The Tor Browser: intl/icu/source/tools/tzcode/localtime.c@fc2d59ddac77 (annotated)

intl/icu/source/tools/tzcode/localtime.c@fc2d59ddac77 (annotated)

intl/icu/source/tools/tzcode/localtime.c

Wed, 31 Dec 2014 07:22:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:22:50 +0100
branch: TOR_BUG_3246
changeset 4: fc2d59ddac77
permissions: -rw-r--r--

Correct previous dual key logic pending first delivery installment.

 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 #ifndef lint
 #ifndef NOID
 static char	elsieid[] = "@(#)localtime.c	8.9";
 #endif /* !defined NOID */
 #endif /* !defined lint */
 /*
 ** Leap second handling from Bradley White.
 ** POSIX-style TZ environment variable handling from Guy Harris.
 */
 /*LINTLIBRARY*/
 #include "private.h"
 #include "tzfile.h"
 #include "fcntl.h"
 #include "float.h"	/* for FLT_MAX and DBL_MAX */
 #ifndef TZ_ABBR_MAX_LEN
 #define TZ_ABBR_MAX_LEN	16
 #endif /* !defined TZ_ABBR_MAX_LEN */
 #ifndef TZ_ABBR_CHAR_SET
 #define TZ_ABBR_CHAR_SET \
 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
 #endif /* !defined TZ_ABBR_CHAR_SET */
 #ifndef TZ_ABBR_ERR_CHAR
 #define TZ_ABBR_ERR_CHAR	'_'
 #endif /* !defined TZ_ABBR_ERR_CHAR */
 /*
 ** SunOS 4.1.1 headers lack O_BINARY.
 */
 #ifdef O_BINARY
 #define OPEN_MODE	(O_RDONLY | O_BINARY)
 #endif /* defined O_BINARY */
 #ifndef O_BINARY
 #define OPEN_MODE	O_RDONLY
 #endif /* !defined O_BINARY */
 #ifndef WILDABBR
 /*
 ** Someone might make incorrect use of a time zone abbreviation:
 **	1.	They might reference tzname[0] before calling tzset (explicitly
 **		or implicitly).
 **	2.	They might reference tzname[1] before calling tzset (explicitly
 **		or implicitly).
 **	3.	They might reference tzname[1] after setting to a time zone
 **		in which Daylight Saving Time is never observed.
 **	4.	They might reference tzname[0] after setting to a time zone
 **		in which Standard Time is never observed.
 **	5.	They might reference tm.TM_ZONE after calling offtime.
 ** What's best to do in the above cases is open to debate;
 ** for now, we just set things up so that in any of the five cases
 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
 ** string "tzname[0] used before set", and similarly for the other cases.
 ** And another: initialize tzname[0] to "ERA", with an explanation in the
 ** manual page of what this "time zone abbreviation" means (doing this so
 ** that tzname[0] has the "normal" length of three characters).
 */
 #define WILDABBR	"   "
 #endif /* !defined WILDABBR */
 static char		wildabbr[] = WILDABBR;
 static const char	gmt[] = "GMT";
 /*
 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
 ** We default to US rules as of 1999-08-17.
 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
 ** implementation dependent; for historical reasons, US rules are a
 ** common default.
 */
 #ifndef TZDEFRULESTRING
 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
 #endif /* !defined TZDEFDST */
 struct ttinfo {				/* time type information */
 	long		tt_gmtoff;	/* UTC offset in seconds */
 	int		tt_isdst;	/* used to set tm_isdst */
 	int		tt_abbrind;	/* abbreviation list index */
 	int		tt_ttisstd;	/* TRUE if transition is std time */
 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
 };
 struct lsinfo {				/* leap second information */
 	time_t		ls_trans;	/* transition time */
 	long		ls_corr;	/* correction to apply */
 };
 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
 #ifdef TZNAME_MAX
 #define MY_TZNAME_MAX	TZNAME_MAX
 #endif /* defined TZNAME_MAX */
 #ifndef TZNAME_MAX
 #define MY_TZNAME_MAX	255
 #endif /* !defined TZNAME_MAX */
 struct state {
 	int		leapcnt;
 	int		timecnt;
 	int		typecnt;
 	int		charcnt;
 	int		goback;
 	int		goahead;
 	time_t		ats[TZ_MAX_TIMES];
 	unsigned char	types[TZ_MAX_TIMES];
 	struct ttinfo	ttis[TZ_MAX_TYPES];
 	char		chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
 				(2 * (MY_TZNAME_MAX + 1)))];
 	struct lsinfo	lsis[TZ_MAX_LEAPS];
 };
 struct rule {
 	int		r_type;		/* type of rule--see below */
 	int		r_day;		/* day number of rule */
 	int		r_week;		/* week number of rule */
 	int		r_mon;		/* month number of rule */
 	long		r_time;		/* transition time of rule */
 };
