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 /*
  59  * What value of "tz" was in effect back then at "time" in the
  60  * local timezone?
  61  */
  62 static int local_tzoffset(unsigned long time)
  63 {
  64         time_t t, t_local;
  65         struct tm tm;
  66         int offset, eastwest;
  67
  68         t = time;
  69         localtime_r(&t, &tm);
  70         t_local = my_mktime(&tm);
  71
  72         if (t_local < t) {
  73                 eastwest = -1;
  74                 offset = t - t_local;
  75         } else {
  76                 eastwest = 1;
  77                 offset = t_local - t;
  78         }
  79         offset /= 60; /* in minutes */
  80         offset = (offset % 60) + ((offset / 60) * 100);
  81         return offset * eastwest;
  82 }
  83
  84 const char *show_date(unsigned long time, int tz, enum date_mode mode)
  85 {
  86         struct tm *tm;
  87         static char timebuf[200];
  88
  89         if (mode == DATE_RELATIVE) {
  90                 unsigned long diff;
  91                 struct timeval now;
  92                 gettimeofday(&now, NULL);
  93                 if (now.tv_sec < time)
  94                         return "in the future";
  95                 diff = now.tv_sec - time;
  96                 if (diff < 90) {
  97                         snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
  98                         return timebuf;
  99                 }
 100                 /* Turn it into minutes */
 101                 diff = (diff + 30) / 60;
 102                 if (diff < 90) {
 103                         snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
 104                         return timebuf;
 105                 }
 106                 /* Turn it into hours */
 107                 diff = (diff + 30) / 60;
 108                 if (diff < 36) {
 109                         snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
 110                         return timebuf;
 111                 }
 112                 /* We deal with number of days from here on */
 113                 diff = (diff + 12) / 24;
 114                 if (diff < 14) {
 115                         snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
 116                         return timebuf;
 117                 }
 118                 /* Say weeks for the past 10 weeks or so */
 119                 if (diff < 70) {
 120                         snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
 121                         return timebuf;
 122                 }
 123                 /* Say months for the past 12 months or so */
 124                 if (diff < 360) {
 125                         snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
 126                         return timebuf;
 127                 }
 128                 /* Else fall back on absolute format.. */
 129         }
 130
 131         if (mode == DATE_LOCAL)
 132                 tz = local_tzoffset(time);
 133
 134         tm = time_to_tm(time, tz);
 135         if (!tm)
 136                 return NULL;
 137         if (mode == DATE_SHORT)
 138                 sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
 139                                 tm->tm_mon + 1, tm->tm_mday);
 140         else
 141                 sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 142                                 weekday_names[tm->tm_wday],
 143                                 month_names[tm->tm_mon],
 144                                 tm->tm_mday,
 145                                 tm->tm_hour, tm->tm_min, tm->tm_sec,
 146                                 tm->tm_year + 1900,
 147                                 (mode == DATE_LOCAL) ? 0 : ' ',
 148                                 tz);
 149         return timebuf;
 150 }
 151
 152 const char *show_rfc2822_date(unsigned long time, int tz)
 153 {
 154         struct tm *tm;
 155         static char timebuf[200];
 156
 157         tm = time_to_tm(time, tz);
 158         if (!tm)
 159                 return NULL;
 160         sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 161                 weekday_names[tm->tm_wday], tm->tm_mday,
 162                 month_names[tm->tm_mon], tm->tm_year + 1900,
 163                 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 164         return timebuf;
 165 }
 166
 167 /*
 168  * Check these. And note how it doesn't do the summer-time conversion.
 169  *
 170  * In my world, it's always summer, and things are probably a bit off
 171  * in other ways too.
