headers/bsd: Add sys/queue.h.

[haiku.git] / src / system / libroot / posix / time / localtime_fading_out.c

/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/

#ifndef lint
#ifndef NOID
static char     elsieid[] = "@(#)localtime.c    8.5";
#endif /* !defined NOID */
#endif /* !defined lint */

/*
** Leap second handling from Bradley White.
** POSIX-style TZ environment variable handling from Guy Harris.
*/

/*LINTLIBRARY*/

#include "private.h"
#include "tzfile.h"
#include "fcntl.h"
#include "float.h"      /* for FLT_MAX and DBL_MAX */

#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 char             wildabbr[] = WILDABBR;

static const char       gmt[] = "GMT";

/*
** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
** We default to US rules as of 1999-08-17.
** POSIX 1003.1 section 8.1.1 says that the default DST rules are
** implementation dependent; for historical reasons, US rules are a
** common default.
*/
#ifndef TZDEFRULESTRING
#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
#endif /* !defined TZDEFDST */

struct ttinfo {                         /* time type information */
        long            tt_gmtoff;      /* UTC 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 UTC */
};

struct lsinfo {                         /* leap second information */
        time_t          ls_trans;       /* transition time */
        long            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];
};

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 */
        long            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 struct tm *      gmtsub P((const time_t * timep, long offset,
                                struct tm * tmp));
static struct tm *      localsub P((const time_t * timep, long offset,
                                struct tm * tmp));
static int              increment_overflow P((int * number, int delta));
static int              leaps_thru_end_of P((int y));
static int              long_increment_overflow P((long * number, int delta));
static int              long_normalize_overflow P((long * tensptr,
                                int * unitsptr, int base));
static int              normalize_overflow P((int * tensptr, int * unitsptr,
                                int base));
static time_t           time1 P((struct tm * tmp,
                                struct tm * (*funcp) P((const time_t *,
                                long, struct tm *)),
                                long offset));
static time_t           time2 P((struct tm *tmp,
                                struct tm * (*funcp) P((const time_t *,
                                long, struct tm*)),
                                long offset, int * okayp));
static time_t           time2sub P((struct tm *tmp,
                                struct tm * (*funcp) P((const time_t *,
                                long, struct tm*)),
                                long offset, int * okayp, int do_norm_secs));
static struct tm *      timesub P((const time_t * timep, long offset,
                                const struct state * sp, struct tm * tmp));
static int              tmcomp P((const struct tm * atmp,
                                const struct tm * btmp));

/*
** Other prototypes.
*/
struct tm* __gmtime_r_fallback(const time_t* timep, struct tm* tmp);
time_t __mktime_fallback(struct tm* tmp);
time_t timegm(struct tm* const tmp);

static struct state     lclmem;
static struct state     gmtmem;
#define lclptr          (&lclmem)
#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
};

/*
** The easy way to behave "as if no library function calls" localtime
** is to not call it--so we drop its guts into "localsub", which can be
** freely called. (And no, the PANS doesn't require the above behavior--
** but it *is* desirable.)
**
** The unused offset argument is for the benefit of mktime variants.
*/

/*ARGSUSED*/
static struct tm *
localsub(timep, offset, tmp)
const time_t * const    timep;
const long              offset;
struct tm * const       tmp;
{
        register struct state *         sp;
        register const struct ttinfo *  ttisp;
        register int                    i;
        register struct tm *            result;
        const time_t                    t = *timep;

        sp = lclptr;
        if ((sp->goback && t < sp->ats[0]) ||
                (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
                        time_t                  newt = t;
                        register time_t         seconds;
                        register time_t         tcycles;
                        register int_fast64_t   icycles;

                        if (t < sp->ats[0])
                                seconds = sp->ats[0] - t;
                        else    seconds = t - sp->ats[sp->timecnt - 1];
                        --seconds;
                        tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
                        ++tcycles;
                        icycles = tcycles;
                        if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
                                return NULL;
                        seconds = icycles;
                        seconds *= YEARSPERREPEAT;
                        seconds *= AVGSECSPERYEAR;
                        if (t < sp->ats[0])
                                newt += seconds;
                        else    newt -= seconds;
                        if (newt < sp->ats[0] ||
                                newt > sp->ats[sp->timecnt - 1])
                                        return NULL;    /* "cannot happen" */
                        result = localsub(&newt, offset, tmp);
                        if (result == tmp) {
                                register time_t newy;

                                newy = tmp->tm_year;
                                if (t < sp->ats[0])
                                        newy -= icycles * YEARSPERREPEAT;
                                else    newy += icycles * YEARSPERREPEAT;
                                tmp->tm_year = newy;
                                if (tmp->tm_year != newy)
                                        return NULL;
                        }
                        return result;
        }
        if (sp->timecnt == 0 || t < sp->ats[0]) {
                i = 0;
                while (sp->ttis[i].tt_isdst)
                        if (++i >= sp->typecnt) {
                                i = 0;
                                break;
                        }
        } else {
                register int    lo = 1;
                register int    hi = sp->timecnt;

                while (lo < hi) {
                        register int    mid = (lo + hi) >> 1;

