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git-p4: introduce asciidoc documentation
[git/mjg.git] / date.c
blob353e0a5e53f13c36549e65452931f254de3423c4
1 /*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
6
7 #include "cache.h"
8
9 /*
10 * This is like mktime, but without normalization of tm_wday and tm_yday.
11 */
12 static time_t tm_to_time_t(const struct tm *tm)
13 {
14 static const int mdays[] = {
15 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
16 };
17 int year = tm->tm_year - 70;
18 int month = tm->tm_mon;
19 int day = tm->tm_mday;
20
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;
31 }
32
33 static const char *month_names[] = {
34 "January", "February", "March", "April", "May", "June",
35 "July", "August", "September", "October", "November", "December"
36 };
37
38 static const char *weekday_names[] = {
39 "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
40 };
41
42 static time_t gm_time_t(unsigned long time, int tz)
43 {
44 int minutes;
45
46 minutes = tz < 0 ? -tz : tz;
47 minutes = (minutes / 100)*60 + (minutes % 100);
48 minutes = tz < 0 ? -minutes : minutes;
49 return time + minutes * 60;
50 }
51
52 /*
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"
56 */
57 static struct tm *time_to_tm(unsigned long time, int tz)
58 {
59 time_t t = gm_time_t(time, tz);
60 return gmtime(&t);
61 }
62
63 /*
64 * What value of "tz" was in effect back then at "time" in the
65 * local timezone?
66 */
67 static int local_tzoffset(unsigned long time)
68 {
69 time_t t, t_local;
70 struct tm tm;
71 int offset, eastwest;
72
73 t = time;
74 localtime_r(&t, &tm);
75 t_local = tm_to_time_t(&tm);
76
77 if (t_local < t) {
78 eastwest = -1;
79 offset = t - t_local;
80 } else {
81 eastwest = 1;
82 offset = t_local - t;
83 }
84 offset /= 60; /* in minutes */
85 offset = (offset % 60) + ((offset / 60) * 100);
86 return offset * eastwest;
87 }
88
89 const char *show_date_relative(unsigned long time, int tz,
90 const struct timeval *now,
91 char *timebuf,
92 size_t timebuf_size)
93 {
94 unsigned long diff;
95 if (now->tv_sec < time)
96 return "in the future";
97 diff = now->tv_sec - time;
98 if (diff < 90) {
99 snprintf(timebuf, timebuf_size, "%lu seconds ago", diff);
100 return timebuf;
101 }
102 /* Turn it into minutes */
103 diff = (diff + 30) / 60;
104 if (diff < 90) {
105 snprintf(timebuf, timebuf_size, "%lu minutes ago", diff);
106 return timebuf;
107 }
108 /* Turn it into hours */
109 diff = (diff + 30) / 60;
110 if (diff < 36) {
111 snprintf(timebuf, timebuf_size, "%lu hours ago", diff);
112 return timebuf;
113 }
114 /* We deal with number of days from here on */
115 diff = (diff + 12) / 24;
116 if (diff < 14) {
117 snprintf(timebuf, timebuf_size, "%lu days ago", diff);
118 return timebuf;
119 }
120 /* Say weeks for the past 10 weeks or so */
121 if (diff < 70) {
122 snprintf(timebuf, timebuf_size, "%lu weeks ago", (diff + 3) / 7);
123 return timebuf;
124 }
125 /* Say months for the past 12 months or so */
126 if (diff < 365) {
127 snprintf(timebuf, timebuf_size, "%lu months ago", (diff + 15) / 30);
128 return timebuf;
129 }
130 /* Give years and months for 5 years or so */
131 if (diff < 1825) {
132 unsigned long totalmonths = (diff * 12 * 2 + 365) / (365 * 2);
133 unsigned long years = totalmonths / 12;
134 unsigned long months = totalmonths % 12;
135 int n;
136 n = snprintf(timebuf, timebuf_size, "%lu year%s",
