Remove building with NOCRYPTO option

[minix3.git] / lib / libc / time / localtime.c

/*      $NetBSD: localtime.c,v 1.98 2015/10/09 17:21:45 christos Exp $  */

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

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char     elsieid[] = "@(#)localtime.c    8.17";
#else
__RCSID("$NetBSD: localtime.c,v 1.98 2015/10/09 17:21:45 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

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

/*LINTLIBRARY*/

#include "namespace.h"
#include <assert.h>
#define LOCALTIME_IMPLEMENTATION
#include "private.h"

#include "tzfile.h"
#include "fcntl.h"
#include "reentrant.h"

#if NETBSD_INSPIRED
# define NETBSD_INSPIRED_EXTERN
#else
# define NETBSD_INSPIRED_EXTERN static
#endif

#if defined(__weak_alias)
__weak_alias(daylight,_daylight)
__weak_alias(tzname,_tzname)
#endif

#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 | O_CLOEXEC)
#endif /* defined O_BINARY */
#ifndef O_BINARY
#define OPEN_MODE       (O_RDONLY | O_CLOEXEC)
#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";

/*
** 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 */
        int_fast32_t    tt_gmtoff;      /* UT offset in seconds */
        bool            tt_isdst;       /* used to set tm_isdst */
        int             tt_abbrind;     /* abbreviation list index */
        bool            tt_ttisstd;     /* transition is std time */
        bool            tt_ttisgmt;     /* transition is UT */
};

struct lsinfo {                         /* leap second information */
        time_t          ls_trans;       /* transition time */
        int_fast64_t    ls_corr;        /* correction to apply */
};

#define SMALLEST(a, b)  (((a) < (b)) ? (a) : (b))
#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 */

#define state __state
struct state {
        int             leapcnt;
        int             timecnt;
        int             typecnt;
        int             charcnt;
        bool            goback;
        bool            goahead;
        time_t          ats[TZ_MAX_TIMES];
        unsigned char   types[TZ_MAX_TIMES];
        struct ttinfo   ttis[TZ_MAX_TYPES];
        char            chars[/*CONSTCOND*/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 */
};

enum r_type {
  JULIAN_DAY,           /* Jn = Julian day */
  DAY_OF_YEAR,          /* n = day of year */
  MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
};

struct rule {
        enum r_type     r_type;         /* type of rule */
        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 */
};

static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
                         struct tm *);
static bool increment_overflow(int *, int);
static bool increment_overflow_time(time_t *, int_fast32_t);
static bool normalize_overflow32(int_fast32_t *, int *, int);
static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
                          struct tm *);
static bool typesequiv(struct state const *, int, int);
static bool tzparse(char const *, struct state *, bool);

static timezone_t lclptr;
static timezone_t gmtptr;

#ifndef TZ_STRLEN_MAX
#define TZ_STRLEN_MAX 255
#endif /* !defined TZ_STRLEN_MAX */

static char             lcl_TZname[TZ_STRLEN_MAX + 1];
static int              lcl_is_set;

#if !defined(__LIBC12_SOURCE__)

__aconst char *         tzname[2] = {
        (__aconst char *)__UNCONST(wildabbr),
        (__aconst char *)__UNCONST(wildabbr)
};

#else

extern __aconst char *  tzname[2];

#endif

#ifdef _REENTRANT
static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
#endif

/*
** Section 4.12.3 of X3.159-1989 requires that
**      Except for the strftime function, these functions [asctime,
**      ctime, gmtime, localtime] return values in one of two static
**      objects: a broken-down time structure and an array of char.
** Thanks to Paul Eggert for noting this.
*/

static struct tm        tm;

#ifdef USG_COMPAT
#if !defined(__LIBC12_SOURCE__)
long                    timezone = 0;
int                     daylight = 0;
#else
extern int              daylight;
extern long             timezone __RENAME(__timezone13);
#endif
#endif /* defined USG_COMPAT */

#ifdef ALTZONE
long                    altzone = 0;
#endif /* defined ALTZONE */

/* Initialize *S to a value based on GMTOFF, ISDST, and ABBRIND.  */
static void
init_ttinfo(struct ttinfo *s, int_fast32_t gmtoff, bool isdst, int abbrind)
{
        s->tt_gmtoff = gmtoff;
        s->tt_isdst = isdst;
        s->tt_abbrind = abbrind;
        s->tt_ttisstd = false;
        s->tt_ttisgmt = false;
}

static int_fast32_t
detzcode(const char *const codep)
{
        int_fast32_t result;
        int     i;
        int_fast32_t one = 1;
        int_fast32_t halfmaxval = one << (32 - 2);
        int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
        int_fast32_t minval = -1 - maxval;

        result = codep[0] & 0x7f;
        for (i = 1; i < 4; ++i)
                result = (result << 8) | (codep[i] & 0xff);

        if (codep[0] & 0x80) {
          /* Do two's-complement negation even on non-two's-complement machines.
             If the result would be minval - 1, return minval.  */
            result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
            result += minval;
        }
        return result;
}

static int_fast64_t
detzcode64(const char *const codep)
{
        int_fast64_t result;
        int     i;
        int_fast64_t one = 1;
        int_fast64_t halfmaxval = one << (64 - 2);
        int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
        int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;

        result = codep[0] & 0x7f;
        for (i = 1; i < 8; ++i)
                result = (result << 8) | (codep[i] & 0xff);

        if (codep[0] & 0x80) {
          /* Do two's-complement negation even on non-two's-complement machines.
             If the result would be minval - 1, return minval.  */
          result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
          result += minval;
        }
        return result;
}

const char *
tzgetname(const timezone_t sp, int isdst)
{
        int i;
        for (i = 0; i < sp->timecnt; ++i) {
                const struct ttinfo *const ttisp = &sp->ttis[sp->types[i]];

                if (ttisp->tt_isdst == isdst)
                        return &sp->chars[ttisp->tt_abbrind];
        }
        errno = ESRCH;
        return NULL;
}

static void
scrub_abbrs(struct state *sp)
{
        int i;

        /*
        ** First, replace bogus characters.
        */
        for (i = 0; i < sp->charcnt; ++i)
                if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
                        sp->chars[i] = TZ_ABBR_ERR_CHAR;
        /*
        ** Second, truncate long abbreviations.
        */
        for (i = 0; i < sp->typecnt; ++i) {
                const struct ttinfo * const     ttisp = &sp->ttis[i];
                char *                          cp = &sp->chars[ttisp->tt_abbrind];

                if (strlen(cp) > TZ_ABBR_MAX_LEN &&
                        strcmp(cp, GRANDPARENTED) != 0)
                                *(cp + TZ_ABBR_MAX_LEN) = '\0';
        }
}

static void
update_tzname_etc(const struct state *sp, const struct ttinfo *ttisp)
{
        tzname[ttisp->tt_isdst] = __UNCONST(&sp->chars[ttisp->tt_abbrind]);
#ifdef USG_COMPAT
        if (!ttisp->tt_isdst)
                timezone = - ttisp->tt_gmtoff;
#endif
#ifdef ALTZONE
        if (ttisp->tt_isdst)
            altzone = - ttisp->tt_gmtoff;
#endif /* defined ALTZONE */
}

static void
settzname(void)
{
        timezone_t const        sp = lclptr;
        int                     i;

