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  • /*
     * Asterisk -- A telephony toolkit for Linux.
     *
     * Multi-timezone Localtime code
     * 
     * Copyright (C) 2003, Mark Spencer
     *
     * This program is free software, distributed under the terms of
     * the GNU General Public License
     *
     * Most of this code is in the public domain, so clarified as of
     * June 5, 1996 by Arthur David Olson (arthur_david_olson@nih.gov).
     *
     * All modifications to this code to abstract timezones away from
     * the environment are by Tilghman Lesher, <tlesher@vcch.com>, with
     * the copyright assigned to Digium.
     */
    
    /*
     * Asterisk defines
     *
     * Don't mess with these unless you're really sure you know what you're doing.
     */
    #define _THREAD_SAFE
    #define TZ_STRLEN_MAX	255
    /* #define DEBUG */
    #include <asterisk/lock.h>
    
    #include <asterisk/localtime.h>
    
    static const char	elsieid[] = "@(#)localtime.c	7.57";
    
    #endif /* !defined NOID */
    #endif /* !defined lint */
    
    /*
    ** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
    ** POSIX-style TZ environment variable handling from Guy Harris
    ** (guy@auspex.com).
    */
    
    /*LINTLIBRARY*/
    
    #include <sys/types.h>
    #include <sys/stat.h>
    #include "private.h"
    #include "tzfile.h"
    
    #include <fcntl.h>
    
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    #ifdef DEBUG
    #include <stdio.h>
    #endif
    
    /*
    ** 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 ast_tzset (explicitly
    **		or implicitly).
    **	2.	They might reference tzname[1] before calling ast_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";
    
    struct ttinfo {				/* time type information */
    	long		tt_gmtoff;	/* GMT 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 GMT */
    };
    
    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 {
    	char	name[TZ_STRLEN_MAX + 1];
    	int		leapcnt;
    	int		timecnt;
    	int		typecnt;
    	int		charcnt;
    	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 state	*next;
    };
    
    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 long		detzcode P((const char * codep));
    static const char *	getnum P((const char * strp, int * nump, int min,
    				int max));
    static const char *	getsecs P((const char * strp, long * secsp));
    static const char *	getoffset P((const char * strp, long * offsetp));
    static const char *	getrule P((const char * strp, struct rule * rulep));
    static void		gmtload P((struct state * sp));
    static void		gmtsub P((const time_t * timep, long offset,
    				struct tm * tmp, const char * zone));
    static void		localsub P((const time_t * timep, long offset,
    				struct tm * tmp, const char * zone));
    static int		increment_overflow P((int * number, int delta));
    static int		normalize_overflow P((int * tensptr, int * unitsptr,
    				int base));
    static time_t		time1 P((struct tm * tmp,
    				void(*funcp) P((const time_t *,
    				long, struct tm *, const char*)),
    				long offset, const char * zone));
    static time_t		time2 P((struct tm *tmp,
    				void(*funcp) P((const time_t *,
    				long, struct tm*, const char*)),
    				long offset, int * okayp, const char * zone));
    static void		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));
    static time_t		transtime P((time_t janfirst, int year,
    				const struct rule * rulep, long offset));
    static int		tzload P((const char * name, struct state * sp));
    static int		tzparse P((const char * name, struct state * sp,
    				int lastditch));
    
    static struct state *	lclptr      = NULL;
    static struct state *	last_lclptr = NULL;
    static struct state *	gmtptr      = NULL;
    
    #ifndef TZ_STRLEN_MAX
    #define TZ_STRLEN_MAX 255
    #endif /* !defined TZ_STRLEN_MAX */
    
    static int		gmt_is_set;
    #ifdef	_THREAD_SAFE
    static ast_mutex_t		lcl_mutex   = AST_MUTEX_INITIALIZER;
    static ast_mutex_t		tzset_mutex	= AST_MUTEX_INITIALIZER;
    static ast_mutex_t		tzsetwall_mutex	= AST_MUTEX_INITIALIZER;
    static ast_mutex_t		gmt_mutex   = AST_MUTEX_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 (eggert@twinsun.com) for noting this.
    */
    
    static long
    detzcode(codep)
    const char * const	codep;
    {
    	register long	result;
    	register int	i;
    
    	result = (codep[0] & 0x80) ? ~0L : 0L;
    	for (i = 0; i < 4; ++i)
    		result = (result << 8) | (codep[i] & 0xff);
    	return result;
    }
    
    static int
    tzload(name, sp)
    register const char *		name;
    register struct state * const	sp;
    {
    	register const char *	p;
    	register int		i;
    	register int		fid;
    