 172  */
 173 static const struct {
 174         const char *name;
 175         int offset;
 176         int dst;
 177 } timezone_names[] = {
 178         { "IDLW", -12, 0, },    /* International Date Line West */
 179         { "NT",   -11, 0, },    /* Nome */
 180         { "CAT",  -10, 0, },    /* Central Alaska */
 181         { "HST",  -10, 0, },    /* Hawaii Standard */
 182         { "HDT",  -10, 1, },    /* Hawaii Daylight */
 183         { "YST",   -9, 0, },    /* Yukon Standard */
 184         { "YDT",   -9, 1, },    /* Yukon Daylight */
 185         { "PST",   -8, 0, },    /* Pacific Standard */
 186         { "PDT",   -8, 1, },    /* Pacific Daylight */
 187         { "MST",   -7, 0, },    /* Mountain Standard */
 188         { "MDT",   -7, 1, },    /* Mountain Daylight */
 189         { "CST",   -6, 0, },    /* Central Standard */
 190         { "CDT",   -6, 1, },    /* Central Daylight */
 191         { "EST",   -5, 0, },    /* Eastern Standard */
 192         { "EDT",   -5, 1, },    /* Eastern Daylight */
 193         { "AST",   -3, 0, },    /* Atlantic Standard */
 194         { "ADT",   -3, 1, },    /* Atlantic Daylight */
 195         { "WAT",   -1, 0, },    /* West Africa */
 196
 197         { "GMT",    0, 0, },    /* Greenwich Mean */
 198         { "UTC",    0, 0, },    /* Universal (Coordinated) */
 199
 200         { "WET",    0, 0, },    /* Western European */
 201         { "BST",    0, 1, },    /* British Summer */
 202         { "CET",   +1, 0, },    /* Central European */
 203         { "MET",   +1, 0, },    /* Middle European */
 204         { "MEWT",  +1, 0, },    /* Middle European Winter */
 205         { "MEST",  +1, 1, },    /* Middle European Summer */
 206         { "CEST",  +1, 1, },    /* Central European Summer */
 207         { "MESZ",  +1, 1, },    /* Middle European Summer */
 208         { "FWT",   +1, 0, },    /* French Winter */
 209         { "FST",   +1, 1, },    /* French Summer */
 210         { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 211         { "EEST",  +2, 1, },    /* Eastern European Daylight */
 212         { "WAST",  +7, 0, },    /* West Australian Standard */
 213         { "WADT",  +7, 1, },    /* West Australian Daylight */
 214         { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 215         { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 216         { "EAST", +10, 0, },    /* Eastern Australian Standard */
 217         { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 218         { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 219         { "NZT",  +11, 0, },    /* New Zealand */
 220         { "NZST", +11, 0, },    /* New Zealand Standard */
 221         { "NZDT", +11, 1, },    /* New Zealand Daylight */
 222         { "IDLE", +12, 0, },    /* International Date Line East */
 223 };
 224
 225 static int match_string(const char *date, const char *str)
 226 {
 227         int i = 0;
 228
 229         for (i = 0; *date; date++, str++, i++) {
 230                 if (*date == *str)
 231                         continue;
 232                 if (toupper(*date) == toupper(*str))
 233                         continue;
 234                 if (!isalnum(*date))
 235                         break;
 236                 return 0;
 237         }
 238         return i;
 239 }
 240
 241 static int skip_alpha(const char *date)
 242 {
 243         int i = 0;
 244         do {
 245                 i++;
 246         } while (isalpha(date[i]));
 247         return i;
 248 }
 249
 250 /*
 251 * Parse month, weekday, or timezone name
 252 */
 253 static int match_alpha(const char *date, struct tm *tm, int *offset)
 254 {
 255         int i;
 256
 257         for (i = 0; i < 12; i++) {
 258                 int match = match_string(date, month_names[i]);
 259                 if (match >= 3) {
 260                         tm->tm_mon = i;
 261                         return match;
 262                 }
 263         }
 264
 265         for (i = 0; i < 7; i++) {
 266                 int match = match_string(date, weekday_names[i]);
 267                 if (match >= 3) {
 268                         tm->tm_wday = i;
 269                         return match;
 270                 }
 271         }
 272
 273         for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 274                 int match = match_string(date, timezone_names[i].name);
 275                 if (match >= 3) {
 276                         int off = timezone_names[i].offset;
 277
 278                         /* This is bogus, but we like summer */
 279                         off += timezone_names[i].dst;
 280
 281                         /* Only use the tz name offset if we don't have anything better */