137 years, (years > 1 ? "s" : ""));
138 if (months)
139 snprintf(timebuf + n, timebuf_size - n,
140 ", %lu month%s ago",
141 months, (months > 1 ? "s" : ""));
142 else
143 snprintf(timebuf + n, timebuf_size - n, " ago");
144 return timebuf;
145 }
146 /* Otherwise, just years. Centuries is probably overkill. */
147 snprintf(timebuf, timebuf_size, "%lu years ago", (diff + 183) / 365);
148 return timebuf;
149 }
150
151 const char *show_date(unsigned long time, int tz, enum date_mode mode)
152 {
153 struct tm *tm;
154 static char timebuf[200];
155
156 if (mode == DATE_RAW) {
157 snprintf(timebuf, sizeof(timebuf), "%lu %+05d", time, tz);
158 return timebuf;
159 }
160
161 if (mode == DATE_RELATIVE) {
162 struct timeval now;
163 gettimeofday(&now, NULL);
164 return show_date_relative(time, tz, &now,
165 timebuf, sizeof(timebuf));
166 }
167
168 if (mode == DATE_LOCAL)
169 tz = local_tzoffset(time);
170
171 tm = time_to_tm(time, tz);
172 if (!tm)
173 return NULL;
174 if (mode == DATE_SHORT)
175 sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
176 tm->tm_mon + 1, tm->tm_mday);
177 else if (mode == DATE_ISO8601)
178 sprintf(timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
179 tm->tm_year + 1900,
180 tm->tm_mon + 1,
181 tm->tm_mday,
182 tm->tm_hour, tm->tm_min, tm->tm_sec,
183 tz);
184 else if (mode == DATE_RFC2822)
185 sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
186 weekday_names[tm->tm_wday], tm->tm_mday,
187 month_names[tm->tm_mon], tm->tm_year + 1900,
188 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
189 else
190 sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
191 weekday_names[tm->tm_wday],
192 month_names[tm->tm_mon],
193 tm->tm_mday,
194 tm->tm_hour, tm->tm_min, tm->tm_sec,
195 tm->tm_year + 1900,
196 (mode == DATE_LOCAL) ? 0 : ' ',
197 tz);
198 return timebuf;
199 }
200
201 /*
202 * Check these. And note how it doesn't do the summer-time conversion.
203 *
204 * In my world, it's always summer, and things are probably a bit off
205 * in other ways too.
206 */
207 static const struct {
208 const char *name;
209 int offset;
210 int dst;
211 } timezone_names[] = {
212 { "IDLW", -12, 0, }, /* International Date Line West */
213 { "NT", -11, 0, }, /* Nome */
214 { "CAT", -10, 0, }, /* Central Alaska */
215 { "HST", -10, 0, }, /* Hawaii Standard */
216 { "HDT", -10, 1, }, /* Hawaii Daylight */
217 { "YST", -9, 0, }, /* Yukon Standard */
218 { "YDT", -9, 1, }, /* Yukon Daylight */
219 { "PST", -8, 0, }, /* Pacific Standard */
220 { "PDT", -8, 1, }, /* Pacific Daylight */
221 { "MST", -7, 0, }, /* Mountain Standard */
222 { "MDT", -7, 1, }, /* Mountain Daylight */
223 { "CST", -6, 0, }, /* Central Standard */
224 { "CDT", -6, 1, }, /* Central Daylight */
225 { "EST", -5, 0, }, /* Eastern Standard */
226 { "EDT", -5, 1, }, /* Eastern Daylight */
227 { "AST", -3, 0, }, /* Atlantic Standard */
228 { "ADT", -3, 1, }, /* Atlantic Daylight */
229 { "WAT", -1, 0, }, /* West Africa */
230
231 { "GMT", 0, 0, }, /* Greenwich Mean */
232 { "UTC", 0, 0, }, /* Universal (Coordinated) */
233 { "Z", 0, 0, }, /* Zulu, alias for UTC */
234
235 { "WET", 0, 0, }, /* Western European */
236 { "BST", 0, 1, }, /* British Summer */
237 { "CET", +1, 0, }, /* Central European */
238 { "MET", +1, 0, }, /* Middle European */
239 { "MEWT", +1, 0, }, /* Middle European Winter */
240 { "MEST", +1, 1, }, /* Middle European Summer */