 #define JULIAN_DAY		0	/* Jn - Julian day */
 #define DAY_OF_YEAR		1	/* n - day of year */
 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
 /*
 ** Prototypes for static functions.
 */
 static long		detzcode(const char * codep);
 static time_t		detzcode64(const char * codep);
 static int		differ_by_repeat(time_t t1, time_t t0);
 static const char *	getzname(const char * strp);
 static const char *	getqzname(const char * strp, const int delim);
 static const char *	getnum(const char * strp, int * nump, int min,
 				int max);
 static const char *	getsecs(const char * strp, long * secsp);
 static const char *	getoffset(const char * strp, long * offsetp);
 static const char *	getrule(const char * strp, struct rule * rulep);
 static void		gmtload(struct state * sp);
 static struct tm *	gmtsub(const time_t * timep, long offset,
 				struct tm * tmp);
 static struct tm *	localsub(const time_t * timep, long offset,
 				struct tm * tmp);
 static int		increment_overflow(int * number, int delta);
 static int		leaps_thru_end_of(int y);
 static int		long_increment_overflow(long * number, int delta);
 static int		long_normalize_overflow(long * tensptr,
 				int * unitsptr, int base);
 static int		normalize_overflow(int * tensptr, int * unitsptr,
 				int base);
 static void		settzname(void);
 static time_t		time1(struct tm * tmp,
 				struct tm * (*funcp)(const time_t *,
 				long, struct tm *),
 				long offset);
 static time_t		time2(struct tm *tmp,
 				struct tm * (*funcp)(const time_t *,
 				long, struct tm*),
 				long offset, int * okayp);
 static time_t		time2sub(struct tm *tmp,
 				struct tm * (*funcp)(const time_t *,
 				long, struct tm*),
 				long offset, int * okayp, int do_norm_secs);
 static struct tm *	timesub(const time_t * timep, long offset,
 				const struct state * sp, struct tm * tmp);
 static int		tmcomp(const struct tm * atmp,
 				const struct tm * btmp);
 static time_t		transtime(time_t janfirst, int year,
 				const struct rule * rulep, long offset);
 static int		typesequiv(const struct state * sp, int a, int b);
 static int		tzload(const char * name, struct state * sp,
 				int doextend);
 static int		tzparse(const char * name, struct state * sp,
 				int lastditch);
 #ifdef ALL_STATE
 static struct state *	lclptr;
 static struct state *	gmtptr;
 #endif /* defined ALL_STATE */
 #ifndef ALL_STATE
 static struct state	lclmem;
 static struct state	gmtmem;
 #define lclptr		(&lclmem)
 #define gmtptr		(&gmtmem)
 #endif /* State Farm */
 #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;
 static int		gmt_is_set;
 char *			tzname[2] = {
 	wildabbr,
 	wildabbr
 };
 /*
 ** 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
 time_t			timezone = 0;
 int			daylight = 0;
 #endif /* defined USG_COMPAT */
 #ifdef ALTZONE
 time_t			altzone = 0;
 #endif /* defined ALTZONE */
 static long
 detzcode(codep)
 const char * const	codep;
 {
 	register long	result;
 	register int	i;
 	result = (codep[0] & 0x80) ? ~0L : 0;
 	for (i = 0; i < 4; ++i)
 		result = (result << 8) | (codep[i] & 0xff);
 	return result;
 }
 static time_t
 detzcode64(codep)
 const char * const	codep;
 {
 	register time_t	result;
 	register int	i;
 	result = (codep[0] & 0x80) ?  (~(int_fast64_t) 0) : 0;
 	for (i = 0; i < 8; ++i)
 		result = result * 256 + (codep[i] & 0xff);
 	return result;
 }
 static void
 settzname(void)
 {
 	register struct state * const	sp = lclptr;
 	register int			i;
 	tzname[0] = wildabbr;
 	tzname[1] = wildabbr;
 #ifdef USG_COMPAT
 	daylight = 0;
 	timezone = 0;
 #endif /* defined USG_COMPAT */
 #ifdef ALTZONE
 	altzone = 0;
 #endif /* defined ALTZONE */
 #ifdef ALL_STATE
 	if (sp == NULL) {
 		tzname[0] = tzname[1] = gmt;
 		return;
 	}
 #endif /* defined ALL_STATE */
 	for (i = 0; i < sp->typecnt; ++i) {
 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
 		tzname[ttisp->tt_isdst] =
 			&sp->chars[ttisp->tt_abbrind];
 #ifdef USG_COMPAT
 		if (ttisp->tt_isdst)
 			daylight = 1;
 		if (i == 0 || !ttisp->tt_isdst)
 			timezone = -(ttisp->tt_gmtoff);
 #endif /* defined USG_COMPAT */
 #ifdef ALTZONE
 		if (i == 0 || ttisp->tt_isdst)
 			altzone = -(ttisp->tt_gmtoff);
 #endif /* defined ALTZONE */
 	}
 	/*
 	** And to get the latest zone names into tzname. . .
 	*/
 	for (i = 0; i < sp->timecnt; ++i) {
 		register const struct ttinfo * const	ttisp =
 							&sp->ttis[
 								sp->types[i]];
 		tzname[ttisp->tt_isdst] =
 			&sp->chars[ttisp->tt_abbrind];
