date.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6
   7 #include "cache.h"
   8
   9 static time_t my_mktime(struct tm *tm)
  10 {
  11         static const int mdays[] = {
  12             0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
  13         };
  14         int year = tm->tm_year - 70;
  15         int month = tm->tm_mon;
  16         int day = tm->tm_mday;
  17
  18         if (year < 0 || year > 129) /* algo only works for 1970-2099 */
  19                 return -1;
  20         if (month < 0 || month > 11) /* array bounds */
  21                 return -1;
  22         if (month < 2 || (year + 2) % 4)
  23                 day--;
  24         return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
  25                 tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
  26 }
  27
  28 static const char *month_names[] = {
  29         "January", "February", "March", "April", "May", "June",
  30         "July", "August", "September", "October", "November", "December"
  31 };
  32
  33 static const char *weekday_names[] = {
  34         "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  35 };
  36
  37 static time_t gm_time_t(unsigned long time, int tz)
  38 {
  39         int minutes;
  40
  41         minutes = tz < 0 ? -tz : tz;
  42         minutes = (minutes / 100)*60 + (minutes % 100);
  43         minutes = tz < 0 ? -minutes : minutes;
  44         return time + minutes * 60;
  45 }
  46
  47 /*
  48  * The "tz" thing is passed in as this strange "decimal parse of tz"
  49  * thing, which means that tz -0100 is passed in as the integer -100,
  50  * even though it means "sixty minutes off"
  51  */
  52 static struct tm *time_to_tm(unsigned long time, int tz)
  53 {
  54         time_t t = gm_time_t(time, tz);
  55         return gmtime(&t);
  56 }
  57
  58 const char *show_date(unsigned long time, int tz, int relative)
  59 {
  60         struct tm *tm;
  61         static char timebuf[200];
  62
  63         if (relative) {
  64                 unsigned long diff;
  65                 time_t t = gm_time_t(time, tz);
  66                 struct timeval now;
  67                 gettimeofday(&now, NULL);
  68                 if (now.tv_sec < t)
  69                         return "in the future";
  70                 diff = now.tv_sec - t;
  71                 if (diff < 90) {
  72                         snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
  73                         return timebuf;
  74                 }
  75                 /* Turn it into minutes */
  76                 diff = (diff + 30) / 60;
  77                 if (diff < 90) {
  78                         snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
  79                         return timebuf;
  80                 }
  81                 /* Turn it into hours */
  82                 diff = (diff + 30) / 60;
  83                 if (diff < 36) {
  84                         snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
  85                         return timebuf;
  86                 }
  87                 /* We deal with number of days from here on */
  88                 diff = (diff + 12) / 24;
  89                 if (diff < 14) {
  90                         snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
  91                         return timebuf;
  92                 }
  93                 /* Say weeks for the past 10 weeks or so */
  94                 if (diff < 70) {
  95                         snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
  96                         return timebuf;
  97                 }
  98                 /* Say months for the past 12 months or so */
  99                 if (diff < 360) {
 100                         snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
 101                         return timebuf;
 102                 }
 103                 /* Else fall back on absolute format.. */
 104         }
 105
 106         tm = time_to_tm(time, tz);
 107         if (!tm)
 108                 return NULL;
 109         sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d %+05d",
 110                 weekday_names[tm->tm_wday],
 111                 month_names[tm->tm_mon],
 112                 tm->tm_mday,
 113                 tm->tm_hour, tm->tm_min, tm->tm_sec,
 114                 tm->tm_year + 1900, tz);
 115         return timebuf;
 116 }
 117
 118 const char *show_rfc2822_date(unsigned long time, int tz)
 119 {
 120         struct tm *tm;
 121         static char timebuf[200];
 122
 123         tm = time_to_tm(time, tz);
 124         if (!tm)
 125                 return NULL;
 126         sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 127                 weekday_names[tm->tm_wday], tm->tm_mday,
 128                 month_names[tm->tm_mon], tm->tm_year + 1900,
 129                 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 130         return timebuf;
 131 }
 132
 133 /*
 134  * Check these. And note how it doesn't do the summer-time conversion.
 135  *
 136  * In my world, it's always summer, and things are probably a bit off
 137  * in other ways too.