241 { "CEST", +1, 1, }, /* Central European Summer */
242 { "MESZ", +1, 1, }, /* Middle European Summer */
243 { "FWT", +1, 0, }, /* French Winter */
244 { "FST", +1, 1, }, /* French Summer */
245 { "EET", +2, 0, }, /* Eastern Europe, USSR Zone 1 */
246 { "EEST", +2, 1, }, /* Eastern European Daylight */
247 { "WAST", +7, 0, }, /* West Australian Standard */
248 { "WADT", +7, 1, }, /* West Australian Daylight */
249 { "CCT", +8, 0, }, /* China Coast, USSR Zone 7 */
250 { "JST", +9, 0, }, /* Japan Standard, USSR Zone 8 */
251 { "EAST", +10, 0, }, /* Eastern Australian Standard */
252 { "EADT", +10, 1, }, /* Eastern Australian Daylight */
253 { "GST", +10, 0, }, /* Guam Standard, USSR Zone 9 */
254 { "NZT", +12, 0, }, /* New Zealand */
255 { "NZST", +12, 0, }, /* New Zealand Standard */
256 { "NZDT", +12, 1, }, /* New Zealand Daylight */
257 { "IDLE", +12, 0, }, /* International Date Line East */
258 };
259
260 static int match_string(const char *date, const char *str)
261 {
262 int i = 0;
263
264 for (i = 0; *date; date++, str++, i++) {
265 if (*date == *str)
266 continue;
267 if (toupper(*date) == toupper(*str))
268 continue;
269 if (!isalnum(*date))
270 break;
271 return 0;
272 }
273 return i;
274 }
275
276 static int skip_alpha(const char *date)
277 {
278 int i = 0;
279 do {
280 i++;
281 } while (isalpha(date[i]));
282 return i;
283 }
284
285 /*
286 * Parse month, weekday, or timezone name
287 */
288 static int match_alpha(const char *date, struct tm *tm, int *offset)
289 {
290 int i;
291
292 for (i = 0; i < 12; i++) {
293 int match = match_string(date, month_names[i]);
294 if (match >= 3) {
295 tm->tm_mon = i;
296 return match;
297 }
298 }
299
300 for (i = 0; i < 7; i++) {
301 int match = match_string(date, weekday_names[i]);
302 if (match >= 3) {
303 tm->tm_wday = i;
304 return match;
305 }
306 }
307
308 for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
309 int match = match_string(date, timezone_names[i].name);
310 if (match >= 3 || match == strlen(timezone_names[i].name)) {
311 int off = timezone_names[i].offset;
312
313 /* This is bogus, but we like summer */
314 off += timezone_names[i].dst;
315
316 /* Only use the tz name offset if we don't have anything better */
317 if (*offset == -1)
318 *offset = 60*off;
319
320 return match;
321 }
322 }
323
324 if (match_string(date, "PM") == 2) {
325 tm->tm_hour = (tm->tm_hour % 12) + 12;
326 return 2;
327 }
328
329 if (match_string(date, "AM") == 2) {
330 tm->tm_hour = (tm->tm_hour % 12) + 0;
331 return 2;
332 }
333
334 /* BAD CRAP */
335 return skip_alpha(date);
336 }
337
338 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
339 {
340 if (month > 0 && month < 13 && day > 0 && day < 32) {
341 struct tm check = *tm;
342 struct tm *r = (now_tm ? &check : tm);
343 time_t specified;
344
345 r->tm_mon = month - 1;
346 r->tm_mday = day;
347 if (year == -1) {
348 if (!now_tm)
349 return 1;
350 r->tm_year = now_tm->tm_year;
351 }
352 else if (year >= 1970 && year < 2100)
353 r->tm_year = year - 1900;
354 else if (year > 70 && year < 100)
355 r->tm_year = year;
356 else if (year < 38)
357 r->tm_year = year + 100;
358 else
359 return 0;
360 if (!now_tm)
361 return 1;
362
363 specified = tm_to_time_t(r);
364
365 /* Be it commit time or author time, it does not make
366 * sense to specify timestamp way into the future. Make
367 * sure it is not later than ten days from now...
