date.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6
   7 #include <time.h>
   8 #include <sys/time.h>
   9
  10 #include "cache.h"
  11
  12 static time_t my_mktime(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         return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
  28                 tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
  29 }
  30
  31 static const char *month_names[] = {
  32         "January", "February", "March", "April", "May", "June",
  33         "July", "August", "September", "October", "November", "December"
  34 };
  35
  36 static const char *weekday_names[] = {
  37         "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  38 };
  39
  40 static time_t gm_time_t(unsigned long time, int tz)
  41 {
  42         int minutes;
  43
  44         minutes = tz < 0 ? -tz : tz;
  45         minutes = (minutes / 100)*60 + (minutes % 100);
  46         minutes = tz < 0 ? -minutes : minutes;
  47         return time + minutes * 60;
  48 }
  49
  50 /*
  51  * The "tz" thing is passed in as this strange "decimal parse of tz"
  52  * thing, which means that tz -0100 is passed in as the integer -100,
  53  * even though it means "sixty minutes off"
  54  */
  55 static struct tm *time_to_tm(unsigned long time, int tz)
  56 {
  57         time_t t = gm_time_t(time, tz);
  58         return gmtime(&t);
  59 }
  60
  61 const char *show_date(unsigned long time, int tz, int relative)
  62 {
  63         struct tm *tm;
  64         static char timebuf[200];
  65
  66         if (relative) {
  67                 unsigned long diff;
  68                 time_t t = gm_time_t(time, tz);
  69                 struct timeval now;
  70                 gettimeofday(&now, NULL);
  71                 if (now.tv_sec < t)
  72                         return "in the future";
  73                 diff = now.tv_sec - t;
  74                 if (diff < 90) {
  75                         snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
  76                         return timebuf;
  77                 }
  78                 /* Turn it into minutes */
  79                 diff = (diff + 30) / 60;
  80                 if (diff < 90) {
  81                         snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
  82                         return timebuf;
  83                 }
  84                 /* Turn it into hours */
  85                 diff = (diff + 30) / 60;
  86                 if (diff < 36) {
  87                         snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
  88                         return timebuf;
  89                 }
  90                 /* We deal with number of days from here on */
  91                 diff = (diff + 12) / 24;
  92                 if (diff < 14) {
  93                         snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
  94                         return timebuf;
  95                 }
  96                 /* Say weeks for the past 10 weeks or so */
  97                 if (diff < 70) {
  98                         snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
  99                         return timebuf;
 100                 }
 101                 /* Say months for the past 12 months or so */
 102                 if (diff < 360) {
 103                         snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
 104                         return timebuf;
 105                 }
 106                 /* Else fall back on absolute format.. */
 107         }
 108
 109         tm = time_to_tm(time, tz);
 110         if (!tm)
 111                 return NULL;
 112         sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d %+05d",
 113                 weekday_names[tm->tm_wday],
 114                 month_names[tm->tm_mon],
 115                 tm->tm_mday,
 116                 tm->tm_hour, tm->tm_min, tm->tm_sec,
 117                 tm->tm_year + 1900, tz);
 118         return timebuf;
 119 }
 120
 121 const char *show_rfc2822_date(unsigned long time, int tz)
 122 {
 123         struct tm *tm;
 124         static char timebuf[200];
 125
 126         tm = time_to_tm(time, tz);
 127         if (!tm)
 128                 return NULL;
 129         sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 130                 weekday_names[tm->tm_wday], tm->tm_mday,
 131                 month_names[tm->tm_mon], tm->tm_year + 1900,
 132                 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 133         return timebuf;
 134 }
 135
 136 /*
 137  * Check these. And note how it doesn't do the summer-time conversion.
 138  *
 139  * In my world, it's always summer, and things are probably a bit off
 140  * in other ways too.
