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localtime.c revision 1.8
      1 /*	$NetBSD: localtime.c,v 1.8 1997/01/23 14:02:29 mrg Exp $	*/
      2 
      3 /*
      4 ** This file is in the public domain, so clarified as of
      5 ** June 5, 1996 by Arthur David Olson (arthur_david_olson (at) nih.gov).
      6 */
      7 
      8 #ifndef lint
      9 #ifndef NOID
     10 static char	elsieid[] = "@(#)localtime.c	7.58";
     11 #endif /* !defined NOID */
     12 #endif /* !defined lint */
     13 
     14 /*
     15 ** Leap second handling from Bradley White (bww (at) k.gp.cs.cmu.edu).
     16 ** POSIX-style TZ environment variable handling from Guy Harris
     17 ** (guy (at) auspex.com).
     18 */
     19 
     20 /*LINTLIBRARY*/
     21 
     22 #include "private.h"
     23 #include "tzfile.h"
     24 #include "fcntl.h"
     25 
     26 /*
     27 ** SunOS 4.1.1 headers lack O_BINARY.
     28 */
     29 
     30 #ifdef O_BINARY
     31 #define OPEN_MODE	(O_RDONLY | O_BINARY)
     32 #endif /* defined O_BINARY */
     33 #ifndef O_BINARY
     34 #define OPEN_MODE	O_RDONLY
     35 #endif /* !defined O_BINARY */
     36 
     37 #ifndef WILDABBR
     38 /*
     39 ** Someone might make incorrect use of a time zone abbreviation:
     40 **	1.	They might reference tzname[0] before calling tzset (explicitly
     41 **		or implicitly).
     42 **	2.	They might reference tzname[1] before calling tzset (explicitly
     43 **		or implicitly).
     44 **	3.	They might reference tzname[1] after setting to a time zone
     45 **		in which Daylight Saving Time is never observed.
     46 **	4.	They might reference tzname[0] after setting to a time zone
     47 **		in which Standard Time is never observed.
     48 **	5.	They might reference tm.TM_ZONE after calling offtime.
     49 ** What's best to do in the above cases is open to debate;
     50 ** for now, we just set things up so that in any of the five cases
     51 ** WILDABBR is used.  Another possibility:  initialize tzname[0] to the
     52 ** string "tzname[0] used before set", and similarly for the other cases.
     53 ** And another:  initialize tzname[0] to "ERA", with an explanation in the
     54 ** manual page of what this "time zone abbreviation" means (doing this so
     55 ** that tzname[0] has the "normal" length of three characters).
     56 */
     57 #define WILDABBR	"   "
     58 #endif /* !defined WILDABBR */
     59 
     60 static char		wildabbr[] = "WILDABBR";
     61 
     62 static const char	gmt[] = "GMT";
     63 
     64 struct ttinfo {				/* time type information */
     65 	long		tt_gmtoff;	/* GMT offset in seconds */
     66 	int		tt_isdst;	/* used to set tm_isdst */
     67 	int		tt_abbrind;	/* abbreviation list index */
     68 	int		tt_ttisstd;	/* TRUE if transition is std time */
     69 	int		tt_ttisgmt;	/* TRUE if transition is GMT */
     70 };
     71 
     72 struct lsinfo {				/* leap second information */
     73 	time_t		ls_trans;	/* transition time */
     74 	long		ls_corr;	/* correction to apply */
     75 };
     76 
     77 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
     78 
     79 #ifdef TZNAME_MAX
     80 #define MY_TZNAME_MAX	TZNAME_MAX
     81 #endif /* defined TZNAME_MAX */
     82 #ifndef TZNAME_MAX
     83 #define MY_TZNAME_MAX	255
     84 #endif /* !defined TZNAME_MAX */
     85 
     86 struct state {
     87 	int		leapcnt;
     88 	int		timecnt;
     89 	int		typecnt;
     90 	int		charcnt;
     91 	time_t		ats[TZ_MAX_TIMES];
     92 	unsigned char	types[TZ_MAX_TIMES];
     93 	struct ttinfo	ttis[TZ_MAX_TYPES];
     94 	char		chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
     95 				(2 * (MY_TZNAME_MAX + 1)))];
     96 	struct lsinfo	lsis[TZ_MAX_LEAPS];
     97 };
     98 
     99 struct rule {
    100 	int		r_type;		/* type of rule--see below */
    101 	int		r_day;		/* day number of rule */
    102 	int		r_week;		/* week number of rule */
    103 	int		r_mon;		/* month number of rule */
    104 	long		r_time;		/* transition time of rule */
    105 };
    106 
    107 #define JULIAN_DAY		0	/* Jn - Julian day */
    108 #define DAY_OF_YEAR		1	/* n - day of year */
    109 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
    110 
    111 /*
    112 ** Prototypes for static functions.
    113 */
    114 
    115 static long		detzcode P((const char * codep));
    116 static const char *	getzname P((const char * strp));
    117 static const char *	getnum P((const char * strp, int * nump, int min,
    118 				int max));
    119 static const char *	getsecs P((const char * strp, long * secsp));
    120 static const char *	getoffset P((const char * strp, long * offsetp));
    121 static const char *	getrule P((const char * strp, struct rule * rulep));
    122 static void		gmtload P((struct state * sp));
    123 static void		gmtsub P((const time_t * timep, long offset,
    124 				struct tm * tmp));
    125 static void		localsub P((const time_t * timep, long offset,
    126 				struct tm * tmp));
    127 static int		increment_overflow P((int * number, int delta));
    128 static int		normalize_overflow P((int * tensptr, int * unitsptr,
    129 				int base));
    130 static void		settzname P((void));
    131 static time_t		time1 P((struct tm * tmp,
    132 				void(*funcp) P((const time_t *,
    133 				long, struct tm *)),
    134 				long offset));
    135 static time_t		time2 P((struct tm *tmp,
    136 				void(*funcp) P((const time_t *,
    137 				long, struct tm*)),
    138 				long offset, int * okayp));
    139 static void		timesub P((const time_t * timep, long offset,
    140 				const struct state * sp, struct tm * tmp));
    141 static int		tmcomp P((const struct tm * atmp,
    142 				const struct tm * btmp));
    143 static time_t		transtime P((time_t janfirst, int year,
    144 				const struct rule * rulep, long offset));
    145 static int		tzload P((const char * name, struct state * sp));
    146 static int		tzparse P((const char * name, struct state * sp,
    147 				int lastditch));
    148 
    149 #ifdef ALL_STATE
    150 static struct state *	lclptr;
    151 static struct state *	gmtptr;
    152 #endif /* defined ALL_STATE */
    153 
    154 #ifndef ALL_STATE
    155 static struct state	lclmem;
    156 static struct state	gmtmem;
    157 #define lclptr		(&lclmem)
    158 #define gmtptr		(&gmtmem)
    159 #endif /* State Farm */
    160 
    161 #ifndef TZ_STRLEN_MAX
    162 #define TZ_STRLEN_MAX 255
    163 #endif /* !defined TZ_STRLEN_MAX */
    164 
    165 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
    166 static int		lcl_is_set;
    167 static int		gmt_is_set;
    168 
    169 char *			tzname[2] = {
    170 	wildabbr,
    171 	wildabbr
    172 };
    173 
    174 /*
    175 ** Section 4.12.3 of X3.159-1989 requires that
    176 **	Except for the strftime function, these functions [asctime,
    177 **	ctime, gmtime, localtime] return values in one of two static
    178 **	objects: a broken-down time structure and an array of char.