368 */
369 if (now + 10*24*3600 < specified)
370 return 0;
371 tm->tm_mon = r->tm_mon;
372 tm->tm_mday = r->tm_mday;
373 if (year != -1)
374 tm->tm_year = r->tm_year;
375 return 1;
376 }
377 return 0;
378 }
379
380 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
381 {
382 time_t now;
383 struct tm now_tm;
384 struct tm *refuse_future;
385 long num2, num3;
386
387 num2 = strtol(end+1, &end, 10);
388 num3 = -1;
389 if (*end == c && isdigit(end[1]))
390 num3 = strtol(end+1, &end, 10);
391
392 /* Time? Date? */
393 switch (c) {
394 case ':':
395 if (num3 < 0)
396 num3 = 0;
397 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
398 tm->tm_hour = num;
399 tm->tm_min = num2;
400 tm->tm_sec = num3;
401 break;
402 }
403 return 0;
404
405 case '-':
406 case '/':
407 case '.':
408 now = time(NULL);
409 refuse_future = NULL;
410 if (gmtime_r(&now, &now_tm))
411 refuse_future = &now_tm;
412
413 if (num > 70) {
414 /* yyyy-mm-dd? */
415 if (is_date(num, num2, num3, refuse_future, now, tm))
416 break;
417 /* yyyy-dd-mm? */
418 if (is_date(num, num3, num2, refuse_future, now, tm))
419 break;
420 }
421 /* Our eastern European friends say dd.mm.yy[yy]
422 * is the norm there, so giving precedence to
423 * mm/dd/yy[yy] form only when separator is not '.'
424 */
425 if (c != '.' &&
426 is_date(num3, num, num2, refuse_future, now, tm))
427 break;
428 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
429 if (is_date(num3, num2, num, refuse_future, now, tm))
430 break;
431 /* Funny European mm.dd.yy */
432 if (c == '.' &&
433 is_date(num3, num, num2, refuse_future, now, tm))
434 break;
435 return 0;
436 }
437 return end - date;
438 }
439
440 /*
441 * Have we filled in any part of the time/date yet?
442 * We just do a binary 'and' to see if the sign bit
443 * is set in all the values.
444 */
445 static inline int nodate(struct tm *tm)
446 {
447 return (tm->tm_year &
448 tm->tm_mon &
449 tm->tm_mday &
450 tm->tm_hour &
451 tm->tm_min &
452 tm->tm_sec) < 0;
453 }
454
455 /*
456 * We've seen a digit. Time? Year? Date?
457 */
458 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
459 {
460 int n;
461 char *end;
462 unsigned long num;
463
464 num = strtoul(date, &end, 10);
465
466 /*
467 * Seconds since 1970? We trigger on that for any numbers with
468 * more than 8 digits. This is because we don't want to rule out
469 * numbers like 20070606 as a YYYYMMDD date.
470 */
471 if (num >= 100000000 && nodate(tm)) {
472 time_t time = num;
473 if (gmtime_r(&time, tm)) {
474 *tm_gmt = 1;
475 return end - date;
476 }
477 }
478
479 /*
480 * Check for special formats: num[-.:/]num[same]num
481 */
482 switch (*end) {
483 case ':':
484 case '.':
485 case '/':
486 case '-':
487 if (isdigit(end[1])) {
488 int match = match_multi_number(num, *end, date, end, tm);
489 if (match)
490 return match;
491 }
492 }
493
494 /*
495 * None of the special formats? Try to guess what
496 * the number meant. We use the number of digits
497 * to make a more educated guess..