    #ifdef DEBUG
    	fprintf(stderr,"tzload called with name=%s, sp=%d\n", name, sp);
    #endif
    	if (name == NULL && (name = TZDEFAULT) == NULL)
    		return -1;
    	{
    		register int	doaccess;
    		struct stat	stab;
    		/*
    		** Section 4.9.1 of the C standard says that
    		** "FILENAME_MAX expands to an integral constant expression
    		** that is the size needed for an array of char large enough
    		** to hold the longest file name string that the implementation
    		** guarantees can be opened."
    		*/
    		char		fullname[FILENAME_MAX + 1];
    
    		if (name[0] == ':')
    			++name;
    		doaccess = name[0] == '/';
    		if (!doaccess) {
    			if ((p = TZDIR) == NULL)
    				return -1;
    			if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
    				return -1;
    			(void) strcpy(fullname, p);
    			(void) strcat(fullname, "/");
    			(void) strcat(fullname, name);
    			/*
    			** Set doaccess if '.' (as in "../") shows up in name.
    			*/
    			if (strchr(name, '.') != NULL)
    				doaccess = TRUE;
    			name = fullname;
    		}
    		if (doaccess && access(name, R_OK) != 0)
    		     	return -1;
    		if ((fid = open(name, OPEN_MODE)) == -1)
    			return -1;
    		if ((fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
    			close(fid);
    			return -1;
    		}
    	}
    	{
    		struct tzhead *	tzhp;
    		char		buf[sizeof *sp + sizeof *tzhp];
    		int		ttisstdcnt;
    		int		ttisgmtcnt;
    
    		i = read(fid, buf, sizeof buf);
    		if (close(fid) != 0)
    			return -1;
    		p = buf;
    		p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
    		ttisstdcnt = (int) detzcode(p);
    		p += 4;
    		ttisgmtcnt = (int) detzcode(p);
    		p += 4;
    		sp->leapcnt = (int) detzcode(p);
    		p += 4;
    		sp->timecnt = (int) detzcode(p);
    		p += 4;
    		sp->typecnt = (int) detzcode(p);
    		p += 4;
    		sp->charcnt = (int) detzcode(p);
    		p += 4;
    		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
    			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
    			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
    			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
    			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
    			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
    				return -1;
    		if (i - (p - buf) < sp->timecnt * 4 +	/* ats */
    			sp->timecnt +			/* types */
    			sp->typecnt * (4 + 2) +		/* ttinfos */
    			sp->charcnt +			/* chars */
    			sp->leapcnt * (4 + 4) +		/* lsinfos */
    			ttisstdcnt +			/* ttisstds */
    			ttisgmtcnt)			/* ttisgmts */
    				return -1;
    		for (i = 0; i < sp->timecnt; ++i) {
    			sp->ats[i] = detzcode(p);
    			p += 4;
    		}
    		for (i = 0; i < sp->timecnt; ++i) {
    			sp->types[i] = (unsigned char) *p++;
    			if (sp->types[i] >= sp->typecnt)
    				return -1;
    		}
    		for (i = 0; i < sp->typecnt; ++i) {
    			register struct ttinfo *	ttisp;
    
    			ttisp = &sp->ttis[i];
    			ttisp->tt_gmtoff = detzcode(p);
    			p += 4;
    			ttisp->tt_isdst = (unsigned char) *p++;
    			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
    				return -1;
    			ttisp->tt_abbrind = (unsigned char) *p++;
    			if (ttisp->tt_abbrind < 0 ||
    				ttisp->tt_abbrind > sp->charcnt)
    					return -1;
    		}
    		for (i = 0; i < sp->charcnt; ++i)
    			sp->chars[i] = *p++;
    		sp->chars[i] = '\0';	/* ensure '\0' at end */
    		for (i = 0; i < sp->leapcnt; ++i) {
    			register struct lsinfo *	lsisp;
    
    			lsisp = &sp->lsis[i];
    			lsisp->ls_trans = detzcode(p);
    			p += 4;
    			lsisp->ls_corr = detzcode(p);
    			p += 4;
    		}
    		for (i = 0; i < sp->typecnt; ++i) {
    			register struct ttinfo *	ttisp;
    
