date.con commit Merge branch 'master' (early part) into pd/bash-4-completion (52c9d8e)
   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 */
  12static time_t tm_to_time_t(const struct tm *tm)
  13{
  14        static const int mdays[] = {
  15            0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
  16        };
  17        int year = tm->tm_year - 70;
  18        int month = tm->tm_mon;
  19        int day = tm->tm_mday;
  20
  21        if (year < 0 || year > 129) /* algo only works for 1970-2099 */
  22                return -1;
  23        if (month < 0 || month > 11) /* array bounds */
  24                return -1;
  25        if (month < 2 || (year + 2) % 4)
  26                day--;
  27        if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_sec < 0)
  28                return -1;
  29        return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
  30                tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
  31}
  32
  33static const char *month_names[] = {
  34        "January", "February", "March", "April", "May", "June",
  35        "July", "August", "September", "October", "November", "December"
  36};
  37
  38static const char *weekday_names[] = {
  39        "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  40};
  41
  42static time_t gm_time_t(unsigned long time, int tz)
  43{
  44        int minutes;
  45
  46        minutes = tz < 0 ? -tz : tz;
  47        minutes = (minutes / 100)*60 + (minutes % 100);
  48        minutes = tz < 0 ? -minutes : minutes;
  49        return time + minutes * 60;
  50}
  51
  52/*
  53 * The "tz" thing is passed in as this strange "decimal parse of tz"
  54 * thing, which means that tz -0100 is passed in as the integer -100,
  55 * even though it means "sixty minutes off"
  56 */
  57static struct tm *time_to_tm(unsigned long time, int tz)
  58{
  59        time_t t = gm_time_t(time, tz);
  60        return gmtime(&t);
  61}
  62
  63/*
  64 * What value of "tz" was in effect back then at "time" in the
  65 * local timezone?
  66 */
  67static int local_tzoffset(unsigned long time)
  68{
  69        time_t t, t_local;
  70        struct tm tm;
  71        int offset, eastwest;
  72
  73        t = time;
  74        localtime_r(&t, &tm);
  75        t_local = tm_to_time_t(&tm);
  76
  77        if (t_local < t) {
  78                eastwest = -1;
  79                offset = t - t_local;
  80        } else {
  81                eastwest = 1;
  82                offset = t_local - t;
  83        }
  84        offset /= 60; /* in minutes */
  85        offset = (offset % 60) + ((offset / 60) * 100);
  86        return offset * eastwest;
  87}
  88
  89const char *show_date_relative(unsigned long time, int tz,
  90                               const struct timeval *now,
  91                               char *timebuf,
  92                               size_t timebuf_size)
  93{
  94        unsigned long diff;
  95        if (now->tv_sec < time)
  96                return "in the future";
  97        diff = now->tv_sec - time;
  98        if (diff < 90) {
  99                snprintf(timebuf, timebuf_size, "%lu seconds ago", diff);
 100                return timebuf;
 101        }
 102        /* Turn it into minutes */
 103        diff = (diff + 30) / 60;
 104        if (diff < 90) {
 105                snprintf(timebuf, timebuf_size, "%lu minutes ago", diff);
 106                return timebuf;
 107        }
 108        /* Turn it into hours */
 109        diff = (diff + 30) / 60;
 110        if (diff < 36) {
 111                snprintf(timebuf, timebuf_size, "%lu hours ago", diff);
 112                return timebuf;
 113        }
 114        /* We deal with number of days from here on */
 115        diff = (diff + 12) / 24;
 116        if (diff < 14) {
 117                snprintf(timebuf, timebuf_size, "%lu days ago", diff);
 118                return timebuf;
 119        }
 120        /* Say weeks for the past 10 weeks or so */
 121        if (diff < 70) {
 122                snprintf(timebuf, timebuf_size, "%lu weeks ago", (diff + 3) / 7);
 123                return timebuf;
 124        }
 125        /* Say months for the past 12 months or so */
 126        if (diff < 365) {
 127                snprintf(timebuf, timebuf_size, "%lu months ago", (diff + 15) / 30);
 128                return timebuf;
 129        }
 130        /* Give years and months for 5 years or so */
 131        if (diff < 1825) {
 132                unsigned long years = diff / 365;
 133                unsigned long months = (diff % 365 + 15) / 30;
 134                int n;
 135                n = snprintf(timebuf, timebuf_size, "%lu year%s",
 136                                years, (years > 1 ? "s" : ""));
 137                if (months)