498 */
499 n = 0;
500 do {
501 n++;
502 } while (isdigit(date[n]));
503
504 /* Four-digit year or a timezone? */
505 if (n == 4) {
506 if (num <= 1400 && *offset == -1) {
507 unsigned int minutes = num % 100;
508 unsigned int hours = num / 100;
509 *offset = hours*60 + minutes;
510 } else if (num > 1900 && num < 2100)
511 tm->tm_year = num - 1900;
512 return n;
513 }
514
515 /*
516 * Ignore lots of numerals. We took care of 4-digit years above.
517 * Days or months must be one or two digits.
518 */
519 if (n > 2)
520 return n;
521
522 /*
523 * NOTE! We will give precedence to day-of-month over month or
524 * year numbers in the 1-12 range. So 05 is always "mday 5",
525 * unless we already have a mday..
526 *
527 * IOW, 01 Apr 05 parses as "April 1st, 2005".
528 */
529 if (num > 0 && num < 32 && tm->tm_mday < 0) {
530 tm->tm_mday = num;
531 return n;
532 }
533
534 /* Two-digit year? */
535 if (n == 2 && tm->tm_year < 0) {
536 if (num < 10 && tm->tm_mday >= 0) {
537 tm->tm_year = num + 100;
538 return n;
539 }
540 if (num >= 70) {
541 tm->tm_year = num;
542 return n;
543 }
544 }
545
546 if (num > 0 && num < 13 && tm->tm_mon < 0)
547 tm->tm_mon = num-1;
548
549 return n;
550 }
551
552 static int match_tz(const char *date, int *offp)
553 {
554 char *end;
555 int hour = strtoul(date + 1, &end, 10);
556 int n = end - (date + 1);
557 int min = 0;
558
559 if (n == 4) {
560 /* hhmm */
561 min = hour % 100;
562 hour = hour / 100;
563 } else if (n != 2) {
564 min = 99; /* random crap */
565 } else if (*end == ':') {
566 /* hh:mm? */
567 min = strtoul(end + 1, &end, 10);
568 if (end - (date + 1) != 5)
569 min = 99; /* random crap */
570 } /* otherwise we parsed "hh" */
571
572 /*
573 * Don't accept any random crap. Even though some places have
574 * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
575 * UTC+14), there is something wrong if hour part is much
576 * larger than that. We might also want to check that the
577 * minutes are divisible by 15 or something too. (Offset of
578 * Kathmandu, Nepal is UTC+5:45)
579 */
580 if (min < 60 && hour < 24) {
581 int offset = hour * 60 + min;
582 if (*date == '-')
583 offset = -offset;
584 *offp = offset;
585 }
586 return end - date;
587 }
588
589 static int date_string(unsigned long date, int offset, char *buf, int len)
590 {
591 int sign = '+';
592
593 if (offset < 0) {
594 offset = -offset;
595 sign = '-';
596 }
597 return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
598 }
599
600 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
601 (i.e. English) day/month names, and it doesn't work correctly with %z. */
602 int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
603 {
604 struct tm tm;
605 int tm_gmt;
606 unsigned long dummy_timestamp;
607 int dummy_offset;
608
609 if (!timestamp)
610 timestamp = &dummy_timestamp;
611 if (!offset)
612 offset = &dummy_offset;
613
614 memset(&tm, 0, sizeof(tm));
615 tm.tm_year = -1;
616 tm.tm_mon = -1;
617 tm.tm_mday = -1;
618 tm.tm_isdst = -1;
619 tm.tm_hour = -1;
620 tm.tm_min = -1;
621 tm.tm_sec = -1;
622 *offset = -1;
623 tm_gmt = 0;
624
625 for (;;) {
