diff options
Diffstat (limited to 'src/third_party/tz/timegm.c')
| -rw-r--r-- | src/third_party/tz/timegm.c | 713 |
1 files changed, 713 insertions, 0 deletions
diff --git a/src/third_party/tz/timegm.c b/src/third_party/tz/timegm.c new file mode 100644 index 00000000000..e9227430010 --- /dev/null +++ b/src/third_party/tz/timegm.c @@ -0,0 +1,713 @@ +/* +** This file is in the public domain, so clarified as of +** 1996-06-05 by Arthur David Olson. +*/ + +/* +** Leap second handling from Bradley White. +** POSIX-style TZ environment variable handling from Guy Harris. +*/ + +/*LINTLIBRARY*/ + +#include "timegm_private.h" +#include "timegm_tzfile.h" + +#ifndef TZ_ABBR_MAX_LEN +#define TZ_ABBR_MAX_LEN 16 +#endif /* !defined TZ_ABBR_MAX_LEN */ + +#ifndef TZ_ABBR_CHAR_SET +#define TZ_ABBR_CHAR_SET \ + "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._" +#endif /* !defined TZ_ABBR_CHAR_SET */ + +#ifndef TZ_ABBR_ERR_CHAR +#define TZ_ABBR_ERR_CHAR '_' +#endif /* !defined TZ_ABBR_ERR_CHAR */ + +/* +** SunOS 4.1.1 headers lack O_BINARY. +*/ + +#ifdef O_BINARY +#define OPEN_MODE (O_RDONLY | O_BINARY) +#endif /* defined O_BINARY */ +#ifndef O_BINARY +#define OPEN_MODE O_RDONLY +#endif /* !defined O_BINARY */ + +#ifndef WILDABBR +/* +** Someone might make incorrect use of a time zone abbreviation: +** 1. They might reference tzname[0] before calling tzset (explicitly +** or implicitly). +** 2. They might reference tzname[1] before calling tzset (explicitly +** or implicitly). +** 3. They might reference tzname[1] after setting to a time zone +** in which Daylight Saving Time is never observed. +** 4. They might reference tzname[0] after setting to a time zone +** in which Standard Time is never observed. +** 5. They might reference tm.TM_ZONE after calling offtime. +** What's best to do in the above cases is open to debate; +** for now, we just set things up so that in any of the five cases +** WILDABBR is used. Another possibility: initialize tzname[0] to the +** string "tzname[0] used before set", and similarly for the other cases. +** And another: initialize tzname[0] to "ERA", with an explanation in the +** manual page of what this "time zone abbreviation" means (doing this so +** that tzname[0] has the "normal" length of three characters). +*/ +#define WILDABBR " " +#endif /* !defined WILDABBR */ + +static const char wildabbr[] = WILDABBR; + +static const char gmt[] = "GMT"; + +struct ttinfo { /* time type information */ + int_fast32_t tt_gmtoff; /* UT offset in seconds */ + int tt_isdst; /* used to set tm_isdst */ + int tt_abbrind; /* abbreviation list index */ + int tt_ttisstd; /* TRUE if transition is std time */ + int tt_ttisgmt; /* TRUE if transition is UT */ +}; + +struct lsinfo { /* leap second information */ + time_t ls_trans; /* transition time */ + int_fast64_t ls_corr; /* correction to apply */ +}; + +#define BIGGEST(a, b) (((a) > (b)) ? (a) : (b)) + +#ifdef TZNAME_MAX +#define MY_TZNAME_MAX TZNAME_MAX +#endif /* defined TZNAME_MAX */ +#ifndef TZNAME_MAX +#define MY_TZNAME_MAX 255 +#endif /* !defined TZNAME_MAX */ + +struct state { + int leapcnt; + int timecnt; + int typecnt; + int charcnt; + int goback; + int goahead; + time_t ats[TZ_MAX_TIMES]; + unsigned char types[TZ_MAX_TIMES]; + struct ttinfo ttis[TZ_MAX_TYPES]; + char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt), + (2 * (MY_TZNAME_MAX + 1)))]; + struct lsinfo lsis[TZ_MAX_LEAPS]; + int defaulttype; /* for early times or if no transitions */ +}; + +struct rule { + int r_type; /* type of rule--see below */ + int r_day; /* day number of rule */ + int r_week; /* week number of rule */ + int r_mon; /* month number of rule */ + int_fast32_t r_time; /* transition time of rule */ +}; + +#define JULIAN_DAY 0 /* Jn - Julian day */ +#define DAY_OF_YEAR 1 /* n - day of year */ +#define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */ + +/* +** Prototypes for static functions. +*/ + +static void gmtload(struct state * sp); +static struct tm * gmtsub(const time_t * timep, int_fast32_t offset, + struct tm * tmp); +static int increment_overflow(int * number, int delta); +static int leaps_thru_end_of(int y) ATTRIBUTE_PURE; +static int increment_overflow32(int_fast32_t * number, int delta); +static int increment_overflow_time(time_t *t, int_fast32_t delta); +static int normalize_overflow32(int_fast32_t * tensptr, + int * unitsptr, int base); +static int normalize_overflow(int * tensptr, int * unitsptr, + int base); +static time_t time1(struct tm * tmp, + struct tm * (*funcp)(const time_t *, + int_fast32_t, struct tm *), + int_fast32_t offset); +static time_t time2(struct tm *tmp, + struct tm * (*funcp)(const time_t *, + int_fast32_t, struct tm*), + int_fast32_t offset, int * okayp); +static time_t time2sub(struct tm *tmp, + struct tm * (*funcp)(const time_t *, + int_fast32_t, struct tm*), + int_fast32_t offset, int * okayp, int do_norm_secs); +static struct tm * timesub(const time_t * timep, int_fast32_t offset, + const struct state * sp, struct tm * tmp); +static int tmcomp(const struct tm * atmp, + const struct tm * btmp); + +static struct state gmtmem; +#define gmtptr (&gmtmem) + +static int gmt_is_set; + +static const int mon_lengths[2][MONSPERYEAR] = { + { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, + { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } +}; + +static const int year_lengths[2] = { + DAYSPERNYEAR, DAYSPERLYEAR +}; + +static void +gmtload(struct state *const sp) +{ + memset(sp, 0, sizeof(struct state)); + sp->typecnt = 1; + sp->charcnt = 4; + sp->chars[0] = 'G'; + sp->chars[1] = 'M'; + sp->chars[2] = 'T'; +} + +/* +** gmtsub is to gmtime as localsub is to localtime. +*/ + +static struct tm * +gmtsub(const time_t *const timep, const int_fast32_t offset, + struct tm *const tmp) +{ + register struct tm * result; + + if (!gmt_is_set) { + gmt_is_set = TRUE; + if (gmtptr != NULL) + gmtload(gmtptr); + } + result = timesub(timep, offset, gmtptr, tmp); +#ifdef TM_ZONE + /* + ** Could get fancy here and deliver something such as + ** "UT+xxxx" or "UT-xxxx" if offset is non-zero, + ** but this is no time for a treasure hunt. + */ + tmp->TM_ZONE = offset ? wildabbr : gmtptr ? gmtptr->chars : gmt; +#endif /* defined TM_ZONE */ + return result; +} + +/* +** Return the number of leap years through the end of the given year +** where, to make the math easy, the answer for year zero is defined as zero. +*/ + +static int +leaps_thru_end_of(register const int y) +{ + return (y >= 0) ? (y / 4 - y / 100 + y / 400) : + -(leaps_thru_end_of(-(y + 1)) + 1); +} + +static struct tm * +timesub(const time_t *const timep, const int_fast32_t offset, + register const struct state *const sp, + register struct tm *const tmp) +{ + register const struct lsinfo * lp; + register time_t tdays; + register int idays; /* unsigned would be so 2003 */ + register int_fast64_t rem; + int y; + register const int * ip; + register int_fast64_t corr; + register int hit; + register int i; + + corr = 0; + hit = 0; + i = (sp == NULL) ? 0 : sp->leapcnt; + while (--i >= 0) { + lp = &sp->lsis[i]; + if (*timep >= lp->ls_trans) { + if (*timep == lp->ls_trans) { + hit = ((i == 0 && lp->ls_corr > 0) || + lp->ls_corr > sp->lsis[i - 1].ls_corr); + if (hit) + while (i > 0 && + sp->lsis[i].ls_trans == + sp->lsis[i - 1].ls_trans + 1 && + sp->lsis[i].ls_corr == + sp->lsis[i - 1].ls_corr + 1) { + ++hit; + --i; + } + } + corr = lp->ls_corr; + break; + } + } + y = EPOCH_YEAR; + tdays = *timep / SECSPERDAY; + rem = *timep - tdays * SECSPERDAY; + while (tdays < 0 || tdays >= year_lengths[isleap(y)]) { + int newy; + register time_t tdelta; + register