        tzname[0] = (__aconst char *)__UNCONST(wildabbr);
        tzname[1] = (__aconst char *)__UNCONST(wildabbr);
#ifdef USG_COMPAT
        daylight = 0;
        timezone = 0;
#endif /* defined USG_COMPAT */
#ifdef ALTZONE
        altzone = 0;
#endif /* defined ALTZONE */
        if (sp == NULL) {
                tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
                return;
        }
        /*
        ** And to get the latest zone names into tzname. . .
        */
        for (i = 0; i < sp->typecnt; ++i)
                update_tzname_etc(sp, &sp->ttis[i]);

        for (i = 0; i < sp->timecnt; ++i) {
                const struct ttinfo * const ttisp = &sp->ttis[sp->types[i]];
                update_tzname_etc(sp, ttisp);
#ifdef USG_COMPAT
                if (ttisp->tt_isdst)
                        daylight = 1;
#endif /* defined USG_COMPAT */
        }
}

static bool
differ_by_repeat(const time_t t1, const time_t t0)
{
        if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
                return 0;
        return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
}

union input_buffer {
        /* The first part of the buffer, interpreted as a header.  */
        struct tzhead tzhead;

        /* The entire buffer.  */
        char buf[2 * sizeof(struct tzhead) + 2 * sizeof (struct state)
          + 4 * TZ_MAX_TIMES];
};

/* Local storage needed for 'tzloadbody'.  */
union local_storage {
        /* The file name to be opened.  */
        char fullname[FILENAME_MAX + 1];

        /* The results of analyzing the file's contents after it is opened.  */
        struct {
                /* The input buffer.  */
                union input_buffer u;

                /* A temporary state used for parsing a TZ string in the file.  */
                struct state st;
        } u;
};

/* Load tz data from the file named NAME into *SP.  Read extended
   format if DOEXTEND.  Use *LSP for temporary storage.  Return 0 on
   success, an errno value on failure.  */
static int
tzloadbody(char const *name, struct state *sp, bool doextend,
  union local_storage *lsp)
{
        int                     i;
        int                     fid;
        int                     stored;
        ssize_t                 nread;
        bool                    doaccess;
        char                    *fullname = lsp->fullname;
        union input_buffer      *up = &lsp->u.u;
        size_t                  tzheadsize = sizeof(struct tzhead);

        sp->goback = sp->goahead = false;

        if (! name) {
                name = TZDEFAULT;
                if (! name)
                        return EINVAL;
        }

        if (name[0] == ':')
                ++name;
        doaccess = name[0] == '/';
        if (!doaccess) {
                char const *p = TZDIR;
                if (! p)
                        return EINVAL;
                if (sizeof lsp->fullname - 1 <= strlen(p) + strlen(name))
                        return ENAMETOOLONG;
                strcpy(fullname, p);
                strcat(fullname, "/");
                strcat(fullname, name);
                /* Set doaccess if '.' (as in "../") shows up in name.  */
                if (strchr(name, '.'))
                        doaccess = true;
                name = fullname;
        }
        if (doaccess && access(name, R_OK) != 0)
                return errno;

        fid = open(name, OPEN_MODE);
        if (fid < 0)
                return errno;
        nread = read(fid, up->buf, sizeof up->buf);
        if (nread < (ssize_t)tzheadsize) {
                int err = nread < 0 ? errno : EINVAL;
                close(fid);
                return err;
        }
        if (close(fid) < 0)
                return errno;
        for (stored = 4; stored <= 8; stored *= 2) {
                int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
                int_fast32_t ttisgmtcnt = detzcode(up->tzhead.tzh_ttisgmtcnt);
                int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
                int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
                int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
                int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
                char const *p = up->buf + tzheadsize;
                if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
                       && 0 < typecnt && typecnt < TZ_MAX_TYPES
                       && 0 <= timecnt && timecnt < TZ_MAX_TIMES
                       && 0 <= charcnt && charcnt < TZ_MAX_CHARS
                       && (ttisstdcnt == typecnt || ttisstdcnt == 0)
                       && (ttisgmtcnt == typecnt || ttisgmtcnt == 0)))
                  return EINVAL;
                if ((size_t)nread
                    < (tzheadsize               /* struct tzhead */
                       + timecnt * stored       /* ats */
                       + timecnt                /* types */
                       + typecnt * 6            /* ttinfos */
                       + charcnt                /* chars */
                       + leapcnt * (stored + 4) /* lsinfos */
                       + ttisstdcnt             /* ttisstds */
                       + ttisgmtcnt))           /* ttisgmts */
                  return EINVAL;
                sp->leapcnt = leapcnt;
                sp->timecnt = timecnt;
                sp->typecnt = typecnt;
                sp->charcnt = charcnt;

                /* Read transitions, discarding those out of time_t range.
                   But pretend the last transition before time_t_min
                   occurred at time_t_min.  */
                timecnt = 0;
                for (i = 0; i < sp->timecnt; ++i) {
                        int_fast64_t at
                          = stored == 4 ? detzcode(p) : detzcode64(p);
                        sp->types[i] = at <= time_t_max;
                        if (sp->types[i]) {
                                time_t attime
                                    = ((TYPE_SIGNED(time_t) ?
                                    at < time_t_min : at < 0)
                                    ? time_t_min : (time_t)at);
                                if (timecnt && attime <= sp->ats[timecnt - 1]) {
                                        if (attime < sp->ats[timecnt - 1])
                                                return EINVAL;
                                        sp->types[i - 1] = 0;
                                        timecnt--;
                                }
                                sp->ats[timecnt++] = attime;
                        }
                        p += stored;
                }

                timecnt = 0;
                for (i = 0; i < sp->timecnt; ++i) {
                        unsigned char typ = *p++;
                        if (sp->typecnt <= typ)
                          return EINVAL;
                        if (sp->types[i])
                                sp->types[timecnt++] = typ;
                }
                sp->timecnt = timecnt;
                for (i = 0; i < sp->typecnt; ++i) {
                        struct ttinfo * ttisp;
                        unsigned char isdst, abbrind;

                        ttisp = &sp->ttis[i];
                        ttisp->tt_gmtoff = detzcode(p);
                        p += 4;
                        isdst = *p++;
                        if (! (isdst < 2))
                                return EINVAL;
                        ttisp->tt_isdst = isdst;
                        abbrind = *p++;
                        if (! (abbrind < sp->charcnt))
                                return EINVAL;
                        ttisp->tt_abbrind = abbrind;
                }
                for (i = 0; i < sp->charcnt; ++i)
                        sp->chars[i] = *p++;
                sp->chars[i] = '\0';    /* ensure '\0' at end */

                /* Read leap seconds, discarding those out of time_t range.  */
                leapcnt = 0;
                for (i = 0; i < sp->leapcnt; ++i) {
                        int_fast64_t tr = stored == 4 ? detzcode(p) :
                            detzcode64(p);
                        int_fast32_t corr = detzcode(p + stored);
                        p += stored + 4;
                        if (tr <= time_t_max) {
                                time_t trans = ((TYPE_SIGNED(time_t) ?
                                    tr < time_t_min : tr < 0)
                                    ? time_t_min : (time_t)tr);
                                if (leapcnt && trans <=
                                    sp->lsis[leapcnt - 1].ls_trans) {
                                        if (trans <
                                            sp->lsis[leapcnt - 1].ls_trans)
                                                return EINVAL;
                                        leapcnt--;
                                }
                                sp->lsis[leapcnt].ls_trans = trans;
                                sp->lsis[leapcnt].ls_corr = corr;
                                leapcnt++;
                        }
                }
                sp->leapcnt = leapcnt;

                for (i = 0; i < sp->typecnt; ++i) {
                        struct ttinfo * ttisp;