 138                        snprintf(timebuf + n, timebuf_size - n,
 139                                        ", %lu month%s ago",
 140                                        months, (months > 1 ? "s" : ""));
 141                else
 142                        snprintf(timebuf + n, timebuf_size - n, " ago");
 143                return timebuf;
 144        }
 145        /* Otherwise, just years. Centuries is probably overkill. */
 146        snprintf(timebuf, timebuf_size, "%lu years ago", (diff + 183) / 365);
 147        return timebuf;
 148}
 149
 150const char *show_date(unsigned long time, int tz, enum date_mode mode)
 151{
 152        struct tm *tm;
 153        static char timebuf[200];
 154
 155        if (mode == DATE_RAW) {
 156                snprintf(timebuf, sizeof(timebuf), "%lu %+05d", time, tz);
 157                return timebuf;
 158        }
 159
 160        if (mode == DATE_RELATIVE) {
 161                struct timeval now;
 162                gettimeofday(&now, NULL);
 163                return show_date_relative(time, tz, &now,
 164                                          timebuf, sizeof(timebuf));
 165        }
 166
 167        if (mode == DATE_LOCAL)
 168                tz = local_tzoffset(time);
 169
 170        tm = time_to_tm(time, tz);
 171        if (!tm)
 172                return NULL;
 173        if (mode == DATE_SHORT)
 174                sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
 175                                tm->tm_mon + 1, tm->tm_mday);
 176        else if (mode == DATE_ISO8601)
 177                sprintf(timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
 178                                tm->tm_year + 1900,
 179                                tm->tm_mon + 1,
 180                                tm->tm_mday,
 181                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 182                                tz);
 183        else if (mode == DATE_RFC2822)
 184                sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 185                        weekday_names[tm->tm_wday], tm->tm_mday,
 186                        month_names[tm->tm_mon], tm->tm_year + 1900,
 187                        tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 188        else
 189                sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 190                                weekday_names[tm->tm_wday],
 191                                month_names[tm->tm_mon],
 192                                tm->tm_mday,
 193                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 194                                tm->tm_year + 1900,
 195                                (mode == DATE_LOCAL) ? 0 : ' ',
 196                                tz);
 197        return timebuf;
 198}
 199
 200/*
 201 * Check these. And note how it doesn't do the summer-time conversion.
 202 *
 203 * In my world, it's always summer, and things are probably a bit off
 204 * in other ways too.
 205 */
 206static const struct {
 207        const char *name;
 208        int offset;
 209        int dst;
 210} timezone_names[] = {
 211        { "IDLW", -12, 0, },    /* International Date Line West */
 212        { "NT",   -11, 0, },    /* Nome */
 213        { "CAT",  -10, 0, },    /* Central Alaska */
 214        { "HST",  -10, 0, },    /* Hawaii Standard */
 215        { "HDT",  -10, 1, },    /* Hawaii Daylight */
 216        { "YST",   -9, 0, },    /* Yukon Standard */
 217        { "YDT",   -9, 1, },    /* Yukon Daylight */
 218        { "PST",   -8, 0, },    /* Pacific Standard */
 219        { "PDT",   -8, 1, },    /* Pacific Daylight */
 220        { "MST",   -7, 0, },    /* Mountain Standard */
 221        { "MDT",   -7, 1, },    /* Mountain Daylight */
 222        { "CST",   -6, 0, },    /* Central Standard */
 223        { "CDT",   -6, 1, },    /* Central Daylight */
 224        { "EST",   -5, 0, },    /* Eastern Standard */
 225        { "EDT",   -5, 1, },    /* Eastern Daylight */
 226        { "AST",   -3, 0, },    /* Atlantic Standard */
 227        { "ADT",   -3, 1, },    /* Atlantic Daylight */
 228        { "WAT",   -1, 0, },    /* West Africa */
 229
 230        { "GMT",    0, 0, },    /* Greenwich Mean */
 231        { "UTC",    0, 0, },    /* Universal (Coordinated) */
 232        { "Z",      0, 0, },    /* Zulu, alias for UTC */
 233
 234        { "WET",    0, 0, },    /* Western European */
 235        { "BST",    0, 1, },    /* British Summer */
 236        { "CET",   +1, 0, },    /* Central European */
 237        { "MET",   +1, 0, },    /* Middle European */
 238        { "MEWT",  +1, 0, },    /* Middle European Winter */
 239        { "MEST",  +1, 1, },    /* Middle European Summer */
 240        { "CEST",  +1, 1, },    /* Central European Summer */
