date.con commit Support 'raw' date format (7dff9b3)
   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 */
  12time_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        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
  31static const char *month_names[] = {
  32        "January", "February", "March", "April", "May", "June",
  33        "July", "August", "September", "October", "November", "December"
  34};
  35
  36static const char *weekday_names[] = {
  37        "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  38};
  39
  40static 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 */
  55static 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/*
  62 * What value of "tz" was in effect back then at "time" in the
  63 * local timezone?
  64 */
  65static int local_tzoffset(unsigned long time)
  66{
  67        time_t t, t_local;
  68        struct tm tm;
  69        int offset, eastwest;
  70
  71        t = time;
  72        localtime_r(&t, &tm);
  73        t_local = tm_to_time_t(&tm);
  74
  75        if (t_local < t) {
  76                eastwest = -1;
  77                offset = t - t_local;
  78        } else {
  79                eastwest = 1;
  80                offset = t_local - t;
  81        }
  82        offset /= 60; /* in minutes */
  83        offset = (offset % 60) + ((offset / 60) * 100);
  84        return offset * eastwest;
  85}
  86
  87const char *show_date(unsigned long time, int tz, enum date_mode mode)
  88{
  89        struct tm *tm;
  90        static char timebuf[200];
  91
  92        if (mode == DATE_RAW) {
  93                snprintf(timebuf, sizeof(timebuf), "%lu %+05d", time, tz);
  94                return timebuf;
  95        }
  96
  97        if (mode == DATE_RELATIVE) {
  98                unsigned long diff;
  99                struct timeval now;
 100                gettimeofday(&now, NULL);
 101                if (now.tv_sec < time)
 102                        return "in the future";
 103                diff = now.tv_sec - time;
 104                if (diff < 90) {
 105                        snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
 106                        return timebuf;
 107                }
 108                /* Turn it into minutes */
 109                diff = (diff + 30) / 60;
 110                if (diff < 90) {
 111                        snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
 112                        return timebuf;
 113                }
 114                /* Turn it into hours */
 115                diff = (diff + 30) / 60;
 116                if (diff < 36) {
 117                        snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
 118                        return timebuf;
 119                }
 120                /* We deal with number of days from here on */
 121                diff = (diff + 12) / 24;
 122                if (diff < 14) {
 123                        snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
 124                        return timebuf;
 125                }
 126                /* Say weeks for the past 10 weeks or so */
 127                if (diff < 70) {
 128                        snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
 129                        return timebuf;
 130                }
 131                /* Say months for the past 12 months or so */
 132                if (diff < 360) {
 133                        snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
 134                        return timebuf;
 135                }
 136                /* Else fall back on absolute format.. */
 137        }
 138
 139        if (mode == DATE_LOCAL)
 140                tz = local_tzoffset(time);
 141
 142        tm = time_to_tm(time, tz);
 143        if (!tm)
 144                return NULL;
 145        if (mode == DATE_SHORT)
 146                sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
 147                                tm->tm_mon + 1, tm->tm_mday);
 148        else if (mode == DATE_ISO8601)
 149                sprintf(timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
 150                                tm->tm_year + 1900,
 151                                tm->tm_mon + 1,
 152                                tm->tm_mday,
 153                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 154                                tz);
 155        else if (mode == DATE_RFC2822)
 156                sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 157                        weekday_names[tm->tm_wday], tm->tm_mday,
 158                        month_names[tm->tm_mon], tm->tm_year + 1900,
 159                        tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 160        else
 161                sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 162                                weekday_names[tm->tm_wday],
 163                                month_names[tm->tm_mon],
 164                                tm->tm_mday,
 165                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 166                                tm->tm_year + 1900,
 167                                (mode == DATE_LOCAL) ? 0 : ' ',
 168                                tz);
 169        return timebuf;
 170}
 171
 172/*
 173 * Check these. And note how it doesn't do the summer-time conversion.
 174 *
 175 * In my world, it's always summer, and things are probably a bit off
 176 * in other ways too.