                        ttisp = &sp->ttis[i];
                        if (ttisstdcnt == 0)
                                ttisp->tt_ttisstd = false;
                        else {
                                if (*p != true && *p != false)
                                  return EINVAL;
                                ttisp->tt_ttisstd = *p++;
                        }
                }
                for (i = 0; i < sp->typecnt; ++i) {
                        struct ttinfo * ttisp;

                        ttisp = &sp->ttis[i];
                        if (ttisgmtcnt == 0)
                                ttisp->tt_ttisgmt = false;
                        else {
                                if (*p != true && *p != false)
                                                return EINVAL;
                                ttisp->tt_ttisgmt = *p++;
                        }
                }
                /*
                ** If this is an old file, we're done.
                */
                if (up->tzhead.tzh_version[0] == '\0')
                        break;
                nread -= p - up->buf;
                memmove(up->buf, p, (size_t)nread);
        }
        if (doextend && nread > 2 &&
                up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
                sp->typecnt + 2 <= TZ_MAX_TYPES) {
                        struct state *ts = &lsp->u.st;

                        up->buf[nread - 1] = '\0';
                        if (tzparse(&up->buf[1], ts, false)
                            && ts->typecnt == 2) {

                          /* Attempt to reuse existing abbreviations.
                             Without this, America/Anchorage would stop
                             working after 2037 when TZ_MAX_CHARS is 50, as
                             sp->charcnt equals 42 (for LMT CAT CAWT CAPT AHST
                             AHDT YST AKDT AKST) and ts->charcnt equals 10
                             (for AKST AKDT).  Reusing means sp->charcnt can
                             stay 42 in this example.  */
                          int gotabbr = 0;
                          int charcnt = sp->charcnt;
                          for (i = 0; i < 2; i++) {
                            char *tsabbr = ts->chars + ts->ttis[i].tt_abbrind;
                            int j;
                            for (j = 0; j < charcnt; j++)
                              if (strcmp(sp->chars + j, tsabbr) == 0) {
                                ts->ttis[i].tt_abbrind = j;
                                gotabbr++;
                                break;
                              }
                            if (! (j < charcnt)) {
                              int tsabbrlen = strlen(tsabbr);
                              if (j + tsabbrlen < TZ_MAX_CHARS) {
                                strcpy(sp->chars + j, tsabbr);
                                charcnt = j + tsabbrlen + 1;
                                ts->ttis[i].tt_abbrind = j;
                                gotabbr++;
                              }
                            }
                          }
                          if (gotabbr == 2) {
                            sp->charcnt = charcnt;
                            for (i = 0; i < ts->timecnt; i++)
                              if (sp->ats[sp->timecnt - 1] < ts->ats[i])
                                break;
                            while (i < ts->timecnt
                                   && sp->timecnt < TZ_MAX_TIMES) {
                              sp->ats[sp->timecnt] = ts->ats[i];
                              sp->types[sp->timecnt] = (sp->typecnt
                                                        + ts->types[i]);
                              sp->timecnt++;
                              i++;
                            }
                            sp->ttis[sp->typecnt++] = ts->ttis[0];
                            sp->ttis[sp->typecnt++] = ts->ttis[1];
                          }
                        }
        }
        if (sp->timecnt > 1) {
                for (i = 1; i < sp->timecnt; ++i)
                        if (typesequiv(sp, sp->types[i], sp->types[0]) &&
                                differ_by_repeat(sp->ats[i], sp->ats[0])) {
                                        sp->goback = true;
                                        break;
                                }
                for (i = sp->timecnt - 2; i >= 0; --i)
                        if (typesequiv(sp, sp->types[sp->timecnt - 1],
                                sp->types[i]) &&
                                differ_by_repeat(sp->ats[sp->timecnt - 1],
                                sp->ats[i])) {
                                        sp->goahead = true;
                                        break;
                }
        }
        /*
        ** If type 0 is is unused in transitions,
        ** it's the type to use for early times.
        */
        for (i = 0; i < sp->timecnt; ++i)
                if (sp->types[i] == 0)
                        break;
        i = i < sp->timecnt ? -1 : 0;
        /*
        ** Absent the above,
        ** if there are transition times
        ** and the first transition is to a daylight time
        ** find the standard type less than and closest to
        ** the type of the first transition.
        */
        if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
                i = sp->types[0];
                while (--i >= 0)
                        if (!sp->ttis[i].tt_isdst)
                                break;
        }
        /*
        ** If no result yet, find the first standard type.
        ** If there is none, punt to type zero.
        */
        if (i < 0) {
                i = 0;
                while (sp->ttis[i].tt_isdst)
                        if (++i >= sp->typecnt) {
                                i = 0;
                                break;
                        }
        }
        sp->defaulttype = i;
        return 0;
}

/* Load tz data from the file named NAME into *SP.  Read extended
   format if DOEXTEND.  Return 0 on success, an errno value on failure.  */
static int
tzload(char const *name, struct state *sp, bool doextend)
{
        union local_storage *lsp = malloc(sizeof *lsp);
        if (!lsp)
                return errno;
        else {
                int err = tzloadbody(name, sp, doextend, lsp);
                free(lsp);
                return err;
        }
}

static bool
typesequiv(const struct state *sp, int a, int b)
{
        bool result;

        if (sp == NULL ||
                a < 0 || a >= sp->typecnt ||
                b < 0 || b >= sp->typecnt)
                        result = false;
        else {
                const struct ttinfo *   ap = &sp->ttis[a];
                const struct ttinfo *   bp = &sp->ttis[b];
                result = ap->tt_gmtoff == bp->tt_gmtoff &&
                        ap->tt_isdst == bp->tt_isdst &&
                        ap->tt_ttisstd == bp->tt_ttisstd &&
                        ap->tt_ttisgmt == bp->tt_ttisgmt &&
                        strcmp(&sp->chars[ap->tt_abbrind],
                        &sp->chars[bp->tt_abbrind]) == 0;
        }
        return result;
}

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
};

/*
** Given a pointer into a time zone string, scan until a character that is not
** a valid character in a zone name is found. Return a pointer to that
** character.
*/

static const char * ATTRIBUTE_PURE
getzname(const char *strp)
{
        char    c;

        while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
                c != '+')
                        ++strp;
        return strp;
}

/*
** Given a pointer into an extended time zone string, scan until the ending
** delimiter of the zone name is located. Return a pointer to the delimiter.
**
** As with getzname above, the legal character set is actually quite
** restricted, with other characters producing undefined results.
** We don't do any checking here; checking is done later in common-case code.
*/

static const char * ATTRIBUTE_PURE
getqzname(const char *strp, const int delim)
{
        int     c;

        while ((c = *strp) != '\0' && c != delim)
                ++strp;
        return strp;
}