    179 ** Thanks to Paul Eggert (eggert (at) twinsun.com) for noting this.
    180 */
    181 
    182 static struct tm	tm;
    183 
    184 #ifdef USG_COMPAT
    185 time_t			timezone = 0;
    186 int			daylight = 0;
    187 #endif /* defined USG_COMPAT */
    188 
    189 #ifdef ALTZONE
    190 time_t			altzone = 0;
    191 #endif /* defined ALTZONE */
    192 
    193 static long
    194 detzcode(codep)
    195 const char * const	codep;
    196 {
    197 	register long	result;
    198 
    199 	/*
    200         ** The first character must be sign extended on systems with >32bit
    201         ** longs.  This was solved differently in the master tzcode sources
    202         ** (the fix first appeared in tzcode95c.tar.gz).  But I believe
    203 	** that this implementation is superior.
    204         */
    205 
    206 #ifdef __STDC__
    207 #define SIGN_EXTEND_CHAR(x)	((signed char) x)
    208 #else
    209 #define SIGN_EXTEND_CHAR(x)	((x & 0x80) ? ((~0 << 8) | x) : x)
    210 #endif
    211 
    212 	result = (SIGN_EXTEND_CHAR(codep[0]) << 24) \
    213 	       | (codep[1] & 0xff) << 16 \
    214 	       | (codep[2] & 0xff) << 8
    215 	       | (codep[3] & 0xff);
    216 	return result;
    217 }
    218 
    219 static void
    220 settzname P((void))
    221 {
    222 	register struct state * const	sp = lclptr;
    223 	register int			i;
    224 
    225 	tzname[0] = wildabbr;
    226 	tzname[1] = wildabbr;
    227 #ifdef USG_COMPAT
    228 	daylight = 0;
    229 	timezone = 0;
    230 #endif /* defined USG_COMPAT */
    231 #ifdef ALTZONE
    232 	altzone = 0;
    233 #endif /* defined ALTZONE */
    234 #ifdef ALL_STATE
    235 	if (sp == NULL) {
    236 		tzname[0] = tzname[1] = gmt;
    237 		return;
    238 	}
    239 #endif /* defined ALL_STATE */
    240 	for (i = 0; i < sp->typecnt; ++i) {
    241 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
    242 
    243 		tzname[ttisp->tt_isdst] =
    244 			&sp->chars[ttisp->tt_abbrind];
    245 #ifdef USG_COMPAT
    246 		if (ttisp->tt_isdst)
    247 			daylight = 1;
    248 		if (i == 0 || !ttisp->tt_isdst)
    249 			timezone = -(ttisp->tt_gmtoff);
    250 #endif /* defined USG_COMPAT */
    251 #ifdef ALTZONE
    252 		if (i == 0 || ttisp->tt_isdst)
    253 			altzone = -(ttisp->tt_gmtoff);
    254 #endif /* defined ALTZONE */
    255 	}
    256 	/*
    257 	** And to get the latest zone names into tzname. . .
    258 	*/
    259 	for (i = 0; i < sp->timecnt; ++i) {
    260 		register const struct ttinfo * const	ttisp =
    261 							&sp->ttis[
    262 								sp->types[i]];
    263 
    264 		tzname[ttisp->tt_isdst] =
    265 			&sp->chars[ttisp->tt_abbrind];
    266 	}
    267 }
    268 
    269 static int
    270 tzload(name, sp)
    271 register const char *		name;
    272 register struct state * const	sp;
    273 {
    274 	register const char *	p;
    275 	register int		i;
    276 	register int		fid;
    277 
    278 	if (name == NULL && (name = TZDEFAULT) == NULL)
    279 		return -1;
    280 	{
    281 		register int	doaccess;
    282 		/*
    283 		** Section 4.9.1 of the C standard says that
    284 		** "FILENAME_MAX expands to an integral constant expression
    285 		** that is the sie needed for an array of char large enough
    286 		** to hold the longest file name string that the implementation
    287 		** guarantees can be opened."
    288 		*/
    289 		char		fullname[FILENAME_MAX + 1];
    290 
    291 		if (name[0] == ':')
    292 			++name;
    293 		doaccess = name[0] == '/';
    294 		if (!doaccess) {
    295 			if ((p = TZDIR) == NULL)
    296 				return -1;
    297 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
    298 				return -1;
    299 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
    300 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
    301 			(void) strcat(fullname, name);	/* XXX strcat is safe */
    302 			/*
    303 			** Set doaccess if '.' (as in "../") shows up in name.
    304 			*/
    305 			if (strchr(name, '.') != NULL)
    306 				doaccess = TRUE;
    307 			name = fullname;
    308 		}
    309 		if (doaccess && access(name, R_OK) != 0)
    310 			return -1;
    311 		if ((fid = open(name, OPEN_MODE)) == -1)
    312 			return -1;
    313 	}
    314 	{
    315 		struct tzhead *	tzhp;
    316 		char		buf[sizeof *sp + sizeof *tzhp];
    317 		int		ttisstdcnt;
    318 		int		ttisgmtcnt;
    319 
    320 		i = read(fid, buf, sizeof buf);
    321 		if (close(fid) != 0)
    322 			return -1;
    323 		p = buf;
    324 		p += sizeof tzhp->tzh_reserved;
    325 		ttisstdcnt = (int) detzcode(p);
    326 		p += 4;
    327 		ttisgmtcnt = (int) detzcode(p);
    328 		p += 4;
    329 		sp->leapcnt = (int) detzcode(p);
    330 		p += 4;
    331 		sp->timecnt = (int) detzcode(p);
    332 		p += 4;
    333 		sp->typecnt = (int) detzcode(p);
    334 		p += 4;
    335 		sp->charcnt = (int) detzcode(p);
    336 		p += 4;
    337 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
    338 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
    339 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
    340 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
    341 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
    342 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
    343 				return -1;
    344 		if (i - (p - buf) < sp->timecnt * 4 +	/* ats */
    345 			sp->timecnt +			/* types */
    346 			sp->typecnt * (4 + 2) +		/* ttinfos */
    347 			sp->charcnt +			/* chars */
    348 			sp->leapcnt * (4 + 4) +		/* lsinfos */
    349 			ttisstdcnt +			/* ttisstds */
    350 			ttisgmtcnt)			/* ttisgmts */
    351 				return -1;
    352 		for (i = 0; i < sp->timecnt; ++i) {
    353 			sp->ats[i] = detzcode(p);
    354 			p += 4;
    355 		}
    356 		for (i = 0; i < sp->timecnt; ++i) {
    357 			sp->types[i] = (unsigned char) *p++;
    358 			if (sp->types[i] >= sp->typecnt)
    359 				return -1;
    360 		}
    361 		for (i = 0; i < sp->typecnt; ++i) {
    362 			register struct ttinfo *	ttisp;
    363 
    364 			ttisp = &sp->ttis[i];
    365 			ttisp->tt_gmtoff = detzcode(p);
    366 			p += 4;
    367 			ttisp->tt_isdst = (unsigned char) *p++;
    368 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
    369 				return -1;
    370 			ttisp->tt_abbrind = (unsigned char) *p++;
    371 			if (ttisp->tt_abbrind < 0 ||
    372 				ttisp->tt_abbrind > sp->charcnt)
    373 					return -1;
    374 		}
    375 		for (i = 0; i < sp->charcnt; ++i)
    376 			sp->chars[i] = *p++;
    377 		sp->chars[i] = '\0';	/* ensure '\0' at end */
    378 		for (i = 0; i < sp->leapcnt; ++i) {
    379 			register struct lsinfo *	lsisp;
    380 
    381 			lsisp = &sp->lsis[i];
    382 			lsisp->ls_trans = detzcode(p);
    383 			p += 4;
    384 			lsisp->ls_corr = detzcode(p);
    385 			p += 4;
    386 		}
    387 		for (i = 0; i < sp->typecnt; ++i) {
    388 			register struct ttinfo *	ttisp;
    389 
    390 			ttisp = &sp->ttis[i];
    391 			if (ttisstdcnt == 0)
    392 				ttisp->tt_ttisstd = FALSE;
    393 			else {
    394 				ttisp->tt_ttisstd = *p++;
    395 				if (ttisp->tt_ttisstd != TRUE &&
    396 					ttisp->tt_ttisstd != FALSE)
    397 						return -1;
    398 			}
    399 		}
    400 		for (i = 0; i < sp->typecnt; ++i) {
    401 			register struct ttinfo *	ttisp;
    402 
    403 			ttisp = &sp->ttis[i];
    404 			if (ttisgmtcnt == 0)
    405 				ttisp->tt_ttisgmt = FALSE;
    406 			else {
    407 				ttisp->tt_ttisgmt = *p++;
    408 				if (ttisp->tt_ttisgmt != TRUE &&
    409 					ttisp->tt_ttisgmt != FALSE)
    410 						return -1;
    411 			}
    412 		}
    413 	}
    414 	return 0;
    415 }
    416 
    417 static const int	mon_lengths[2][MONSPERYEAR] = {
    418 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
    419 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
    420 };
    421 
    422 static const int	year_lengths[2] = {
    423 	DAYSPERNYEAR, DAYSPERLYEAR
    424 };
    425 
    426 /*
    427 ** Given a pointer into a time zone string, scan until a character that is not
    428 ** a valid character in a zone name is found.  Return a pointer to that
    429 ** character.
