal with number of days from here on */
119 diff = (diff + 12) / 24;
120 if (diff < 14) {
121 strbuf_addf(timebuf,
122 Q_("%lu day ago", "%lu days ago", diff), diff);
123 return;
125 /* Say weeks for the past 10 weeks or so */
126 if (diff < 70) {
127 strbuf_addf(timebuf,
128 Q_("%lu week ago", "%lu weeks ago", (diff + 3) / 7),
129 (diff + 3) / 7);
130 return;
132 /* Say months for the past 12 months or so */
133 if (diff < 365) {
134 strbuf_addf(timebuf,
135 Q_("%lu month ago", "%lu months ago", (diff + 15) / 30),
136 (diff + 15) / 30);
137 return;
139 /* Give years and months for 5 years or so */
140 if (diff < 1825) {
141 unsigned long totalmonths = (diff * 12 * 2 + 365) / (365 * 2);
142 unsigned long years = totalmonths / 12;
143 unsigned long months = totalmonths % 12;
144 if (months) {
145 struct strbuf sb = STRBUF_INIT;
146 strbuf_addf(&sb, Q_("%lu year", "%lu years", years), years);
147 strbuf_addf(timebuf,
148 /* TRANSLATORS: "%s" is "<n> years" */
149 Q_("%s, %lu month ago", "%s, %lu months ago", months),
150 sb.buf, months);
151 strbuf_release(&sb);
152 } else
153 strbuf_addf(timebuf,
154 Q_("%lu year ago", "%lu years ago", years), years);
155 return;
157 /* Otherwise, just years. Centuries is probably overkill. */
158 strbuf_addf(timebuf,
159 Q_("%lu year ago", "%lu years ago", (diff + 183) / 365),
160 (diff + 183) / 365);
163 const char *show_date(unsigned long time, int tz, enum date_mode mode)
165 struct tm *tm;
166 static struct strbuf timebuf = STRBUF_INIT;
168 if (mode == DATE_RAW) {
169 strbuf_reset(&timebuf);
170 strbuf_addf(&timebuf, "%lu %+05d", time, tz);
171 return timebuf.buf;
174 if (mode == DATE_RELATIVE) {
175 struct timeval now;
177 strbuf_reset(&timebuf);
178 gettimeofday(&now, NULL);
179 show_date_relative(time, tz, &now, &timebuf);
180 return timebuf.buf;
183 if (mode == DATE_LOCAL)
184 tz = local_tzoffset(time);
186 tm = time_to_tm(time, tz);
187 if (!tm) {
188 tm = time_to_tm(0, 0);
189 tz = 0;
192 strbuf_reset(&timebuf);
193 if (mode == DATE_SHORT)
194 strbuf_addf(&timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
195 tm->tm_mon + 1, tm->tm_mday);
196 else if (mode == DATE_ISO8601)
197 strbuf_addf(&timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
198 tm->tm_year + 1900,
199 tm->tm_mon + 1,
200 tm->tm_mday,
201 tm->tm_hour, tm->tm_min, tm->tm_sec,
202 tz);
203 else if (mode == DATE_ISO8601_STRICT) {
204 char sign = (tz >= 0) ? '+' : '-';
205 tz = abs(tz);
206 strbuf_addf(&timebuf, "%04d-%02d-%02dT%02d:%02d:%02d%c%02d:%02d",
207 tm->tm_year + 1900,
208 tm->tm_mon + 1,
209 tm->tm_mday,
210 tm->tm_hour, tm->tm_min, tm->tm_sec,
211 sign, tz / 100, tz % 100);
212 } else if (mode == DATE_RFC2822)
213 strbuf_addf(&timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
214 weekday_names[tm->tm_wday], tm->tm_mday,
215 month_names[tm->tm_mon], tm->tm_year + 1900,
216 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
217 else
218 strbuf_addf(&timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
219 weekday_names[tm->tm_wday],
220 month_names[tm->tm_mon],
221 tm->tm_mday,
222 tm->tm_hour, tm->tm_min, tm->tm_sec,
223 tm->tm_year + 1900,
224 (mode == DATE_LOCAL) ? 0 : ' ',
225 tz);
226 return timebuf.buf;
230 * Check these. And note how it doesn't do the summer-time conversion.