/*
** Given a pointer into a time zone string, extract a number from that string.
** Check that the number is within a specified range; if it is not, return
** NULL.
** Otherwise, return a pointer to the first character not part of the number.
*/

static const char *
getnum(const char *strp, int *const nump, const int min, const int max)
{
        char    c;
        int     num;

        if (strp == NULL || !is_digit(c = *strp)) {
                errno = EINVAL;
                return NULL;
        }
        num = 0;
        do {
                num = num * 10 + (c - '0');
                if (num > max) {
                        errno = EOVERFLOW;
                        return NULL;    /* illegal value */
                }
                c = *++strp;
        } while (is_digit(c));
        if (num < min) {
                errno = EINVAL;
                return NULL;            /* illegal value */
        }
        *nump = num;
        return strp;
}

/*
** Given a pointer into a time zone string, extract a number of seconds,
** in hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the number
** of seconds.
*/

static const char *
getsecs(const char *strp, int_fast32_t *const secsp)
{
        int     num;

        /*
        ** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
        ** "M10.4.6/26", which does not conform to Posix,
        ** but which specifies the equivalent of
        ** "02:00 on the first Sunday on or after 23 Oct".
        */
        strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
        if (strp == NULL)
                return NULL;
        *secsp = num * (int_fast32_t) SECSPERHOUR;
        if (*strp == ':') {
                ++strp;
                strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
                if (strp == NULL)
                        return NULL;
                *secsp += num * SECSPERMIN;
                if (*strp == ':') {
                        ++strp;
                        /* 'SECSPERMIN' allows for leap seconds.  */
                        strp = getnum(strp, &num, 0, SECSPERMIN);
                        if (strp == NULL)
                                return NULL;
                        *secsp += num;
                }
        }
        return strp;
}

/*
** Given a pointer into a time zone string, extract an offset, in
** [+-]hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the time.
*/

static const char *
getoffset(const char *strp, int_fast32_t *const offsetp)
{
        bool neg = false;

        if (*strp == '-') {
                neg = true;
                ++strp;
        } else if (*strp == '+')
                ++strp;
        strp = getsecs(strp, offsetp);
        if (strp == NULL)
                return NULL;            /* illegal time */
        if (neg)
                *offsetp = -*offsetp;
        return strp;
}

/*
** Given a pointer into a time zone string, extract a rule in the form
** date[/time]. See POSIX section 8 for the format of "date" and "time".
** If a valid rule is not found, return NULL.
** Otherwise, return a pointer to the first character not part of the rule.
*/

static const char *
getrule(const char *strp, struct rule *const rulep)
{
        if (*strp == 'J') {
                /*
                ** Julian day.
                */
                rulep->r_type = JULIAN_DAY;
                ++strp;
                strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
        } else if (*strp == 'M') {
                /*
                ** Month, week, day.
                */
                rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
                ++strp;
                strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
                if (strp == NULL)
                        return NULL;
                if (*strp++ != '.')
                        return NULL;
                strp = getnum(strp, &rulep->r_week, 1, 5);
                if (strp == NULL)
                        return NULL;
                if (*strp++ != '.')
                        return NULL;
                strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
        } else if (is_digit(*strp)) {
                /*
                ** Day of year.
                */
                rulep->r_type = DAY_OF_YEAR;
                strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
        } else  return NULL;            /* invalid format */
        if (strp == NULL)
                return NULL;
        if (*strp == '/') {
                /*
                ** Time specified.
                */
                ++strp;
                strp = getoffset(strp, &rulep->r_time);
        } else  rulep->r_time = 2 * SECSPERHOUR;        /* default = 2:00:00 */
        return strp;
}

/*
** Given a year, a rule, and the offset from UT at the time that rule takes
** effect, calculate the year-relative time that rule takes effect.
*/

static int_fast32_t ATTRIBUTE_PURE
transtime(const int year, const struct rule *const rulep,
          const int_fast32_t offset)
{
        bool    leapyear;
        int_fast32_t value;
        int     i;
        int             d, m1, yy0, yy1, yy2, dow;

        INITIALIZE(value);
        leapyear = isleap(year);
        switch (rulep->r_type) {

        case JULIAN_DAY:
                /*
                ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
                ** years.
                ** In non-leap years, or if the day number is 59 or less, just
                ** add SECSPERDAY times the day number-1 to the time of
                ** January 1, midnight, to get the day.
                */
                value = (rulep->r_day - 1) * SECSPERDAY;
                if (leapyear && rulep->r_day >= 60)
                        value += SECSPERDAY;
                break;

        case DAY_OF_YEAR:
                /*
                ** n - day of year.
                ** Just add SECSPERDAY times the day number to the time of
                ** January 1, midnight, to get the day.
                */
                value = rulep->r_day * SECSPERDAY;
                break;

        case MONTH_NTH_DAY_OF_WEEK:
                /*
                ** Mm.n.d - nth "dth day" of month m.
                */

                /*
                ** Use Zeller's Congruence to get day-of-week of first day of
                ** month.
                */
                m1 = (rulep->r_mon + 9) % 12 + 1;
                yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
                yy1 = yy0 / 100;
                yy2 = yy0 % 100;
                dow = ((26 * m1 - 2) / 10 +
                        1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
                if (dow < 0)
                        dow += DAYSPERWEEK;

                /*
                ** "dow" is the day-of-week of the first day of the month. Get
                ** the day-of-month (zero-origin) of the first "dow" day of the
                ** month.
                */
                d = rulep->r_day - dow;
                if (d < 0)
                        d += DAYSPERWEEK;
                for (i = 1; i < rulep->r_week; ++i) {
                        if (d + DAYSPERWEEK >=
                                mon_lengths[leapyear][rulep->r_mon - 1])
                                        break;
                        d += DAYSPERWEEK;
                }

                /*
                ** "d" is the day-of-month (zero-origin) of the day we want.
                */
                value = d * SECSPERDAY;
                for (i = 0; i < rulep->r_mon - 1; ++i)
                        value += mon_lengths[leapyear][i] * SECSPERDAY;
                break;
        }

        /*
        ** "value" is the year-relative time of 00:00:00 UT on the day in
        ** question. To get the year-relative time of the specified local
        ** time on that day, add the transition time and the current offset
        ** from UT.
        */
        return value + rulep->r_time + offset;
}

/*
** Given a POSIX section 8-style TZ string, fill in the rule tables as
** appropriate.
*/

static bool
tzparse(const char *name, struct state *sp, bool lastditch)
{
        const char *    stdname;
        const char *    dstname;
        size_t          stdlen;
        size_t          dstlen;
        size_t          charcnt;
        int_fast32_t    stdoffset;
        int_fast32_t    dstoffset;
        char *          cp;
        bool            load_ok;