    			ttisp = &sp->ttis[i];
    			if (ttisstdcnt == 0)
    				ttisp->tt_ttisstd = FALSE;
    			else {
    				ttisp->tt_ttisstd = *p++;
    				if (ttisp->tt_ttisstd != TRUE &&
    					ttisp->tt_ttisstd != FALSE)
    						return -1;
    			}
    		}
    		for (i = 0; i < sp->typecnt; ++i) {
    			register struct ttinfo *	ttisp;
    
    			ttisp = &sp->ttis[i];
    			if (ttisgmtcnt == 0)
    				ttisp->tt_ttisgmt = FALSE;
    			else {
    				ttisp->tt_ttisgmt = *p++;
    				if (ttisp->tt_ttisgmt != TRUE &&
    					ttisp->tt_ttisgmt != FALSE)
    						return -1;
    			}
    		}
    	}
    	return 0;
    }
    
    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, 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(strp, nump, min, max)
    register const char *	strp;
    int * const		nump;
    const int		min;
    const int		max;
    {
    	register char	c;
    	register int	num;
    
    	if (strp == NULL || !is_digit(c = *strp))
    		return NULL;
    	num = 0;
    	do {
    		num = num * 10 + (c - '0');
    		if (num > max)
    			return NULL;	/* illegal value */
    		c = *++strp;
    	} while (is_digit(c));
    	if (num < min)
    		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(strp, secsp)
    register const char *	strp;
    long * 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 * (long) 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(strp, offsetp)
    register const char *	strp;
    long * const		offsetp;
    {
    	register int	neg = 0;
    
    	if (*strp == '-') {
    		neg = 1;
    		++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(strp, rulep)
    const char *			strp;
    register 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 = getsecs(strp, &rulep->r_time);
    	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
    	return strp;
    }
    
    /*
    ** Given the Epoch-relative time of January 1, 00:00:00 GMT, in a year, the
    ** year, a rule, and the offset from GMT at the time that rule takes effect,
    ** calculate the Epoch-relative time that rule takes effect.
    */
    
    static time_t
    transtime(janfirst, year, rulep, offset)
    const time_t				janfirst;
    const int				year;
    register const struct rule * const	rulep;
    const long				offset;
    {
    	register int	leapyear;
    	register time_t	value = 0;
    	register int	i;
    	int		d, m1, yy0, yy1, yy2, dow;
    
    	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 = janfirst + (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 = janfirst + rulep->r_day * SECSPERDAY;
    		break;
    
    	case MONTH_NTH_DAY_OF_WEEK:
    		/*
    		** Mm.n.d - nth "dth day" of month m.
    		*/
    		value = janfirst;
    		for (i = 0; i < rulep->r_mon - 1; ++i)
    			value += mon_lengths[leapyear][i] * SECSPERDAY;
    
    		/*
    		** 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;
    		break;
    	}
    
    	/*
    	** "value" is the Epoch-relative time of 00:00:00 GMT on the day in
    	** question.  To get the Epoch-relative time of the specified local
    	** time on that day, add the transition time and the current offset
    	** from GMT.
    	*/
    	return value + rulep->r_time + offset;
    }
    
    /*
    ** Given a POSIX section 8-style TZ string, fill in the rule tables as
    ** appropriate.
    */
    
    static int
    tzparse(name, sp, lastditch)
    const char *			name;
    register struct state * const	sp;
    const int			lastditch;
    {
    	const char *			stdname;
    	const char *			dstname = NULL;
    	size_t				stdlen = 0;
    	size_t				dstlen = 0;
    	long				stdoffset = 0L;
    	long				dstoffset = 0L;
    	register time_t *		atp;
    	register unsigned char *	typep;
    	register char *			cp;
    	register int			load_result;
    
    	stdname = name;
    
    #ifdef DEBUG
    	fprintf(stderr, "tzparse(): loading default rules\n");
    #endif
    
    	load_result = tzload(TZDEFRULES, sp);
    	if (load_result != 0)
    		sp->leapcnt = 0;		/* so, we're off a little */
    	if (*name != '\0') {
    		if (*name != '\0' && *name != ',' && *name != ';') {
    			name = getoffset(name, &dstoffset);
    			if (name == NULL)
    				return -1;
    		} else	dstoffset = stdoffset - SECSPERHOUR;
    		if (*name == ',' || *name == ';') {
    			struct rule	start;
    			struct rule	end;
    			register int	year;
    			register time_t	janfirst;
    			time_t		starttime;
    			time_t		endtime;
    