    430 */
    431 
    432 static const char *
    433 getzname(strp)
    434 register const char *	strp;
    435 {
    436 	register char	c;
    437 
    438 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
    439 		c != '+')
    440 			++strp;
    441 	return strp;
    442 }
    443 
    444 /*
    445 ** Given a pointer into a time zone string, extract a number from that string.
    446 ** Check that the number is within a specified range; if it is not, return
    447 ** NULL.
    448 ** Otherwise, return a pointer to the first character not part of the number.
    449 */
    450 
    451 static const char *
    452 getnum(strp, nump, min, max)
    453 register const char *	strp;
    454 int * const		nump;
    455 const int		min;
    456 const int		max;
    457 {
    458 	register char	c;
    459 	register int	num;
    460 
    461 	if (strp == NULL || !is_digit(c = *strp))
    462 		return NULL;
    463 	num = 0;
    464 	do {
    465 		num = num * 10 + (c - '0');
    466 		if (num > max)
    467 			return NULL;	/* illegal value */
    468 		c = *++strp;
    469 	} while (is_digit(c));
    470 	if (num < min)
    471 		return NULL;		/* illegal value */
    472 	*nump = num;
    473 	return strp;
    474 }
    475 
    476 /*
    477 ** Given a pointer into a time zone string, extract a number of seconds,
    478 ** in hh[:mm[:ss]] form, from the string.
    479 ** If any error occurs, return NULL.
    480 ** Otherwise, return a pointer to the first character not part of the number
    481 ** of seconds.
    482 */
    483 
    484 static const char *
    485 getsecs(strp, secsp)
    486 register const char *	strp;
    487 long * const		secsp;
    488 {
    489 	int	num;
    490 
    491 	/*
    492 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
    493 	** "M10.4.6/26", which does not conform to Posix,
    494 	** but which specifies the equivalent of
    495 	** ``02:00 on the first Sunday on or after 23 Oct''.
    496 	*/
    497 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
    498 	if (strp == NULL)
    499 		return NULL;
    500 	*secsp = num * (long) SECSPERHOUR;
    501 	if (*strp == ':') {
    502 		++strp;
    503 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
    504 		if (strp == NULL)
    505 			return NULL;
    506 		*secsp += num * SECSPERMIN;
    507 		if (*strp == ':') {
    508 			++strp;
    509 			/* `SECSPERMIN' allows for leap seconds.  */
    510 			strp = getnum(strp, &num, 0, SECSPERMIN);
    511 			if (strp == NULL)
    512 				return NULL;
    513 			*secsp += num;
    514 		}
    515 	}
    516 	return strp;
    517 }
    518 
    519 /*
    520 ** Given a pointer into a time zone string, extract an offset, in
    521 ** [+-]hh[:mm[:ss]] form, from the string.
    522 ** If any error occurs, return NULL.
    523 ** Otherwise, return a pointer to the first character not part of the time.
    524 */
    525 
    526 static const char *
    527 getoffset(strp, offsetp)
    528 register const char *	strp;
    529 long * const		offsetp;
    530 {
    531 	register int	neg = 0;
    532 
    533 	if (*strp == '-') {
    534 		neg = 1;
    535 		++strp;
    536 	} else if (*strp == '+')
    537 		++strp;
    538 	strp = getsecs(strp, offsetp);
    539 	if (strp == NULL)
    540 		return NULL;		/* illegal time */
    541 	if (neg)
    542 		*offsetp = -*offsetp;
    543 	return strp;
    544 }
    545 
    546 /*
    547 ** Given a pointer into a time zone string, extract a rule in the form
    548 ** date[/time].  See POSIX section 8 for the format of "date" and "time".
    549 ** If a valid rule is not found, return NULL.
    550 ** Otherwise, return a pointer to the first character not part of the rule.
    551 */
    552 
    553 static const char *
    554 getrule(strp, rulep)
    555 const char *			strp;
    556 register struct rule * const	rulep;
    557 {
    558 	if (*strp == 'J') {
    559 		/*
    560 		** Julian day.
    561 		*/
    562 		rulep->r_type = JULIAN_DAY;
    563 		++strp;
    564 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
    565 	} else if (*strp == 'M') {
    566 		/*
    567 		** Month, week, day.
    568 		*/
    569 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
    570 		++strp;
    571 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
    572 		if (strp == NULL)
    573 			return NULL;
    574 		if (*strp++ != '.')
    575 			return NULL;
    576 		strp = getnum(strp, &rulep->r_week, 1, 5);
    577 		if (strp == NULL)
    578 			return NULL;
    579 		if (*strp++ != '.')
    580 			return NULL;
    581 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
    582 	} else if (is_digit(*strp)) {
    583 		/*
    584 		** Day of year.
    585 		*/
    586 		rulep->r_type = DAY_OF_YEAR;
    587 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
    588 	} else	return NULL;		/* invalid format */
    589 	if (strp == NULL)
    590 		return NULL;
    591 	if (*strp == '/') {
    592 		/*
    593 		** Time specified.
    594 		*/
    595 		++strp;
    596 		strp = getsecs(strp, &rulep->r_time);
    597 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
    598 	return strp;
    599 }
    600 
    601 /*
    602 ** Given the Epoch-relative time of January 1, 00:00:00 GMT, in a year, the
    603 ** year, a rule, and the offset from GMT at the time that rule takes effect,
    604 ** calculate the Epoch-relative time that rule takes effect.