232 * In my world, it's always summer, and things are probably a bit off
233 * in other ways too.
235 static const struct {
236 const char *name;
237 int offset;
238 int dst;
239 } timezone_names[] = {
240 { "IDLW", -12, 0, }, /* International Date Line West */
241 { "NT", -11, 0, }, /* Nome */
242 { "CAT", -10, 0, }, /* Central Alaska */
243 { "HST", -10, 0, }, /* Hawaii Standard */
244 { "HDT", -10, 1, }, /* Hawaii Daylight */
245 { "YST", -9, 0, }, /* Yukon Standard */
246 { "YDT", -9, 1, }, /* Yukon Daylight */
247 { "PST", -8, 0, }, /* Pacific Standard */
248 { "PDT", -8, 1, }, /* Pacific Daylight */
249 { "MST", -7, 0, }, /* Mountain Standard */
250 { "MDT", -7, 1, }, /* Mountain Daylight */
251 { "CST", -6, 0, }, /* Central Standard */
252 { "CDT", -6, 1, }, /* Central Daylight */
253 { "EST", -5, 0, }, /* Eastern Standard */
254 { "EDT", -5, 1, }, /* Eastern Daylight */
255 { "AST", -3, 0, }, /* Atlantic Standard */
256 { "ADT", -3, 1, }, /* Atlantic Daylight */
257 { "WAT", -1, 0, }, /* West Africa */
259 { "GMT", 0, 0, }, /* Greenwich Mean */
260 { "UTC", 0, 0, }, /* Universal (Coordinated) */
261 { "Z", 0, 0, }, /* Zulu, alias for UTC */
263 { "WET", 0, 0, }, /* Western European */
264 { "BST", 0, 1, }, /* British Summer */
265 { "CET", +1, 0, }, /* Central European */
266 { "MET", +1, 0, }, /* Middle European */
267 { "MEWT", +1, 0, }, /* Middle European Winter */
268 { "MEST", +1, 1, }, /* Middle European Summer */
269 { "CEST", +1, 1, }, /* Central European Summer */
270 { "MESZ", +1, 1, }, /* Middle European Summer */
271 { "FWT", +1, 0, }, /* French Winter */
272 { "FST", +1, 1, }, /* French Summer */
273 { "EET", +2, 0, }, /* Eastern Europe, USSR Zone 1 */
274 { "EEST", +2, 1, }, /* Eastern European Daylight */
275 { "WAST", +7, 0, }, /* West Australian Standard */
276 { "WADT", +7, 1, }, /* West Australian Daylight */
277 { "CCT", +8, 0, }, /* China Coast, USSR Zone 7 */
278 { "JST", +9, 0, }, /* Japan Standard, USSR Zone 8 */
279 { "EAST", +10, 0, }, /* Eastern Australian Standard */
280 { "EADT", +10, 1, }, /* Eastern Australian Daylight */
281 { "GST", +10, 0, }, /* Guam Standard, USSR Zone 9 */
282 { "NZT", +12, 0, }, /* New Zealand */
283 { "NZST", +12, 0, }, /* New Zealand Standard */
284 { "NZDT", +12, 1, }, /* New Zealand Daylight */
285 { "IDLE", +12, 0, }, /* International Date Line East */
288 static int match_string(const char *date, const char *str)
290 int i = 0;
292 for (i = 0; *date; date++, str++, i++) {
293 if (*date == *str)
294 continue;
295 if (toupper(*date) == toupper(*str))
296 continue;
297 if (!isalnum(*date))
298 break;
299 return 0;
301 return i;
304 static int skip_alpha(const char *date)
306 int i = 0;
307 do {
308 i++;
309 } while (isalpha(date[i]));
310 return i;
314 * Parse month, weekday, or timezone name
316 static int match_alpha(const char *date, struct tm *tm, int *offset)
318 int i;
320 for (i = 0; i < 12; i++) {
321 int match = match_string(date, month_names[i]);
322 if (match >= 3) {
323 tm->tm_mon = i;
324 return match;
328 for (i = 0; i < 7; i++) {
329 int match = match_string(date, weekday_names[i]);
330 if (match >= 3) {
331 tm->tm_wday = i;
332 return match;
336 for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
337 int match = match_string(date, timezone_names[i].name);
338 if (match >= 3 || match == strlen(timezone_names[i].name)) {
339 int off = timezone_names[i].offset;
341 /* This is bogus, but we like summer */
342 off += timezone_names[i].dst;