 	}
 	/*
 	** Finally, scrub the abbreviations.
 	** 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) {
 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
 		register 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 int
 differ_by_repeat(t1, t0)
 const time_t	t1;
 const time_t	t0;
 {
 	if (TYPE_INTEGRAL(time_t) &&
 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
 			return 0;
 	return t1 - t0 == SECSPERREPEAT;
 }
 static int
 tzload(name, sp, doextend)
 register const char *		name;
 register struct state * const	sp;
 register const int		doextend;
 {
 	register const char *		p;
 	register int			i;
 	register int			fid;
 	register int			stored;
 	register int			nread;
 	union {
 		struct tzhead	tzhead;
 		char		buf[2 * sizeof(struct tzhead) +
 * sizeof *sp +
 * TZ_MAX_TIMES];
 	} u;
 	if (name == NULL && (name = TZDEFAULT) == NULL)
 		return -1;
 	{
 		register int	doaccess;
 		/*
 		** 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) + 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;
 	}
 	nread = read(fid, u.buf, sizeof u.buf);
 	if (close(fid) < 0 || nread <= 0)
 		return -1;
 	for (stored = 4; stored <= 8; stored *= 2) {
 		int		ttisstdcnt;
 		int		ttisgmtcnt;
 		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
 		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
 		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
 		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
 		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
 		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
 		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
 		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 (nread - (p - u.buf) <
 			sp->timecnt * stored +		/* ats */
 			sp->timecnt +			/* types */
 			sp->typecnt * 6 +		/* ttinfos */
 			sp->charcnt +			/* chars */
 			sp->leapcnt * (stored + 4) +	/* lsinfos */
 			ttisstdcnt +			/* ttisstds */
 			ttisgmtcnt)			/* ttisgmts */
 				return -1;
 		for (i = 0; i < sp->timecnt; ++i) {
 			sp->ats[i] = (stored == 4) ?
 				detzcode(p) : detzcode64(p);
 			p += stored;
 		}
 		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 = (stored == 4) ?
 				detzcode(p) : detzcode64(p);
 			p += stored;
 			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;
 			}
 		}
 		/*
 		** Out-of-sort ats should mean we're running on a
 		** signed time_t system but using a data file with
 		** unsigned values (or vice versa).
 		*/
 		for (i = 0; i < sp->timecnt - 2; ++i)
 			if (sp->ats[i] > sp->ats[i + 1]) {
 				++i;
 				if (TYPE_SIGNED(time_t)) {
 					/*
 					** Ignore the end (easy).
 					*/
 					sp->timecnt = i;
 				} else {
 					/*
 					** Ignore the beginning (harder).
 					*/
 					register int	j;
 					for (j = 0; j + i < sp->timecnt; ++j) {
 						sp->ats[j] = sp->ats[j + i];
 						sp->types[j] = sp->types[j + i];
 					}
 					sp->timecnt = j;
 				}
 				break;
 			}
 		/*
 		** If this is an old file, we're done.
 		*/
 		if (u.tzhead.tzh_version[0] == '\0')
 			break;
 		nread -= p - u.buf;
 		for (i = 0; i < nread; ++i)
 			u.buf[i] = p[i];
 		/*
 		** If this is a narrow integer time_t system, we're done.
 		*/
 		if (stored >= (int) sizeof(time_t) && TYPE_INTEGRAL(time_t))
 			break;
 	}
 	if (doextend && nread > 2 &&
 		u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
 			struct state	ts;
 			register int	result;
 			u.buf[nread - 1] = '\0';
 			result = tzparse(&u.buf[1], &ts, FALSE);
 			if (result == 0 && ts.typecnt == 2 &&
 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
 					for (i = 0; i < 2; ++i)
 						ts.ttis[i].tt_abbrind +=
 							sp->charcnt;
 					for (i = 0; i < ts.charcnt; ++i)
 						sp->chars[sp->charcnt++] =
 							ts.chars[i];
 					i = 0;
 					while (i < ts.timecnt &&
 						ts.ats[i] <=
 						sp->ats[sp->timecnt - 1])
 							++i;
 					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];
 			}
 	}
 	sp->goback = sp->goahead = FALSE;
 	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;
 		}
 	}
 	return 0;
 }
 static int
 typesequiv(sp, a, b)
 const struct state * const	sp;
 const int			a;
 const int			b;
 {
 	register int	result;
 	if (sp == NULL ||
 		a < 0 || a >= sp->typecnt ||
 		b < 0 || b >= sp->typecnt)
 			result = FALSE;
 	else {
 		register const struct ttinfo *	ap = &sp->ttis[a];
 		register 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 *
 getzname(strp)
 register const char *	strp;
 {
 	register 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 *
 getqzname(register const char *strp, const int delim)
 {
 	register 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(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 UTC, in a year, the
 ** year, a rule, and the offset from UTC 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;
 	register 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 = 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 +
 + 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 UTC 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 UTC.
 	*/
 	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;
 	size_t				stdlen;
 	size_t				dstlen;
 	long				stdoffset;
 	long				dstoffset;
 	register time_t *		atp;
 	register unsigned char *	typep;
 	register char *			cp;
 	register int			load_result;
 	INITIALIZE(dstname);
 	stdname = name;
 	if (lastditch) {
 		stdlen = strlen(name);	/* length of standard zone name */
 		name += stdlen;
 		if (stdlen >= sizeof sp->chars)
 			stdlen = (sizeof sp->chars) - 1;
 		stdoffset = 0;
 	} else {
 		if (*name == '<') {
 			name++;
 			stdname = name;
 			name = getqzname(name, '>');
 			if (*name != '>')
 				return (-1);
 			stdlen = name - stdname;
 			name++;
 		} else {
 			name = getzname(name);
 			stdlen = name - stdname;
 		}
 		if (*name == '\0')
 			return -1;
 		name = getoffset(name, &stdoffset);
 		if (name == NULL)
 			return -1;
 	}
 	load_result = tzload(TZDEFRULES, sp, FALSE);
 	if (load_result != 0)
 		sp->leapcnt = 0;		/* so, we're off a little */
 	if (*name != '\0') {
 		if (*name == '<') {
 			dstname = ++name;
 			name = getqzname(name, '>');
 			if (*name != '>')
 				return -1;
 			dstlen = name - dstname;
 			name++;
 		} else {
 			dstname = name;
 			name = getzname(name);
 			dstlen = name - dstname; /* length of DST zone name */
 		}
 		if (*name != '\0' && *name != ',' && *name != ';') {
 			name = getoffset(name, &dstoffset);
 			if (name == NULL)
 				return -1;
 		} else	dstoffset = stdoffset - SECSPERHOUR;
 		if (*name == '\0' && load_result != 0)
 			name = TZDEFRULESTRING;
 		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 forward.