 177 */
 178static const struct {
 179        const char *name;
 180        int offset;
 181        int dst;
 182} timezone_names[] = {
 183        { "IDLW", -12, 0, },    /* International Date Line West */
 184        { "NT",   -11, 0, },    /* Nome */
 185        { "CAT",  -10, 0, },    /* Central Alaska */
 186        { "HST",  -10, 0, },    /* Hawaii Standard */
 187        { "HDT",  -10, 1, },    /* Hawaii Daylight */
 188        { "YST",   -9, 0, },    /* Yukon Standard */
 189        { "YDT",   -9, 1, },    /* Yukon Daylight */
 190        { "PST",   -8, 0, },    /* Pacific Standard */
 191        { "PDT",   -8, 1, },    /* Pacific Daylight */
 192        { "MST",   -7, 0, },    /* Mountain Standard */
 193        { "MDT",   -7, 1, },    /* Mountain Daylight */
 194        { "CST",   -6, 0, },    /* Central Standard */
 195        { "CDT",   -6, 1, },    /* Central Daylight */
 196        { "EST",   -5, 0, },    /* Eastern Standard */
 197        { "EDT",   -5, 1, },    /* Eastern Daylight */
 198        { "AST",   -3, 0, },    /* Atlantic Standard */
 199        { "ADT",   -3, 1, },    /* Atlantic Daylight */
 200        { "WAT",   -1, 0, },    /* West Africa */
 201
 202        { "GMT",    0, 0, },    /* Greenwich Mean */
 203        { "UTC",    0, 0, },    /* Universal (Coordinated) */
 204
 205        { "WET",    0, 0, },    /* Western European */
 206        { "BST",    0, 1, },    /* British Summer */
 207        { "CET",   +1, 0, },    /* Central European */
 208        { "MET",   +1, 0, },    /* Middle European */
 209        { "MEWT",  +1, 0, },    /* Middle European Winter */
 210        { "MEST",  +1, 1, },    /* Middle European Summer */
 211        { "CEST",  +1, 1, },    /* Central European Summer */
 212        { "MESZ",  +1, 1, },    /* Middle European Summer */
 213        { "FWT",   +1, 0, },    /* French Winter */
 214        { "FST",   +1, 1, },    /* French Summer */
 215        { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 216        { "EEST",  +2, 1, },    /* Eastern European Daylight */
 217        { "WAST",  +7, 0, },    /* West Australian Standard */
 218        { "WADT",  +7, 1, },    /* West Australian Daylight */
 219        { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 220        { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 221        { "EAST", +10, 0, },    /* Eastern Australian Standard */
 222        { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 223        { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 224        { "NZT",  +12, 0, },    /* New Zealand */
 225        { "NZST", +12, 0, },    /* New Zealand Standard */
 226        { "NZDT", +12, 1, },    /* New Zealand Daylight */
 227        { "IDLE", +12, 0, },    /* International Date Line East */
 228};
 229
 230static int match_string(const char *date, const char *str)
 231{
 232        int i = 0;
 233
 234        for (i = 0; *date; date++, str++, i++) {
 235                if (*date == *str)
 236                        continue;
 237                if (toupper(*date) == toupper(*str))
 238                        continue;
 239                if (!isalnum(*date))
 240                        break;
 241                return 0;
 242        }
 243        return i;
 244}
 245
 246static int skip_alpha(const char *date)
 247{
 248        int i = 0;
 249        do {
 250                i++;
 251        } while (isalpha(date[i]));
 252        return i;
 253}
 254
 255/*
 256* Parse month, weekday, or timezone name
 257*/
 258static int match_alpha(const char *date, struct tm *tm, int *offset)
 259{
 260        int i;
 261
 262        for (i = 0; i < 12; i++) {
 263                int match = match_string(date, month_names[i]);
 264                if (match >= 3) {
 265                        tm->tm_mon = i;
 266                        return match;
 267                }
 268        }
 269
 270        for (i = 0; i < 7; i++) {
 271                int match = match_string(date, weekday_names[i]);
 272                if (match >= 3) {
 273                        tm->tm_wday = i;
 274                        return match;
 275                }
 276        }
 277
 278        for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 279                int match = match_string(date, timezone_names[i].name);
 280                if (match >= 3) {
 281                        int off = timezone_names[i].offset;
 282
 283                        /* This is bogus, but we like summer */
 284                        off += timezone_names[i].dst;
 285
 286                        /* Only use the tz name offset if we don't have anything better */
 287                        if (*offset == -1)
 288                                *offset = 60*off;
 289
 290                        return match;
 291                }
 292        }
 293
 294        if (match_string(date, "PM") == 2) {
 295                tm->tm_hour = (tm->tm_hour % 12) + 12;
 296                return 2;
 297        }