int idelta; + register int leapdays; + + tdelta = tdays / DAYSPERLYEAR; + if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta) + && tdelta <= INT_MAX)) + return NULL; + idelta = tdelta; + if (idelta == 0) + idelta = (tdays < 0) ? -1 : 1; + newy = y; + if (increment_overflow(&newy, idelta)) + return NULL; + leapdays = leaps_thru_end_of(newy - 1) - + leaps_thru_end_of(y - 1); + tdays -= ((time_t) newy - y) * DAYSPERNYEAR; + tdays -= leapdays; + y = newy; + } + { + register int_fast32_t seconds; + + seconds = tdays * SECSPERDAY; + tdays = seconds / SECSPERDAY; + rem += seconds - tdays * SECSPERDAY; + } + /* + ** Given the range, we can now fearlessly cast... + */ + idays = tdays; + rem += offset - corr; + while (rem < 0) { + rem += SECSPERDAY; + --idays; + } + while (rem >= SECSPERDAY) { + rem -= SECSPERDAY; + ++idays; + } + while (idays < 0) { + if (increment_overflow(&y, -1)) + return NULL; + idays += year_lengths[isleap(y)]; + } + while (idays >= year_lengths[isleap(y)]) { + idays -= year_lengths[isleap(y)]; + if (increment_overflow(&y, 1)) + return NULL; + } + tmp->tm_year = y; + if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE)) + return NULL; + tmp->tm_yday = idays; + /* + ** The "extra" mods below avoid overflow problems. + */ + tmp->tm_wday = EPOCH_WDAY + + ((y - EPOCH_YEAR) % DAYSPERWEEK) * + (DAYSPERNYEAR % DAYSPERWEEK) + + leaps_thru_end_of(y - 1) - + leaps_thru_end_of(EPOCH_YEAR - 1) + + idays; + tmp->tm_wday %= DAYSPERWEEK; + if (tmp->tm_wday < 0) + tmp->tm_wday += DAYSPERWEEK; + tmp->tm_hour = (int) (rem / SECSPERHOUR); + rem %= SECSPERHOUR; + tmp->tm_min = (int) (rem / SECSPERMIN); + /* + ** A positive leap second requires a special + ** representation. This uses "... ??:59:60" et seq. + */ + tmp->tm_sec = (int) (rem % SECSPERMIN) + hit; + ip = mon_lengths[isleap(y)]; + for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon)) + idays -= ip[tmp->tm_mon]; + tmp->tm_mday = (int) (idays + 1); + tmp->tm_isdst = 0; +#ifdef TM_GMTOFF + tmp->TM_GMTOFF = offset; +#endif /* defined TM_GMTOFF */ + return tmp; +} + +/* +** Adapted from code provided by Robert Elz, who writes: +** The "best" way to do mktime I think is based on an idea of Bob +** Kridle's (so its said...) from a long time ago. +** It does a binary search of the time_t space. Since time_t's are +** just 32 bits, its a max of 32 iterations (even at 64 bits it +** would still be very reasonable). +*/ + +#ifndef WRONG +#define WRONG (-1) +#endif /* !defined WRONG */ + +/* +** Normalize logic courtesy Paul Eggert. +*/ + +static int +increment_overflow(int *const ip, int j) +{ + register int const i = *ip; + + /* + ** If i >= 0 there can only be overflow if i + j > INT_MAX + ** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow. + ** If i < 0 there can only be overflow if i + j < INT_MIN + ** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow. + */ + if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i)) + return TRUE; + *ip += j; + return FALSE; +} + +static int +increment_overflow32(int_fast32_t *const lp, int const m) +{ + register int_fast32_t const l = *lp; + + if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l)) + return TRUE; + *lp += m; + return FALSE; +} + +static int +increment_overflow_time(time_t *tp, int_fast32_t j) +{ + /* + ** This is like + ** 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...', + ** except that it does the right thing even if *tp + j would overflow. + */ + if (! (j < 0 + ? (TYPE_SIGNED(time_t) ? time_t_min - j <= *tp : -1 - j < *tp) + : *tp <= time_t_max - j)) + return TRUE; + *tp += j; + return FALSE; +} + +static int +normalize_overflow(int *const tensptr, int *const unitsptr, const int base) +{ + register int tensdelta; + + tensdelta = (*unitsptr >= 0) ? + (*unitsptr / base) : + (-1 - (-1 - *unitsptr) / base); + *unitsptr -= tensdelta * base; + return increment_overflow(tensptr, tensdelta); +} + +static int +normalize_overflow32(int_fast32_t *const tensptr, int *const unitsptr, + const int base) +{ + register int tensdelta; + + tensdelta = (*unitsptr >= 0) ? + (*unitsptr / base) : + (-1 - (-1 - *unitsptr) / base); + *unitsptr -= tensdelta * base; + return increment_overflow32(tensptr, tensdelta); +} + +static int +tmcomp(register const struct tm *const atmp, + register const struct tm *const btmp) +{ + register int result; + + if (atmp->tm_year != btmp->tm_year) + return atmp->tm_year < btmp->tm_year ? -1 : 1; + if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 && + (result = (atmp->tm_mday - btmp->tm_mday)) == 0 && + (result = (atmp->tm_hour - btmp->tm_hour)) == 0 && + (result = (atmp->tm_min - btmp->tm_min)) == 0) + result = atmp->tm_sec - btmp->tm_sec; + return result; +} + +static time_t +time2sub(struct tm *const tmp, + struct tm *(*const funcp)(const time_t *, int_fast32_t, struct tm *), + const int_fast32_t offset, + int *const okayp, + const int do_norm_secs) +{ + register const struct state * sp; + register int dir; + register int i, j; + register int saved_seconds; + register int_fast32_t li; + register time_t lo; + register time_t hi; + int_fast32_t y; + time_t newt; + time_t t; + struct tm yourtm, mytm; + + *okayp = FALSE; + yourtm = *tmp; + if (do_norm_secs) { + if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec, + SECSPERMIN)) + return WRONG; + } + if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR)) + return WRONG; + if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY)) + return WRONG; + y = yourtm.tm_year; + if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR)) + return WRONG; + /* + ** Turn y into an actual year number for now. + ** It is converted back to an offset from TM_YEAR_BASE later. + */ + if (increment_overflow32(&y, TM_YEAR_BASE)) + return WRONG; + while (yourtm.tm_mday <= 0) { + if (increment_overflow32(&y, -1)) + return WRONG; + li = y + (1 < yourtm.tm_mon); + yourtm.tm_mday += year_lengths[isleap(li)]; + } + while (yourtm.tm_mday > DAYSPERLYEAR) { + li = y + (1 < yourtm.tm_mon); + yourtm.tm_mday -= year_lengths[isleap(li)]; + if (increment_overflow32(&y, 1)) + return WRONG; + } + for ( ; ; ) { + i = mon_lengths[isleap(y)][yourtm.tm_mon]; + if (yourtm.tm_mday <= i) + break; + yourtm.tm_mday -= i; + if (++yourtm.tm_mon >= MONSPERYEAR) { + yourtm.tm_mon = 0; + if (increment_overflow32(&y, 1)) + return WRONG; + } + } + if (increment_overflow32(&y, -TM_YEAR_BASE)) + return WRONG; + yourtm.tm_year = y; + if (yourtm.tm_year != y) + return WRONG; + if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN) + saved_seconds = 0; + else if (y + TM_YEAR_BASE < EPOCH_YEAR) { + /* + ** We can't set tm_sec to 0, because that might push the + ** time below the minimum representable time. + ** Set tm_sec to 59 instead. + ** This assumes that the minimum representable time is + ** not in the same minute that a leap second was deleted from, + ** which is a safer assumption than using 58 would be. + */ + if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN)) + return WRONG; + saved_seconds = yourtm.tm_sec; + yourtm.tm_sec = SECSPERMIN - 1; + } else { + saved_seconds = yourtm.tm_sec; + yourtm.tm_sec = 0; + } + /* + ** Do a binary search (this works whatever time_t's type is). + */ + if (!TYPE_SIGNED(time_t)) { + lo = 0; + hi = lo - 1; + } else { + lo = 1; + for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i) + lo *= 2; + hi = -(lo + 1); + } + for ( ; ; ) { + t = lo / 2 + hi / 2; + if (t < lo) + t = lo; + else if (t > hi) + t = hi; + if ((*funcp)(&t, offset, &mytm) == NULL) { + /* + ** Assume that t is too extreme to be represented in + ** a struct tm; arrange things so that it is less + ** extreme on the next pass. + */ + dir = (t > 0) ? 