        dstname = NULL; /* XXX gcc */
        stdname = name;
        if (lastditch) {
                stdlen = sizeof gmt - 1;
                name += stdlen;
                stdoffset = 0;
        } else {
                if (*name == '<') {
                        name++;
                        stdname = name;
                        name = getqzname(name, '>');
                        if (*name != '>')
                          return false;
                        stdlen = name - stdname;
                        name++;
                } else {
                        name = getzname(name);
                        stdlen = name - stdname;
                }
                if (!stdlen)
                        return false;
                name = getoffset(name, &stdoffset);
                if (name == NULL)
                        return false;
        }
        charcnt = stdlen + 1;
        if (sizeof sp->chars < charcnt)
                return false;
        load_ok = tzload(TZDEFRULES, sp, false) == 0;
        if (!load_ok)
                sp->leapcnt = 0;                /* so, we're off a little */
        if (*name != '\0') {
                if (*name == '<') {
                        dstname = ++name;
                        name = getqzname(name, '>');
                        if (*name != '>')
                                return false;
                        dstlen = name - dstname;
                        name++;
                } else {
                        dstname = name;
                        name = getzname(name);
                        dstlen = name - dstname; /* length of DST zone name */
                }
                if (!dstlen)
                  return false;
                charcnt += dstlen + 1;
                if (sizeof sp->chars < charcnt)
                  return false;
                if (*name != '\0' && *name != ',' && *name != ';') {
                        name = getoffset(name, &dstoffset);
                        if (name == NULL)
                          return false;
                } else  dstoffset = stdoffset - SECSPERHOUR;
                if (*name == '\0' && !load_ok)
                        name = TZDEFRULESTRING;
                if (*name == ',' || *name == ';') {
                        struct rule     start;
                        struct rule     end;
                        int             year;
                        int             yearlim;
                        int             timecnt;
                        time_t          janfirst;

                        ++name;
                        if ((name = getrule(name, &start)) == NULL)
                                return false;
                        if (*name++ != ',')
                                return false;
                        if ((name = getrule(name, &end)) == NULL)
                                return false;
                        if (*name != '\0')
                                return false;
                        sp->typecnt = 2;        /* standard time and DST */
                        /*
                        ** Two transitions per year, from EPOCH_YEAR forward.
                        */
                        init_ttinfo(&sp->ttis[0], -dstoffset, true, 
                            (int)(stdlen + 1));
                        init_ttinfo(&sp->ttis[1], -stdoffset, false, 0);
                        sp->defaulttype = 0;
                        timecnt = 0;
                        janfirst = 0;
                        yearlim = EPOCH_YEAR + YEARSPERREPEAT;
                        for (year = EPOCH_YEAR; year < yearlim; year++) {
                                int_fast32_t
                                  starttime = transtime(year, &start, stdoffset),
                                  endtime = transtime(year, &end, dstoffset);
                                int_fast32_t
                                  yearsecs = (year_lengths[isleap(year)]
                                              * SECSPERDAY);
                                bool reversed = endtime < starttime;
                                if (reversed) {
                                        int_fast32_t swap = starttime;
                                        starttime = endtime;
                                        endtime = swap;
                                }
                                if (reversed
                                    || (starttime < endtime
                                        && (endtime - starttime
                                            < (yearsecs
                                               + (stdoffset - dstoffset))))) {
                                        if (TZ_MAX_TIMES - 2 < timecnt)
                                                break;
                                        yearlim = year + YEARSPERREPEAT + 1;
                                        sp->ats[timecnt] = janfirst;
                                        if (increment_overflow_time
                                            (&sp->ats[timecnt], starttime))
                                                break;
                                        sp->types[timecnt++] = reversed;
                                        sp->ats[timecnt] = janfirst;
                                        if (increment_overflow_time
                                            (&sp->ats[timecnt], endtime))
                                                break;
                                        sp->types[timecnt++] = !reversed;
                                }
                                if (increment_overflow_time(&janfirst, yearsecs))
                                        break;
                        }
                        sp->timecnt = timecnt;
                        if (!timecnt)
                                sp->typecnt = 1;        /* Perpetual DST.  */
                } else {
                        int_fast32_t    theirstdoffset;
                        int_fast32_t    theirdstoffset;
                        int_fast32_t    theiroffset;
                        bool            isdst;
                        int             i;
                        int             j;

                        if (*name != '\0')
                                return false;
                        /*
                        ** Initial values of theirstdoffset and theirdstoffset.
                        */
                        theirstdoffset = 0;
                        for (i = 0; i < sp->timecnt; ++i) {
                                j = sp->types[i];
                                if (!sp->ttis[j].tt_isdst) {
                                        theirstdoffset =
                                                -sp->ttis[j].tt_gmtoff;
                                        break;
                                }
                        }
                        theirdstoffset = 0;
                        for (i = 0; i < sp->timecnt; ++i) {
                                j = sp->types[i];
                                if (sp->ttis[j].tt_isdst) {
                                        theirdstoffset =
                                                -sp->ttis[j].tt_gmtoff;
                                        break;
                                }
                        }
                        /*
                        ** Initially we're assumed to be in standard time.
                        */
                        isdst = false;
                        theiroffset = theirstdoffset;
                        /*
                        ** Now juggle transition times and types
                        ** tracking offsets as you do.
                        */
                        for (i = 0; i < sp->timecnt; ++i) {
                                j = sp->types[i];
                                sp->types[i] = sp->ttis[j].tt_isdst;
                                if (sp->ttis[j].tt_ttisgmt) {
                                        /* No adjustment to transition time */
                                } else {
                                        /*
                                        ** If summer time is in effect, and the
                                        ** transition time was not specified as
                                        ** standard time, add the summer time
                                        ** offset to the transition time;
                                        ** otherwise, add the standard time
                                        ** offset to the transition time.
                                        */
                                        /*
                                        ** Transitions from DST to DDST
                                        ** will effectively disappear since
                                        ** POSIX provides for only one DST
                                        ** offset.
                                        */
                                        if (isdst && !sp->ttis[j].tt_ttisstd) {
                                                sp->ats[i] += (time_t)
                                                    (dstoffset - theirdstoffset);
                                        } else {
                                                sp->ats[i] += (time_t)
                                                    (stdoffset - theirstdoffset);
                                        }
                                }
                                theiroffset = -sp->ttis[j].tt_gmtoff;
                                if (sp->ttis[j].tt_isdst)
                                        theirstdoffset = theiroffset;
                                else    theirdstoffset = theiroffset;
                        }
                        /*
                        ** Finally, fill in ttis.
                        */
                        init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
                        init_ttinfo(&sp->ttis[1], -dstoffset, true,
                            (int)(stdlen + 1));
                        sp->typecnt = 2;
                        sp->defaulttype = 0;
                }
        } else {
                dstlen = 0;
                sp->typecnt = 1;                /* only standard time */
                sp->timecnt = 0;
                init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
                init_ttinfo(&sp->ttis[1], 0, false, 0);
                sp->defaulttype = 0;
        }
        sp->charcnt = charcnt;
        cp = sp->chars;
        (void) memcpy(cp, stdname, stdlen);
        cp += stdlen;
        *cp++ = '\0';
        if (dstlen != 0) {
                (void) memcpy(cp, dstname, dstlen);
                *(cp + dstlen) = '\0';
        }
        return true;
}

static void
gmtload(struct state *const sp)
{
        if (tzload(gmt, sp, true) != 0)
                (void) tzparse(gmt, sp, true);
}

static int
zoneinit(struct state *sp, char const *name)
{
        if (name && ! name[0]) {
                /*
                ** User wants it fast rather than right.
                */
                sp->leapcnt = 0;                /* so, we're off a little */
                sp->timecnt = 0;
                sp->typecnt = 0;
                sp->charcnt = 0;
                sp->goback = sp->goahead = false;
                init_ttinfo(&sp->ttis[0], 0, false, 0);
                strcpy(sp->chars, gmt);
                sp->defaulttype = 0;
                return 0;
        } else {
                int err = tzload(name, sp, true);
                if (err != 0 && name && name[0] != ':' &&
                    tzparse(name, sp, false))
                        err = 0;
                if (err == 0)
                        scrub_abbrs(sp);
                return err;
        }
}
 
static void
tzsetlcl(char const *name)
{
        struct state *sp = lclptr;
        int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;
        if (lcl < 0 ? lcl_is_set < 0
            : 0 < lcl_is_set && strcmp(lcl_TZname, name) == 0)
                return;

        if (! sp)
                lclptr = sp = malloc(sizeof *lclptr);
        if (sp) {
                if (zoneinit(sp, name) != 0)
                        zoneinit(sp, "");
                if (0 < lcl)
                        strcpy(lcl_TZname, name);
        }
        settzname();
        lcl_is_set = lcl;
}