 141  */
 142 static const struct {
 143         const char *name;
 144         int offset;
 145         int dst;
 146 } timezone_names[] = {
 147         { "IDLW", -12, 0, },    /* International Date Line West */
 148         { "NT",   -11, 0, },    /* Nome */
 149         { "CAT",  -10, 0, },    /* Central Alaska */
 150         { "HST",  -10, 0, },    /* Hawaii Standard */
 151         { "HDT",  -10, 1, },    /* Hawaii Daylight */
 152         { "YST",   -9, 0, },    /* Yukon Standard */
 153         { "YDT",   -9, 1, },    /* Yukon Daylight */
 154         { "PST",   -8, 0, },    /* Pacific Standard */
 155         { "PDT",   -8, 1, },    /* Pacific Daylight */
 156         { "MST",   -7, 0, },    /* Mountain Standard */
 157         { "MDT",   -7, 1, },    /* Mountain Daylight */
 158         { "CST",   -6, 0, },    /* Central Standard */
 159         { "CDT",   -6, 1, },    /* Central Daylight */
 160         { "EST",   -5, 0, },    /* Eastern Standard */
 161         { "EDT",   -5, 1, },    /* Eastern Daylight */
 162         { "AST",   -3, 0, },    /* Atlantic Standard */
 163         { "ADT",   -3, 1, },    /* Atlantic Daylight */
 164         { "WAT",   -1, 0, },    /* West Africa */
 165
 166         { "GMT",    0, 0, },    /* Greenwich Mean */
 167         { "UTC",    0, 0, },    /* Universal (Coordinated) */
 168
 169         { "WET",    0, 0, },    /* Western European */
 170         { "BST",    0, 1, },    /* British Summer */
 171         { "CET",   +1, 0, },    /* Central European */
 172         { "MET",   +1, 0, },    /* Middle European */
 173         { "MEWT",  +1, 0, },    /* Middle European Winter */
 174         { "MEST",  +1, 1, },    /* Middle European Summer */
 175         { "CEST",  +1, 1, },    /* Central European Summer */
 176         { "MESZ",  +1, 1, },    /* Middle European Summer */
 177         { "FWT",   +1, 0, },    /* French Winter */
 178         { "FST",   +1, 1, },    /* French Summer */
 179         { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 180         { "EEST",  +2, 1, },    /* Eastern European Daylight */
 181         { "WAST",  +7, 0, },    /* West Australian Standard */
 182         { "WADT",  +7, 1, },    /* West Australian Daylight */
 183         { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 184         { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 185         { "EAST", +10, 0, },    /* Eastern Australian Standard */
 186         { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 187         { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 188         { "NZT",  +11, 0, },    /* New Zealand */
 189         { "NZST", +11, 0, },    /* New Zealand Standard */
 190         { "NZDT", +11, 1, },    /* New Zealand Daylight */
 191         { "IDLE", +12, 0, },    /* International Date Line East */
 192 };
 193
 194 static int match_string(const char *date, const char *str)
 195 {
 196         int i = 0;
 197
 198         for (i = 0; *date; date++, str++, i++) {
 199                 if (*date == *str)
 200                         continue;
 201                 if (toupper(*date) == toupper(*str))
 202                         continue;
 203                 if (!isalnum(*date))
 204                         break;
 205                 return 0;
 206         }
 207         return i;
 208 }
 209
 210 static int skip_alpha(const char *date)
 211 {
 212         int i = 0;
 213         do {
 214                 i++;
 215         } while (isalpha(date[i]));
 216         return i;
 217 }
 218
 219 /*
 220 * Parse month, weekday, or timezone name
 221 */
 222 static int match_alpha(const char *date, struct tm *tm, int *offset)
 223 {
 224         int i;
 225
 226         for (i = 0; i < 12; i++) {
 227                 int match = match_string(date, month_names[i]);
 228                 if (match >= 3) {
 229                         tm->tm_mon = i;
 230                         return match;
 231                 }
 232         }
 233
 234         for (i = 0; i < 7; i++) {
 235                 int match = match_string(date, weekday_names[i]);
 236                 if (match >= 3) {
 237                         tm->tm_wday = i;
 238                         return match;
 239                 }
 240         }
 241
 242         for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 243                 int match = match_string(date, timezone_names[i].name);
 244                 if (match >= 3) {
 245                         int off = timezone_names[i].offset;
 246
 247                         /* This is bogus, but we like summer */
 248                         off += timezone_names[i].dst;
 249
 250                         /* Only use the tz name offset if we don't have anything better */