1 : -1; + } else dir = tmcomp(&mytm, &yourtm); + if (dir != 0) { + if (t == lo) { + if (t == time_t_max) + return WRONG; + ++t; + ++lo; + } else if (t == hi) { + if (t == time_t_min) + return WRONG; + --t; + --hi; + } + if (lo > hi) + return WRONG; + if (dir > 0) + hi = t; + else lo = t; + continue; + } + if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst) + break; + /* + ** Right time, wrong type. + ** Hunt for right time, right type. + ** It's okay to guess wrong since the guess + ** gets checked. + */ + sp = (const struct state *) gmtptr; + if (sp == NULL) + return WRONG; + for (i = sp->typecnt - 1; i >= 0; --i) { + if (sp->ttis[i].tt_isdst != yourtm.tm_isdst) + continue; + for (j = sp->typecnt - 1; j >= 0; --j) { + if (sp->ttis[j].tt_isdst == yourtm.tm_isdst) + continue; + newt = t + sp->ttis[j].tt_gmtoff - + sp->ttis[i].tt_gmtoff; + if ((*funcp)(&newt, offset, &mytm) == NULL) + continue; + if (tmcomp(&mytm, &yourtm) != 0) + continue; + if (mytm.tm_isdst != yourtm.tm_isdst) + continue; + /* + ** We have a match. + */ + t = newt; + goto label; + } + } + return WRONG; + } +label: + newt = t + saved_seconds; + if ((newt < t) != (saved_seconds < 0)) + return WRONG; + t = newt; + if ((*funcp)(&t, offset, tmp)) + *okayp = TRUE; + return t; +} + +static time_t +time2(struct tm * const tmp, + struct tm * (*const funcp)(const time_t *, int_fast32_t, struct tm *), + const int_fast32_t offset, + int *const okayp) +{ + time_t t; + + /* + ** First try without normalization of seconds + ** (in case tm_sec contains a value associated with a leap second). + ** If that fails, try with normalization of seconds. + */ + t = time2sub(tmp, funcp, offset, okayp, FALSE); + return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE); +} + +static time_t +time1(struct tm *const tmp, + struct tm *(*const funcp) (const time_t *, int_fast32_t, struct tm *), + const int_fast32_t offset) +{ + register time_t t; + register const struct state * sp; + register int samei, otheri; + register int sameind, otherind; + register int i; + register int nseen; + int seen[TZ_MAX_TYPES]; + int types[TZ_MAX_TYPES]; + int okay; + + if (tmp == NULL) { + errno = EINVAL; + return WRONG; + } + if (tmp->tm_isdst > 1) + tmp->tm_isdst = 1; + t = time2(tmp, funcp, offset, &okay); + if (okay) + return t; + if (tmp->tm_isdst < 0) +#ifdef PCTS + /* + ** POSIX Conformance Test Suite code courtesy Grant Sullivan. + */ + tmp->tm_isdst = 0; /* reset to std and try again */ +#else + return t; +#endif /* !defined PCTS */ + /* + ** We're supposed to assume that somebody took a time of one type + ** and did some math on it that yielded a "struct tm" that's bad. + ** We try to divine the type they started from and adjust to the + ** type they need. + */ + sp = (const struct state *) gmtptr; + if (sp == NULL) + return WRONG; + for (i = 0; i < sp->typecnt; ++i) + seen[i] = FALSE; + nseen = 0; + for (i = sp->timecnt - 1; i >= 0; --i) + if (!seen[sp->types[i]]) { + seen[sp->types[i]] = TRUE; + types[nseen++] = sp->types[i]; + } + for (sameind = 0; sameind < nseen; ++sameind) { + samei = types[sameind]; + if (sp->ttis[samei].tt_isdst != tmp->tm_isdst) + continue; + for (otherind = 0; otherind < nseen; ++otherind) { + otheri = types[otherind]; + if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst) + continue; + tmp->tm_sec += sp->ttis[otheri].tt_gmtoff - + sp->ttis[samei].tt_gmtoff; + tmp->tm_isdst = !tmp->tm_isdst; + t = time2(tmp, funcp, offset, &okay); + if (okay) + return t; + tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff - + sp->ttis[samei].tt_gmtoff; + tmp->tm_isdst = !tmp->tm_isdst; + } + } + return WRONG; +} + +time_t +timegm(struct tm *const tmp) +{ + if (tmp != NULL) + tmp->tm_isdst = 0; + return time1(tmp, gmtsub, 0L); +} |