    605 */
    606 
    607 static time_t
    608 transtime(janfirst, year, rulep, offset)
    609 const time_t				janfirst;
    610 const int				year;
    611 register const struct rule * const	rulep;
    612 const long				offset;
    613 {
    614 	register int	leapyear;
    615 	register time_t	value;
    616 	register int	i;
    617 	int		d, m1, yy0, yy1, yy2, dow;
    618 
    619 	INITIALIZE(value);
    620 	leapyear = isleap(year);
    621 	switch (rulep->r_type) {
    622 
    623 	case JULIAN_DAY:
    624 		/*
    625 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
    626 		** years.
    627 		** In non-leap years, or if the day number is 59 or less, just
    628 		** add SECSPERDAY times the day number-1 to the time of
    629 		** January 1, midnight, to get the day.
    630 		*/
    631 		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
    632 		if (leapyear && rulep->r_day >= 60)
    633 			value += SECSPERDAY;
    634 		break;
    635 
    636 	case DAY_OF_YEAR:
    637 		/*
    638 		** n - day of year.
    639 		** Just add SECSPERDAY times the day number to the time of
    640 		** January 1, midnight, to get the day.
    641 		*/
    642 		value = janfirst + rulep->r_day * SECSPERDAY;
    643 		break;
    644 
    645 	case MONTH_NTH_DAY_OF_WEEK:
    646 		/*
    647 		** Mm.n.d - nth "dth day" of month m.
    648 		*/
    649 		value = janfirst;
    650 		for (i = 0; i < rulep->r_mon - 1; ++i)
    651 			value += mon_lengths[leapyear][i] * SECSPERDAY;
    652 
    653 		/*
    654 		** Use Zeller's Congruence to get day-of-week of first day of
    655 		** month.
    656 		*/
    657 		m1 = (rulep->r_mon + 9) % 12 + 1;
    658 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
    659 		yy1 = yy0 / 100;
    660 		yy2 = yy0 % 100;
    661 		dow = ((26 * m1 - 2) / 10 +
    662 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
    663 		if (dow < 0)
    664 			dow += DAYSPERWEEK;
    665 
    666 		/*
    667 		** "dow" is the day-of-week of the first day of the month.  Get
    668 		** the day-of-month (zero-origin) of the first "dow" day of the
    669 		** month.
    670 		*/
    671 		d = rulep->r_day - dow;
    672 		if (d < 0)
    673 			d += DAYSPERWEEK;
    674 		for (i = 1; i < rulep->r_week; ++i) {
    675 			if (d + DAYSPERWEEK >=
    676 				mon_lengths[leapyear][rulep->r_mon - 1])
    677 					break;
    678 			d += DAYSPERWEEK;
    679 		}
    680 
    681 		/*
    682 		** "d" is the day-of-month (zero-origin) of the day we want.
    683 		*/
    684 		value += d * SECSPERDAY;
    685 		break;
    686 	}
    687 
    688 	/*
    689 	** "value" is the Epoch-relative time of 00:00:00 GMT on the day in
    690 	** question.  To get the Epoch-relative time of the specified local
    691 	** time on that day, add the transition time and the current offset
    692 	** from GMT.
    693 	*/
    694 	return value + rulep->r_time + offset;
    695 }
    696 
    697 /*
    698 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
    699 ** appropriate.
    700 */
    701 
    702 static int
    703 tzparse(name, sp, lastditch)
    704 const char *			name;
    705 register struct state * const	sp;
    706 const int			lastditch;
    707 {
    708 	const char *			stdname;
    709 	const char *			dstname;
    710 	size_t				stdlen;
    711 	size_t				dstlen;
    712 	long				stdoffset;
    713 	long				dstoffset;
    714 	register time_t *		atp;
    715 	register unsigned char *	typep;
    716 	register char *			cp;
    717 	register int			load_result;
    718 
    719 	INITIALIZE(dstname);
    720 	stdname = name;
    721 	if (lastditch) {
    722 		stdlen = strlen(name);	/* length of standard zone name */
    723 		name += stdlen;
    724 		if (stdlen >= sizeof sp->chars)
    725 			stdlen = (sizeof sp->chars) - 1;
    726 	} else {
    727 		name = getzname(name);
    728 		stdlen = name - stdname;
    729 		if (stdlen < 3)
    730 			return -1;
    731 	}
    732 	if (*name == '\0')
    733 		return -1;	/* was "stdoffset = 0;" */
    734 	else {
    735 		name = getoffset(name, &stdoffset);
    736 		if (name == NULL)
    737 			return -1;
    738 	}
    739 	load_result = tzload(TZDEFRULES, sp);
    740 	if (load_result != 0)
    741 		sp->leapcnt = 0;		/* so, we're off a little */
    742 	if (*name != '\0') {
    743 		dstname = name;
    744 		name = getzname(name);
    745 		dstlen = name - dstname;	/* length of DST zone name */
    746 		if (dstlen < 3)
    747 			return -1;
    748 		if (*name != '\0' && *name != ',' && *name != ';') {
    749 			name = getoffset(name, &dstoffset);
    750 			if (name == NULL)
    751 				return -1;
    752 		} else	dstoffset = stdoffset - SECSPERHOUR;
    753 		if (*name == ',' || *name == ';') {
    754 			struct rule	start;
    755 			struct rule	end;
    756 			register int	year;
    757 			register time_t	janfirst;
    758 			time_t		starttime;
    759 			time_t		endtime;
    760 
    761 			++name;
    762 			if ((name = getrule(name, &start)) == NULL)
    763 				return -1;
    764 			if (*name++ != ',')
    765 				return -1;
    766 			if ((name = getrule(name, &end)) == NULL)
    767 				return -1;
    768 			if (*name != '\0')
    769 				return -1;
    770 			sp->typecnt = 2;	/* standard time and DST */
    771 			/*
    772 			** Two transitions per year, from EPOCH_YEAR to 2037.
    773 			*/
    774 			sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
    775 			if (sp->timecnt > TZ_MAX_TIMES)
    776 				return -1;
    777 			sp->ttis[0].tt_gmtoff = -dstoffset;
    778 			sp->ttis[0].tt_isdst = 1;
    779 			sp->ttis[0].tt_abbrind = stdlen + 1;
    780 			sp->ttis[1].tt_gmtoff = -stdoffset;
    781 			sp->ttis[1].tt_isdst = 0;
    782 			sp->ttis[1].tt_abbrind = 0;
    783 			atp = sp->ats;
    784 			typep = sp->types;
    785 			janfirst = 0;
    786 			for (year = EPOCH_YEAR; year <= 2037; ++year) {
    787 				starttime = transtime(janfirst, year, &start,
    788 					stdoffset);
    789 				endtime = transtime(janfirst, year, &end,
    790 					dstoffset);
    791 				if (starttime > endtime) {
    792 					*atp++ = endtime;
    793 					*typep++ = 1;	/* DST ends */
    794 					*atp++ = starttime;
    795 					*typep++ = 0;	/* DST begins */
    796 				} else {
    797 					*atp++ = starttime;
    798 					*typep++ = 0;	/* DST begins */
    799 					*atp++ = endtime;
    800 					*typep++ = 1;	/* DST ends */
    801 				}
    802 				janfirst += year_lengths[isleap(year)] *
    803 					SECSPERDAY;
    804 			}
    805 		} else {
    806 			register long	theirstdoffset;
    807 			register long	theirdstoffset;
    808 			register long	theiroffset;
    809 			register int	isdst;
    810 			register int	i;
    811 			register int	j;
    812 
    813 			if (*name != '\0')
    814 				return -1;
    815 			if (load_result != 0)
    816 				return -1;
    817 			/*
    818 			** Initial values of theirstdoffset and theirdstoffset.