 			*/
 			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;
 			sp->timecnt = 0;
 			for (year = EPOCH_YEAR;
 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
 			    ++year) {
 			    	time_t	newfirst;
 				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 */
 				}
 				sp->timecnt += 2;
 				newfirst = janfirst;
 				newfirst += year_lengths[isleap(year)] *
 					SECSPERDAY;
 				if (newfirst <= janfirst)
 					break;
 				janfirst = newfirst;
 			}
 		} else {
 			register long	theirstdoffset;
 			register long	theirdstoffset;
 			register long	theiroffset;
 			register int	isdst;
 			register int	i;
 			register int	j;
 			if (*name != '\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;
 			sp->typecnt = 2;
 		}
 	} 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 ((size_t) 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, TRUE) != 0)
 		(void) tzparse(gmt, sp, TRUE);
 }
 #ifndef STD_INSPIRED
 /*
 ** A non-static declaration of tzsetwall in a system header file
 ** may cause a warning about this upcoming static declaration...
 */
 static
 #endif /* !defined STD_INSPIRED */
 void
 tzsetwall(void)
 {
 	if (lcl_is_set < 0)
 		return;
 	lcl_is_set = -1;
 #ifdef ALL_STATE
 	if (lclptr == NULL) {
 		lclptr = (struct state *) malloc(sizeof *lclptr);
 		if (lclptr == NULL) {
 			settzname();	/* all we can do */
 			return;
 		}
 	}
 #endif /* defined ALL_STATE */
 	if (tzload((char *) NULL, lclptr, TRUE) != 0)
 		gmtload(lclptr);
 	settzname();
 }
 void
 tzset(void)
 {
 	register const char *	name;
 	name = getenv("TZ");
 	if (name == NULL) {
 		tzsetwall();
 		return;
 	}
 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
 		return;
 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
 	if (lcl_is_set)
 		(void) strcpy(lcl_TZname, name);
 #ifdef ALL_STATE
 	if (lclptr == NULL) {
 		lclptr = (struct state *) malloc(sizeof *lclptr);
 		if (lclptr == NULL) {
 			settzname();	/* all we can do */
 			return;
 		}
 	}
 #endif /* defined ALL_STATE */
 	if (*name == '\0') {
 		/*
 		** User wants it fast rather than right.
 		*/
 		lclptr->leapcnt = 0;		/* so, we're off a little */
 		lclptr->timecnt = 0;
 		lclptr->typecnt = 0;
 		lclptr->ttis[0].tt_isdst = 0;
 		lclptr->ttis[0].tt_gmtoff = 0;
 		lclptr->ttis[0].tt_abbrind = 0;
 		(void) strcpy(lclptr->chars, gmt);
 	} else if (tzload(name, lclptr, TRUE) != 0)
 		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
 			(void) gmtload(lclptr);
 	settzname();