 282                         if (*offset == -1)
 283                                 *offset = 60*off;
 284
 285                         return match;
 286                 }
 287         }
 288
 289         if (match_string(date, "PM") == 2) {
 290                 tm->tm_hour = (tm->tm_hour % 12) + 12;
 291                 return 2;
 292         }
 293
 294         if (match_string(date, "AM") == 2) {
 295                 tm->tm_hour = (tm->tm_hour % 12) + 0;
 296                 return 2;
 297         }
 298
 299         /* BAD CRAP */
 300         return skip_alpha(date);
 301 }
 302
 303 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 304 {
 305         if (month > 0 && month < 13 && day > 0 && day < 32) {
 306                 struct tm check = *tm;
 307                 struct tm *r = (now_tm ? &check : tm);
 308                 time_t specified;
 309
 310                 r->tm_mon = month - 1;
 311                 r->tm_mday = day;
 312                 if (year == -1) {
 313                         if (!now_tm)
 314                                 return 1;
 315                         r->tm_year = now_tm->tm_year;
 316                 }
 317                 else if (year >= 1970 && year < 2100)
 318                         r->tm_year = year - 1900;
 319                 else if (year > 70 && year < 100)
 320                         r->tm_year = year;
 321                 else if (year < 38)
 322                         r->tm_year = year + 100;
 323                 else
 324                         return 0;
 325                 if (!now_tm)
 326                         return 1;
 327
 328                 specified = my_mktime(r);
 329
 330                 /* Be it commit time or author time, it does not make
 331                  * sense to specify timestamp way into the future.  Make
 332                  * sure it is not later than ten days from now...
 333                  */
 334                 if (now + 10*24*3600 < specified)
 335                         return 0;
 336                 tm->tm_mon = r->tm_mon;
 337                 tm->tm_mday = r->tm_mday;
 338                 if (year != -1)
 339                         tm->tm_year = r->tm_year;
 340                 return 1;
 341         }
 342         return 0;
 343 }
 344
 345 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 346 {
 347         time_t now;
 348         struct tm now_tm;
 349         struct tm *refuse_future;
 350         long num2, num3;
 351
 352         num2 = strtol(end+1, &end, 10);
 353         num3 = -1;
 354         if (*end == c && isdigit(end[1]))
 355                 num3 = strtol(end+1, &end, 10);
 356
 357         /* Time? Date? */
 358         switch (c) {
 359         case ':':
 360                 if (num3 < 0)
 361                         num3 = 0;
 362                 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 363                         tm->tm_hour = num;
 364                         tm->tm_min = num2;
 365                         tm->tm_sec = num3;
 366                         break;
 367                 }
 368                 return 0;
 369
 370         case '-':
 371         case '/':
 372         case '.':
 373                 now = time(NULL);
 374                 refuse_future = NULL;
 375                 if (gmtime_r(&now, &now_tm))
 376                         refuse_future = &now_tm;
 377
 378                 if (num > 70) {
 379                         /* yyyy-mm-dd? */
 380                         if (is_date(num, num2, num3, refuse_future, now, tm))
 381                                 break;
 382                         /* yyyy-dd-mm? */
 383                         if (is_date(num, num3, num2, refuse_future, now, tm))
 384                                 break;
 385                 }
 386                 /* Our eastern European friends say dd.mm.yy[yy]
 387                  * is the norm there, so giving precedence to
 388                  * mm/dd/yy[yy] form only when separator is not '.'
 389                  */
 390                 if (c != '.' &&
 391                     is_date(num3, num, num2, refuse_future, now, tm))
 392                         break;
 393                 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 394                 if (is_date(num3, num2, num, refuse_future, now, tm))
 395                         break;
 396                 /* Funny European mm.dd.yy */
 397                 if (c == '.' &&
 398                     is_date(num3, num, num2, refuse_future, now, tm))
 399                         break;
 400                 return 0;
 401         }
 402         return end - date;
 403 }
 404
 405 /*
 406  * We've seen a digit. Time? Year? Date?