 298
 299        if (match_string(date, "AM") == 2) {
 300                tm->tm_hour = (tm->tm_hour % 12) + 0;
 301                return 2;
 302        }
 303
 304        /* BAD CRAP */
 305        return skip_alpha(date);
 306}
 307
 308static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 309{
 310        if (month > 0 && month < 13 && day > 0 && day < 32) {
 311                struct tm check = *tm;
 312                struct tm *r = (now_tm ? &check : tm);
 313                time_t specified;
 314
 315                r->tm_mon = month - 1;
 316                r->tm_mday = day;
 317                if (year == -1) {
 318                        if (!now_tm)
 319                                return 1;
 320                        r->tm_year = now_tm->tm_year;
 321                }
 322                else if (year >= 1970 && year < 2100)
 323                        r->tm_year = year - 1900;
 324                else if (year > 70 && year < 100)
 325                        r->tm_year = year;
 326                else if (year < 38)
 327                        r->tm_year = year + 100;
 328                else
 329                        return 0;
 330                if (!now_tm)
 331                        return 1;
 332
 333                specified = tm_to_time_t(r);
 334
 335                /* Be it commit time or author time, it does not make
 336                 * sense to specify timestamp way into the future.  Make
 337                 * sure it is not later than ten days from now...
 338                 */
 339                if (now + 10*24*3600 < specified)
 340                        return 0;
 341                tm->tm_mon = r->tm_mon;
 342                tm->tm_mday = r->tm_mday;
 343                if (year != -1)
 344                        tm->tm_year = r->tm_year;
 345                return 1;
 346        }
 347        return 0;
 348}
 349
 350static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 351{
 352        time_t now;
 353        struct tm now_tm;
 354        struct tm *refuse_future;
 355        long num2, num3;
 356
 357        num2 = strtol(end+1, &end, 10);
 358        num3 = -1;
 359        if (*end == c && isdigit(end[1]))
 360                num3 = strtol(end+1, &end, 10);
 361
 362        /* Time? Date? */
 363        switch (c) {
 364        case ':':
 365                if (num3 < 0)
 366                        num3 = 0;
 367                if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 368                        tm->tm_hour = num;
 369                        tm->tm_min = num2;
 370                        tm->tm_sec = num3;
 371                        break;
 372                }
 373                return 0;
 374
 375        case '-':
 376        case '/':
 377        case '.':
 378                now = time(NULL);
 379                refuse_future = NULL;
 380                if (gmtime_r(&now, &now_tm))
 381                        refuse_future = &now_tm;
 382
 383                if (num > 70) {
 384                        /* yyyy-mm-dd? */
 385                        if (is_date(num, num2, num3, refuse_future, now, tm))
 386                                break;
 387                        /* yyyy-dd-mm? */
 388                        if (is_date(num, num3, num2, refuse_future, now, tm))
 389                                break;
 390                }
 391                /* Our eastern European friends say dd.mm.yy[yy]
 392                 * is the norm there, so giving precedence to
 393                 * mm/dd/yy[yy] form only when separator is not '.'
 394                 */
 395                if (c != '.' &&
 396                    is_date(num3, num, num2, refuse_future, now, tm))
 397                        break;
 398                /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 399                if (is_date(num3, num2, num, refuse_future, now, tm))
 400                        break;
 401                /* Funny European mm.dd.yy */
 402                if (c == '.' &&
 403                    is_date(num3, num, num2, refuse_future, now, tm))
 404                        break;
 405                return 0;
 406        }
 407        return end - date;
 408}
 409
 410/* Have we filled in any part of the time/date yet? */
 411static inline int nodate(struct tm *tm)
 412{
 413        return tm->tm_year < 0 &&
 414                tm->tm_mon < 0 &&
 415                tm->tm_mday < 0 &&
 416                !(tm->tm_hour | tm->tm_min | tm->tm_sec);
 417}
 418
 419/*
 420 * We've seen a digit. Time? Year? Date?
 421 */
 422static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 423{
 424        int n;
 425        char *end;
 426        unsigned long num;
 427
 428        num = strtoul(date, &end, 10);
 429
 430        /*
 431         * Seconds since 1970? We trigger on that for any numbers with
 432         * more than 8 digits. This is because we don't want to rule out
 433         * numbers like 20070606 as a YYYYMMDD date.