 }
 /*
 ** The easy way to behave "as if no library function calls" localtime
 ** is to not call it--so we drop its guts into "localsub", which can be
 ** freely called. (And no, the PANS doesn't require the above behavior--
 ** but it *is* desirable.)
 **
 ** The unused offset argument is for the benefit of mktime variants.
 */
 /*ARGSUSED*/
 static struct tm *
 localsub(timep, offset, tmp)
 const time_t * const	timep;
 const long		offset;
 struct tm * const	tmp;
 {
 	register struct state *		sp;
 	register const struct ttinfo *	ttisp;
 	register int			i;
 	register struct tm *		result;
 	const time_t			t = *timep;
 	sp = lclptr;
 #ifdef ALL_STATE
 	if (sp == NULL)
 		return gmtsub(timep, offset, tmp);
 #endif /* defined ALL_STATE */
 	if ((sp->goback && t < sp->ats[0]) ||
 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
 			time_t			newt = t;
 			register time_t		seconds;
 			register time_t		tcycles;
 			register int_fast64_t	icycles;
 			if (t < sp->ats[0])
 				seconds = sp->ats[0] - t;
 			else	seconds = t - sp->ats[sp->timecnt - 1];
 			--seconds;
 			tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
 			++tcycles;
 			icycles = tcycles;
 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
 				return NULL;
 			seconds = icycles;
 			seconds *= YEARSPERREPEAT;
 			seconds *= AVGSECSPERYEAR;
 			if (t < sp->ats[0])
 				newt += seconds;
 			else	newt -= seconds;
 			if (newt < sp->ats[0] ||
 				newt > sp->ats[sp->timecnt - 1])
 					return NULL;	/* "cannot happen" */
 			result = localsub(&newt, offset, tmp);
 			if (result == tmp) {
 				register time_t	newy;
 				newy = tmp->tm_year;
 				if (t < sp->ats[0])
 					newy -= icycles * YEARSPERREPEAT;
 				else	newy += icycles * YEARSPERREPEAT;
 				tmp->tm_year = newy;
 				if (tmp->tm_year != newy)
 					return NULL;
 			}
 			return result;
 	}
 	if (sp->timecnt == 0 || t < sp->ats[0]) {
 		i = 0;
 		while (sp->ttis[i].tt_isdst)
 			if (++i >= sp->typecnt) {
 				i = 0;
 				break;
 			}
 	} else {
 		register int	lo = 1;
 		register int	hi = sp->timecnt;
 		while (lo < hi) {
 			register int	mid = (lo + hi) >> 1;
 			if (t < sp->ats[mid])
 				hi = mid;
 			else	lo = mid + 1;
 		}
 		i = (int) sp->types[lo - 1];
 	}
 	ttisp = &sp->ttis[i];
 	/*
 	** To get (wrong) behavior that's compatible with System V Release 2.0
 	** you'd replace the statement below with
 	**	t += ttisp->tt_gmtoff;
 	**	timesub(&t, 0L, sp, tmp);
 	*/
 	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
 	tmp->tm_isdst = ttisp->tt_isdst;
 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
 #ifdef TM_ZONE
 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
 #endif /* defined TM_ZONE */
 	return result;
 }
 struct tm *
 localtime(timep)
 const time_t * const	timep;
 {
 	tzset();
 	return localsub(timep, 0L, &tm);
 }
 /*
 ** Re-entrant version of localtime.
 */
 struct tm *
 localtime_r(timep, tmp)
 const time_t * const	timep;
 struct tm *		tmp;
 {
 	return localsub(timep, 0L, tmp);
 }
 /*
 ** gmtsub is to gmtime as localsub is to localtime.
 */
 static struct tm *
 gmtsub(timep, offset, tmp)
 const time_t * const	timep;
 const long		offset;
 struct tm * const	tmp;
 {
 	register struct tm *	result;
 	if (!gmt_is_set) {
 		gmt_is_set = TRUE;
 #ifdef ALL_STATE
 		gmtptr = (struct state *) malloc(sizeof *gmtptr);
 		if (gmtptr != NULL)
 #endif /* defined ALL_STATE */
 			gmtload(gmtptr);
 	}
 	result = timesub(timep, offset, gmtptr, tmp);
 #ifdef TM_ZONE
 	/*
 	** Could get fancy here and deliver something such as
 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
 	** but this is no time for a treasure hunt.
 	*/
 	if (offset != 0)
 		tmp->TM_ZONE = wildabbr;
 	else {
 #ifdef ALL_STATE
 		if (gmtptr == NULL)
 			tmp->TM_ZONE = gmt;
 		else	tmp->TM_ZONE = gmtptr->chars;
 #endif /* defined ALL_STATE */
 #ifndef ALL_STATE
 		tmp->TM_ZONE = gmtptr->chars;
 #endif /* State Farm */
 	}
 #endif /* defined TM_ZONE */
 	return result;
 }
 struct tm *
 gmtime(timep)
 const time_t * const	timep;
 {
 	return gmtsub(timep, 0L, &tm);
 }
 /*
 * Re-entrant version of gmtime.
 */
 struct tm *
 gmtime_r(timep, tmp)
 const time_t * const	timep;
 struct tm *		tmp;
 {
 	return gmtsub(timep, 0L, tmp);
 }
 #ifdef STD_INSPIRED
 struct tm *
 offtime(timep, offset)
 const time_t * const	timep;
 const long		offset;
 {
 	return gmtsub(timep, offset, &tm);
 }
 #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
 leaps_thru_end_of(y)
 register const int	y;
 {
 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
 		-(leaps_thru_end_of(-(y + 1)) + 1);
 }
 static struct tm *
 timesub(timep, offset, sp, tmp)
 const time_t * const			timep;
 const long				offset;
 register const struct state * const	sp;
 register struct tm * const		tmp;
 {
 	register const struct lsinfo *	lp;
 	register time_t			tdays;
 	register int			idays;	/* unsigned would be so 2003 */
 	register long			rem;
 	int				y;
 	register const int *		ip;
 	register long			corr;
 	register int			hit;
 	register int			i;
 	corr = 0;
 	hit = 0;
 #ifdef ALL_STATE
 	i = (sp == NULL) ? 0 : sp->leapcnt;
 #endif /* defined ALL_STATE */
 #ifndef ALL_STATE
 	i = sp->leapcnt;
 #endif /* State Farm */
 	while (--i >= 0) {
 		lp = &sp->lsis[i];
 		if (*timep >= lp->ls_trans) {
 			if (*timep == lp->ls_trans) {
 				hit = ((i == 0 && lp->ls_corr > 0) ||
 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
 				if (hit)
 					while (i > 0 &&
 						sp->lsis[i].ls_trans ==
 						sp->lsis[i - 1].ls_trans + 1 &&
 						sp->lsis[i].ls_corr ==
 						sp->lsis[i - 1].ls_corr + 1) {
 							++hit;
 							--i;
 					}
 			}
 			corr = lp->ls_corr;
 			break;
 		}
 	}
 	y = EPOCH_YEAR;
 	tdays = *timep / SECSPERDAY;
 	rem = *timep - tdays * SECSPERDAY;
 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
 		int		newy;
 		register time_t	tdelta;
 		register int	idelta;
 		register int	leapdays;
 		tdelta = tdays / DAYSPERLYEAR;
 		idelta = tdelta;
 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
 			return NULL;
 		if (idelta == 0)
 			idelta = (tdays < 0) ? -1 : 1;
 		newy = y;
 		if (increment_overflow(&newy, idelta))
 			return NULL;
 		leapdays = leaps_thru_end_of(newy - 1) -
 			leaps_thru_end_of(y - 1);
 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
 		tdays -= leapdays;
 		y = newy;
 	}
 	{
 		register long	seconds;
 		seconds = tdays * SECSPERDAY + 0.5;
 		tdays = seconds / SECSPERDAY;
 		rem += seconds - tdays * SECSPERDAY;