 241        { "MESZ",  +1, 1, },    /* Middle European Summer */
 242        { "FWT",   +1, 0, },    /* French Winter */
 243        { "FST",   +1, 1, },    /* French Summer */
 244        { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 245        { "EEST",  +2, 1, },    /* Eastern European Daylight */
 246        { "WAST",  +7, 0, },    /* West Australian Standard */
 247        { "WADT",  +7, 1, },    /* West Australian Daylight */
 248        { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 249        { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 250        { "EAST", +10, 0, },    /* Eastern Australian Standard */
 251        { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 252        { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 253        { "NZT",  +12, 0, },    /* New Zealand */
 254        { "NZST", +12, 0, },    /* New Zealand Standard */
 255        { "NZDT", +12, 1, },    /* New Zealand Daylight */
 256        { "IDLE", +12, 0, },    /* International Date Line East */
 257};
 258
 259static int match_string(const char *date, const char *str)
 260{
 261        int i = 0;
 262
 263        for (i = 0; *date; date++, str++, i++) {
 264                if (*date == *str)
 265                        continue;
 266                if (toupper(*date) == toupper(*str))
 267                        continue;
 268                if (!isalnum(*date))
 269                        break;
 270                return 0;
 271        }
 272        return i;
 273}
 274
 275static int skip_alpha(const char *date)
 276{
 277        int i = 0;
 278        do {
 279                i++;
 280        } while (isalpha(date[i]));
 281        return i;
 282}
 283
 284/*
 285* Parse month, weekday, or timezone name
 286*/
 287static int match_alpha(const char *date, struct tm *tm, int *offset)
 288{
 289        int i;
 290
 291        for (i = 0; i < 12; i++) {
 292                int match = match_string(date, month_names[i]);
 293                if (match >= 3) {
 294                        tm->tm_mon = i;
 295                        return match;
 296                }
 297        }
 298
 299        for (i = 0; i < 7; i++) {
 300                int match = match_string(date, weekday_names[i]);
 301                if (match >= 3) {
 302                        tm->tm_wday = i;
 303                        return match;
 304                }
 305        }
 306
 307        for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 308                int match = match_string(date, timezone_names[i].name);
 309                if (match >= 3 || match == strlen(timezone_names[i].name)) {
 310                        int off = timezone_names[i].offset;
 311
 312                        /* This is bogus, but we like summer */
 313                        off += timezone_names[i].dst;
 314
 315                        /* Only use the tz name offset if we don't have anything better */
 316                        if (*offset == -1)
 317                                *offset = 60*off;
 318
 319                        return match;
 320                }
 321        }
 322
 323        if (match_string(date, "PM") == 2) {
 324                tm->tm_hour = (tm->tm_hour % 12) + 12;
 325                return 2;
 326        }
 327
 328        if (match_string(date, "AM") == 2) {
 329                tm->tm_hour = (tm->tm_hour % 12) + 0;
 330                return 2;
 331        }
 332
 333        /* BAD CRAP */
 334        return skip_alpha(date);
 335}
 336
 337static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 338{
 339        if (month > 0 && month < 13 && day > 0 && day < 32) {
 340                struct tm check = *tm;
 341                struct tm *r = (now_tm ? &check : tm);
 342                time_t specified;
 343
 344                r->tm_mon = month - 1;
 345                r->tm_mday = day;
 346                if (year == -1) {
 347                        if (!now_tm)
 348                                return 1;
 349                        r->tm_year = now_tm->tm_year;
 350                }
 351                else if (year >= 1970 && year < 2100)
 352                        r->tm_year = year - 1900;
 353                else if (year > 70 && year < 100)
 354                        r->tm_year = year;
 355                else if (year < 38)
 356                        r->tm_year = year + 100;
 357                else
 358                        return 0;
 359                if (!now_tm)
 360                        return 1;
 361
 362                specified = tm_to_time_t(r);
 363
 364                /* Be it commit time or author time, it does not make
 365                 * sense to specify timestamp way into the future.  Make
 366                 * sure it is not later than ten days from now...