626 int match = 0;
627 unsigned char c = *date;
628
629 /* Stop at end of string or newline */
630 if (!c || c == '\n')
631 break;
632
633 if (isalpha(c))
634 match = match_alpha(date, &tm, offset);
635 else if (isdigit(c))
636 match = match_digit(date, &tm, offset, &tm_gmt);
637 else if ((c == '-' || c == '+') && isdigit(date[1]))
638 match = match_tz(date, offset);
639
640 if (!match) {
641 /* BAD CRAP */
642 match = 1;
643 }
644
645 date += match;
646 }
647
648 /* mktime uses local timezone */
649 *timestamp = tm_to_time_t(&tm);
650 if (*offset == -1)
651 *offset = ((time_t)*timestamp - mktime(&tm)) / 60;
652
653 if (*timestamp == -1)
654 return -1;
655
656 if (!tm_gmt)
657 *timestamp -= *offset * 60;
658 return 0; /* success */
659 }
660
661 int parse_date(const char *date, char *result, int maxlen)
662 {
663 unsigned long timestamp;
664 int offset;
665 if (parse_date_basic(date, &timestamp, &offset))
666 return -1;
667 return date_string(timestamp, offset, result, maxlen);
668 }
669
670 enum date_mode parse_date_format(const char *format)
671 {
672 if (!strcmp(format, "relative"))
673 return DATE_RELATIVE;
674 else if (!strcmp(format, "iso8601") ||
675 !strcmp(format, "iso"))
676 return DATE_ISO8601;
677 else if (!strcmp(format, "rfc2822") ||
678 !strcmp(format, "rfc"))
679 return DATE_RFC2822;
680 else if (!strcmp(format, "short"))
681 return DATE_SHORT;
682 else if (!strcmp(format, "local"))
683 return DATE_LOCAL;
684 else if (!strcmp(format, "default"))
685 return DATE_NORMAL;
686 else if (!strcmp(format, "raw"))
687 return DATE_RAW;
688 else
689 die("unknown date format %s", format);
690 }
691
692 void datestamp(char *buf, int bufsize)
693 {
694 time_t now;
695 int offset;
696
697 time(&now);
698
699 offset = tm_to_time_t(localtime(&now)) - now;
700 offset /= 60;
701
702 date_string(now, offset, buf, bufsize);
703 }
704
705 /*
706 * Relative time update (eg "2 days ago"). If we haven't set the time
707 * yet, we need to set it from current time.
708 */
709 static unsigned long update_tm(struct tm *tm, struct tm *now, unsigned long sec)
710 {
711 time_t n;
712
713 if (tm->tm_mday < 0)
714 tm->tm_mday = now->tm_mday;
715 if (tm->tm_mon < 0)
716 tm->tm_mon = now->tm_mon;
717 if (tm->tm_year < 0) {
718 tm->tm_year = now->tm_year;
719 if (tm->tm_mon > now->tm_mon)
720 tm->tm_year--;
721 }
722
723 n = mktime(tm) - sec;
724 localtime_r(&n, tm);
725 return n;
726 }
727
728 static void date_now(struct tm *tm, struct tm *now, int *num)
729 {
730 update_tm(tm, now, 0);
731 }
732
733 static void date_yesterday(struct tm *tm, struct tm *now, int *num)
734 {
735 update_tm(tm, now, 24*60*60);
736 }
737
738 static void date_time(struct tm *tm, struct tm *now, int hour)
739 {
740 if (tm->tm_hour < hour)
741 date_yesterday(tm, now, NULL);
742 tm->tm_hour = hour;
743 tm->tm_min = 0;
744 tm->tm_sec = 0;
745 }
746
747 static void date_midnight(struct tm *tm, struct tm *now, int *num)
748 {
749 date_time(tm, now, 0);
750 }
751
752 static void date_noon(struct tm *tm, struct tm *now, int *num)
753 {
754 date_time(tm, now, 12);
755 }
756