 138  */
 139 static const struct {
 140         const char *name;
 141         int offset;
 142         int dst;
 143 } timezone_names[] = {
 144         { "IDLW", -12, 0, },    /* International Date Line West */
 145         { "NT",   -11, 0, },    /* Nome */
 146         { "CAT",  -10, 0, },    /* Central Alaska */
 147         { "HST",  -10, 0, },    /* Hawaii Standard */
 148         { "HDT",  -10, 1, },    /* Hawaii Daylight */
 149         { "YST",   -9, 0, },    /* Yukon Standard */
 150         { "YDT",   -9, 1, },    /* Yukon Daylight */
 151         { "PST",   -8, 0, },    /* Pacific Standard */
 152         { "PDT",   -8, 1, },    /* Pacific Daylight */
 153         { "MST",   -7, 0, },    /* Mountain Standard */
 154         { "MDT",   -7, 1, },    /* Mountain Daylight */
 155         { "CST",   -6, 0, },    /* Central Standard */
 156         { "CDT",   -6, 1, },    /* Central Daylight */
 157         { "EST",   -5, 0, },    /* Eastern Standard */
 158         { "EDT",   -5, 1, },    /* Eastern Daylight */
 159         { "AST",   -3, 0, },    /* Atlantic Standard */
 160         { "ADT",   -3, 1, },    /* Atlantic Daylight */
 161         { "WAT",   -1, 0, },    /* West Africa */
 162
 163         { "GMT",    0, 0, },    /* Greenwich Mean */
 164         { "UTC",    0, 0, },    /* Universal (Coordinated) */
 165
 166         { "WET",    0, 0, },    /* Western European */
 167         { "BST",    0, 1, },    /* British Summer */
 168         { "CET",   +1, 0, },    /* Central European */
 169         { "MET",   +1, 0, },    /* Middle European */
 170         { "MEWT",  +1, 0, },    /* Middle European Winter */
 171         { "MEST",  +1, 1, },    /* Middle European Summer */
 172         { "CEST",  +1, 1, },    /* Central European Summer */
 173         { "MESZ",  +1, 1, },    /* Middle European Summer */
 174         { "FWT",   +1, 0, },    /* French Winter */
 175         { "FST",   +1, 1, },    /* French Summer */
 176         { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 177         { "EEST",  +2, 1, },    /* Eastern European Daylight */
 178         { "WAST",  +7, 0, },    /* West Australian Standard */
 179         { "WADT",  +7, 1, },    /* West Australian Daylight */
 180         { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 181         { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 182         { "EAST", +10, 0, },    /* Eastern Australian Standard */
 183         { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 184         { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 185         { "NZT",  +11, 0, },    /* New Zealand */
 186         { "NZST", +11, 0, },    /* New Zealand Standard */
 187         { "NZDT", +11, 1, },    /* New Zealand Daylight */
 188         { "IDLE", +12, 0, },    /* International Date Line East */
 189 };
 190
 191 static int match_string(const char *date, const char *str)
 192 {
 193         int i = 0;
 194
 195         for (i = 0; *date; date++, str++, i++) {
 196                 if (*date == *str)
 197                         continue;
 198                 if (toupper(*date) == toupper(*str))
 199                         continue;
 200                 if (!isalnum(*date))
 201                         break;
 202                 return 0;
 203         }
 204         return i;
 205 }
 206
 207 static int skip_alpha(const char *date)
 208 {
 209         int i = 0;
 210         do {
 211                 i++;
 212         } while (isalpha(date[i]));
 213         return i;
 214 }
 215
 216 /*
 217 * Parse month, weekday, or timezone name
 218 */
 219 static int match_alpha(const char *date, struct tm *tm, int *offset)
 220 {
 221         int i;
 222
 223         for (i = 0; i < 12; i++) {
 224                 int match = match_string(date, month_names[i]);
 225                 if (match >= 3) {
 226                         tm->tm_mon = i;
 227                         return match;
 228                 }
 229         }
 230
 231         for (i = 0; i < 7; i++) {
 232                 int match = match_string(date, weekday_names[i]);
 233                 if (match >= 3) {
 234                         tm->tm_wday = i;
 235                         return match;
 236                 }
 237         }
 238
 239         for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 240                 int match = match_string(date, timezone_names[i].name);
 241                 if (match >= 3) {
 242                         int off = timezone_names[i].offset;
 243
 244                         /* This is bogus, but we like summer */
 245                         off += timezone_names[i].dst;
 246
 247                         /* Only use the tz name offset if we don't have anything better */