 367                 */
 368                if (now + 10*24*3600 < specified)
 369                        return 0;
 370                tm->tm_mon = r->tm_mon;
 371                tm->tm_mday = r->tm_mday;
 372                if (year != -1)
 373                        tm->tm_year = r->tm_year;
 374                return 1;
 375        }
 376        return 0;
 377}
 378
 379static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 380{
 381        time_t now;
 382        struct tm now_tm;
 383        struct tm *refuse_future;
 384        long num2, num3;
 385
 386        num2 = strtol(end+1, &end, 10);
 387        num3 = -1;
 388        if (*end == c && isdigit(end[1]))
 389                num3 = strtol(end+1, &end, 10);
 390
 391        /* Time? Date? */
 392        switch (c) {
 393        case ':':
 394                if (num3 < 0)
 395                        num3 = 0;
 396                if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 397                        tm->tm_hour = num;
 398                        tm->tm_min = num2;
 399                        tm->tm_sec = num3;
 400                        break;
 401                }
 402                return 0;
 403
 404        case '-':
 405        case '/':
 406        case '.':
 407                now = time(NULL);
 408                refuse_future = NULL;
 409                if (gmtime_r(&now, &now_tm))
 410                        refuse_future = &now_tm;
 411
 412                if (num > 70) {
 413                        /* yyyy-mm-dd? */
 414                        if (is_date(num, num2, num3, refuse_future, now, tm))
 415                                break;
 416                        /* yyyy-dd-mm? */
 417                        if (is_date(num, num3, num2, refuse_future, now, tm))
 418                                break;
 419                }
 420                /* Our eastern European friends say dd.mm.yy[yy]
 421                 * is the norm there, so giving precedence to
 422                 * mm/dd/yy[yy] form only when separator is not '.'
 423                 */
 424                if (c != '.' &&
 425                    is_date(num3, num, num2, refuse_future, now, tm))
 426                        break;
 427                /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 428                if (is_date(num3, num2, num, refuse_future, now, tm))
 429                        break;
 430                /* Funny European mm.dd.yy */
 431                if (c == '.' &&
 432                    is_date(num3, num, num2, refuse_future, now, tm))
 433                        break;
 434                return 0;
 435        }
 436        return end - date;
 437}
 438
 439/*
 440 * Have we filled in any part of the time/date yet?
 441 * We just do a binary 'and' to see if the sign bit
 442 * is set in all the values.
 443 */
 444static inline int nodate(struct tm *tm)
 445{
 446        return (tm->tm_year &
 447                tm->tm_mon &
 448                tm->tm_mday &
 449                tm->tm_hour &
 450                tm->tm_min &
 451                tm->tm_sec) < 0;
 452}
 453
 454/*
 455 * We've seen a digit. Time? Year? Date?
 456 */
 457static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 458{
 459        int n;
 460        char *end;
 461        unsigned long num;
 462
 463        num = strtoul(date, &end, 10);
 464
 465        /*
 466         * Seconds since 1970? We trigger on that for any numbers with
 467         * more than 8 digits. This is because we don't want to rule out
 468         * numbers like 20070606 as a YYYYMMDD date.