757 static void date_tea(struct tm *tm, struct tm *now, int *num)
758 {
759 date_time(tm, now, 17);
760 }
761
762 static void date_pm(struct tm *tm, struct tm *now, int *num)
763 {
764 int hour, n = *num;
765 *num = 0;
766
767 hour = tm->tm_hour;
768 if (n) {
769 hour = n;
770 tm->tm_min = 0;
771 tm->tm_sec = 0;
772 }
773 tm->tm_hour = (hour % 12) + 12;
774 }
775
776 static void date_am(struct tm *tm, struct tm *now, int *num)
777 {
778 int hour, n = *num;
779 *num = 0;
780
781 hour = tm->tm_hour;
782 if (n) {
783 hour = n;
784 tm->tm_min = 0;
785 tm->tm_sec = 0;
786 }
787 tm->tm_hour = (hour % 12);
788 }
789
790 static void date_never(struct tm *tm, struct tm *now, int *num)
791 {
792 time_t n = 0;
793 localtime_r(&n, tm);
794 }
795
796 static const struct special {
797 const char *name;
798 void (*fn)(struct tm *, struct tm *, int *);
799 } special[] = {
800 { "yesterday", date_yesterday },
801 { "noon", date_noon },
802 { "midnight", date_midnight },
803 { "tea", date_tea },
804 { "PM", date_pm },
805 { "AM", date_am },
806 { "never", date_never },
807 { "now", date_now },
808 { NULL }
809 };
810
811 static const char *number_name[] = {
812 "zero", "one", "two", "three", "four",
813 "five", "six", "seven", "eight", "nine", "ten",
814 };
815
816 static const struct typelen {
817 const char *type;
818 int length;
819 } typelen[] = {
820 { "seconds", 1 },
821 { "minutes", 60 },
822 { "hours", 60*60 },
823 { "days", 24*60*60 },
824 { "weeks", 7*24*60*60 },
825 { NULL }
826 };
827
828 static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
829 {
830 const struct typelen *tl;
831 const struct special *s;
832 const char *end = date;
833 int i;
834
835 while (isalpha(*++end));
836 ;
837
838 for (i = 0; i < 12; i++) {
839 int match = match_string(date, month_names[i]);
840 if (match >= 3) {
841 tm->tm_mon = i;
842 *touched = 1;
843 return end;
844 }
845 }
846
847 for (s = special; s->name; s++) {
848 int len = strlen(s->name);
849 if (match_string(date, s->name) == len) {
850 s->fn(tm, now, num);
851 *touched = 1;
852 return end;
853 }
854 }
855
856 if (!*num) {
857 for (i = 1; i < 11; i++) {
858 int len = strlen(number_name[i]);
859 if (match_string(date, number_name[i]) == len) {
860 *num = i;
861 *touched = 1;
862 return end;
863 }
864 }
865 if (match_string(date, "last") == 4) {
866 *num = 1;
867 *touched = 1;
868 }
869 return end;
870 }
871
872 tl = typelen;
873 while (tl->type) {
874 int len = strlen(tl->type);
875 if (match_string(date, tl->type) >= len-1) {
876 update_tm(tm, now, tl->length * *num);
877 *num = 0;
878 *touched = 1;
879 return end;
880 }
881 tl++;
882 }
883
884 for (i = 0; i < 7; i++) {
885 int match = match_string(date, weekday_names[i]);
886 if (match >= 3) {
887 int diff, n = *num -1;
888 *num = 0;
889
890 diff = tm->tm_wday - i;
891 if (diff <= 0)
892 n++;
893 diff += 7*n;
894
895 update_tm(tm, now, diff * 24 * 60 * 60);
896 *touched = 1;
897 return end;
898 }
899 }
900
901 if (match_string(date, "months") >= 5) {
902 int n;
903 update_tm(tm, now, 0); /* fill in date fields if needed */
904 n = tm->tm_mon - *num;
905 *num = 0;
906 while (n < 0) {