 248                         if (*offset == -1)
 249                                 *offset = 60*off;
 250
 251                         return match;
 252                 }
 253         }
 254
 255         if (match_string(date, "PM") == 2) {
 256                 tm->tm_hour = (tm->tm_hour % 12) + 12;
 257                 return 2;
 258         }
 259
 260         if (match_string(date, "AM") == 2) {
 261                 tm->tm_hour = (tm->tm_hour % 12) + 0;
 262                 return 2;
 263         }
 264
 265         /* BAD CRAP */
 266         return skip_alpha(date);
 267 }
 268
 269 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 270 {
 271         if (month > 0 && month < 13 && day > 0 && day < 32) {
 272                 struct tm check = *tm;
 273                 struct tm *r = (now_tm ? &check : tm);
 274                 time_t specified;
 275
 276                 r->tm_mon = month - 1;
 277                 r->tm_mday = day;
 278                 if (year == -1) {
 279                         if (!now_tm)
 280                                 return 1;
 281                         r->tm_year = now_tm->tm_year;
 282                 }
 283                 else if (year >= 1970 && year < 2100)
 284                         r->tm_year = year - 1900;
 285                 else if (year > 70 && year < 100)
 286                         r->tm_year = year;
 287                 else if (year < 38)
 288                         r->tm_year = year + 100;
 289                 else
 290                         return 0;
 291                 if (!now_tm)
 292                         return 1;
 293
 294                 specified = my_mktime(r);
 295
 296                 /* Be it commit time or author time, it does not make
 297                  * sense to specify timestamp way into the future.  Make
 298                  * sure it is not later than ten days from now...
 299                  */
 300                 if (now + 10*24*3600 < specified)
 301                         return 0;
 302                 tm->tm_mon = r->tm_mon;
 303                 tm->tm_mday = r->tm_mday;
 304                 if (year != -1)
 305                         tm->tm_year = r->tm_year;
 306                 return 1;
 307         }
 308         return 0;
 309 }
 310
 311 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 312 {
 313         time_t now;
 314         struct tm now_tm;
 315         struct tm *refuse_future;
 316         long num2, num3;
 317
 318         num2 = strtol(end+1, &end, 10);
 319         num3 = -1;
 320         if (*end == c && isdigit(end[1]))
 321                 num3 = strtol(end+1, &end, 10);
 322
 323         /* Time? Date? */
 324         switch (c) {
 325         case ':':
 326                 if (num3 < 0)
 327                         num3 = 0;
 328                 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 329                         tm->tm_hour = num;
 330                         tm->tm_min = num2;
 331                         tm->tm_sec = num3;
 332                         break;
 333                 }
 334                 return 0;
 335
 336         case '-':
 337         case '/':
 338         case '.':
 339                 now = time(NULL);
 340                 refuse_future = NULL;
 341                 if (gmtime_r(&now, &now_tm))
 342                         refuse_future = &now_tm;
 343
 344                 if (num > 70) {
 345                         /* yyyy-mm-dd? */
 346                         if (is_date(num, num2, num3, refuse_future, now, tm))
 347                                 break;
 348                         /* yyyy-dd-mm? */
 349                         if (is_date(num, num3, num2, refuse_future, now, tm))
 350                                 break;
 351                 }
 352                 /* Our eastern European friends say dd.mm.yy[yy]
 353                  * is the norm there, so giving precedence to
 354                  * mm/dd/yy[yy] form only when separator is not '.'
 355                  */
 356                 if (c != '.' &&
 357                     is_date(num3, num, num2, refuse_future, now, tm))
 358                         break;
 359                 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 360                 if (is_date(num3, num2, num, refuse_future, now, tm))
 361                         break;
 362                 /* Funny European mm.dd.yy */
 363                 if (c == '.' &&
 364                     is_date(num3, num, num2, refuse_future, now, tm))
 365                         break;
 366                 return 0;
 367         }
 368         return end - date;
 369 }
 370
 371 /*
 372  * We've seen a digit. Time? Year? Date?