 251                         if (*offset == -1)
 252                                 *offset = 60*off;
 253
 254                         return match;
 255                 }
 256         }
 257
 258         if (match_string(date, "PM") == 2) {
 259                 tm->tm_hour = (tm->tm_hour % 12) + 12;
 260                 return 2;
 261         }
 262
 263         if (match_string(date, "AM") == 2) {
 264                 tm->tm_hour = (tm->tm_hour % 12) + 0;
 265                 return 2;
 266         }
 267
 268         /* BAD CRAP */
 269         return skip_alpha(date);
 270 }
 271
 272 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 273 {
 274         if (month > 0 && month < 13 && day > 0 && day < 32) {
 275                 struct tm check = *tm;
 276                 struct tm *r = (now_tm ? &check : tm);
 277                 time_t specified;
 278
 279                 r->tm_mon = month - 1;
 280                 r->tm_mday = day;
 281                 if (year == -1) {
 282                         if (!now_tm)
 283                                 return 1;
 284                         r->tm_year = now_tm->tm_year;
 285                 }
 286                 else if (year >= 1970 && year < 2100)
 287                         r->tm_year = year - 1900;
 288                 else if (year > 70 && year < 100)
 289                         r->tm_year = year;
 290                 else if (year < 38)
 291                         r->tm_year = year + 100;
 292                 else
 293                         return 0;
 294                 if (!now_tm)
 295                         return 1;
 296
 297                 specified = my_mktime(r);
 298
 299                 /* Be it commit time or author time, it does not make
 300                  * sense to specify timestamp way into the future.  Make
 301                  * sure it is not later than ten days from now...
 302                  */
 303                 if (now + 10*24*3600 < specified)
 304                         return 0;
 305                 tm->tm_mon = r->tm_mon;
 306                 tm->tm_mday = r->tm_mday;
 307                 if (year != -1)
 308                         tm->tm_year = r->tm_year;
 309                 return 1;
 310         }
 311         return 0;
 312 }
 313
 314 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 315 {
 316         time_t now;
 317         struct tm now_tm;
 318         struct tm *refuse_future;
 319         long num2, num3;
 320
 321         num2 = strtol(end+1, &end, 10);
 322         num3 = -1;
 323         if (*end == c && isdigit(end[1]))
 324                 num3 = strtol(end+1, &end, 10);
 325
 326         /* Time? Date? */
 327         switch (c) {
 328         case ':':
 329                 if (num3 < 0)
 330                         num3 = 0;
 331                 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 332                         tm->tm_hour = num;
 333                         tm->tm_min = num2;
 334                         tm->tm_sec = num3;
 335                         break;
 336                 }
 337                 return 0;
 338
 339         case '-':
 340         case '/':
 341         case '.':
 342                 now = time(NULL);
 343                 refuse_future = NULL;
 344                 if (gmtime_r(&now, &now_tm))
 345                         refuse_future = &now_tm;
 346
 347                 if (num > 70) {
 348                         /* yyyy-mm-dd? */
 349                         if (is_date(num, num2, num3, refuse_future, now, tm))
 350                                 break;
 351                         /* yyyy-dd-mm? */
 352                         if (is_date(num, num3, num2, refuse_future, now, tm))
 353                                 break;
 354                 }
 355                 /* Our eastern European friends say dd.mm.yy[yy]
 356                  * is the norm there, so giving precedence to
 357                  * mm/dd/yy[yy] form only when separator is not '.'
 358                  */
 359                 if (c != '.' &&
 360                     is_date(num3, num, num2, refuse_future, now, tm))
 361                         break;
 362                 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 363                 if (is_date(num3, num2, num, refuse_future, now, tm))
 364                         break;
 365                 /* Funny European mm.dd.yy */
 366                 if (c == '.' &&
 367                     is_date(num3, num, num2, refuse_future, now, tm))
 368                         break;
 369                 return 0;
 370         }
 371         return end - date;
 372 }
 373
 374 /*
 375  * We've seen a digit. Time? Year? Date?