 469         */
 470        if (num >= 100000000 && nodate(tm)) {
 471                time_t time = num;
 472                if (gmtime_r(&time, tm)) {
 473                        *tm_gmt = 1;
 474                        return end - date;
 475                }
 476        }
 477
 478        /*
 479         * Check for special formats: num[-.:/]num[same]num
 480         */
 481        switch (*end) {
 482        case ':':
 483        case '.':
 484        case '/':
 485        case '-':
 486                if (isdigit(end[1])) {
 487                        int match = match_multi_number(num, *end, date, end, tm);
 488                        if (match)
 489                                return match;
 490                }
 491        }
 492
 493        /*
 494         * None of the special formats? Try to guess what
 495         * the number meant. We use the number of digits
 496         * to make a more educated guess..
 497         */
 498        n = 0;
 499        do {
 500                n++;
 501        } while (isdigit(date[n]));
 502
 503        /* Four-digit year or a timezone? */
 504        if (n == 4) {
 505                if (num <= 1400 && *offset == -1) {
 506                        unsigned int minutes = num % 100;
 507                        unsigned int hours = num / 100;
 508                        *offset = hours*60 + minutes;
 509                } else if (num > 1900 && num < 2100)
 510                        tm->tm_year = num - 1900;
 511                return n;
 512        }
 513
 514        /*
 515         * Ignore lots of numerals. We took care of 4-digit years above.
 516         * Days or months must be one or two digits.
 517         */
 518        if (n > 2)
 519                return n;
 520
 521        /*
 522         * NOTE! We will give precedence to day-of-month over month or
 523         * year numbers in the 1-12 range. So 05 is always "mday 5",
 524         * unless we already have a mday..
 525         *
 526         * IOW, 01 Apr 05 parses as "April 1st, 2005".
 527         */
 528        if (num > 0 && num < 32 && tm->tm_mday < 0) {
 529                tm->tm_mday = num;
 530                return n;
 531        }
 532
 533        /* Two-digit year? */
 534        if (n == 2 && tm->tm_year < 0) {
 535                if (num < 10 && tm->tm_mday >= 0) {
 536                        tm->tm_year = num + 100;
 537                        return n;
 538                }
 539                if (num >= 70) {
 540                        tm->tm_year = num;
 541                        return n;
 542                }
 543        }
 544
 545        if (num > 0 && num < 13 && tm->tm_mon < 0)
 546                tm->tm_mon = num-1;
 547
 548        return n;
 549}
 550
 551static int match_tz(const char *date, int *offp)
 552{
 553        char *end;
 554        int offset = strtoul(date+1, &end, 10);
 555        int min, hour;
 556        int n = end - date - 1;
 557
 558        min = offset % 100;
 559        hour = offset / 100;
 560
 561        /*
 562         * Don't accept any random crap.. At least 3 digits, and
 563         * a valid minute. We might want to check that the minutes
 564         * are divisible by 30 or something too.
 565         */
 566        if (min < 60 && n > 2) {
 567                offset = hour*60+min;
 568                if (*date == '-')
 569                        offset = -offset;
 570
 571                *offp = offset;
 572        }
 573        return end - date;
 574}
 575
 576static int date_string(unsigned long date, int offset, char *buf, int len)
 577{
 578        int sign = '+';
 579
 580        if (offset < 0) {
 581                offset = -offset;
 582                sign = '-';
 583        }
 584        return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 585}
 586
 587/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 588   (i.e. English) day/month names, and it doesn't work correctly with %z. */
 589int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
 590{
 591        struct tm tm;
 592        int tm_gmt;
 593        unsigned long dummy_timestamp;
 594        int dummy_offset;
 595
 596        if (!timestamp)
 597                timestamp = &dummy_timestamp;
 598        if (!offset)
 599                offset = &dummy_offset;
 600
 601        memset(&tm, 0, sizeof(tm));
 602        tm.tm_year = -1;
 603        tm.tm_mon = -1;
 604        tm.tm_mday = -1;
 605        tm.tm_isdst = -1;