 	}
 	/*
 	** Given the range, we can now fearlessly cast...
 	*/
 	idays = tdays;
 	rem += offset - corr;
 	while (rem < 0) {
 		rem += SECSPERDAY;
 		--idays;
 	}
 	while (rem >= SECSPERDAY) {
 		rem -= SECSPERDAY;
 		++idays;
 	}
 	while (idays < 0) {
 		if (increment_overflow(&y, -1))
 			return NULL;
 		idays += year_lengths[isleap(y)];
 	}
 	while (idays >= year_lengths[isleap(y)]) {
 		idays -= year_lengths[isleap(y)];
 		if (increment_overflow(&y, 1))
 			return NULL;
 	}
 	tmp->tm_year = y;
 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
 		return NULL;
 	tmp->tm_yday = idays;
 	/*
 	** The "extra" mods below avoid overflow problems.
 	*/
 	tmp->tm_wday = EPOCH_WDAY +
 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
 		(DAYSPERNYEAR % DAYSPERWEEK) +
 		leaps_thru_end_of(y - 1) -
 		leaps_thru_end_of(EPOCH_YEAR - 1) +
 		idays;
 	tmp->tm_wday %= DAYSPERWEEK;
 	if (tmp->tm_wday < 0)
 		tmp->tm_wday += DAYSPERWEEK;
 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
 	rem %= SECSPERHOUR;
 	tmp->tm_min = (int) (rem / SECSPERMIN);
 	/*
 	** A positive leap second requires a special
 	** representation. This uses "... ??:59:60" et seq.
 	*/
 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
 	ip = mon_lengths[isleap(y)];
 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
 		idays -= ip[tmp->tm_mon];
 	tmp->tm_mday = (int) (idays + 1);
 	tmp->tm_isdst = 0;
 #ifdef TM_GMTOFF
 	tmp->TM_GMTOFF = offset;
 #endif /* defined TM_GMTOFF */
 	return tmp;
 }
 char *
 ctime(timep)
 const time_t * const	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))
 */
 	return asctime(localtime(timep));
 }
 char *
 ctime_r(timep, buf)
 const time_t * const	timep;
 char *			buf;
 {
 	struct tm	mytm;
 	return asctime_r(localtime_r(timep, &mytm), buf);
 }
 /*
 ** Adapted from code provided by Robert Elz, who writes:
 **	The "best" way to do mktime I think is based on an idea of Bob
 **	Kridle's (so its said...) from a long time ago.
 **	It does a binary search of the time_t space. Since time_t's are
 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
 **	would still be very reasonable).
 */
 #ifndef WRONG
 #define WRONG	(-1)
 #endif /* !defined WRONG */
 /*
 ** Simplified normalize logic courtesy Paul Eggert.
 */
 static int
 increment_overflow(number, delta)
 int *	number;
 int	delta;
 {
 	int	number0;
 	number0 = *number;
 	*number += delta;
 	return (*number < number0) != (delta < 0);
 }
 static int
 long_increment_overflow(number, delta)
 long *	number;
 int	delta;
 {
 	long	number0;
 	number0 = *number;
 	*number += delta;
 	return (*number < number0) != (delta < 0);
 }
 static int
 normalize_overflow(tensptr, unitsptr, base)
 int * const	tensptr;
 int * const	unitsptr;
 const int	base;
 {
 	register int	tensdelta;
 	tensdelta = (*unitsptr >= 0) ?
 		(*unitsptr / base) :
 		(-1 - (-1 - *unitsptr) / base);
 	*unitsptr -= tensdelta * base;
 	return increment_overflow(tensptr, tensdelta);
 }
 static int
 long_normalize_overflow(tensptr, unitsptr, base)
 long * const	tensptr;
 int * const	unitsptr;
 const int	base;
 {
 	register int	tensdelta;
 	tensdelta = (*unitsptr >= 0) ?