 407  */
 408 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 409 {
 410         int n;
 411         char *end;
 412         unsigned long num;
 413
 414         num = strtoul(date, &end, 10);
 415
 416         /*
 417          * Seconds since 1970? We trigger on that for anything after Jan 1, 2000
 418          */
 419         if (num > 946684800) {
 420                 time_t time = num;
 421                 if (gmtime_r(&time, tm)) {
 422                         *tm_gmt = 1;
 423                         return end - date;
 424                 }
 425         }
 426
 427         /*
 428          * Check for special formats: num[-.:/]num[same]num
 429          */
 430         switch (*end) {
 431         case ':':
 432         case '.':
 433         case '/':
 434         case '-':
 435                 if (isdigit(end[1])) {
 436                         int match = match_multi_number(num, *end, date, end, tm);
 437                         if (match)
 438                                 return match;
 439                 }
 440         }
 441
 442         /*
 443          * None of the special formats? Try to guess what
 444          * the number meant. We use the number of digits
 445          * to make a more educated guess..
 446          */
 447         n = 0;
 448         do {
 449                 n++;
 450         } while (isdigit(date[n]));
 451
 452         /* Four-digit year or a timezone? */
 453         if (n == 4) {
 454                 if (num <= 1400 && *offset == -1) {
 455                         unsigned int minutes = num % 100;
 456                         unsigned int hours = num / 100;
 457                         *offset = hours*60 + minutes;
 458                 } else if (num > 1900 && num < 2100)
 459                         tm->tm_year = num - 1900;
 460                 return n;
 461         }
 462
 463         /*
 464          * NOTE! We will give precedence to day-of-month over month or
 465          * year numbers in the 1-12 range. So 05 is always "mday 5",
 466          * unless we already have a mday..
 467          *
 468          * IOW, 01 Apr 05 parses as "April 1st, 2005".
 469          */
 470         if (num > 0 && num < 32 && tm->tm_mday < 0) {
 471                 tm->tm_mday = num;
 472                 return n;
 473         }
 474
 475         /* Two-digit year? */
 476         if (n == 2 && tm->tm_year < 0) {
 477                 if (num < 10 && tm->tm_mday >= 0) {
 478                         tm->tm_year = num + 100;
 479                         return n;
 480                 }
 481                 if (num >= 70) {
 482                         tm->tm_year = num;
 483                         return n;
 484                 }
 485         }
 486
 487         if (num > 0 && num < 32) {
 488                 tm->tm_mday = num;
 489         } else if (num > 1900) {
 490                 tm->tm_year = num - 1900;
 491         } else if (num > 70) {
 492                 tm->tm_year = num;
 493         } else if (num > 0 && num < 13) {
 494                 tm->tm_mon = num-1;
 495         }
 496
 497         return n;
 498 }
 499
 500 static int match_tz(const char *date, int *offp)
 501 {
 502         char *end;
 503         int offset = strtoul(date+1, &end, 10);
 504         int min, hour;
 505         int n = end - date - 1;
 506
 507         min = offset % 100;
 508         hour = offset / 100;
 509
 510         /*
 511          * Don't accept any random crap.. At least 3 digits, and
 512          * a valid minute. We might want to check that the minutes
 513          * are divisible by 30 or something too.