 606        tm.tm_hour = -1;
 607        tm.tm_min = -1;
 608        tm.tm_sec = -1;
 609        *offset = -1;
 610        tm_gmt = 0;
 611
 612        for (;;) {
 613                int match = 0;
 614                unsigned char c = *date;
 615
 616                /* Stop at end of string or newline */
 617                if (!c || c == '\n')
 618                        break;
 619
 620                if (isalpha(c))
 621                        match = match_alpha(date, &tm, offset);
 622                else if (isdigit(c))
 623                        match = match_digit(date, &tm, offset, &tm_gmt);
 624                else if ((c == '-' || c == '+') && isdigit(date[1]))
 625                        match = match_tz(date, offset);
 626
 627                if (!match) {
 628                        /* BAD CRAP */
 629                        match = 1;
 630                }
 631
 632                date += match;
 633        }
 634
 635        /* mktime uses local timezone */
 636        *timestamp = tm_to_time_t(&tm);
 637        if (*offset == -1)
 638                *offset = ((time_t)*timestamp - mktime(&tm)) / 60;
 639
 640        if (*timestamp == -1)
 641                return -1;
 642
 643        if (!tm_gmt)
 644                *timestamp -= *offset * 60;
 645        return 0; /* success */
 646}
 647
 648int parse_date(const char *date, char *result, int maxlen)
 649{
 650        unsigned long timestamp;
 651        int offset;
 652        if (parse_date_basic(date, &timestamp, &offset))
 653                return -1;
 654        return date_string(timestamp, offset, result, maxlen);
 655}
 656
 657enum date_mode parse_date_format(const char *format)
 658{
 659        if (!strcmp(format, "relative"))
 660                return DATE_RELATIVE;
 661        else if (!strcmp(format, "iso8601") ||
 662                 !strcmp(format, "iso"))
 663                return DATE_ISO8601;
 664        else if (!strcmp(format, "rfc2822") ||
 665                 !strcmp(format, "rfc"))
 666                return DATE_RFC2822;
 667        else if (!strcmp(format, "short"))
 668                return DATE_SHORT;
 669        else if (!strcmp(format, "local"))
 670                return DATE_LOCAL;
 671        else if (!strcmp(format, "default"))
 672                return DATE_NORMAL;
 673        else if (!strcmp(format, "raw"))
 674                return DATE_RAW;
 675        else
 676                die("unknown date format %s", format);
 677}
 678
 679void datestamp(char *buf, int bufsize)
 680{
 681        time_t now;
 682        int offset;
 683
 684        time(&now);
 685
 686        offset = tm_to_time_t(localtime(&now)) - now;
 687        offset /= 60;
 688
 689        date_string(now, offset, buf, bufsize);
 690}
 691
 692/*
 693 * Relative time update (eg "2 days ago").  If we haven't set the time
 694 * yet, we need to set it from current time.
 695 */
 696static unsigned long update_tm(struct tm *tm, struct tm *now, unsigned long sec)
 697{
 698        time_t n;
 699
 700        if (tm->tm_mday < 0)
 701                tm->tm_mday = now->tm_mday;
 702        if (tm->tm_mon < 0)
 703                tm->tm_mon = now->tm_mon;
 704        if (tm->tm_year < 0) {
 705                tm->tm_year = now->tm_year;
 706                if (tm->tm_mon > now->tm_mon)
 707                        tm->tm_year--;
 708        }
 709
 710        n = mktime(tm) - sec;
 711        localtime_r(&n, tm);
 712        return n;
 713}
 714
 715static void date_now(struct tm *tm, struct tm *now, int *num)
 716{
 717        update_tm(tm, now, 0);
 718}
 719
 720static void date_yesterday(struct tm *tm, struct tm *now, int *num)
 721{
 722        update_tm(tm, now, 24*60*60);
 723}
 724
 725static void date_time(struct tm *tm, struct tm *now, int hour)
 726{
 727        if (tm->tm_hour < hour)
 728                date_yesterday(tm, now, NULL);
 729        tm->tm_hour = hour;
 730        tm->tm_min = 0;
 731        tm->tm_sec = 0;
 732}
 733
 734static void date_midnight(struct tm *tm, struct tm *now, int *num)
 735{
 736        date_time(tm, now, 0);
 737}
 738
 739static void date_noon(struct tm *tm, struct tm *now, int *num)
 740{
 741        date_time(tm, now, 12);
 742}
 743
 744static void date_tea(struct tm *tm, struct tm *now, int *num)
 745{
 746        date_time(tm, now, 17);
 747}
 748
 749static void date_pm(struct tm *tm, struct tm *now, int *num)
 750{
 751        int hour, n = *num;
 752        *num = 0;