344 /* Only use the tz name offset if we don't have anything better */
345 if (*offset == -1)
346 *offset = 60*off;
348 return match;
352 if (match_string(date, "PM") == 2) {
353 tm->tm_hour = (tm->tm_hour % 12) + 12;
354 return 2;
357 if (match_string(date, "AM") == 2) {
358 tm->tm_hour = (tm->tm_hour % 12) + 0;
359 return 2;
362 /* BAD CRAP */
363 return skip_alpha(date);
366 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
368 if (month > 0 && month < 13 && day > 0 && day < 32) {
369 struct tm check = *tm;
370 struct tm *r = (now_tm ? &check : tm);
371 time_t specified;
373 r->tm_mon = month - 1;
374 r->tm_mday = day;
375 if (year == -1) {
376 if (!now_tm)
377 return 1;
378 r->tm_year = now_tm->tm_year;
380 else if (year >= 1970 && year < 2100)
381 r->tm_year = year - 1900;
382 else if (year > 70 && year < 100)
383 r->tm_year = year;
384 else if (year < 38)
385 r->tm_year = year + 100;
386 else
387 return 0;
388 if (!now_tm)
389 return 1;
391 specified = tm_to_time_t(r);
393 /* Be it commit time or author time, it does not make
394 * sense to specify timestamp way into the future. Make
395 * sure it is not later than ten days from now...
397 if ((specified != -1) && (now + 10*24*3600 < specified))
398 return 0;
399 tm->tm_mon = r->tm_mon;
400 tm->tm_mday = r->tm_mday;
401 if (year != -1)
402 tm->tm_year = r->tm_year;
403 return 1;
405 return 0;
408 static int match_multi_number(unsigned long num, char c, const char *date,
409 char *end, struct tm *tm, time_t now)
411 struct tm now_tm;
412 struct tm *refuse_future;
413 long num2, num3;
415 num2 = strtol(end+1, &end, 10);
416 num3 = -1;
417 if (*end == c && isdigit(end[1]))
418 num3 = strtol(end+1, &end, 10);
420 /* Time? Date? */
421 switch (c) {
422 case ':':
423 if (num3 < 0)
424 num3 = 0;
425 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
426 tm->tm_hour = num;
427 tm->tm_min = num2;
428 tm->tm_sec = num3;
429 break;
431 return 0;
433 case '-':
434 case '/':
435 case '.':
436 if (!now)
437 now = time(NULL);
438 refuse_future = NULL;
439 if (gmtime_r(&now, &now_tm))
440 refuse_future = &now_tm;
442 if (num > 70) {
443 /* yyyy-mm-dd? */
444 if (is_date(num, num2, num3, NULL, now, tm))
445 break;
446 /* yyyy-dd-mm? */
447 if (is_date(num, num3, num2, NULL, now, tm))
448 break;
450 /* Our eastern European friends say dd.mm.yy[yy]
451 * is the norm there, so giving precedence to
452 * mm/dd/yy[yy] form only when separator is not '.'
454 if (c != '.' &&
455 is_date(num3, num, num2, refuse_future, now, tm))
456 break;
457 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
458 if (is_date(num3, num2, num, refuse_future, now, tm))
459 break;
460 /* Funny European mm.dd.yy */
461 if (c == '.' &&
462 is_date(num3, num, num2, refuse_future, now, tm))
463 break;
464 return 0;
466 return end - date;
470 * Have we filled in any part of the time/date yet?
471 * We just do a binary 'and' to see if the sign bit
472 * is set in all the values.
474 static inline int nodate(struct tm *tm)
476 return (tm->tm_year &
477 tm->tm_mon &
478 tm->tm_mday &
479 tm->tm_hour &
480 tm->tm_min &
481 tm->tm_sec) < 0;
485 * We've seen a digit. Time? Year? Date?
487 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
489 int n;
490 char *end;
491 unsigned long num;
493 num = strtoul(date, &end, 10);
496 * Seconds since 1970? We trigger on that for any numbers with
497 * more than 8 digits. This is because we don't want to rule out
498 * numbers like 20070606 as a YYYYMMDD date.