 514          */
 515         if (min < 60 && n > 2) {
 516                 offset = hour*60+min;
 517                 if (*date == '-')
 518                         offset = -offset;
 519
 520                 *offp = offset;
 521         }
 522         return end - date;
 523 }
 524
 525 static int date_string(unsigned long date, int offset, char *buf, int len)
 526 {
 527         int sign = '+';
 528
 529         if (offset < 0) {
 530                 offset = -offset;
 531                 sign = '-';
 532         }
 533         return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 534 }
 535
 536 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 537    (i.e. English) day/month names, and it doesn't work correctly with %z. */
 538 int parse_date(const char *date, char *result, int maxlen)
 539 {
 540         struct tm tm;
 541         int offset, tm_gmt;
 542         time_t then;
 543
 544         memset(&tm, 0, sizeof(tm));
 545         tm.tm_year = -1;
 546         tm.tm_mon = -1;
 547         tm.tm_mday = -1;
 548         tm.tm_isdst = -1;
 549         offset = -1;
 550         tm_gmt = 0;
 551
 552         for (;;) {
 553                 int match = 0;
 554                 unsigned char c = *date;
 555
 556                 /* Stop at end of string or newline */
 557                 if (!c || c == '\n')
 558                         break;
 559
 560                 if (isalpha(c))
 561                         match = match_alpha(date, &tm, &offset);
 562                 else if (isdigit(c))
 563                         match = match_digit(date, &tm, &offset, &tm_gmt);
 564                 else if ((c == '-' || c == '+') && isdigit(date[1]))
 565                         match = match_tz(date, &offset);
 566
 567                 if (!match) {
 568                         /* BAD CRAP */
 569                         match = 1;
 570                 }
 571
 572                 date += match;
 573         }
 574
 575         /* mktime uses local timezone */
 576         then = my_mktime(&tm);
 577         if (offset == -1)
 578                 offset = (then - mktime(&tm)) / 60;
 579
 580         if (then == -1)
 581                 return -1;
 582
 583         if (!tm_gmt)
 584                 then -= offset * 60;
 585         return date_string(then, offset, result, maxlen);
 586 }
 587
 588 void datestamp(char *buf, int bufsize)
 589 {
 590         time_t now;
 591         int offset;
 592
 593         time(&now);
 594
 595         offset = my_mktime(localtime(&now)) - now;
 596         offset /= 60;
 597
 598         date_string(now, offset, buf, bufsize);
 599 }
 600
 601 static void update_tm(struct tm *tm, unsigned long sec)
 602 {
 603         time_t n = mktime(tm) - sec;
 604         localtime_r(&n, tm);
 605 }
 606
 607 static void date_yesterday(struct tm *tm, int *num)
 608 {
 609         update_tm(tm, 24*60*60);
 610 }
 611
 612 static void date_time(struct tm *tm, int hour)
 613 {
 614         if (tm->tm_hour < hour)
 615                 date_yesterday(tm, NULL);
 616         tm->tm_hour = hour;
 617         tm->tm_min = 0;
 618         tm->tm_sec = 0;
 619 }
 620
 621 static void date_midnight(struct tm *tm, int *num)
 622 {
 623         date_time(tm, 0);
 624 }
 625
 626 static void date_noon(struct tm *tm, int *num)
 627 {
 628         date_time(tm, 12);
 629 }
 630
 631 static void date_tea(struct tm *tm, int *num)
 632 {
 633         date_time(tm, 17);
 634 }
 635
 636 static void date_pm(struct tm *tm, int *num)
 637 {
 638         int hour, n = *num;
 639         *num = 0;
 640
 641         hour = tm->tm_hour;
 642         if (n) {
 643                 hour = n;
 644                 tm->tm_min = 0;
 645                 tm->tm_sec = 0;
 646         }
 647         tm->tm_hour = (hour % 12) + 12;
 648 }
 649
 650 static void date_am(struct tm *tm, int *num)
 651 {
 652         int hour, n = *num;
 653         *num = 0;
 654
 655         hour = tm->tm_hour;
 656         if (n) {
 657                 hour = n;
 658                 tm->tm_min = 0;
 659                 tm->tm_sec = 0;
 660         }
 661         tm->tm_hour = (hour % 12);
 662 }
 663
 664 static const struct special {
 665         const char *name;
 666         void (*fn)(struct tm *, int *);
 667 } special[] = {
 668         { "yesterday", date_yesterday },
 669         { "noon", date_noon },
 670         { "midnight", date_midnight },
 671         { "tea", date_tea },
 672         { "PM", date_pm },
 673         { "AM", date_am },
 674         { NULL }
 675 };
 676
 677 static const char *number_name[] = {
 678         "zero", "one", "two", "three", "four",
 679         "five", "six", "seven", "eight", "nine", "ten",
 680 };
 681
 682 static const struct typelen {
 683         const char *type;
 684         int length;
 685 } typelen[] = {