    			++name;
    			if ((name = getrule(name, &start)) == NULL)
    				return -1;
    			if (*name++ != ',')
    				return -1;
    			if ((name = getrule(name, &end)) == NULL)
    				return -1;
    			if (*name != '\0')
    				return -1;
    			sp->typecnt = 2;	/* standard time and DST */
    			/*
    			** Two transitions per year, from EPOCH_YEAR to 2037.
    			*/
    			sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
    			if (sp->timecnt > TZ_MAX_TIMES)
    				return -1;
    			sp->ttis[0].tt_gmtoff = -dstoffset;
    			sp->ttis[0].tt_isdst = 1;
    			sp->ttis[0].tt_abbrind = stdlen + 1;
    			sp->ttis[1].tt_gmtoff = -stdoffset;
    			sp->ttis[1].tt_isdst = 0;
    			sp->ttis[1].tt_abbrind = 0;
    			atp = sp->ats;
    			typep = sp->types;
    			janfirst = 0;
    			for (year = EPOCH_YEAR; year <= 2037; ++year) {
    				starttime = transtime(janfirst, year, &start,
    					stdoffset);
    				endtime = transtime(janfirst, year, &end,
    					dstoffset);
    				if (starttime > endtime) {
    					*atp++ = endtime;
    					*typep++ = 1;	/* DST ends */
    					*atp++ = starttime;
    					*typep++ = 0;	/* DST begins */
    				} else {
    					*atp++ = starttime;
    					*typep++ = 0;	/* DST begins */
    					*atp++ = endtime;
    					*typep++ = 1;	/* DST ends */
    				}
    				janfirst += year_lengths[isleap(year)] *
    					SECSPERDAY;
    			}
    		} else {
    			register long	theirstdoffset;
    			register long	theirdstoffset;
    			register long	theiroffset;
    			register int	isdst;
    			register int	i;
    			register int	j;
    
    			if (*name != '\0')
    				return -1;
    			if (load_result != 0)
    				return -1;
    			/*
    			** 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] += dstoffset -
    							theirdstoffset;
    					} else {
    						sp->ats[i] += stdoffset -
    							theirstdoffset;
    					}
    				}
    				theiroffset = -sp->ttis[j].tt_gmtoff;
    				if (sp->ttis[j].tt_isdst)
    					theirdstoffset = theiroffset;
    				else	theirstdoffset = theiroffset;
    			}
    			/*
    			** Finally, fill in ttis.
    			** ttisstd and ttisgmt need not be handled.
    			*/
    			sp->ttis[0].tt_gmtoff = -stdoffset;
    			sp->ttis[0].tt_isdst = FALSE;
    			sp->ttis[0].tt_abbrind = 0;
    			sp->ttis[1].tt_gmtoff = -dstoffset;
    			sp->ttis[1].tt_isdst = TRUE;
    			sp->ttis[1].tt_abbrind = stdlen + 1;
    		}
    	} else {
    		dstlen = 0;
    		sp->typecnt = 1;		/* only standard time */
    		sp->timecnt = 0;
    		sp->ttis[0].tt_gmtoff = -stdoffset;
    		sp->ttis[0].tt_isdst = 0;
    		sp->ttis[0].tt_abbrind = 0;
    	}
    	sp->charcnt = stdlen + 1;
    	if (dstlen != 0)
    		sp->charcnt += dstlen + 1;
    	if (sp->charcnt > sizeof sp->chars)
    		return -1;
    	cp = sp->chars;
    	(void) strncpy(cp, stdname, stdlen);
    	cp += stdlen;
    	*cp++ = '\0';
    	if (dstlen != 0) {
    		(void) strncpy(cp, dstname, dstlen);
    		*(cp + dstlen) = '\0';
    	}
    	return 0;
    }
    
    static void
    gmtload(sp)
    struct state * const	sp;
    {
    	if (tzload(gmt, sp) != 0)
    		(void) tzparse(gmt, sp, TRUE);
    }
    
    /*
    ** A non-static declaration of ast_tzsetwall in a system header file
    ** may cause a warning about this upcoming static declaration...
    */
    static
    #ifdef	_THREAD_SAFE
    int
    ast_tzsetwall_basic P((void))
    #else
    int
    ast_tzsetwall P((void))
    #endif
    {
    	struct state *cur_state = lclptr;
    