 434         */
 435        if (num >= 100000000 && nodate(tm)) {
 436                time_t time = num;
 437                if (gmtime_r(&time, tm)) {
 438                        *tm_gmt = 1;
 439                        return end - date;
 440                }
 441        }
 442
 443        /*
 444         * Check for special formats: num[-.:/]num[same]num
 445         */
 446        switch (*end) {
 447        case ':':
 448        case '.':
 449        case '/':
 450        case '-':
 451                if (isdigit(end[1])) {
 452                        int match = match_multi_number(num, *end, date, end, tm);
 453                        if (match)
 454                                return match;
 455                }
 456        }
 457
 458        /*
 459         * None of the special formats? Try to guess what
 460         * the number meant. We use the number of digits
 461         * to make a more educated guess..
 462         */
 463        n = 0;
 464        do {
 465                n++;
 466        } while (isdigit(date[n]));
 467
 468        /* Four-digit year or a timezone? */
 469        if (n == 4) {
 470                if (num <= 1400 && *offset == -1) {
 471                        unsigned int minutes = num % 100;
 472                        unsigned int hours = num / 100;
 473                        *offset = hours*60 + minutes;
 474                } else if (num > 1900 && num < 2100)
 475                        tm->tm_year = num - 1900;
 476                return n;
 477        }
 478
 479        /*
 480         * Ignore lots of numerals. We took care of 4-digit years above.
 481         * Days or months must be one or two digits.
 482         */
 483        if (n > 2)
 484                return n;
 485
 486        /*
 487         * NOTE! We will give precedence to day-of-month over month or
 488         * year numbers in the 1-12 range. So 05 is always "mday 5",
 489         * unless we already have a mday..
 490         *
 491         * IOW, 01 Apr 05 parses as "April 1st, 2005".
 492         */
 493        if (num > 0 && num < 32 && tm->tm_mday < 0) {
 494                tm->tm_mday = num;
 495                return n;
 496        }
 497
 498        /* Two-digit year? */
 499        if (n == 2 && tm->tm_year < 0) {
 500                if (num < 10 && tm->tm_mday >= 0) {
 501                        tm->tm_year = num + 100;
 502                        return n;
 503                }
 504                if (num >= 70) {
 505                        tm->tm_year = num;
 506                        return n;
 507                }
 508        }
 509
 510        if (num > 0 && num < 32) {
 511                tm->tm_mday = num;
 512        } else if (num > 0 && num < 13) {
 513                tm->tm_mon = num-1;
 514        }
 515
 516        return n;
 517}
 518
 519static int match_tz(const char *date, int *offp)
 520{
 521        char *end;
 522        int offset = strtoul(date+1, &end, 10);
 523        int min, hour;
 524        int n = end - date - 1;
 525
 526        min = offset % 100;
 527        hour = offset / 100;
 528
 529        /*
 530         * Don't accept any random crap.. At least 3 digits, and
 531         * a valid minute. We might want to check that the minutes
 532         * are divisible by 30 or something too.