500 if (num >= 100000000 && nodate(tm)) {
501 time_t time = num;
502 if (gmtime_r(&time, tm)) {
503 *tm_gmt = 1;
504 return end - date;
509 * Check for special formats: num[-.:/]num[same]num
511 switch (*end) {
512 case ':':
513 case '.':
514 case '/':
515 case '-':
516 if (isdigit(end[1])) {
517 int match = match_multi_number(num, *end, date, end, tm, 0);
518 if (match)
519 return match;
524 * None of the special formats? Try to guess what
525 * the number meant. We use the number of digits
526 * to make a more educated guess..
528 n = 0;
529 do {
530 n++;
531 } while (isdigit(date[n]));
533 /* Four-digit year or a timezone? */
534 if (n == 4) {
535 if (num <= 1400 && *offset == -1) {
536 unsigned int minutes = num % 100;
537 unsigned int hours = num / 100;
538 *offset = hours*60 + minutes;
539 } else if (num > 1900 && num < 2100)
540 tm->tm_year = num - 1900;
541 return n;
545 * Ignore lots of numerals. We took care of 4-digit years above.
546 * Days or months must be one or two digits.
548 if (n > 2)
549 return n;
552 * NOTE! We will give precedence to day-of-month over month or
553 * year numbers in the 1-12 range. So 05 is always "mday 5",
554 * unless we already have a mday..
556 * IOW, 01 Apr 05 parses as "April 1st, 2005".
558 if (num > 0 && num < 32 && tm->tm_mday < 0) {
559 tm->tm_mday = num;
560 return n;
563 /* Two-digit year? */
564 if (n == 2 && tm->tm_year < 0) {
565 if (num < 10 && tm->tm_mday >= 0) {
566 tm->tm_year = num + 100;
567 return n;
569 if (num >= 70) {
570 tm->tm_year = num;
571 return n;
575 if (num > 0 && num < 13 && tm->tm_mon < 0)
576 tm->tm_mon = num-1;
578 return n;
581 static int match_tz(const char *date, int *offp)
583 char *end;
584 int hour = strtoul(date + 1, &end, 10);
585 int n = end - (date + 1);
586 int min = 0;
588 if (n == 4) {
589 /* hhmm */
590 min = hour % 100;
591 hour = hour / 100;
592 } else if (n != 2) {
593 min = 99; /* random crap */
594 } else if (*end == ':') {
595 /* hh:mm? */
596 min = strtoul(end + 1, &end, 10);
597 if (end - (date + 1) != 5)
598 min = 99; /* random crap */
599 } /* otherwise we parsed "hh" */
602 * Don't accept any random crap. Even though some places have
603 * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
604 * UTC+14), there is something wrong if hour part is much
605 * larger than that. We might also want to check that the
606 * minutes are divisible by 15 or something too. (Offset of
607 * Kathmandu, Nepal is UTC+5:45)
609 if (min < 60 && hour < 24) {
610 int offset = hour * 60 + min;
611 if (*date == '-')
612 offset = -offset;
613 *offp = offset;
615 return end - date;
618 static void date_string(unsigned long date, int offset, struct strbuf *buf)
620 int sign = '+';
622 if (offset < 0) {
623 offset = -offset;
624 sign = '-';
626 strbuf_addf(buf, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
630 * Parse a string like "0 +0000" as ancient timestamp near epoch, but
631 * only when it appears not as part of any other string.