#ifdef STD_INSPIRED
void
tzsetwall(void)
{
        rwlock_wrlock(&lcl_lock);
        tzsetlcl(NULL);
        rwlock_unlock(&lcl_lock);
}
#endif

static void
tzset_unlocked(void)
{
        tzsetlcl(getenv("TZ"));
}

void
tzset(void)
{
        rwlock_wrlock(&lcl_lock);
        tzset_unlocked();
        rwlock_unlock(&lcl_lock);
}

static void
gmtcheck(void)
{
        static bool gmt_is_set;
        rwlock_wrlock(&lcl_lock);
        if (! gmt_is_set) {
                gmtptr = malloc(sizeof *gmtptr);
                if (gmtptr)
                        gmtload(gmtptr);
                gmt_is_set = true;
        }
        rwlock_unlock(&lcl_lock);
}

#if NETBSD_INSPIRED

timezone_t
tzalloc(const char *name)
{
        timezone_t sp = malloc(sizeof *sp);
        if (sp) {
                int err = zoneinit(sp, name);
                if (err != 0) {
                        free(sp);
                        errno = err;
                        return NULL;
                }
        }
        return sp;
}

void
tzfree(timezone_t sp)
{
        free(sp);
}

/*
** NetBSD 6.1.4 has ctime_rz, but omit it because POSIX says ctime and
** ctime_r are obsolescent and have potential security problems that
** ctime_rz would share.  Callers can instead use localtime_rz + strftime.
**
** NetBSD 6.1.4 has tzgetname, but omit it because it doesn't work
** in zones with three or more time zone abbreviations.
** Callers can instead use localtime_rz + strftime.
*/

#endif

/*
** 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.)
**
** If successful and SETNAME is nonzero,
** set the applicable parts of tzname, timezone and altzone;
** however, it's OK to omit this step if the time zone is POSIX-compatible,
** since in that case tzset should have already done this step correctly.
** SETNAME's type is intfast32_t for compatibility with gmtsub,
** but it is actually a boolean and its value should be 0 or 1.
*/

/*ARGSUSED*/
static struct tm *
localsub(struct state const *sp, time_t const *timep, int_fast32_t setname,
         struct tm *const tmp)
{
        const struct ttinfo *   ttisp;
        int                     i;
        struct tm *             result;
        const time_t                    t = *timep;

        if (sp == NULL) {
                /* Don't bother to set tzname etc.; tzset has already done it.  */
                return gmtsub(gmtptr, timep, 0, tmp);
        }
        if ((sp->goback && t < sp->ats[0]) ||
                (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
                        time_t                  newt = t;
                        time_t          seconds;
                        time_t          years;

                        if (t < sp->ats[0])
                                seconds = sp->ats[0] - t;
                        else    seconds = t - sp->ats[sp->timecnt - 1];
                        --seconds;
                        years = (time_t)((seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT);
                        seconds = (time_t)(years * AVGSECSPERYEAR);
                        if (t < sp->ats[0])
                                newt += seconds;
                        else    newt -= seconds;
                        if (newt < sp->ats[0] ||
                                newt > sp->ats[sp->timecnt - 1]) {
                                errno = EINVAL;
                                return NULL;    /* "cannot happen" */
                        }
                        result = localsub(sp, &newt, setname, tmp);
                        if (result) {
                                int_fast64_t newy;

                                newy = result->tm_year;
                                if (t < sp->ats[0])
                                        newy -= years;
                                else    newy += years;
                                if (! (INT_MIN <= newy && newy <= INT_MAX)) {
                                        errno = EOVERFLOW;
                                        return NULL;
                                }
                                result->tm_year = (int)newy;
                        }
                        return result;
        }
        if (sp->timecnt == 0 || t < sp->ats[0]) {
                i = sp->defaulttype;
        } else {
                int     lo = 1;
                int     hi = sp->timecnt;

                while (lo < hi) {
                        int     mid = (lo + hi) / 2;

                        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);
        if (result) {
                result->tm_isdst = ttisp->tt_isdst;
#ifdef TM_ZONE
                result->TM_ZONE = __UNCONST(&sp->chars[ttisp->tt_abbrind]);
#endif /* defined TM_ZONE */
                if (setname)
                        update_tzname_etc(sp, ttisp);
        }
        return result;
}

#if NETBSD_INSPIRED

struct tm *
localtime_rz(timezone_t sp, time_t const *timep, struct tm *tmp)
{
        return localsub(sp, timep, 0, tmp);
}

#endif

static struct tm *
localtime_tzset(time_t const *timep, struct tm *tmp, bool setname)
{
        rwlock_wrlock(&lcl_lock);
        if (setname || !lcl_is_set)
                tzset_unlocked();
        tmp = localsub(lclptr, timep, setname, tmp);
        rwlock_unlock(&lcl_lock);
        return tmp;
}

struct tm *
localtime(const time_t *timep)
{
        return localtime_tzset(timep, &tm, true);
}

struct tm *
localtime_r(const time_t * __restrict timep, struct tm *tmp)
{
        return localtime_tzset(timep, tmp, false);
}

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

static struct tm *
gmtsub(struct state const *sp, const time_t *timep, int_fast32_t offset,
       struct tm *tmp)
{
        struct tm *     result;

        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.
        */
        if (result)
                result->TM_ZONE = offset ? __UNCONST(wildabbr) : gmtptr ?
                    gmtptr->chars : __UNCONST(gmt);
#endif /* defined TM_ZONE */
        return result;
}


/*
** Re-entrant version of gmtime.
*/

struct tm *
gmtime_r(const time_t *timep, struct tm *tmp)
{
        gmtcheck();
        return gmtsub(NULL, timep, 0, tmp);
}

struct tm *
gmtime(const time_t *timep)
{
        return gmtime_r(timep, &tm);
}
#ifdef STD_INSPIRED

struct tm *
offtime(const time_t *timep, long offset)
{
        gmtcheck();
        return gmtsub(gmtptr, timep, (int_fast32_t)offset, &tm);
}

struct tm *
offtime_r(const time_t *timep, long offset, struct tm *tmp)
{
        gmtcheck();
        return gmtsub(NULL, timep, (int_fast32_t)offset, tmp);
}