                        if (t < sp->ats[mid])
                                hi = mid;
                        else    lo = mid + 1;
                }
                i = (int) sp->types[lo - 1];
        }
        ttisp = &sp->ttis[i];
        /*
        ** To get (wrong) behavior that's compatible with System V Release 2.0
        ** you'd replace the statement below with
        **      t += ttisp->tt_gmtoff;
        **      timesub(&t, 0L, sp, tmp);
        */
        result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
        tmp->tm_isdst = ttisp->tt_isdst;
        tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
#ifdef TM_ZONE
        tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
#endif /* defined TM_ZONE */
        return result;
}


/*
** gmtsub is to gmtime as localsub is to localtime.
*/

static struct tm *
gmtsub(timep, offset, tmp)
const time_t * const    timep;
const long              offset;
struct tm * const       tmp;
{
        register struct tm *    result;

        if (!gmt_is_set)
                gmt_is_set = TRUE;
        result = timesub(timep, offset, gmtptr, tmp);
#ifdef TM_ZONE
        /*
        ** Could get fancy here and deliver something such as
        ** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
        ** but this is no time for a treasure hunt.
        */
        if (offset != 0)
                tmp->TM_ZONE = wildabbr;
        else
                tmp->TM_ZONE = gmtptr->chars;
#endif /* defined TM_ZONE */
        return result;
}



// used in Haiku as fallback when the locale backend could not be loaded
struct tm*
__gmtime_r_fallback(const time_t* timep, struct tm* tmp)
{
        return gmtsub(timep, 0L, tmp);
}

/*
** 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(y)
register const int      y;
{
        return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
                -(leaps_thru_end_of(-(y + 1)) + 1);
}

static struct tm *
timesub(timep, offset, sp, tmp)
const time_t * const                    timep;
const long                              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 long                   rem;
        int                             y;
        register const int *            ip;
        register long                   corr;
        register int                    hit;
        register int                    i;

        corr = 0;
        hit = 0;
        i = 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;
                idelta = tdelta;
                if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
                        return NULL;
                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 long   seconds;

                seconds = tdays * SECSPERDAY + 0.5;
                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 */

/*
** Simplified normalize logic courtesy Paul Eggert.
*/

static int
increment_overflow(number, delta)
int *   number;
int     delta;
{
        int     number0;

        number0 = *number;
        *number += delta;
        return (*number < number0) != (delta < 0);
}

static int
long_increment_overflow(number, delta)
long *  number;
int     delta;
{
        long    number0;

        number0 = *number;
        *number += delta;
        return (*number < number0) != (delta < 0);
}

static int
normalize_overflow(tensptr, unitsptr, base)
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
long_normalize_overflow(tensptr, unitsptr, base)
long * const    tensptr;
int * const     unitsptr;
const int       base;
{
        register int    tensdelta;

        tensdelta = (*unitsptr >= 0) ?
                (*unitsptr / base) :
                (-1 - (-1 - *unitsptr) / base);
        *unitsptr -= tensdelta * base;
        return long_increment_overflow(tensptr, tensdelta);
}

static int
tmcomp(atmp, btmp)
register const struct tm * const atmp;
register const struct tm * const btmp;
{
        register int    result;

        if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
                (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(tmp, funcp, offset, okayp, do_norm_secs)
struct tm * const       tmp;
struct tm * (* const    funcp) P((const time_t*, long, struct tm*));
const long              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 long                   li;
        register time_t                 lo;
        register time_t                 hi;
        long                            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 (long_normalize_overflow(&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 (long_increment_overflow(&y, TM_YEAR_BASE))
                return WRONG;
        while (yourtm.tm_mday <= 0) {
                if (long_increment_overflow(&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 (long_increment_overflow(&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 (long_increment_overflow(&y, 1))
                                return WRONG;
                }
        }
        if (long_increment_overflow(&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 if (!TYPE_INTEGRAL(time_t)) {
                if (sizeof(time_t) > sizeof(float))
                        hi = (time_t) DBL_MAX;
                else    hi = (time_t) FLT_MAX;
                lo = -hi;
        } 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) {
                                ++t;
                                if (t <= lo)
                                        return WRONG;
                                ++lo;
                        } else if (t == hi) {
                                --t;
                                if (t >= hi)
                                        return WRONG;
                                --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.
                */
                /*
                ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
                */
                sp = (const struct state *)
                        (((void *) funcp == (void *) localsub) ?
                        lclptr : gmtptr);
                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(tmp, funcp, offset, okayp)
struct tm * const       tmp;
struct tm * (* const    funcp) P((const time_t*, long, struct tm*));
const long              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(tmp, funcp, offset)
struct tm * const       tmp;
struct tm * (* const    funcp) P((const time_t *, long, struct tm *));
const long              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->tm_isdst > 1)
                tmp->tm_isdst = 1;
        t = time2(tmp, funcp, offset, &okay);
        /*
        ** PCTS code courtesy Grant Sullivan.
        */
        if (okay)
                return t;
        if (tmp->tm_isdst < 0)
                tmp->tm_isdst = 0;      /* reset to std and try again */
        /*
        ** 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.
        */
        /*
        ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
        */
        sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
                lclptr : gmtptr);
        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;
}


// used in Haiku as fallback when the locale backend could not be loaded
time_t
__mktime_fallback(struct tm* tmp)
{
        return time1(tmp, localsub, 0L);
}



time_t
timegm(tmp)
struct tm * const       tmp;
{
        tmp->tm_isdst = 0;
        return time1(tmp, gmtsub, 0L);
}