907 n += 12;
908 tm->tm_year--;
909 }
910 tm->tm_mon = n;
911 *touched = 1;
912 return end;
913 }
914
915 if (match_string(date, "years") >= 4) {
916 update_tm(tm, now, 0); /* fill in date fields if needed */
917 tm->tm_year -= *num;
918 *num = 0;
919 *touched = 1;
920 return end;
921 }
922
923 return end;
924 }
925
926 static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
927 {
928 char *end;
929 unsigned long number = strtoul(date, &end, 10);
930
931 switch (*end) {
932 case ':':
933 case '.':
934 case '/':
935 case '-':
936 if (isdigit(end[1])) {
937 int match = match_multi_number(number, *end, date, end, tm);
938 if (match)
939 return date + match;
940 }
941 }
942
943 /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
944 if (date[0] != '0' || end - date <= 2)
945 *num = number;
946 return end;
947 }
948
949 /*
950 * Do we have a pending number at the end, or when
951 * we see a new one? Let's assume it's a month day,
952 * as in "Dec 6, 1992"
953 */
954 static void pending_number(struct tm *tm, int *num)
955 {
956 int number = *num;
957
958 if (number) {
959 *num = 0;
960 if (tm->tm_mday < 0 && number < 32)
961 tm->tm_mday = number;
962 else if (tm->tm_mon < 0 && number < 13)
963 tm->tm_mon = number-1;
964 else if (tm->tm_year < 0) {
965 if (number > 1969 && number < 2100)
966 tm->tm_year = number - 1900;
967 else if (number > 69 && number < 100)
968 tm->tm_year = number;
969 else if (number < 38)
970 tm->tm_year = 100 + number;
971 /* We screw up for number = 00 ? */
972 }
973 }
974 }
975
976 static unsigned long approxidate_str(const char *date,
977 const struct timeval *tv,
978 int *error_ret)
979 {
980 int number = 0;
981 int touched = 0;
982 struct tm tm, now;
983 time_t time_sec;
984
985 time_sec = tv->tv_sec;
986 localtime_r(&time_sec, &tm);
987 now = tm;
988
989 tm.tm_year = -1;
990 tm.tm_mon = -1;
991 tm.tm_mday = -1;
992
993 for (;;) {
994 unsigned char c = *date;
995 if (!c)
996 break;
997 date++;
998 if (isdigit(c)) {
999 pending_number(&tm, &number);
1000 date = approxidate_digit(date-1, &tm, &number);
1001 touched = 1;
1002 continue;
1003 }
1004 if (isalpha(c))
1005 date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
1006 }
1007 pending_number(&tm, &number);
1008 if (!touched)
1009 *error_ret = 1;
1010 return update_tm(&tm, &now, 0);
1011 }
1012
1013 unsigned long approxidate_relative(const char *date, const struct timeval *tv)
1014 {
1015 unsigned long timestamp;
1016 int offset;
1017 int errors = 0;
1018
1019 if (!parse_date_basic(date, &timestamp, &offset))
1020 return timestamp;
1021 return approxidate_str(date, tv, &errors);
1022 }
1023
1024 unsigned long approxidate_careful(const char *date, int *error_ret)
1025 {
1026 struct timeval tv;
1027 unsigned long timestamp;
1028 int offset;
1029 int dummy = 0;
1030 if (!error_ret)
1031 error_ret = &dummy;
1032
1033 if (!parse_date_basic(date, &timestamp, &offset)) {
1034 *error_ret = 0;
1035 return timestamp;
1036 }
1037
1038 gettimeofday(&tv, NULL);
1039 return approxidate_str(date, &tv, error_ret);
1040 }
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