 376  */
 377 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 378 {
 379         int n;
 380         char *end;
 381         unsigned long num;
 382
 383         num = strtoul(date, &end, 10);
 384
 385         /*
 386          * Seconds since 1970? We trigger on that for anything after Jan 1, 2000
 387          */
 388         if (num > 946684800) {
 389                 time_t time = num;
 390                 if (gmtime_r(&time, tm)) {
 391                         *tm_gmt = 1;
 392                         return end - date;
 393                 }
 394         }
 395
 396         /*
 397          * Check for special formats: num[-.:/]num[same]num
 398          */
 399         switch (*end) {
 400         case ':':
 401         case '.':
 402         case '/':
 403         case '-':
 404                 if (isdigit(end[1])) {
 405                         int match = match_multi_number(num, *end, date, end, tm);
 406                         if (match)
 407                                 return match;
 408                 }
 409         }
 410
 411         /*
 412          * None of the special formats? Try to guess what
 413          * the number meant. We use the number of digits
 414          * to make a more educated guess..
 415          */
 416         n = 0;
 417         do {
 418                 n++;
 419         } while (isdigit(date[n]));
 420
 421         /* Four-digit year or a timezone? */
 422         if (n == 4) {
 423                 if (num <= 1400 && *offset == -1) {
 424                         unsigned int minutes = num % 100;
 425                         unsigned int hours = num / 100;
 426                         *offset = hours*60 + minutes;
 427                 } else if (num > 1900 && num < 2100)
 428                         tm->tm_year = num - 1900;
 429                 return n;
 430         }
 431
 432         /*
 433          * NOTE! We will give precedence to day-of-month over month or
 434          * year numbers in the 1-12 range. So 05 is always "mday 5",
 435          * unless we already have a mday..
 436          *
 437          * IOW, 01 Apr 05 parses as "April 1st, 2005".
 438          */
 439         if (num > 0 && num < 32 && tm->tm_mday < 0) {
 440                 tm->tm_mday = num;
 441                 return n;
 442         }
 443
 444         /* Two-digit year? */
 445         if (n == 2 && tm->tm_year < 0) {
 446                 if (num < 10 && tm->tm_mday >= 0) {
 447                         tm->tm_year = num + 100;
 448                         return n;
 449                 }
 450                 if (num >= 70) {
 451                         tm->tm_year = num;
 452                         return n;
 453                 }
 454         }
 455
 456         if (num > 0 && num < 32) {
 457                 tm->tm_mday = num;
 458         } else if (num > 1900) {
 459                 tm->tm_year = num - 1900;
 460         } else if (num > 70) {
 461                 tm->tm_year = num;
 462         } else if (num > 0 && num < 13) {
 463                 tm->tm_mon = num-1;
 464         }
 465
 466         return n;
 467 }
 468
 469 static int match_tz(const char *date, int *offp)
 470 {
 471         char *end;
 472         int offset = strtoul(date+1, &end, 10);
 473         int min, hour;
 474         int n = end - date - 1;
 475
 476         min = offset % 100;
 477         hour = offset / 100;
 478
 479         /*
 480          * Don't accept any random crap.. At least 3 digits, and
 481          * a valid minute. We might want to check that the minutes
 482          * are divisible by 30 or something too.