    819 			*/
    820 			theirstdoffset = 0;
    821 			for (i = 0; i < sp->timecnt; ++i) {
    822 				j = sp->types[i];
    823 				if (!sp->ttis[j].tt_isdst) {
    824 					theirstdoffset =
    825 						-sp->ttis[j].tt_gmtoff;
    826 					break;
    827 				}
    828 			}
    829 			theirdstoffset = 0;
    830 			for (i = 0; i < sp->timecnt; ++i) {
    831 				j = sp->types[i];
    832 				if (sp->ttis[j].tt_isdst) {
    833 					theirdstoffset =
    834 						-sp->ttis[j].tt_gmtoff;
    835 					break;
    836 				}
    837 			}
    838 			/*
    839 			** Initially we're assumed to be in standard time.
    840 			*/
    841 			isdst = FALSE;
    842 			theiroffset = theirstdoffset;
    843 			/*
    844 			** Now juggle transition times and types
    845 			** tracking offsets as you do.
    846 			*/
    847 			for (i = 0; i < sp->timecnt; ++i) {
    848 				j = sp->types[i];
    849 				sp->types[i] = sp->ttis[j].tt_isdst;
    850 				if (sp->ttis[j].tt_ttisgmt) {
    851 					/* No adjustment to transition time */
    852 				} else {
    853 					/*
    854 					** If summer time is in effect, and the
    855 					** transition time was not specified as
    856 					** standard time, add the summer time
    857 					** offset to the transition time;
    858 					** otherwise, add the standard time
    859 					** offset to the transition time.
    860 					*/
    861 					/*
    862 					** Transitions from DST to DDST
    863 					** will effectively disappear since
    864 					** POSIX provides for only one DST
    865 					** offset.
    866 					*/
    867 					if (isdst && !sp->ttis[j].tt_ttisstd) {
    868 						sp->ats[i] += dstoffset -
    869 							theirdstoffset;
    870 					} else {
    871 						sp->ats[i] += stdoffset -
    872 							theirstdoffset;
    873 					}
    874 				}
    875 				theiroffset = -sp->ttis[j].tt_gmtoff;
    876 				if (sp->ttis[j].tt_isdst)
    877 					theirdstoffset = theiroffset;
    878 				else	theirstdoffset = theiroffset;
    879 			}
    880 			/*
    881 			** Finally, fill in ttis.
    882 			** ttisstd and ttisgmt need not be handled.
    883 			*/
    884 			sp->ttis[0].tt_gmtoff = -stdoffset;
    885 			sp->ttis[0].tt_isdst = FALSE;
    886 			sp->ttis[0].tt_abbrind = 0;
    887 			sp->ttis[1].tt_gmtoff = -dstoffset;
    888 			sp->ttis[1].tt_isdst = TRUE;
    889 			sp->ttis[1].tt_abbrind = stdlen + 1;
    890 			sp->typecnt = 2;
    891 		}
    892 	} else {
    893 		dstlen = 0;
    894 		sp->typecnt = 1;		/* only standard time */
    895 		sp->timecnt = 0;
    896 		sp->ttis[0].tt_gmtoff = -stdoffset;
    897 		sp->ttis[0].tt_isdst = 0;
    898 		sp->ttis[0].tt_abbrind = 0;
    899 	}
    900 	sp->charcnt = stdlen + 1;
    901 	if (dstlen != 0)
    902 		sp->charcnt += dstlen + 1;
    903 	if (sp->charcnt > sizeof sp->chars)
    904 		return -1;
    905 	cp = sp->chars;
    906 	(void) strncpy(cp, stdname, stdlen);
    907 	cp += stdlen;
    908 	*cp++ = '\0';
    909 	if (dstlen != 0) {
    910 		(void) strncpy(cp, dstname, dstlen);
    911 		*(cp + dstlen) = '\0';
    912 	}
    913 	return 0;
    914 }
    915 
    916 static void
    917 gmtload(sp)
    918 struct state * const	sp;
    919 {
    920 	if (tzload(gmt, sp) != 0)
    921 		(void) tzparse(gmt, sp, TRUE);
    922 }
    923 
    924 #ifndef STD_INSPIRED
    925 /*
    926 ** A non-static declaration of tzsetwall in a system header file
    927 ** may cause a warning about this upcoming static declaration...
    928 */
    929 static
    930 #endif /* !defined STD_INSPIRED */
    931 void
    932 tzsetwall P((void))
    933 {
    934 	if (lcl_is_set < 0)
    935 		return;
    936 	lcl_is_set = -1;
    937 
    938 #ifdef ALL_STATE
    939 	if (lclptr == NULL) {
    940 		lclptr = (struct state *) malloc(sizeof *lclptr);
    941 		if (lclptr == NULL) {
    942 			settzname();	/* all we can do */
    943 			return;
    944 		}
    945 	}
    946 #endif /* defined ALL_STATE */
    947 	if (tzload((char *) NULL, lclptr) != 0)
    948 		gmtload(lclptr);
    949 	settzname();
    950 }
    951 
    952 void
    953 tzset P((void))
    954 {
    955 	register const char *	name;
    956 
    957 	name = getenv("TZ");
    958 	if (name == NULL) {
    959 		tzsetwall();
    960 		return;
    961 	}
    962 
    963 	if (lcl_is_set > 0  &&  strcmp(lcl_TZname, name) == 0)
    964 		return;
    965 	lcl_is_set = (strlen(name) < sizeof(lcl_TZname));
    966 	if (lcl_is_set)
    967 		(void)strncpy(lcl_TZname, name, sizeof(lcl_TZname) - 1);
    968 
    969 #ifdef ALL_STATE
    970 	if (lclptr == NULL) {
    971 		lclptr = (struct state *) malloc(sizeof *lclptr);
    972 		if (lclptr == NULL) {
    973 			settzname();	/* all we can do */
    974 			return;
    975 		}
    976 	}
    977 #endif /* defined ALL_STATE */
    978 	if (*name == '\0') {
    979 		/*
    980 		** User wants it fast rather than right.
    981 		*/
    982 		lclptr->leapcnt = 0;		/* so, we're off a little */
    983 		lclptr->timecnt = 0;
    984 		lclptr->ttis[0].tt_gmtoff = 0;
    985 		lclptr->ttis[0].tt_abbrind = 0;
    986 		(void)strncpy(lclptr->chars, gmt, sizeof(lclptr->chars) - 1);
    987 	} else if (tzload(name, lclptr) != 0)
    988 		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
    989 			(void) gmtload(lclptr);
    990 	settzname();
    991 }
    992 
    993 /*
    994 ** The easy way to behave "as if no library function calls" localtime
    995 ** is to not call it--so we drop its guts into "localsub", which can be
    996 ** freely called.  (And no, the PANS doesn't require the above behavior--
    997 ** but it *is* desirable.)