633 static int match_object_header_date(const char *date, unsigned long *timestamp, int *offset)
635 char *end;
636 unsigned long stamp;
637 int ofs;
639 if (*date < '0' || '9' < *date)
640 return -1;
641 stamp = strtoul(date, &end, 10);
642 if (*end != ' ' || stamp == ULONG_MAX || (end[1] != '+' && end[1] != '-'))
643 return -1;
644 date = end + 2;
645 ofs = strtol(date, &end, 10);
646 if ((*end != '\0' && (*end != '\n')) || end != date + 4)
647 return -1;
648 ofs = (ofs / 100) * 60 + (ofs % 100);
649 if (date[-1] == '-')
650 ofs = -ofs;
651 *timestamp = stamp;
652 *offset = ofs;
653 return 0;
656 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
657 (i.e. English) day/month names, and it doesn't work correctly with %z. */
658 int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
660 struct tm tm;
661 int tm_gmt;
662 unsigned long dummy_timestamp;
663 int dummy_offset;
665 if (!timestamp)
666 timestamp = &dummy_timestamp;
667 if (!offset)
668 offset = &dummy_offset;
670 memset(&tm, 0, sizeof(tm));
671 tm.tm_year = -1;
672 tm.tm_mon = -1;
673 tm.tm_mday = -1;
674 tm.tm_isdst = -1;
675 tm.tm_hour = -1;
676 tm.tm_min = -1;
677 tm.tm_sec = -1;
678 *offset = -1;
679 tm_gmt = 0;
681 if (*date == '@' &&
682 !match_object_header_date(date + 1, timestamp, offset))
683 return 0; /* success */
684 for (;;) {
685 int match = 0;
686 unsigned char c = *date;
688 /* Stop at end of string or newline */
689 if (!c || c == '\n')
690 break;
692 if (isalpha(c))
693 match = match_alpha(date, &tm, offset);
694 else if (isdigit(c))
695 match = match_digit(date, &tm, offset, &tm_gmt);
696 else if ((c == '-' || c == '+') && isdigit(date[1]))
697 match = match_tz(date, offset);
699 if (!match) {
700 /* BAD CRAP */
701 match = 1;
704 date += match;
707 /* mktime uses local timezone */
708 *timestamp = tm_to_time_t(&tm);
709 if (*offset == -1) {
710 time_t temp_time = mktime(&tm);
711 if ((time_t)*timestamp > temp_time) {
712 *offset = ((time_t)*timestamp - temp_time) / 60;
713 } else {
714 *offset = -(int)((temp_time - (time_t)*timestamp) / 60);
718 if (*timestamp == -1)
719 return -1;
721 if (!tm_gmt)
722 *timestamp -= *offset * 60;
723 return 0; /* success */
726 int parse_expiry_date(const char *date, unsigned long *timestamp)
728 int errors = 0;
730 if (!strcmp(date, "never") || !strcmp(date, "false"))
731 *timestamp = 0;
732 else if (!strcmp(date, "all") || !strcmp(date, "now"))
734 * We take over "now" here, which usually translates
735 * to the current timestamp. This is because the user
736 * really means to expire everything she has done in
737 * the past, and by definition reflogs are the record
738 * of the past, and there is nothing from the future
739 * to be kept.
741 *timestamp = ULONG_MAX;
742 else
743 *timestamp = approxidate_careful(date, &errors);
745 return errors;
748 int parse_date(const char *date, struct strbuf *result)
750 unsigned long timestamp;
751 int offset;
752 if (parse_date_basic(date, &timestamp, &offset))
753 return -1;
754 date_string(timestamp, offset, result);
755 return 0;
758 enum date_mode parse_date_format(const char *format)
760 if (!strcmp(format, "relative"))
761 return DATE_RELATIVE;
762 else if (!strcmp(format, "iso8601") ||
763 !strcmp(format, "iso"))
764 return DATE_ISO8601;
765 else if (!strcmp(format, "iso8601-strict") ||
766 !strcmp(format, "iso-strict"))
767 return DATE_ISO8601_STRICT;
768 else if (!strcmp(format, "rfc2822") ||
769 !strcmp(format, "rfc"))
770 return DATE_RFC2822;
771 else if (!strcmp(format, "short"))
772 return DATE_SHORT;
773 else if (!strcmp(format, "local"))
774 return DATE_LOCAL;
775 else if (!strcmp(format, "default"))
776 return DATE_NORMAL;
777 else if (!strcmp(format, "raw"))
778 return DATE_RAW;
779 else
780 die("unknown date format %s", format);
783 void datestamp(struct strbuf *out)
785 time_t now;
786 int offset;
788 time(&now);
790 offset = tm_to_time_t(localtime(&now)) - now;
791 offset /= 60;
793 date_string(now, offset, out);
797 * Relative time update (eg "2 days ago"). If we haven't set the time
798 * yet, we need to set it from current time.