 483          */
 484         if (min < 60 && n > 2) {
 485                 offset = hour*60+min;
 486                 if (*date == '-')
 487                         offset = -offset;
 488
 489                 *offp = offset;
 490         }
 491         return end - date;
 492 }
 493
 494 static int date_string(unsigned long date, int offset, char *buf, int len)
 495 {
 496         int sign = '+';
 497
 498         if (offset < 0) {
 499                 offset = -offset;
 500                 sign = '-';
 501         }
 502         return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 503 }
 504
 505 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 506    (i.e. English) day/month names, and it doesn't work correctly with %z. */
 507 int parse_date(const char *date, char *result, int maxlen)
 508 {
 509         struct tm tm;
 510         int offset, tm_gmt;
 511         time_t then;
 512
 513         memset(&tm, 0, sizeof(tm));
 514         tm.tm_year = -1;
 515         tm.tm_mon = -1;
 516         tm.tm_mday = -1;
 517         tm.tm_isdst = -1;
 518         offset = -1;
 519         tm_gmt = 0;
 520
 521         for (;;) {
 522                 int match = 0;
 523                 unsigned char c = *date;
 524
 525                 /* Stop at end of string or newline */
 526                 if (!c || c == '\n')
 527                         break;
 528
 529                 if (isalpha(c))
 530                         match = match_alpha(date, &tm, &offset);
 531                 else if (isdigit(c))
 532                         match = match_digit(date, &tm, &offset, &tm_gmt);
 533                 else if ((c == '-' || c == '+') && isdigit(date[1]))
 534                         match = match_tz(date, &offset);
 535
 536                 if (!match) {
 537                         /* BAD CRAP */
 538                         match = 1;
 539                 }
 540
 541                 date += match;
 542         }
 543
 544         /* mktime uses local timezone */
 545         then = my_mktime(&tm);
 546         if (offset == -1)
 547                 offset = (then - mktime(&tm)) / 60;
 548
 549         if (then == -1)
 550                 return -1;
 551
 552         if (!tm_gmt)
 553                 then -= offset * 60;
 554         return date_string(then, offset, result, maxlen);
 555 }
 556
 557 void datestamp(char *buf, int bufsize)
 558 {
 559         time_t now;
 560         int offset;
 561
 562         time(&now);
 563
 564         offset = my_mktime(localtime(&now)) - now;
 565         offset /= 60;
 566
 567         date_string(now, offset, buf, bufsize);
 568 }
 569
 570 static void update_tm(struct tm *tm, unsigned long sec)
 571 {
 572         time_t n = mktime(tm) - sec;
 573         localtime_r(&n, tm);
 574 }
 575
 576 static void date_yesterday(struct tm *tm, int *num)
 577 {
 578         update_tm(tm, 24*60*60);
 579 }
 580
 581 static void date_time(struct tm *tm, int hour)
 582 {
 583         if (tm->tm_hour < hour)
 584                 date_yesterday(tm, NULL);
 585         tm->tm_hour = hour;
 586         tm->tm_min = 0;
 587         tm->tm_sec = 0;
 588 }
 589
 590 static void date_midnight(struct tm *tm, int *num)
 591 {
 592         date_time(tm, 0);
 593 }
 594
 595 static void date_noon(struct tm *tm, int *num)
 596 {
 597         date_time(tm, 12);
 598 }
 599
 600 static void date_tea(struct tm *tm, int *num)
 601 {
 602         date_time(tm, 17);
 603 }
 604
 605 static void date_pm(struct tm *tm, int *num)
 606 {
 607         int hour, n = *num;
 608         *num = 0;
 609
 610         hour = tm->tm_hour;
 611         if (n) {
 612                 hour = n;
 613                 tm->tm_min = 0;
 614                 tm->tm_sec = 0;
 615         }
 616         tm->tm_hour = (hour % 12) + 12;
 617 }
 618
 619 static void date_am(struct tm *tm, int *num)
 620 {
 621         int hour, n = *num;
 622         *num = 0;
 623
 624         hour = tm->tm_hour;
 625         if (n) {
 626                 hour = n;
 627                 tm->tm_min = 0;
 628                 tm->tm_sec = 0;
 629         }
 630         tm->tm_hour = (hour % 12);
 631 }
 632
 633 static const struct special {
 634         const char *name;
 635         void (*fn)(struct tm *, int *);
 636 } special[] = {
 637         { "yesterday", date_yesterday },
 638         { "noon", date_noon },
 639         { "midnight", date_midnight },
 640         { "tea", date_tea },
 641         { "PM", date_pm },
 642         { "AM", date_am },
 643         { NULL }
 644 };
 645
 646 static const char *number_name[] = {
 647         "zero", "one", "two", "three", "four",
 648         "five", "six", "seven", "eight", "nine", "ten",
 649 };
 650
 651 static const struct typelen {
 652         const char *type;
 653         int length;
 654 } typelen[] = {