 686         { "seconds", 1 },
 687         { "minutes", 60 },
 688         { "hours", 60*60 },
 689         { "days", 24*60*60 },
 690         { "weeks", 7*24*60*60 },
 691         { NULL }
 692 };
 693
 694 static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
 695 {
 696         const struct typelen *tl;
 697         const struct special *s;
 698         const char *end = date;
 699         int i;
 700
 701         while (isalpha(*++end));
 702                 ;
 703
 704         for (i = 0; i < 12; i++) {
 705                 int match = match_string(date, month_names[i]);
 706                 if (match >= 3) {
 707                         tm->tm_mon = i;
 708                         return end;
 709                 }
 710         }
 711
 712         for (s = special; s->name; s++) {
 713                 int len = strlen(s->name);
 714                 if (match_string(date, s->name) == len) {
 715                         s->fn(tm, num);
 716                         return end;
 717                 }
 718         }
 719
 720         if (!*num) {
 721                 for (i = 1; i < 11; i++) {
 722                         int len = strlen(number_name[i]);
 723                         if (match_string(date, number_name[i]) == len) {
 724                                 *num = i;
 725                                 return end;
 726                         }
 727                 }
 728                 if (match_string(date, "last") == 4)
 729                         *num = 1;
 730                 return end;
 731         }
 732
 733         tl = typelen;
 734         while (tl->type) {
 735                 int len = strlen(tl->type);
 736                 if (match_string(date, tl->type) >= len-1) {
 737                         update_tm(tm, tl->length * *num);
 738                         *num = 0;
 739                         return end;
 740                 }
 741                 tl++;
 742         }
 743
 744         for (i = 0; i < 7; i++) {
 745                 int match = match_string(date, weekday_names[i]);
 746                 if (match >= 3) {
 747                         int diff, n = *num -1;
 748                         *num = 0;
 749
 750                         diff = tm->tm_wday - i;
 751                         if (diff <= 0)
 752                                 n++;
 753                         diff += 7*n;
 754
 755                         update_tm(tm, diff * 24 * 60 * 60);
 756                         return end;
 757                 }
 758         }
 759
 760         if (match_string(date, "months") >= 5) {
 761                 int n = tm->tm_mon - *num;
 762                 *num = 0;
 763                 while (n < 0) {
 764                         n += 12;
 765                         tm->tm_year--;
 766                 }
 767                 tm->tm_mon = n;
 768                 return end;
 769         }
 770
 771         if (match_string(date, "years") >= 4) {
 772                 tm->tm_year -= *num;
 773                 *num = 0;
 774                 return end;
 775         }
 776
 777         return end;
 778 }
 779
 780 static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 781 {
 782         char *end;
 783         unsigned long number = strtoul(date, &end, 10);
 784
 785         switch (*end) {
 786         case ':':
 787         case '.':
 788         case '/':
 789         case '-':
 790                 if (isdigit(end[1])) {
 791                         int match = match_multi_number(number, *end, date, end, tm);
 792                         if (match)
 793                                 return date + match;
 794                 }
 795         }
 796
 797         *num = number;
 798         return end;
 799 }
 800
 801 unsigned long approxidate(const char *date)
 802 {
 803         int number = 0;
 804         struct tm tm, now;
 805         struct timeval tv;
 806         char buffer[50];
 807
 808         if (parse_date(date, buffer, sizeof(buffer)) > 0)
 809                 return strtoul(buffer, NULL, 10);
 810
 811         gettimeofday(&tv, NULL);
 812         localtime_r(&tv.tv_sec, &tm);
 813         now = tm;
 814         for (;;) {
 815                 unsigned char c = *date;
 816                 if (!c)
 817                         break;
 818                 date++;
 819                 if (isdigit(c)) {
 820                         date = approxidate_digit(date-1, &tm, &number);
 821                         continue;
 822                 }
 823                 if (isalpha(c))
 824                         date = approxidate_alpha(date-1, &tm, &number);
 825         }
 826         if (number > 0 && number < 32)
 827                 tm.tm_mday = number;
 828         if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
 829                 tm.tm_year--;
 830         return mktime(&tm);
 831 }