 		(*unitsptr / base) :
 		(-1 - (-1 - *unitsptr) / base);
 	*unitsptr -= tensdelta * base;
 	return long_increment_overflow(tensptr, tensdelta);
 }
 static int
 tmcomp(atmp, btmp)
 register const struct tm * const atmp;
 register const struct tm * const btmp;
 {
 	register int	result;
 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
 			result = atmp->tm_sec - btmp->tm_sec;
 	return result;
 }
 static time_t
 time2sub(tmp, funcp, offset, okayp, do_norm_secs)
 struct tm * const	tmp;
 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
 const long		offset;
 int * const		okayp;
 const int		do_norm_secs;
 {
 	register const struct state *	sp;
 	register int			dir;
 	register int			i, j;
 	register int			saved_seconds;
 	register long			li;
 	register time_t			lo;
 	register time_t			hi;
 	long				y;
 	time_t				newt;
 	time_t				t;
 	struct tm			yourtm, mytm;
 	*okayp = FALSE;
 	yourtm = *tmp;
 	if (do_norm_secs) {
 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
 			SECSPERMIN))
 				return WRONG;
 	}
 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
 		return WRONG;
 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
 		return WRONG;
 	y = yourtm.tm_year;
 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
 		return WRONG;
 	/*
 	** Turn y into an actual year number for now.
 	** It is converted back to an offset from TM_YEAR_BASE later.
 	*/
 	if (long_increment_overflow(&y, TM_YEAR_BASE))
 		return WRONG;
 	while (yourtm.tm_mday <= 0) {
 		if (long_increment_overflow(&y, -1))
 			return WRONG;
 		li = y + (1 < yourtm.tm_mon);
 		yourtm.tm_mday += year_lengths[isleap(li)];
 	}
 	while (yourtm.tm_mday > DAYSPERLYEAR) {
 		li = y + (1 < yourtm.tm_mon);
 		yourtm.tm_mday -= year_lengths[isleap(li)];
 		if (long_increment_overflow(&y, 1))
 			return WRONG;
 	}
 	for ( ; ; ) {
 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
 		if (yourtm.tm_mday <= i)
 			break;
 		yourtm.tm_mday -= i;
 		if (++yourtm.tm_mon >= MONSPERYEAR) {
 			yourtm.tm_mon = 0;
 			if (long_increment_overflow(&y, 1))
 				return WRONG;
 		}
 	}
 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
 		return WRONG;
 	yourtm.tm_year = y;
 	if (yourtm.tm_year != y)
 		return WRONG;
 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
 		saved_seconds = 0;
 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
 		/*
 		** We can't set tm_sec to 0, because that might push the
 		** time below the minimum representable time.
 		** Set tm_sec to 59 instead.
 		** This assumes that the minimum representable time is
 		** not in the same minute that a leap second was deleted from,
 		** which is a safer assumption than using 58 would be.
 		*/
 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
 			return WRONG;
 		saved_seconds = yourtm.tm_sec;
 		yourtm.tm_sec = SECSPERMIN - 1;
 	} else {
 		saved_seconds = yourtm.tm_sec;
 		yourtm.tm_sec = 0;
 	}
 	/*
 	** Do a binary search (this works whatever time_t's type is).
 	*/
 	if (!TYPE_SIGNED(time_t)) {
 		lo = 0;
 		hi = lo - 1;
 	} else if (!TYPE_INTEGRAL(time_t)) {
 		if (sizeof(time_t) > sizeof(float))
 			hi = (time_t) DBL_MAX;
 		else	hi = (time_t) FLT_MAX;
 		lo = -hi;
 	} else {
 		lo = 1;
 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
 			lo *= 2;
 		hi = -(lo + 1);
 	}
 	for ( ; ; ) {
 		t = lo / 2 + hi / 2;
 		if (t < lo)
 			t = lo;
 		else if (t > hi)
 			t = hi;
 		if ((*funcp)(&t, offset, &mytm) == NULL) {
 			/*
 			** Assume that t is too extreme to be represented in
 			** a struct tm; arrange things so that it is less
 			** extreme on the next pass.
 			*/
 			dir = (t > 0) ? 1 : -1;
 		} else	dir = tmcomp(&mytm, &yourtm);
 		if (dir != 0) {
 			if (t == lo) {
 				++t;
 				if (t <= lo)
 					return WRONG;
 				++lo;
 			} else if (t == hi) {
 				--t;
 				if (t >= hi)
 					return WRONG;
 				--hi;
 			}
 			if (lo > hi)
 				return WRONG;
 			if (dir > 0)
 				hi = t;
 			else	lo = t;
 			continue;
 		}
 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
 			break;
 		/*
 		** Right time, wrong type.
 		** Hunt for right time, right type.
 		** It's okay to guess wrong since the guess
 		** gets checked.
 		*/
 		sp = (const struct state *)
 			((funcp == localsub) ? lclptr : gmtptr);
 #ifdef ALL_STATE
 		if (sp == NULL)
 			return WRONG;
 #endif /* defined ALL_STATE */
 		for (i = sp->typecnt - 1; i >= 0; --i) {
 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
 				continue;
 			for (j = sp->typecnt - 1; j >= 0; --j) {
 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
 					continue;
 				newt = t + sp->ttis[j].tt_gmtoff -
 					sp->ttis[i].tt_gmtoff;
 				if ((*funcp)(&newt, offset, &mytm) == NULL)
 					continue;
 				if (tmcomp(&mytm, &yourtm) != 0)
 					continue;
 				if (mytm.tm_isdst != yourtm.tm_isdst)
 					continue;
 				/*
 				** We have a match.
 				*/
 				t = newt;
 				goto label;
 			}
 		}
 		return WRONG;
 	}
 label:
 	newt = t + saved_seconds;
 	if ((newt < t) != (saved_seconds < 0))
 		return WRONG;
 	t = newt;
 	if ((*funcp)(&t, offset, tmp))
 		*okayp = TRUE;
 	return t;
 }
 static time_t
 time2(tmp, funcp, offset, okayp)
 struct tm * const	tmp;
 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
 const long		offset;
 int * const		okayp;
 {
 	time_t	t;