 373  */
 374 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 375 {
 376         int n;
 377         char *end;
 378         unsigned long num;
 379
 380         num = strtoul(date, &end, 10);
 381
 382         /*
 383          * Seconds since 1970? We trigger on that for anything after Jan 1, 2000
 384          */
 385         if (num > 946684800) {
 386                 time_t time = num;
 387                 if (gmtime_r(&time, tm)) {
 388                         *tm_gmt = 1;
 389                         return end - date;
 390                 }
 391         }
 392
 393         /*
 394          * Check for special formats: num[-.:/]num[same]num
 395          */
 396         switch (*end) {
 397         case ':':
 398         case '.':
 399         case '/':
 400         case '-':
 401                 if (isdigit(end[1])) {
 402                         int match = match_multi_number(num, *end, date, end, tm);
 403                         if (match)
 404                                 return match;
 405                 }
 406         }
 407
 408         /*
 409          * None of the special formats? Try to guess what
 410          * the number meant. We use the number of digits
 411          * to make a more educated guess..
 412          */
 413         n = 0;
 414         do {
 415                 n++;
 416         } while (isdigit(date[n]));
 417
 418         /* Four-digit year or a timezone? */
 419         if (n == 4) {
 420                 if (num <= 1400 && *offset == -1) {
 421                         unsigned int minutes = num % 100;
 422                         unsigned int hours = num / 100;
 423                         *offset = hours*60 + minutes;
 424                 } else if (num > 1900 && num < 2100)
 425                         tm->tm_year = num - 1900;
 426                 return n;
 427         }
 428
 429         /*
 430          * NOTE! We will give precedence to day-of-month over month or
 431          * year numbers in the 1-12 range. So 05 is always "mday 5",
 432          * unless we already have a mday..
 433          *
 434          * IOW, 01 Apr 05 parses as "April 1st, 2005".
 435          */
 436         if (num > 0 && num < 32 && tm->tm_mday < 0) {
 437                 tm->tm_mday = num;
 438                 return n;
 439         }
 440
 441         /* Two-digit year? */
 442         if (n == 2 && tm->tm_year < 0) {
 443                 if (num < 10 && tm->tm_mday >= 0) {
 444                         tm->tm_year = num + 100;
 445                         return n;
 446                 }
 447                 if (num >= 70) {
 448                         tm->tm_year = num;
 449                         return n;
 450                 }
 451         }
 452
 453         if (num > 0 && num < 32) {
 454                 tm->tm_mday = num;
 455         } else if (num > 1900) {
 456                 tm->tm_year = num - 1900;
 457         } else if (num > 70) {
 458                 tm->tm_year = num;
 459         } else if (num > 0 && num < 13) {
 460                 tm->tm_mon = num-1;
 461         }
 462
 463         return n;
 464 }
 465
 466 static int match_tz(const char *date, int *offp)
 467 {
 468         char *end;
 469         int offset = strtoul(date+1, &end, 10);
 470         int min, hour;
 471         int n = end - date - 1;
 472
 473         min = offset % 100;
 474         hour = offset / 100;
 475
 476         /*
 477          * Don't accept any random crap.. At least 3 digits, and
 478          * a valid minute. We might want to check that the minutes
 479          * are divisible by 30 or something too.