800 static unsigned long update_tm(struct tm *tm, struct tm *now, unsigned long sec)
802 time_t n;
804 if (tm->tm_mday < 0)
805 tm->tm_mday = now->tm_mday;
806 if (tm->tm_mon < 0)
807 tm->tm_mon = now->tm_mon;
808 if (tm->tm_year < 0) {
809 tm->tm_year = now->tm_year;
810 if (tm->tm_mon > now->tm_mon)
811 tm->tm_year--;
814 n = mktime(tm) - sec;
815 localtime_r(&n, tm);
816 return n;
819 static void date_now(struct tm *tm, struct tm *now, int *num)
821 update_tm(tm, now, 0);
824 static void date_yesterday(struct tm *tm, struct tm *now, int *num)
826 update_tm(tm, now, 24*60*60);
829 static void date_time(struct tm *tm, struct tm *now, int hour)
831 if (tm->tm_hour < hour)
832 date_yesterday(tm, now, NULL);
833 tm->tm_hour = hour;
834 tm->tm_min = 0;
835 tm->tm_sec = 0;
838 static void date_midnight(struct tm *tm, struct tm *now, int *num)
840 date_time(tm, now, 0);
843 static void date_noon(struct tm *tm, struct tm *now, int *num)
845 date_time(tm, now, 12);
848 static void date_tea(struct tm *tm, struct tm *now, int *num)
850 date_time(tm, now, 17);
853 static void date_pm(struct tm *tm, struct tm *now, int *num)
855 int hour, n = *num;
856 *num = 0;
858 hour = tm->tm_hour;
859 if (n) {
860 hour = n;
861 tm->tm_min = 0;
862 tm->tm_sec = 0;
864 tm->tm_hour = (hour % 12) + 12;
867 static void date_am(struct tm *tm, struct tm *now, int *num)
869 int hour, n = *num;
870 *num = 0;
872 hour = tm->tm_hour;
873 if (n) {
874 hour = n;
875 tm->tm_min = 0;
876 tm->tm_sec = 0;
878 tm->tm_hour = (hour % 12);
881 static void date_never(struct tm *tm, struct tm *now, int *num)
883 time_t n = 0;
884 localtime_r(&n, tm);
887 static const struct special {
888 const char *name;
889 void (*fn)(struct tm *, struct tm *, int *);
890 } special[] = {
891 { "yesterday", date_yesterday },
892 { "noon", date_noon },
893 { "midnight", date_midnight },
894 { "tea", date_tea },
895 { "PM", date_pm },
896 { "AM", date_am },
897 { "never", date_never },
898 { "now", date_now },
899 { NULL }
902 static const char *number_name[] = {
903 "zero", "one", "two", "three", "four",
904 "five", "six", "seven", "eight", "nine", "ten",
907 static const struct typelen {
908 const char *type;
909 int length;
910 } typelen[] = {
911 { "seconds", 1 },
912 { "minutes", 60 },
913 { "hours", 60*60 },
914 { "days", 24*60*60 },
915 { "weeks", 7*24*60*60 },
916 { NULL }
919 static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
921 const struct typelen *tl;
922 const struct special *s;
923 const char *end = date;
924 int i;
926 while (isalpha(*++end))
929 for (i = 0; i < 12; i++) {
930 int match = match_string(date, month_names[i]);
931 if (match >= 3) {
932 tm->tm_mon = i;
933 *touched = 1;
934 return end;
938 for (s = special; s->name; s++) {
939 int len = strlen(s->name);
940 if (match_string(date, s->name) == len) {
941 s->fn(tm, now, num);
942 *touched = 1;
943 return end;
947 if (!*num) {
948 for (i = 1; i < 11; i++) {
949 int len = strlen(number_name[i]);
950 if (match_string(date, number_name[i]) == len) {
951 *num = i;
952 *touched = 1;
953 return end;
956 if (match_string(date, "last") == 4) {
957 *num = 1;
958 *touched = 1;
960 return end;
963 tl = typelen;
964 while (tl->type) {
965 int len = strlen(tl->type);
966 if (match_string(date, tl->type) >= len-1) {
967 update_tm(tm, now, tl->length * *num);
968 *num = 0;
969 *touched = 1;
970 return end;
972 tl++;
975 for (i = 0; i < 7; i++) {
976 int match = match_string(date, weekday_names[i]);
977 if (match >= 3) {
978 int diff, n = *num -1;
979 *num = 0;
981 diff = tm->tm_wday - i;
982 if (diff <= 0)
983 n++;
984 diff += 7*n;