    998 **
    999 ** The unused offset argument is for the benefit of mktime variants.
   1000 */
   1001 
   1002 /*ARGSUSED*/
   1003 static void
   1004 localsub(timep, offset, tmp)
   1005 const time_t * const	timep;
   1006 const long		offset;
   1007 struct tm * const	tmp;
   1008 {
   1009 	register struct state *		sp;
   1010 	register const struct ttinfo *	ttisp;
   1011 	register int			i;
   1012 	const time_t			t = *timep;
   1013 
   1014 	sp = lclptr;
   1015 #ifdef ALL_STATE
   1016 	if (sp == NULL) {
   1017 		gmtsub(timep, offset, tmp);
   1018 		return;
   1019 	}
   1020 #endif /* defined ALL_STATE */
   1021 	if (sp->timecnt == 0 || t < sp->ats[0]) {
   1022 		i = 0;
   1023 		while (sp->ttis[i].tt_isdst)
   1024 			if (++i >= sp->typecnt) {
   1025 				i = 0;
   1026 				break;
   1027 			}
   1028 	} else {
   1029 		for (i = 1; i < sp->timecnt; ++i)
   1030 			if (t < sp->ats[i])
   1031 				break;
   1032 		i = sp->types[i - 1];
   1033 	}
   1034 	ttisp = &sp->ttis[i];
   1035 	/*
   1036 	** To get (wrong) behavior that's compatible with System V Release 2.0
   1037 	** you'd replace the statement below with
   1038 	**	t += ttisp->tt_gmtoff;
   1039 	**	timesub(&t, 0L, sp, tmp);
   1040 	*/
   1041 	timesub(&t, ttisp->tt_gmtoff, sp, tmp);
   1042 	tmp->tm_isdst = ttisp->tt_isdst;
   1043 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
   1044 #ifdef TM_ZONE
   1045 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
   1046 #endif /* defined TM_ZONE */
   1047 }
   1048 
   1049 struct tm *
   1050 localtime(timep)
   1051 const time_t * const	timep;
   1052 {
   1053 	tzset();
   1054 	localsub(timep, 0L, &tm);
   1055 	return &tm;
   1056 }
   1057 
   1058 /*
   1059 ** gmtsub is to gmtime as localsub is to localtime.
   1060 */
   1061 
   1062 static void
   1063 gmtsub(timep, offset, tmp)
   1064 const time_t * const	timep;
   1065 const long		offset;
   1066 struct tm * const	tmp;
   1067 {
   1068 	if (!gmt_is_set) {
   1069 		gmt_is_set = TRUE;
   1070 #ifdef ALL_STATE
   1071 		gmtptr = (struct state *) malloc(sizeof *gmtptr);
   1072 		if (gmtptr != NULL)
   1073 #endif /* defined ALL_STATE */
   1074 			gmtload(gmtptr);
   1075 	}
   1076 	timesub(timep, offset, gmtptr, tmp);
   1077 #ifdef TM_ZONE
   1078 	/*
   1079 	** Could get fancy here and deliver something such as
   1080 	** "GMT+xxxx" or "GMT-xxxx" if offset is non-zero,
   1081 	** but this is no time for a treasure hunt.
   1082 	*/
   1083 	if (offset != 0)
   1084 		tmp->TM_ZONE = wildabbr;
   1085 	else {
   1086 #ifdef ALL_STATE
   1087 		if (gmtptr == NULL)
   1088 			tmp->TM_ZONE = gmt;
   1089 		else	tmp->TM_ZONE = gmtptr->chars;
   1090 #endif /* defined ALL_STATE */
   1091 #ifndef ALL_STATE
   1092 		tmp->TM_ZONE = gmtptr->chars;
   1093 #endif /* State Farm */
   1094 	}
   1095 #endif /* defined TM_ZONE */
   1096 }
   1097 
   1098 struct tm *
   1099 gmtime(timep)
   1100 const time_t * const	timep;
   1101 {
   1102 	gmtsub(timep, 0L, &tm);
   1103 	return &tm;
   1104 }
   1105 
   1106 #ifdef STD_INSPIRED
   1107 
   1108 struct tm *
   1109 offtime(timep, offset)
   1110 const time_t * const	timep;
   1111 const long		offset;
   1112 {
   1113 	gmtsub(timep, offset, &tm);
   1114 	return &tm;
   1115 }
   1116 
   1117 #endif /* defined STD_INSPIRED */
   1118 
   1119 static void
   1120 timesub(timep, offset, sp, tmp)
   1121 const time_t * const			timep;
   1122 const long				offset;
   1123 register const struct state * const	sp;
   1124 register struct tm * const		tmp;
   1125 {
   1126 	register const struct lsinfo *	lp;
   1127 	register long			days;
   1128 	register long			rem;
   1129 	register int			y;
   1130 	register int			yleap;
   1131 	register const int *		ip;
   1132 	register long			corr;
   1133 	register int			hit;
   1134 	register int			i;
   1135 
   1136 	corr = 0;
   1137 	hit = 0;
   1138 #ifdef ALL_STATE
   1139 	i = (sp == NULL) ? 0 : sp->leapcnt;
   1140 #endif /* defined ALL_STATE */
   1141 #ifndef ALL_STATE
   1142 	i = sp->leapcnt;
   1143 #endif /* State Farm */
   1144 	while (--i >= 0) {
   1145 		lp = &sp->lsis[i];
   1146 		if (*timep >= lp->ls_trans) {
   1147 			if (*timep == lp->ls_trans) {
   1148 				hit = ((i == 0 && lp->ls_corr > 0) ||
   1149 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
   1150 				if (hit)
   1151 					while (i > 0 &&
   1152 						sp->lsis[i].ls_trans ==
   1153 						sp->lsis[i - 1].ls_trans + 1 &&
   1154 						sp->lsis[i].ls_corr ==
   1155 						sp->lsis[i - 1].ls_corr + 1) {
   1156 							++hit;
   1157 							--i;
   1158 					}
   1159 			}
   1160 			corr = lp->ls_corr;
   1161 			break;
   1162 		}
   1163 	}
   1164 	days = *timep / SECSPERDAY;
   1165 	rem = *timep % SECSPERDAY;
   1166 #ifdef mc68k
   1167 	if (*timep == 0x80000000) {
   1168 		/*
   1169 		** A 3B1 muffs the division on the most negative number.
   1170 		*/
   1171 		days = -24855;
   1172 		rem = -11648;
   1173 	}
   1174 #endif /* defined mc68k */
   1175 	rem += (offset - corr);
   1176 	while (rem < 0) {
   1177 		rem += SECSPERDAY;
   1178 		--days;
   1179 	}
   1180 	while (rem >= SECSPERDAY) {
   1181 		rem -= SECSPERDAY;
   1182 		++days;
   1183 	}
   1184 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
   1185 	rem = rem % SECSPERHOUR;
   1186 	tmp->tm_min = (int) (rem / SECSPERMIN);
   1187 	/*
   1188 	** A positive leap second requires a special
   1189 	** representation.  This uses "... ??:59:60" et seq.