 753
 754        hour = tm->tm_hour;
 755        if (n) {
 756                hour = n;
 757                tm->tm_min = 0;
 758                tm->tm_sec = 0;
 759        }
 760        tm->tm_hour = (hour % 12) + 12;
 761}
 762
 763static void date_am(struct tm *tm, struct tm *now, int *num)
 764{
 765        int hour, n = *num;
 766        *num = 0;
 767
 768        hour = tm->tm_hour;
 769        if (n) {
 770                hour = n;
 771                tm->tm_min = 0;
 772                tm->tm_sec = 0;
 773        }
 774        tm->tm_hour = (hour % 12);
 775}
 776
 777static void date_never(struct tm *tm, struct tm *now, int *num)
 778{
 779        time_t n = 0;
 780        localtime_r(&n, tm);
 781}
 782
 783static const struct special {
 784        const char *name;
 785        void (*fn)(struct tm *, struct tm *, int *);
 786} special[] = {
 787        { "yesterday", date_yesterday },
 788        { "noon", date_noon },
 789        { "midnight", date_midnight },
 790        { "tea", date_tea },
 791        { "PM", date_pm },
 792        { "AM", date_am },
 793        { "never", date_never },
 794        { "now", date_now },
 795        { NULL }
 796};
 797
 798static const char *number_name[] = {
 799        "zero", "one", "two", "three", "four",
 800        "five", "six", "seven", "eight", "nine", "ten",
 801};
 802
 803static const struct typelen {
 804        const char *type;
 805        int length;
 806} typelen[] = {
 807        { "seconds", 1 },
 808        { "minutes", 60 },
 809        { "hours", 60*60 },
 810        { "days", 24*60*60 },
 811        { "weeks", 7*24*60*60 },
 812        { NULL }
 813};
 814
 815static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
 816{
 817        const struct typelen *tl;
 818        const struct special *s;
 819        const char *end = date;
 820        int i;
 821
 822        while (isalpha(*++end));
 823                ;
 824
 825        for (i = 0; i < 12; i++) {
 826                int match = match_string(date, month_names[i]);
 827                if (match >= 3) {
 828                        tm->tm_mon = i;
 829                        *touched = 1;
 830                        return end;
 831                }
 832        }
 833
 834        for (s = special; s->name; s++) {
 835                int len = strlen(s->name);
 836                if (match_string(date, s->name) == len) {
 837                        s->fn(tm, now, num);
 838                        *touched = 1;
 839                        return end;
 840                }
 841        }
 842
 843        if (!*num) {
 844                for (i = 1; i < 11; i++) {
 845                        int len = strlen(number_name[i]);
 846                        if (match_string(date, number_name[i]) == len) {
 847                                *num = i;
 848                                *touched = 1;
 849                                return end;
 850                        }
 851                }
 852                if (match_string(date, "last") == 4) {
 853                        *num = 1;
 854                        *touched = 1;
 855                }
 856                return end;
 857        }
 858
 859        tl = typelen;
 860        while (tl->type) {
 861                int len = strlen(tl->type);
 862                if (match_string(date, tl->type) >= len-1) {
 863                        update_tm(tm, now, tl->length * *num);
 864                        *num = 0;
 865                        *touched = 1;
 866                        return end;
 867                }
 868                tl++;
 869        }
 870
 871        for (i = 0; i < 7; i++) {
 872                int match = match_string(date, weekday_names[i]);
 873                if (match >= 3) {
 874                        int diff, n = *num -1;
 875                        *num = 0;
 876
 877                        diff = tm->tm_wday - i;
 878                        if (diff <= 0)
 879                                n++;
 880                        diff += 7*n;
 881
 882                        update_tm(tm, now, diff * 24 * 60 * 60);
 883                        *touched = 1;
 884                        return end;
 885                }
 886        }
 887
 888        if (match_string(date, "months") >= 5) {
 889                int n;
 890                update_tm(tm, now, 0); /* fill in date fields if needed */
 891                n = tm->tm_mon - *num;
 892                *num = 0;