    	/* Find the appropriate structure, if already parsed */
    	while (cur_state != NULL) {
    		if (cur_state->name[0] == '\0')
    			break;
    		cur_state = cur_state->next;
    	}
    	if (cur_state != NULL)
    		return 0;
    	cur_state = malloc(sizeof(struct state));
    	if (cur_state == NULL) {
    		return -1;
    	}
    	memset(cur_state,0,sizeof(struct state));
    	if (tzload((char *) NULL, cur_state) != 0)
    
    #ifdef DEBUG
    	{
    		fprintf(stderr, "ast_tzsetwall: calling gmtload()\n");
    #endif
    
    #ifdef DEBUG
    	}
    #endif
    
    
    	if (last_lclptr)
    		last_lclptr->next = cur_state;
    	else
    		lclptr = cur_state;
    	last_lclptr = cur_state;
    	return 0;
    }
    
    #ifdef	_THREAD_SAFE
    int
    ast_tzsetwall P((void))
    {
    	ast_mutex_lock(&tzsetwall_mutex);
    	ast_tzsetwall_basic();
    	ast_mutex_unlock(&tzsetwall_mutex);
    	return 0;
    }
    #endif
    
    #ifdef	_THREAD_SAFE
    static int
    ast_tzset_basic P((const char *name))
    #else
    int
    ast_tzset P((const char *name))
    #endif
    {
    	struct state *cur_state = lclptr;
    
    	/* Not set at all */
    	if (name == NULL) {
    		return ast_tzsetwall();
    	}
    
    	/* Find the appropriate structure, if already parsed */
    	while (cur_state != NULL) {
    		if (!strcmp(cur_state->name,name))
    			break;
    		cur_state = cur_state->next;
    	}
    	if (cur_state != NULL)
    		return 0;
    
    	cur_state = malloc(sizeof(struct state));
    	if (cur_state == NULL) {
    		return -1;
    	}
    	memset(cur_state,0,sizeof(*cur_state));
    
    	/* Name is set, but set to the empty string == no adjustments */
    	if (name[0] == '\0') {
    		/*
    		** User wants it fast rather than right.
    		*/
    		cur_state->leapcnt = 0;		/* so, we're off a little */
    		cur_state->timecnt = 0;
    		cur_state->ttis[0].tt_gmtoff = 0;
    		cur_state->ttis[0].tt_abbrind = 0;
    		(void) strcpy(cur_state->chars, gmt);
    
    	} else if (tzload(name, cur_state) != 0) {
    
    		if (name[0] == ':') {
    
    		} else if (tzparse(name, cur_state, FALSE) != 0) {
    			/* If not found, load localtime */
    			if (tzload("/etc/localtime", cur_state) != 0)
    				/* Last ditch, get GMT */
    				(void) gmtload(cur_state);
    		}
    
    	strncpy(cur_state->name,name,sizeof(cur_state->name));
    	if (last_lclptr)
    		last_lclptr->next = cur_state;
    	else
    		lclptr = cur_state;
    	last_lclptr = cur_state;
    	return 0;
    }
    
    #ifdef	_THREAD_SAFE
    void
    ast_tzset P((const char *name))
    {
    	ast_mutex_lock(&tzset_mutex);
    	ast_tzset_basic(name);
    	ast_mutex_unlock(&tzset_mutex);
    }
    #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.)
    **
    ** The unused offset argument is for the benefit of mktime variants.
    */
    
    /*ARGSUSED*/
    static void
    localsub(timep, offset, tmp, zone)
    const time_t * const	timep;
    const long		offset;
    struct tm * const	tmp;
    const char * const	zone;
    {
    	register struct state *		sp;
    	register const struct ttinfo *	ttisp;
    	register int			i;
    	const time_t			t = *timep;
    
    	sp = lclptr;
    	/* Find the right zone record */
    
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    	if (zone == NULL)
    		sp = NULL;
    	else
    		while (sp != NULL) {
    			if (!strcmp(sp->name,zone))
    				break;
    			sp = sp->next;
    		}
    
    	if (sp == NULL) {
    		ast_tzsetwall();
    		sp = lclptr;
    		/* Find the default zone record */
    		while (sp != NULL) {
    			if (sp->name[0] == '\0')