 480          */
 481         if (min < 60 && n > 2) {
 482                 offset = hour*60+min;
 483                 if (*date == '-')
 484                         offset = -offset;
 485
 486                 *offp = offset;
 487         }
 488         return end - date;
 489 }
 490
 491 static int date_string(unsigned long date, int offset, char *buf, int len)
 492 {
 493         int sign = '+';
 494
 495         if (offset < 0) {
 496                 offset = -offset;
 497                 sign = '-';
 498         }
 499         return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 500 }
 501
 502 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 503    (i.e. English) day/month names, and it doesn't work correctly with %z. */
 504 int parse_date(const char *date, char *result, int maxlen)
 505 {
 506         struct tm tm;
 507         int offset, tm_gmt;
 508         time_t then;
 509
 510         memset(&tm, 0, sizeof(tm));
 511         tm.tm_year = -1;
 512         tm.tm_mon = -1;
 513         tm.tm_mday = -1;
 514         tm.tm_isdst = -1;
 515         offset = -1;
 516         tm_gmt = 0;
 517
 518         for (;;) {
 519                 int match = 0;
 520                 unsigned char c = *date;
 521
 522                 /* Stop at end of string or newline */
 523                 if (!c || c == '\n')
 524                         break;
 525
 526                 if (isalpha(c))
 527                         match = match_alpha(date, &tm, &offset);
 528                 else if (isdigit(c))
 529                         match = match_digit(date, &tm, &offset, &tm_gmt);
 530                 else if ((c == '-' || c == '+') && isdigit(date[1]))
 531                         match = match_tz(date, &offset);
 532
 533                 if (!match) {
 534                         /* BAD CRAP */
 535                         match = 1;
 536                 }
 537
 538                 date += match;
 539         }
 540
 541         /* mktime uses local timezone */
 542         then = my_mktime(&tm);
 543         if (offset == -1)
 544                 offset = (then - mktime(&tm)) / 60;
 545
 546         if (then == -1)
 547                 return -1;
 548
 549         if (!tm_gmt)
 550                 then -= offset * 60;
 551         return date_string(then, offset, result, maxlen);
 552 }
 553
 554 void datestamp(char *buf, int bufsize)
 555 {
 556         time_t now;
 557         int offset;
 558
 559         time(&now);
 560
 561         offset = my_mktime(localtime(&now)) - now;
 562         offset /= 60;
 563
 564         date_string(now, offset, buf, bufsize);
 565 }
 566
 567 static void update_tm(struct tm *tm, unsigned long sec)
 568 {
 569         time_t n = mktime(tm) - sec;
 570         localtime_r(&n, tm);
 571 }
 572
 573 static void date_yesterday(struct tm *tm, int *num)
 574 {
 575         update_tm(tm, 24*60*60);
 576 }
 577
 578 static void date_time(struct tm *tm, int hour)
 579 {
 580         if (tm->tm_hour < hour)
 581                 date_yesterday(tm, NULL);
 582         tm->tm_hour = hour;
 583         tm->tm_min = 0;
 584         tm->tm_sec = 0;
 585 }
 586
 587 static void date_midnight(struct tm *tm, int *num)
 588 {
 589         date_time(tm, 0);
 590 }
 591
 592 static void date_noon(struct tm *tm, int *num)
 593 {
 594         date_time(tm, 12);
 595 }
 596
 597 static void date_tea(struct tm *tm, int *num)
 598 {
 599         date_time(tm, 17);
 600 }
 601
 602 static void date_pm(struct tm *tm, int *num)
 603 {
 604         int hour, n = *num;
 605         *num = 0;
 606
 607         hour = tm->tm_hour;
 608         if (n) {
 609                 hour = n;
 610                 tm->tm_min = 0;
 611                 tm->tm_sec = 0;
 612         }
 613         tm->tm_hour = (hour % 12) + 12;
 614 }
 615
 616 static void date_am(struct tm *tm, int *num)
 617 {
 618         int hour, n = *num;
 619         *num = 0;
 620
 621         hour = tm->tm_hour;
 622         if (n) {
 623                 hour = n;
 624                 tm->tm_min = 0;
 625                 tm->tm_sec = 0;
 626         }
 627         tm->tm_hour = (hour % 12);
 628 }
 629
 630 static const struct special {
 631         const char *name;
 632         void (*fn)(struct tm *, int *);
 633 } special[] = {
 634         { "yesterday", date_yesterday },
 635         { "noon", date_noon },
 636         { "midnight", date_midnight },
 637         { "tea", date_tea },
 638         { "PM", date_pm },
 639         { "AM", date_am },
 640         { NULL }
 641 };
 642
 643 static const char *number_name[] = {
 644         "zero", "one", "two", "three", "four",
 645         "five", "six", "seven", "eight", "nine", "ten",
 646 };
 647
 648 static const struct typelen {
 649         const char *type;
 650         int length;
 651 } typelen[] = {