986 update_tm(tm, now, diff * 24 * 60 * 60);
987 *touched = 1;
988 return end;
992 if (match_string(date, "months") >= 5) {
993 int n;
994 update_tm(tm, now, 0); /* fill in date fields if needed */
995 n = tm->tm_mon - *num;
996 *num = 0;
997 while (n < 0) {
998 n += 12;
999 tm->tm_year--;
1001 tm->tm_mon = n;
1002 *touched = 1;
1003 return end;
1006 if (match_string(date, "years") >= 4) {
1007 update_tm(tm, now, 0); /* fill in date fields if needed */
1008 tm->tm_year -= *num;
1009 *num = 0;
1010 *touched = 1;
1011 return end;
1014 return end;
1017 static const char *approxidate_digit(const char *date, struct tm *tm, int *num,
1018 time_t now)
1020 char *end;
1021 unsigned long number = strtoul(date, &end, 10);
1023 switch (*end) {
1024 case ':':
1025 case '.':
1026 case '/':
1027 case '-':
1028 if (isdigit(end[1])) {
1029 int match = match_multi_number(number, *end, date, end,
1030 tm, now);
1031 if (match)
1032 return date + match;
1036 /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
1037 if (date[0] != '0' || end - date <= 2)
1038 *num = number;
1039 return end;
1043 * Do we have a pending number at the end, or when
1044 * we see a new one? Let's assume it's a month day,
1045 * as in "Dec 6, 1992"
1047 static void pending_number(struct tm *tm, int *num)
1049 int number = *num;
1051 if (number) {
1052 *num = 0;
1053 if (tm->tm_mday < 0 && number < 32)
1054 tm->tm_mday = number;
1055 else if (tm->tm_mon < 0 && number < 13)
1056 tm->tm_mon = number-1;
1057 else if (tm->tm_year < 0) {
1058 if (number > 1969 && number < 2100)
1059 tm->tm_year = number - 1900;
1060 else if (number > 69 && number < 100)
1061 tm->tm_year = number;
1062 else if (number < 38)
1063 tm->tm_year = 100 + number;
1064 /* We screw up for number = 00 ? */
1069 static unsigned long approxidate_str(const char *date,
1070 const struct timeval *tv,
1071 int *error_ret)
1073 int number = 0;
1074 int touched = 0;
1075 struct tm tm, now;
1076 time_t time_sec;
1078 time_sec = tv->tv_sec;
1079 localtime_r(&time_sec, &tm);
1080 now = tm;
1082 tm.tm_year = -1;
1083 tm.tm_mon = -1;
1084 tm.tm_mday = -1;
1086 for (;;) {
1087 unsigned char c = *date;
1088 if (!c)
1089 break;
1090 date++;
1091 if (isdigit(c)) {
1092 pending_number(&tm, &number);
1093 date = approxidate_digit(date-1, &tm, &number, time_sec);
1094 touched = 1;
1095 continue;
1097 if (isalpha(c))
1098 date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
1100 pending_number(&tm, &number);
1101 if (!touched)
1102 *error_ret = 1;
1103 return update_tm(&tm, &now, 0);
1106 unsigned long approxidate_relative(const char *date, const struct timeval *tv)
1108 unsigned long timestamp;
1109 int offset;
1110 int errors = 0;
1112 if (!parse_date_basic(date, &timestamp, &offset))
1113 return timestamp;
1114 return approxidate_str(date, tv, &errors);
1117 unsigned long approxidate_careful(const char *date, int *error_ret)
1119 struct timeval tv;
1120 unsigned long timestamp;
1121 int offset;
1122 int dummy = 0;
1123 if (!error_ret)
1124 error_ret = &dummy;
1126 if (!parse_date_basic(date, &timestamp, &offset)) {
1127 *error_ret = 0;
1128 return timestamp;
1131 gettimeofday(&tv, NULL);
1132 return approxidate_str(date, &tv, error_ret);
1135 int date_overflows(unsigned long t)
1137 time_t sys;
1139 /* If we overflowed our unsigned long, that's bad... */
1140 if (t == ULONG_MAX)
1141 return 1;
1144 * ...but we also are going to feed the result to system
1145 * functions that expect time_t, which is often "signed long".
1146 * Make sure that we fit into time_t, as well.
1148 sys = t;
1149 return t != sys || (t < 1) != (sys < 1);