#endif /* defined STD_INSPIRED */

/*
** 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 ATTRIBUTE_PURE
leaps_thru_end_of(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 *timep, int_fast32_t offset,
    const struct state *sp, struct tm *tmp)
{
        const struct lsinfo *   lp;
        time_t                  tdays;
        int                     idays;  /* unsigned would be so 2003 */
        int_fast64_t            rem;
        int                     y;
        const int *             ip;
        int_fast64_t            corr;
        bool                    hit;
        int                     i;

        corr = 0;
        hit = false;
        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 = (time_t)(*timep / SECSPERDAY);
        rem = *timep % SECSPERDAY;
        while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
                int             newy;
                time_t  tdelta;
                int     idelta;
                int     leapdays;

                tdelta = tdays / DAYSPERLYEAR;
                if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
                       && tdelta <= INT_MAX))
                        goto out_of_range;
                _DIAGASSERT(__type_fit(int, tdelta));
                idelta = (int)tdelta;
                if (idelta == 0)
                        idelta = (tdays < 0) ? -1 : 1;
                newy = y;
                if (increment_overflow(&newy, idelta))
                        goto out_of_range;
                leapdays = leaps_thru_end_of(newy - 1) -
                        leaps_thru_end_of(y - 1);
                tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
                tdays -= leapdays;
                y = newy;
        }
        /*
        ** Given the range, we can now fearlessly cast...
        */
        idays = (int) tdays;
        rem += offset - corr;
        while (rem < 0) {
                rem += SECSPERDAY;
                --idays;
        }
        while (rem >= SECSPERDAY) {
                rem -= SECSPERDAY;
                ++idays;
        }
        while (idays < 0) {
                if (increment_overflow(&y, -1))
                        goto out_of_range;
                idays += year_lengths[isleap(y)];
        }
        while (idays >= year_lengths[isleap(y)]) {
                idays -= year_lengths[isleap(y)];
                if (increment_overflow(&y, 1))
                        goto out_of_range;
        }
        tmp->tm_year = y;
        if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
                goto out_of_range;
        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;
out_of_range:
        errno = EOVERFLOW;
        return NULL;
}

#if !defined(__minix) || !defined(_LIBMINC)
char *
ctime(const time_t *timep)
{
/*
** Section 4.12.3.2 of X3.159-1989 requires that
**      The ctime function converts the calendar time pointed to by timer
**      to local time in the form of a string. It is equivalent to
**              asctime(localtime(timer))
*/
        struct tm *tmp = localtime(timep);
        return tmp ? asctime(tmp) : NULL;
}

char *
ctime_r(const time_t *timep, char *buf)
{
        struct tm mytm;
        struct tm *tmp = localtime_r(timep, &mytm);
        return tmp ? asctime_r(tmp, buf) : NULL;
}

char *
ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
{
        struct tm       mytm, *rtm;

        rtm = localtime_rz(sp, timep, &mytm);
        if (rtm == NULL)
                return NULL;
        return asctime_r(rtm, buf);
}
#endif /* !defined(__minix) || !defined(_LIBMINC) */

/*
** 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   ((time_t)-1)
#endif /* !defined WRONG */

/*
** Normalize logic courtesy Paul Eggert.
*/

static bool
increment_overflow(int *ip, int j)
{
        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 bool
increment_overflow32(int_fast32_t *const lp, int const m)
{
        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 bool
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 bool
normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
{
        int     tensdelta;

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

static bool
normalize_overflow32(int_fast32_t *tensptr, int *unitsptr, int base)
{
        int     tensdelta;

        tensdelta = (*unitsptr >= 0) ?
                (*unitsptr / base) :
                (-1 - (-1 - *unitsptr) / base);
        *unitsptr -= tensdelta * base;
        return increment_overflow32(tensptr, tensdelta);
}

static int
tmcomp(const struct tm *const atmp,
       const struct tm *const btmp)
{
        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 *(*funcp)(struct state const *, time_t const *,
                             int_fast32_t, struct tm *),
         struct state const *sp,
         const int_fast32_t offset,
         bool *okayp,
         bool do_norm_secs)
{
        int                     dir;
        int                     i, j;
        int                     saved_seconds;
        int_fast32_t            li;
        time_t                  lo;
        time_t                  hi;
#ifdef NO_ERROR_IN_DST_GAP
        time_t                  ilo;
#endif
        int_fast32_t            y;
        time_t                  newt;
        time_t                  t;
        struct tm               yourtm, mytm;

        *okayp = false;
        yourtm = *tmp;
#ifdef NO_ERROR_IN_DST_GAP
again:
#endif
        if (do_norm_secs) {
                if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
                    SECSPERMIN))
                        goto out_of_range;
        }
        if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
                goto out_of_range;
        if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
                goto out_of_range;
        y = yourtm.tm_year;
        if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
                goto out_of_range;
        /*
        ** 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))
                goto out_of_range;
        while (yourtm.tm_mday <= 0) {
                if (increment_overflow32(&y, -1))
                        goto out_of_range;
                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))
                        goto out_of_range;
        }
        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))
                                goto out_of_range;
                }
        }
        if (increment_overflow32(&y, -TM_YEAR_BASE))
                goto out_of_range;
        if (! (INT_MIN <= y && y <= INT_MAX))
                goto out_of_range;
        yourtm.tm_year = (int)y;
        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))
                        goto out_of_range;
                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).
        */
        lo = time_t_min;
        hi = time_t_max;
#ifdef NO_ERROR_IN_DST_GAP
        ilo = lo;
#endif
        for ( ; ; ) {
                t = lo / 2 + hi / 2;
                if (t < lo)
                        t = lo;
                else if (t > hi)
                        t = hi;
                if (! funcp(sp, &t, offset, &mytm)) {
                        /*
                        ** 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)
                                        goto out_of_range;
                                ++t;
                                ++lo;
                        } else if (t == hi) {
                                if (t == time_t_min)
                                        goto out_of_range;
                                --t;
                                --hi;
                        }
#ifdef NO_ERROR_IN_DST_GAP
                        if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0 &&
                            do_norm_secs) {
                                for (i = sp->typecnt - 1; i >= 0; --i) {
                                        for (j = sp->typecnt - 1; j >= 0; --j) {
                                                time_t off;
                                                if (sp->ttis[j].tt_isdst ==
                                                    sp->ttis[i].tt_isdst)
                                                        continue;
                                                off = sp->ttis[j].tt_gmtoff -
                                                    sp->ttis[i].tt_gmtoff;
                                                yourtm.tm_sec += off < 0 ?
                                                    -off : off;
                                                goto again;
                                        }
                                }
                        }
#endif
                        if (lo > hi)
                                goto invalid;
                        if (dir > 0)
                                hi = t;
                        else    lo = t;
                        continue;
                }
#if defined TM_GMTOFF && ! UNINIT_TRAP
                if (mytm.TM_GMTOFF != yourtm.TM_GMTOFF
                    && (yourtm.TM_GMTOFF < 0
                        ? (-SECSPERDAY <= yourtm.TM_GMTOFF
                           && (mytm.TM_GMTOFF <=
                               (/*CONSTCOND*/SMALLEST (INT_FAST32_MAX, LONG_MAX)
                                + yourtm.TM_GMTOFF)))
                        : (yourtm.TM_GMTOFF <= SECSPERDAY
                           && ((/*CONSTCOND*/BIGGEST (INT_FAST32_MIN, LONG_MIN)
                                + yourtm.TM_GMTOFF)
                               <= mytm.TM_GMTOFF)))) {
                  /* MYTM matches YOURTM except with the wrong UTC offset.
                     YOURTM.TM_GMTOFF is plausible, so try it instead.
                     It's OK if YOURTM.TM_GMTOFF contains uninitialized data,
                     since the guess gets checked.  */
                  time_t altt = t;
                  int_fast32_t diff = (int_fast32_t)
                      (mytm.TM_GMTOFF - yourtm.TM_GMTOFF);
                  if (!increment_overflow_time(&altt, diff)) {
                    struct tm alttm;
                    if (! funcp(sp, &altt, offset, &alttm)
                        && alttm.tm_isdst == mytm.tm_isdst
                        && alttm.TM_GMTOFF == yourtm.TM_GMTOFF
                        && tmcomp(&alttm, &yourtm)) {
                      t = altt;
                      mytm = alttm;
                    }
                  }
                }
#endif
                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.
                */
                if (sp == NULL)
                        goto invalid;
                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 = (time_t)(t + sp->ttis[j].tt_gmtoff -
                                    sp->ttis[i].tt_gmtoff);
                                if (! funcp(sp, &newt, offset, &mytm))
                                        continue;
                                if (tmcomp(&mytm, &yourtm) != 0)
                                        continue;
                                if (mytm.tm_isdst != yourtm.tm_isdst)
                                        continue;
                                /*
                                ** We have a match.
                                */
                                t = newt;
                                goto label;
                        }
                }
                goto invalid;
        }
label:
        newt = t + saved_seconds;
        if ((newt < t) != (saved_seconds < 0))
                goto out_of_range;
        t = newt;
        if (funcp(sp, &t, offset, tmp)) {
                *okayp = true;
                return t;
        }
out_of_range:
        errno = EOVERFLOW;
        return WRONG;
invalid:
        errno = EINVAL;
        return WRONG;
}