 652         { "seconds", 1 },
 653         { "minutes", 60 },
 654         { "hours", 60*60 },
 655         { "days", 24*60*60 },
 656         { "weeks", 7*24*60*60 },
 657         { NULL }
 658 };
 659
 660 static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
 661 {
 662         const struct typelen *tl;
 663         const struct special *s;
 664         const char *end = date;
 665         int i;
 666
 667         while (isalpha(*++end));
 668                 ;
 669
 670         for (i = 0; i < 12; i++) {
 671                 int match = match_string(date, month_names[i]);
 672                 if (match >= 3) {
 673                         tm->tm_mon = i;
 674                         return end;
 675                 }
 676         }
 677
 678         for (s = special; s->name; s++) {
 679                 int len = strlen(s->name);
 680                 if (match_string(date, s->name) == len) {
 681                         s->fn(tm, num);
 682                         return end;
 683                 }
 684         }
 685
 686         if (!*num) {
 687                 for (i = 1; i < 11; i++) {
 688                         int len = strlen(number_name[i]);
 689                         if (match_string(date, number_name[i]) == len) {
 690                                 *num = i;
 691                                 return end;
 692                         }
 693                 }
 694                 if (match_string(date, "last") == 4)
 695                         *num = 1;
 696                 return end;
 697         }
 698
 699         tl = typelen;
 700         while (tl->type) {
 701                 int len = strlen(tl->type);
 702                 if (match_string(date, tl->type) >= len-1) {
 703                         update_tm(tm, tl->length * *num);
 704                         *num = 0;
 705                         return end;
 706                 }
 707                 tl++;
 708         }
 709
 710         for (i = 0; i < 7; i++) {
 711                 int match = match_string(date, weekday_names[i]);
 712                 if (match >= 3) {
 713                         int diff, n = *num -1;
 714                         *num = 0;
 715
 716                         diff = tm->tm_wday - i;
 717                         if (diff <= 0)
 718                                 n++;
 719                         diff += 7*n;
 720
 721                         update_tm(tm, diff * 24 * 60 * 60);
 722                         return end;
 723                 }
 724         }
 725
 726         if (match_string(date, "months") >= 5) {
 727                 int n = tm->tm_mon - *num;
 728                 *num = 0;
 729                 while (n < 0) {
 730                         n += 12;
 731                         tm->tm_year--;
 732                 }
 733                 tm->tm_mon = n;
 734                 return end;
 735         }
 736
 737         if (match_string(date, "years") >= 4) {
 738                 tm->tm_year -= *num;
 739                 *num = 0;
 740                 return end;
 741         }
 742
 743         return end;
 744 }
 745
 746 static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 747 {
 748         char *end;
 749         unsigned long number = strtoul(date, &end, 10);
 750
 751         switch (*end) {
 752         case ':':
 753         case '.':
 754         case '/':
 755         case '-':
 756                 if (isdigit(end[1])) {
 757                         int match = match_multi_number(number, *end, date, end, tm);
 758                         if (match)
 759                                 return date + match;
 760                 }
 761         }
 762
 763         *num = number;
 764         return end;
 765 }
 766
 767 unsigned long approxidate(const char *date)
 768 {
 769         int number = 0;
 770         struct tm tm, now;
 771         struct timeval tv;
 772         char buffer[50];
 773
 774         if (parse_date(date, buffer, sizeof(buffer)) > 0)
 775                 return strtoul(buffer, NULL, 10);
 776
 777         gettimeofday(&tv, NULL);
 778         localtime_r(&tv.tv_sec, &tm);
 779         now = tm;
 780         for (;;) {
 781                 unsigned char c = *date;
 782                 if (!c)
 783                         break;
 784                 date++;
 785                 if (isdigit(c)) {
 786                         date = approxidate_digit(date-1, &tm, &number);
 787                         continue;
 788                 }
 789                 if (isalpha(c))
 790                         date = approxidate_alpha(date-1, &tm, &number);
 791         }
 792         if (number > 0 && number < 32)
 793                 tm.tm_mday = number;
 794         if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
 795                 tm.tm_year--;
 796         return mktime(&tm);
 797 }