 533         */
 534        if (min < 60 && n > 2) {
 535                offset = hour*60+min;
 536                if (*date == '-')
 537                        offset = -offset;
 538
 539                *offp = offset;
 540        }
 541        return end - date;
 542}
 543
 544static int date_string(unsigned long date, int offset, char *buf, int len)
 545{
 546        int sign = '+';
 547
 548        if (offset < 0) {
 549                offset = -offset;
 550                sign = '-';
 551        }
 552        return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 553}
 554
 555/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 556   (i.e. English) day/month names, and it doesn't work correctly with %z. */
 557int parse_date(const char *date, char *result, int maxlen)
 558{
 559        struct tm tm;
 560        int offset, tm_gmt;
 561        time_t then;
 562
 563        memset(&tm, 0, sizeof(tm));
 564        tm.tm_year = -1;
 565        tm.tm_mon = -1;
 566        tm.tm_mday = -1;
 567        tm.tm_isdst = -1;
 568        offset = -1;
 569        tm_gmt = 0;
 570
 571        for (;;) {
 572                int match = 0;
 573                unsigned char c = *date;
 574
 575                /* Stop at end of string or newline */
 576                if (!c || c == '\n')
 577                        break;
 578
 579                if (isalpha(c))
 580                        match = match_alpha(date, &tm, &offset);
 581                else if (isdigit(c))
 582                        match = match_digit(date, &tm, &offset, &tm_gmt);
 583                else if ((c == '-' || c == '+') && isdigit(date[1]))
 584                        match = match_tz(date, &offset);
 585
 586                if (!match) {
 587                        /* BAD CRAP */
 588                        match = 1;
 589                }
 590
 591                date += match;
 592        }
 593
 594        /* mktime uses local timezone */
 595        then = tm_to_time_t(&tm);
 596        if (offset == -1)
 597                offset = (then - mktime(&tm)) / 60;
 598
 599        if (then == -1)
 600                return -1;
 601
 602        if (!tm_gmt)
 603                then -= offset * 60;
 604        return date_string(then, offset, result, maxlen);
 605}
 606
 607enum date_mode parse_date_format(const char *format)
 608{
 609        if (!strcmp(format, "relative"))
 610                return DATE_RELATIVE;
 611        else if (!strcmp(format, "iso8601") ||
 612                 !strcmp(format, "iso"))
 613                return DATE_ISO8601;
 614        else if (!strcmp(format, "rfc2822") ||
 615                 !strcmp(format, "rfc"))
 616                return DATE_RFC2822;
 617        else if (!strcmp(format, "short"))
 618                return DATE_SHORT;
 619        else if (!strcmp(format, "local"))
 620                return DATE_LOCAL;
 621        else if (!strcmp(format, "default"))
 622                return DATE_NORMAL;
 623        else if (!strcmp(format, "raw"))
 624                return DATE_RAW;
 625        else
 626                die("unknown date format %s", format);
 627}
 628
 629void datestamp(char *buf, int bufsize)
 630{
 631        time_t now;
 632        int offset;
 633
 634        time(&now);
 635
 636        offset = tm_to_time_t(localtime(&now)) - now;
 637        offset /= 60;
 638
 639        date_string(now, offset, buf, bufsize);
 640}
 641
 642static void update_tm(struct tm *tm, unsigned long sec)
 643{
 644        time_t n = mktime(tm) - sec;
 645        localtime_r(&n, tm);
 646}
 647
 648static void date_yesterday(struct tm *tm, int *num)
 649{
 650        update_tm(tm, 24*60*60);
 651}
 652
 653static void date_time(struct tm *tm, int hour)
 654{
 655        if (tm->tm_hour < hour)
 656                date_yesterday(tm, NULL);
 657        tm->tm_hour = hour;
 658        tm->tm_min = 0;
 659        tm->tm_sec = 0;
 660}
 661
 662static void date_midnight(struct tm *tm, int *num)
 663{
 664        date_time(tm, 0);
 665}
 666
 667static void date_noon(struct tm *tm, int *num)
 668{
 669        date_time(tm, 12);
 670}
 671
 672static void date_tea(struct tm *tm, int *num)
 673{
 674        date_time(tm, 17);
 675}
 676
 677static void date_pm(struct tm *tm, int *num)
 678{
 679        int hour, n = *num;
 680        *num = 0;
 681
 682        hour = tm->tm_hour;
 683        if (n) {
 684                hour = n;
 685                tm->tm_min = 0;
 686                tm->tm_sec = 0;
 687        }
 688        tm->tm_hour = (hour % 12) + 12;
 689}
 690
 691static void date_am(struct tm *tm, int *num)
 692{
 693        int hour, n = *num;
 694        *num = 0;
 695
 696        hour = tm->tm_hour;
 697        if (n) {
 698                hour = n;
 699                tm->tm_min = 0;
 700                tm->tm_sec = 0;
 701        }
 702        tm->tm_hour = (hour % 12);
 703}
 704
 705static void date_never(struct tm *tm, int *num)
 706{
 707        time_t n = 0;
 708        localtime_r(&n, tm);
 709}
 710
 711static const struct special {
 712        const char *name;
 713        void (*fn)(struct tm *, int *);
 714} special[] = {
 715        { "yesterday", date_yesterday },
 716        { "noon", date_noon },
 717        { "midnight", date_midnight },