 893                while (n < 0) {
 894                        n += 12;
 895                        tm->tm_year--;
 896                }
 897                tm->tm_mon = n;
 898                *touched = 1;
 899                return end;
 900        }
 901
 902        if (match_string(date, "years") >= 4) {
 903                update_tm(tm, now, 0); /* fill in date fields if needed */
 904                tm->tm_year -= *num;
 905                *num = 0;
 906                *touched = 1;
 907                return end;
 908        }
 909
 910        return end;
 911}
 912
 913static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 914{
 915        char *end;
 916        unsigned long number = strtoul(date, &end, 10);
 917
 918        switch (*end) {
 919        case ':':
 920        case '.':
 921        case '/':
 922        case '-':
 923                if (isdigit(end[1])) {
 924                        int match = match_multi_number(number, *end, date, end, tm);
 925                        if (match)
 926                                return date + match;
 927                }
 928        }
 929
 930        /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
 931        if (date[0] != '0' || end - date <= 2)
 932                *num = number;
 933        return end;
 934}
 935
 936/*
 937 * Do we have a pending number at the end, or when
 938 * we see a new one? Let's assume it's a month day,
 939 * as in "Dec 6, 1992"
 940 */
 941static void pending_number(struct tm *tm, int *num)
 942{
 943        int number = *num;
 944
 945        if (number) {
 946                *num = 0;
 947                if (tm->tm_mday < 0 && number < 32)
 948                        tm->tm_mday = number;
 949                else if (tm->tm_mon < 0 && number < 13)
 950                        tm->tm_mon = number-1;
 951                else if (tm->tm_year < 0) {
 952                        if (number > 1969 && number < 2100)
 953                                tm->tm_year = number - 1900;
 954                        else if (number > 69 && number < 100)
 955                                tm->tm_year = number;
 956                        else if (number < 38)
 957                                tm->tm_year = 100 + number;
 958                        /* We screw up for number = 00 ? */
 959                }
 960        }
 961}
 962
 963static unsigned long approxidate_str(const char *date,
 964                                     const struct timeval *tv,
 965                                     int *error_ret)
 966{
 967        int number = 0;
 968        int touched = 0;
 969        struct tm tm, now;
 970        time_t time_sec;
 971
 972        time_sec = tv->tv_sec;
 973        localtime_r(&time_sec, &tm);
 974        now = tm;
 975
 976        tm.tm_year = -1;
 977        tm.tm_mon = -1;
 978        tm.tm_mday = -1;
 979
 980        for (;;) {
 981                unsigned char c = *date;
 982                if (!c)
 983                        break;
 984                date++;
 985                if (isdigit(c)) {
 986                        pending_number(&tm, &number);
 987                        date = approxidate_digit(date-1, &tm, &number);
 988                        touched = 1;
 989                        continue;
 990                }
 991                if (isalpha(c))
 992                        date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
 993        }
 994        pending_number(&tm, &number);
 995        if (!touched)
 996                *error_ret = 1;
 997        return update_tm(&tm, &now, 0);
 998}
 999
1000unsigned long approxidate_relative(const char *date, const struct timeval *tv)
1001{
1002        unsigned long timestamp;
1003        int offset;
1004        int errors = 0;
1005
1006        if (!parse_date_basic(date, &timestamp, &offset))
1007                return timestamp;
1008        return approxidate_str(date, tv, &errors);
1009}
1010
1011unsigned long approxidate_careful(const char *date, int *error_ret)
1012{
1013        struct timeval tv;
1014        unsigned long timestamp;
1015        int offset;
1016        int dummy = 0;
1017        if (!error_ret)
1018                error_ret = &dummy;
1019
1020        if (!parse_date_basic(date, &timestamp, &offset)) {
1021                *error_ret = 0;
1022                return timestamp;
1023        }
1024
1025        gettimeofday(&tv, NULL);
1026        return approxidate_str(date, &tv, error_ret);
1027}