 	/*
 	** First try without normalization of seconds
 	** (in case tm_sec contains a value associated with a leap second).
 	** If that fails, try with normalization of seconds.
 	*/
 	t = time2sub(tmp, funcp, offset, okayp, FALSE);
 	return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
 }
 static time_t
 time1(tmp, funcp, offset)
 struct tm * const	tmp;
 struct tm * (* const	funcp)(const time_t *, long, struct tm *);
 const long		offset;
 {
 	register time_t			t;
 	register const struct state *	sp;
 	register int			samei, otheri;
 	register int			sameind, otherind;
 	register int			i;
 	register int			nseen;
 	int				seen[TZ_MAX_TYPES];
 	int				types[TZ_MAX_TYPES];
 	int				okay;
 	if (tmp->tm_isdst > 1)
 		tmp->tm_isdst = 1;
 	t = time2(tmp, funcp, offset, &okay);
 #ifdef PCTS
 	/*
 	** PCTS code courtesy Grant Sullivan.
 	*/
 	if (okay)
 		return t;
 	if (tmp->tm_isdst < 0)
 		tmp->tm_isdst = 0;	/* reset to std and try again */
 #endif /* defined PCTS */
 #ifndef PCTS
 	if (okay || tmp->tm_isdst < 0)
 		return t;
 #endif /* !defined PCTS */
 	/*
 	** We're supposed to assume that somebody took a time of one type
 	** and did some math on it that yielded a "struct tm" that's bad.
 	** We try to divine the type they started from and adjust to the
 	** type they need.
 	*/
 	sp = (const struct state *) ((funcp == localsub) ?  lclptr : gmtptr);
 #ifdef ALL_STATE
 	if (sp == NULL)
 		return WRONG;
 #endif /* defined ALL_STATE */
 	for (i = 0; i < sp->typecnt; ++i)
 		seen[i] = FALSE;
 	nseen = 0;
 	for (i = sp->timecnt - 1; i >= 0; --i)
 		if (!seen[sp->types[i]]) {
 			seen[sp->types[i]] = TRUE;
 			types[nseen++] = sp->types[i];
 		}
 	for (sameind = 0; sameind < nseen; ++sameind) {
 		samei = types[sameind];
 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
 			continue;
 		for (otherind = 0; otherind < nseen; ++otherind) {
 			otheri = types[otherind];
 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
 				continue;
 			tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
 					sp->ttis[samei].tt_gmtoff;
 			tmp->tm_isdst = !tmp->tm_isdst;
 			t = time2(tmp, funcp, offset, &okay);
 			if (okay)
 				return t;
 			tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
 					sp->ttis[samei].tt_gmtoff;
 			tmp->tm_isdst = !tmp->tm_isdst;
 		}
 	}
 	return WRONG;
 }
 time_t
 mktime(tmp)
 struct tm * const	tmp;
 {
 	tzset();
 	return time1(tmp, localsub, 0L);
 }
 #ifdef STD_INSPIRED
 time_t
 timelocal(tmp)
 struct tm * const	tmp;
 {
 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
 	return mktime(tmp);
 }
 time_t
 timegm(tmp)
 struct tm * const	tmp;
 {
 	tmp->tm_isdst = 0;
 	return time1(tmp, gmtsub, 0L);
 }
 time_t
 timeoff(tmp, offset)
 struct tm * const	tmp;
 const long		offset;
 {
 	tmp->tm_isdst = 0;
 	return time1(tmp, gmtsub, offset);
 }
 #endif /* defined STD_INSPIRED */
 #ifdef CMUCS
 /*
 ** The following is supplied for compatibility with
 ** previous versions of the CMUCS runtime library.
 */
 long
 gtime(tmp)
 struct tm * const	tmp;
 {
 	const time_t	t = mktime(tmp);
 	if (t == WRONG)
 		return -1;
 	return t;
 }
 #endif /* defined CMUCS */
 /*
 ** 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 long
 leapcorr(timep)
 time_t *	timep;
 {
 	register struct state *		sp;
 	register struct lsinfo *	lp;
 	register int			i;
 	sp = lclptr;
 	i = sp->leapcnt;
 	while (--i >= 0) {
 		lp = &sp->lsis[i];
 		if (*timep >= lp->ls_trans)
 			return lp->ls_corr;
 	}
 	return 0;
 }
 time_t
 time2posix(t)
 time_t	t;
 {
 	tzset();
 	return t - leapcorr(&t);
 }
 time_t
 posix2time(t)
 time_t	t;
 {
 	time_t	x;
 	time_t	y;
 	tzset();
 	/*
 	** 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 = t + leapcorr(&t);
 	y = x - leapcorr(&x);
 	if (y < t) {
 		do {
 			x++;
 			y = x - leapcorr(&x);
 		} while (y < t);
 		if (t != y)
 			return x - 1;
 	} else if (y > t) {
 		do {
 			--x;
 			y = x - leapcorr(&x);
 		} while (y > t);
 		if (t != y)
 			return x + 1;
 	}
 	return x;
 }
 #endif /* defined STD_INSPIRED */

The Tor Browser / annotate

intl/icu/source/tools/tzcode/localtime.c@fc2d59ddac77 (annotated)

intl/icu/source/tools/tzcode/localtime.c