   1190 	*/
   1191 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
   1192 	tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
   1193 	if (tmp->tm_wday < 0)
   1194 		tmp->tm_wday += DAYSPERWEEK;
   1195 	y = EPOCH_YEAR;
   1196 #define LEAPS_THRU_END_OF(y)	((y) / 4 - (y) / 100 + (y) / 400)
   1197 	while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
   1198 		register int	newy;
   1199 
   1200 		newy = y + days / DAYSPERNYEAR;
   1201 		if (days < 0)
   1202 			--newy;
   1203 		days -= (newy - y) * DAYSPERNYEAR +
   1204 			LEAPS_THRU_END_OF(newy - 1) -
   1205 			LEAPS_THRU_END_OF(y - 1);
   1206 		y = newy;
   1207 	}
   1208 	tmp->tm_year = y - TM_YEAR_BASE;
   1209 	tmp->tm_yday = (int) days;
   1210 	ip = mon_lengths[yleap];
   1211 	for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
   1212 		days = days - (long) ip[tmp->tm_mon];
   1213 	tmp->tm_mday = (int) (days + 1);
   1214 	tmp->tm_isdst = 0;
   1215 #ifdef TM_GMTOFF
   1216 	tmp->TM_GMTOFF = offset;
   1217 #endif /* defined TM_GMTOFF */
   1218 }
   1219 
   1220 char *
   1221 ctime(timep)
   1222 const time_t * const	timep;
   1223 {
   1224 /*
   1225 ** Section 4.12.3.2 of X3.159-1989 requires that
   1226 **	The ctime funciton converts the calendar time pointed to by timer
   1227 **	to local time in the form of a string.  It is equivalent to
   1228 **		asctime(localtime(timer))
   1229 */
   1230 	return asctime(localtime(timep));
   1231 }
   1232 
   1233 /*
   1234 ** Adapted from code provided by Robert Elz, who writes:
   1235 **	The "best" way to do mktime I think is based on an idea of Bob
   1236 **	Kridle's (so its said...) from a long time ago.
   1237 **	[kridle (at) xinet.com as of 1996-01-16.]
   1238 **	It does a binary search of the time_t space.  Since time_t's are
   1239 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
   1240 **	would still be very reasonable).
   1241 */
   1242 
   1243 #ifndef WRONG
   1244 #define WRONG	(-1)
   1245 #endif /* !defined WRONG */
   1246 
   1247 /*
   1248 ** Simplified normalize logic courtesy Paul Eggert (eggert (at) twinsun.com).
   1249 */
   1250 
   1251 static int
   1252 increment_overflow(number, delta)
   1253 int *	number;
   1254 int	delta;
   1255 {
   1256 	int	number0;
   1257 
   1258 	number0 = *number;
   1259 	*number += delta;
   1260 	return (*number < number0) != (delta < 0);
   1261 }
   1262 
   1263 static int
   1264 normalize_overflow(tensptr, unitsptr, base)
   1265 int * const	tensptr;
   1266 int * const	unitsptr;
   1267 const int	base;
   1268 {
   1269 	register int	tensdelta;
   1270 
   1271 	tensdelta = (*unitsptr >= 0) ?
   1272 		(*unitsptr / base) :
   1273 		(-1 - (-1 - *unitsptr) / base);
   1274 	*unitsptr -= tensdelta * base;
   1275 	return increment_overflow(tensptr, tensdelta);
   1276 }
   1277 
   1278 static int
   1279 tmcomp(atmp, btmp)
   1280 register const struct tm * const atmp;
   1281 register const struct tm * const btmp;
   1282 {
   1283 	register int	result;
   1284 
   1285 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
   1286 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
   1287 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
   1288 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
   1289 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
   1290 			result = atmp->tm_sec - btmp->tm_sec;
   1291 	return result;
   1292 }
   1293 
   1294 static time_t
   1295 time2(tmp, funcp, offset, okayp)
   1296 struct tm * const	tmp;
   1297 void (* const		funcp) P((const time_t*, long, struct tm*));
   1298 const long		offset;
   1299 int * const		okayp;
   1300 {
   1301 	register const struct state *	sp;
   1302 	register int			dir;
   1303 	register int			bits;
   1304 	register int			i, j ;
   1305 	register int			saved_seconds;
   1306 	time_t				newt;
   1307 	time_t				t;
   1308 	struct tm			yourtm, mytm;
   1309 
   1310 	*okayp = FALSE;
   1311 	yourtm = *tmp;
   1312 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
   1313 		return WRONG;
   1314 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
   1315 		return WRONG;
   1316 	if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
   1317 		return WRONG;
   1318 	/*
   1319 	** Turn yourtm.tm_year into an actual year number for now.
   1320 	** It is converted back to an offset from TM_YEAR_BASE later.
   1321 	*/
   1322 	if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
   1323 		return WRONG;
   1324 	while (yourtm.tm_mday <= 0) {
   1325 		if (increment_overflow(&yourtm.tm_year, -1))
   1326 			return WRONG;
   1327 		i = yourtm.tm_year + (1 < yourtm.tm_mon);
   1328 		yourtm.tm_mday += year_lengths[isleap(i)];
   1329 	}
   1330 	while (yourtm.tm_mday > DAYSPERLYEAR) {
   1331 		i = yourtm.tm_year + (1 < yourtm.tm_mon);
   1332 		yourtm.tm_mday -= year_lengths[isleap(i)];
   1333 		if (increment_overflow(&yourtm.tm_year, 1))
   1334 			return WRONG;
   1335 	}
   1336 	for ( ; ; ) {
   1337 		i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
   1338 		if (yourtm.tm_mday <= i)
   1339 			break;
   1340 		yourtm.tm_mday -= i;
   1341 		if (++yourtm.tm_mon >= MONSPERYEAR) {
   1342 			yourtm.tm_mon = 0;
   1343 			if (increment_overflow(&yourtm.tm_year, 1))
   1344 				return WRONG;
   1345 		}
   1346 	}
   1347 	if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
   1348 		return WRONG;
   1349 	if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
   1350 		/*
   1351 		** We can't set tm_sec to 0, because that might push the
   1352 		** time below the minimum representable time.
   1353 		** Set tm_sec to 59 instead.
   1354 		** This assumes that the minimum representable time is
   1355 		** not in the same minute that a leap second was deleted from,
   1356 		** which is a safer assumption than using 58 would be.
   1357 		*/
   1358 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
   1359 			return WRONG;
   1360 		saved_seconds = yourtm.tm_sec;
   1361 		yourtm.tm_sec = SECSPERMIN - 1;
   1362 	} else {
   1363 		saved_seconds = yourtm.tm_sec;
   1364 		yourtm.tm_sec = 0;
   1365 	}
   1366 	/*
   1367 	** Divide the search space in half
   1368 	** (this works whether time_t is signed or unsigned).
   1369 	*/
   1370 	bits = TYPE_BIT(time_t) - 1;
   1371 	/*
   1372 	** If time_t is signed, then 0 is just above the median,
   1373 	** assuming two's complement arithmetic.
   1374 	** If time_t is unsigned, then (1 << bits) is just above the median.
   1375 	*/
   1376 	t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
   1377 	for ( ; ; ) {
   1378 		(*funcp)(&t, offset, &mytm);
   1379 		dir = tmcomp(&mytm, &yourtm);
   1380 		if (dir != 0) {
   1381 			if (bits-- < 0)
   1382 				return WRONG;
   1383 			if (bits < 0)
   1384 				--t; /* may be needed if new t is minimal */
   1385 			else if (dir > 0)
   1386 				t -= ((time_t) 1) << bits;
   1387 			else	t += ((time_t) 1) << bits;
   1388 			continue;
   1389 		}
   1390 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
   1391 			break;
   1392 		/*
   1393 		** Right time, wrong type.