 655         { "seconds", 1 },
 656         { "minutes", 60 },
 657         { "hours", 60*60 },
 658         { "days", 24*60*60 },
 659         { "weeks", 7*24*60*60 },
 660         { NULL }
 661 };
 662
 663 static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
 664 {
 665         const struct typelen *tl;
 666         const struct special *s;
 667         const char *end = date;
 668         int i;
 669
 670         while (isalpha(*++end));
 671                 ;
 672
 673         for (i = 0; i < 12; i++) {
 674                 int match = match_string(date, month_names[i]);
 675                 if (match >= 3) {
 676                         tm->tm_mon = i;
 677                         return end;
 678                 }
 679         }
 680
 681         for (s = special; s->name; s++) {
 682                 int len = strlen(s->name);
 683                 if (match_string(date, s->name) == len) {
 684                         s->fn(tm, num);
 685                         return end;
 686                 }
 687         }
 688
 689         if (!*num) {
 690                 for (i = 1; i < 11; i++) {
 691                         int len = strlen(number_name[i]);
 692                         if (match_string(date, number_name[i]) == len) {
 693                                 *num = i;
 694                                 return end;
 695                         }
 696                 }
 697                 if (match_string(date, "last") == 4)
 698                         *num = 1;
 699                 return end;
 700         }
 701
 702         tl = typelen;
 703         while (tl->type) {
 704                 int len = strlen(tl->type);
 705                 if (match_string(date, tl->type) >= len-1) {
 706                         update_tm(tm, tl->length * *num);
 707                         *num = 0;
 708                         return end;
 709                 }
 710                 tl++;
 711         }
 712
 713         for (i = 0; i < 7; i++) {
 714                 int match = match_string(date, weekday_names[i]);
 715                 if (match >= 3) {
 716                         int diff, n = *num -1;
 717                         *num = 0;
 718
 719                         diff = tm->tm_wday - i;
 720                         if (diff <= 0)
 721                                 n++;
 722                         diff += 7*n;
 723
 724                         update_tm(tm, diff * 24 * 60 * 60);
 725                         return end;
 726                 }
 727         }
 728
 729         if (match_string(date, "months") >= 5) {
 730                 int n = tm->tm_mon - *num;
 731                 *num = 0;
 732                 while (n < 0) {
 733                         n += 12;
 734                         tm->tm_year--;
 735                 }
 736                 tm->tm_mon = n;
 737                 return end;
 738         }
 739
 740         if (match_string(date, "years") >= 4) {
 741                 tm->tm_year -= *num;
 742                 *num = 0;
 743                 return end;
 744         }
 745
 746         return end;
 747 }
 748
 749 static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 750 {
 751         char *end;
 752         unsigned long number = strtoul(date, &end, 10);
 753
 754         switch (*end) {
 755         case ':':
 756         case '.':
 757         case '/':
 758         case '-':
 759                 if (isdigit(end[1])) {
 760                         int match = match_multi_number(number, *end, date, end, tm);
 761                         if (match)
 762                                 return date + match;
 763                 }
 764         }
 765
 766         *num = number;
 767         return end;
 768 }
 769
 770 unsigned long approxidate(const char *date)
 771 {
 772         int number = 0;
 773         struct tm tm, now;
 774         struct timeval tv;
 775         char buffer[50];
 776
 777         if (parse_date(date, buffer, sizeof(buffer)) > 0)
 778                 return strtoul(buffer, NULL, 10);
 779
 780         gettimeofday(&tv, NULL);
 781         localtime_r(&tv.tv_sec, &tm);
 782         now = tm;
 783         for (;;) {
 784                 unsigned char c = *date;
 785                 if (!c)
 786                         break;
 787                 date++;
 788                 if (isdigit(c)) {
 789                         date = approxidate_digit(date-1, &tm, &number);
 790                         continue;
 791                 }
 792                 if (isalpha(c))
 793                         date = approxidate_alpha(date-1, &tm, &number);
 794         }
 795         if (number > 0 && number < 32)
 796                 tm.tm_mday = number;
 797         if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
 798                 tm.tm_year--;
 799         return mktime(&tm);
 800 }