 718        { "tea", date_tea },
 719        { "PM", date_pm },
 720        { "AM", date_am },
 721        { "never", date_never },
 722        { NULL }
 723};
 724
 725static const char *number_name[] = {
 726        "zero", "one", "two", "three", "four",
 727        "five", "six", "seven", "eight", "nine", "ten",
 728};
 729
 730static const struct typelen {
 731        const char *type;
 732        int length;
 733} typelen[] = {
 734        { "seconds", 1 },
 735        { "minutes", 60 },
 736        { "hours", 60*60 },
 737        { "days", 24*60*60 },
 738        { "weeks", 7*24*60*60 },
 739        { NULL }
 740};
 741
 742static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
 743{
 744        const struct typelen *tl;
 745        const struct special *s;
 746        const char *end = date;
 747        int i;
 748
 749        while (isalpha(*++end));
 750                ;
 751
 752        for (i = 0; i < 12; i++) {
 753                int match = match_string(date, month_names[i]);
 754                if (match >= 3) {
 755                        tm->tm_mon = i;
 756                        return end;
 757                }
 758        }
 759
 760        for (s = special; s->name; s++) {
 761                int len = strlen(s->name);
 762                if (match_string(date, s->name) == len) {
 763                        s->fn(tm, num);
 764                        return end;
 765                }
 766        }
 767
 768        if (!*num) {
 769                for (i = 1; i < 11; i++) {
 770                        int len = strlen(number_name[i]);
 771                        if (match_string(date, number_name[i]) == len) {
 772                                *num = i;
 773                                return end;
 774                        }
 775                }
 776                if (match_string(date, "last") == 4)
 777                        *num = 1;
 778                return end;
 779        }
 780
 781        tl = typelen;
 782        while (tl->type) {
 783                int len = strlen(tl->type);
 784                if (match_string(date, tl->type) >= len-1) {
 785                        update_tm(tm, tl->length * *num);
 786                        *num = 0;
 787                        return end;
 788                }
 789                tl++;
 790        }
 791
 792        for (i = 0; i < 7; i++) {
 793                int match = match_string(date, weekday_names[i]);
 794                if (match >= 3) {
 795                        int diff, n = *num -1;
 796                        *num = 0;
 797
 798                        diff = tm->tm_wday - i;
 799                        if (diff <= 0)
 800                                n++;
 801                        diff += 7*n;
 802
 803                        update_tm(tm, diff * 24 * 60 * 60);
 804                        return end;
 805                }
 806        }
 807
 808        if (match_string(date, "months") >= 5) {
 809                int n = tm->tm_mon - *num;
 810                *num = 0;
 811                while (n < 0) {
 812                        n += 12;
 813                        tm->tm_year--;
 814                }
 815                tm->tm_mon = n;
 816                return end;
 817        }
 818
 819        if (match_string(date, "years") >= 4) {
 820                tm->tm_year -= *num;
 821                *num = 0;
 822                return end;
 823        }
 824
 825        return end;
 826}
 827
 828static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 829{
 830        char *end;
 831        unsigned long number = strtoul(date, &end, 10);
 832
 833        switch (*end) {
 834        case ':':
 835        case '.':
 836        case '/':
 837        case '-':
 838                if (isdigit(end[1])) {
 839                        int match = match_multi_number(number, *end, date, end, tm);
 840                        if (match)
 841                                return date + match;
 842                }
 843        }
 844
 845        /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
 846        if (date[0] != '0' || end - date <= 2)
 847                *num = number;
 848        return end;
 849}
 850
 851unsigned long approxidate(const char *date)
 852{
 853        int number = 0;
 854        struct tm tm, now;
 855        struct timeval tv;
 856        char buffer[50];
 857
 858        if (parse_date(date, buffer, sizeof(buffer)) > 0)
 859                return strtoul(buffer, NULL, 10);
 860
 861        gettimeofday(&tv, NULL);
 862        localtime_r(&tv.tv_sec, &tm);
 863        now = tm;
 864        for (;;) {
 865                unsigned char c = *date;
 866                if (!c)
 867                        break;
 868                date++;
 869                if (isdigit(c)) {
 870                        date = approxidate_digit(date-1, &tm, &number);
 871                        continue;
 872                }
 873                if (isalpha(c))
 874                        date = approxidate_alpha(date-1, &tm, &number);
 875        }
 876        if (number > 0 && number < 32)
 877                tm.tm_mday = number;
 878        if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
 879                tm.tm_year--;
 880        return mktime(&tm);
 881}