static time_t
time2(struct tm * const tmp,
      struct tm *(*funcp)(struct state const *, time_t const *,
                          int_fast32_t, struct tm *),
      struct state const *sp,
      const int_fast32_t offset,
      bool *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, sp, offset, okayp, false);
        return *okayp ? t : time2sub(tmp, funcp, sp, offset, okayp, true);
}

static time_t
time1(struct tm *const tmp,
      struct tm *(*funcp) (struct state const *, time_t const *,
                           int_fast32_t, struct tm *),
      struct state const *sp,
      const int_fast32_t offset)
{
        time_t                  t;
        int                     samei, otheri;
        int                     sameind, otherind;
        int                     i;
        int                     nseen;
        int                     save_errno;
        char                            seen[TZ_MAX_TYPES];
        unsigned char                   types[TZ_MAX_TYPES];
        bool                            okay;

        if (tmp == NULL) {
                errno = EINVAL;
                return WRONG;
        }
        if (tmp->tm_isdst > 1)
                tmp->tm_isdst = 1;
        save_errno = errno;
        t = time2(tmp, funcp, sp, offset, &okay);
        if (okay) {
                errno = save_errno;
                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.
        */
        if (sp == NULL) {
                errno = EINVAL;
                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 += (int)(sp->ttis[otheri].tt_gmtoff -
                                        sp->ttis[samei].tt_gmtoff);
                        tmp->tm_isdst = !tmp->tm_isdst;
                        t = time2(tmp, funcp, sp, offset, &okay);
                        if (okay) {
                                errno = save_errno;
                                return t;
                        }
                        tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
                                        sp->ttis[samei].tt_gmtoff);
                        tmp->tm_isdst = !tmp->tm_isdst;
                }
        }
        errno = EOVERFLOW;
        return WRONG;
}

static time_t
mktime_tzname(timezone_t sp, struct tm *tmp, bool setname)
{
        if (sp)
                return time1(tmp, localsub, sp, setname);
        else {
                gmtcheck();
                return time1(tmp, gmtsub, gmtptr, 0);
        }
}

#if NETBSD_INSPIRED

time_t
mktime_z(timezone_t sp, struct tm *const tmp)
{
        return mktime_tzname(sp, tmp, false);
}

#endif

time_t
mktime(struct tm *tmp)
{
        time_t t;

        rwlock_wrlock(&lcl_lock);
        tzset_unlocked();
        t = mktime_tzname(lclptr, tmp, true);
        rwlock_unlock(&lcl_lock);
        return t;
}

#ifdef STD_INSPIRED

time_t
timelocal_z(const timezone_t sp, struct tm *const tmp)
{
        if (tmp != NULL)
                tmp->tm_isdst = -1;     /* in case it wasn't initialized */
        return mktime_z(sp, tmp);
}

time_t
timelocal(struct tm *tmp)
{
        if (tmp != NULL)
                tmp->tm_isdst = -1;     /* in case it wasn't initialized */
        return mktime(tmp);
}

time_t
timegm(struct tm *tmp)
{

        return timeoff(tmp, 0);
}

time_t
timeoff(struct tm *tmp, long offset)
{
        if (tmp)
                tmp->tm_isdst = 0;
        gmtcheck();
        return time1(tmp, gmtsub, gmtptr, (int_fast32_t)offset);
}

#endif /* defined STD_INSPIRED */

/*
** XXX--is the below the right way to conditionalize??
*/

#ifdef STD_INSPIRED

/*
** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
** is not the case if we are accounting for leap seconds.
** So, we provide the following conversion routines for use
** when exchanging timestamps with POSIX conforming systems.
*/

static int_fast64_t
leapcorr(const timezone_t sp, time_t t)
{
        struct lsinfo const * lp;
        int             i;

        i = sp->leapcnt;
        while (--i >= 0) {
                lp = &sp->lsis[i];
                if (t >= lp->ls_trans)
                        return lp->ls_corr;
        }
        return 0;
}

NETBSD_INSPIRED_EXTERN time_t ATTRIBUTE_PURE
time2posix_z(timezone_t sp, time_t t)
{
        return (time_t)(t - leapcorr(sp, t));
}

time_t
time2posix(time_t t)
{
        rwlock_wrlock(&lcl_lock);
        if (!lcl_is_set)
                tzset_unlocked();
        if (lclptr)
                t = (time_t)(t - leapcorr(lclptr, t));
        rwlock_unlock(&lcl_lock);
        return t;
}

NETBSD_INSPIRED_EXTERN time_t ATTRIBUTE_PURE
posix2time_z(timezone_t sp, time_t t)
{
        time_t  x;
        time_t  y;

        /*
        ** For a positive leap second hit, the result
        ** is not unique. For a negative leap second
        ** hit, the corresponding time doesn't exist,
        ** so we return an adjacent second.
        */
        x = (time_t)(t + leapcorr(sp, t));
        y = (time_t)(x - leapcorr(sp, x));
        if (y < t) {
                do {
                        x++;
                        y = (time_t)(x - leapcorr(sp, x));
                } while (y < t);
                x -= y != t;
        } else if (y > t) {
                do {
                        --x;
                        y = (time_t)(x - leapcorr(sp, x));
                } while (y > t);
                x += y != t;
        }
        return x;
}

time_t
posix2time(time_t t)
{
        rwlock_wrlock(&lcl_lock);
        if (!lcl_is_set)
                tzset_unlocked();
        if (lclptr)
                t = posix2time_z(lclptr, t);
        rwlock_unlock(&lcl_lock);
        return t;
}

#endif /* defined STD_INSPIRED */