   1394 		** Hunt for right time, right type.
   1395 		** It's okay to guess wrong since the guess
   1396 		** gets checked.
   1397 		*/
   1398 		/*
   1399 		** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
   1400 		*/
   1401 		sp = (const struct state *)
   1402 			(((void *) funcp == (void *) localsub) ?
   1403 			lclptr : gmtptr);
   1404 #ifdef ALL_STATE
   1405 		if (sp == NULL)
   1406 			return WRONG;
   1407 #endif /* defined ALL_STATE */
   1408 		for (i = sp->typecnt - 1; i >= 0; --i) {
   1409 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
   1410 				continue;
   1411 			for (j = sp->typecnt - 1; j >= 0; --j) {
   1412 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
   1413 					continue;
   1414 				newt = t + sp->ttis[j].tt_gmtoff -
   1415 					sp->ttis[i].tt_gmtoff;
   1416 				(*funcp)(&newt, offset, &mytm);
   1417 				if (tmcomp(&mytm, &yourtm) != 0)
   1418 					continue;
   1419 				if (mytm.tm_isdst != yourtm.tm_isdst)
   1420 					continue;
   1421 				/*
   1422 				** We have a match.
   1423 				*/
   1424 				t = newt;
   1425 				goto label;
   1426 			}
   1427 		}
   1428 		return WRONG;
   1429 	}
   1430 label:
   1431 	newt = t + saved_seconds;
   1432 	if ((newt < t) != (saved_seconds < 0))
   1433 		return WRONG;
   1434 	t = newt;
   1435 	(*funcp)(&t, offset, tmp);
   1436 	*okayp = TRUE;
   1437 	return t;
   1438 }
   1439 
   1440 static time_t
   1441 time1(tmp, funcp, offset)
   1442 struct tm * const	tmp;
   1443 void (* const		funcp) P((const time_t *, long, struct tm *));
   1444 const long		offset;
   1445 {
   1446 	register time_t			t;
   1447 	register const struct state *	sp;
   1448 	register int			samei, otheri;
   1449 	int				okay;
   1450 
   1451 	if (tmp->tm_isdst > 1)
   1452 		tmp->tm_isdst = 1;
   1453 	t = time2(tmp, funcp, offset, &okay);
   1454 #ifdef PCTS
   1455 	/*
   1456 	** PCTS code courtesy Grant Sullivan (grant (at) osf.org).
   1457 	*/
   1458 	if (okay)
   1459 		return t;
   1460 	if (tmp->tm_isdst < 0)
   1461 		tmp->tm_isdst = 0;	/* reset to std and try again */
   1462 #endif /* defined PCTS */
   1463 #ifndef PCTS
   1464 	if (okay || tmp->tm_isdst < 0)
   1465 		return t;
   1466 #endif /* !defined PCTS */
   1467 	/*
   1468 	** We're supposed to assume that somebody took a time of one type
   1469 	** and did some math on it that yielded a "struct tm" that's bad.
   1470 	** We try to divine the type they started from and adjust to the
   1471 	** type they need.
   1472 	*/
   1473 	/*
   1474 	** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
   1475 	*/
   1476 	sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
   1477 		lclptr : gmtptr);
   1478 #ifdef ALL_STATE
   1479 	if (sp == NULL)
   1480 		return WRONG;
   1481 #endif /* defined ALL_STATE */
   1482 	for (samei = sp->typecnt - 1; samei >= 0; --samei) {
   1483 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
   1484 			continue;
   1485 		for (otheri = sp->typecnt - 1; otheri >= 0; --otheri) {
   1486 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
   1487 				continue;
   1488 			tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
   1489 					sp->ttis[samei].tt_gmtoff;
   1490 			tmp->tm_isdst = !tmp->tm_isdst;
   1491 			t = time2(tmp, funcp, offset, &okay);
   1492 			if (okay)
   1493 				return t;
   1494 			tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
   1495 					sp->ttis[samei].tt_gmtoff;
   1496 			tmp->tm_isdst = !tmp->tm_isdst;
   1497 		}
   1498 	}
   1499 	return WRONG;
   1500 }
   1501 
   1502 time_t
   1503 mktime(tmp)
   1504 struct tm * const	tmp;
   1505 {
   1506 	tzset();
   1507 	return time1(tmp, localsub, 0L);
   1508 }
   1509 
   1510 #ifdef STD_INSPIRED
   1511 
   1512 time_t
   1513 timelocal(tmp)
   1514 struct tm * const	tmp;
   1515 {
   1516 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
   1517 	return mktime(tmp);
   1518 }
   1519 
   1520 time_t
   1521 timegm(tmp)
   1522 struct tm * const	tmp;
   1523 {
   1524 	tmp->tm_isdst = 0;
   1525 	return time1(tmp, gmtsub, 0L);
   1526 }
   1527 
   1528 time_t
   1529 timeoff(tmp, offset)
   1530 struct tm * const	tmp;
   1531 const long		offset;
   1532 {
   1533 	tmp->tm_isdst = 0;
   1534 	return time1(tmp, gmtsub, offset);
   1535 }
   1536 
   1537 #endif /* defined STD_INSPIRED */
   1538 
   1539 #ifdef CMUCS
   1540 
   1541 /*
   1542 ** The following is supplied for compatibility with
   1543 ** previous versions of the CMUCS runtime library.
   1544 */
   1545 
   1546 long
   1547 gtime(tmp)
   1548 struct tm * const	tmp;
   1549 {
   1550 	const time_t	t = mktime(tmp);
   1551 
   1552 	if (t == WRONG)
   1553 		return -1;
   1554 	return t;
   1555 }
   1556 
   1557 #endif /* defined CMUCS */
   1558 
   1559 /*
   1560 ** XXX--is the below the right way to conditionalize??
   1561 */
   1562 
   1563 #ifdef STD_INSPIRED
   1564 
   1565 /*
   1566 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
   1567 ** shall correspond to "Wed Dec 31 23:59:59 GMT 1986", which
   1568 ** is not the case if we are accounting for leap seconds.
   1569 ** So, we provide the following conversion routines for use
   1570 ** when exchanging timestamps with POSIX conforming systems.
   1571 */
   1572 
   1573 static long
   1574 leapcorr(timep)
   1575 time_t *	timep;
   1576 {
   1577 	register struct state *		sp;
   1578 	register struct lsinfo *	lp;
   1579 	register int			i;
   1580 
   1581 	sp = lclptr;
   1582 	i = sp->leapcnt;
   1583 	while (--i >= 0) {
   1584 		lp = &sp->lsis[i];
   1585 		if (*timep >= lp->ls_trans)
   1586 			return lp->ls_corr;
   1587 	}
   1588 	return 0;
   1589 }
   1590 
   1591 time_t
   1592 time2posix(t)
   1593 time_t	t;
   1594 {
   1595 	tzset();
   1596 	return t - leapcorr(&t);
   1597 }
   1598 
   1599 time_t
   1600 posix2time(t)
   1601 time_t	t;
   1602 {
   1603 	time_t	x;
   1604 	time_t	y;
   1605 
   1606 	tzset();
   1607 	/*
   1608 	** For a positive leap second hit, the result
   1609 	** is not unique.  For a negative leap second
   1610 	** hit, the corresponding time doesn't exist,
   1611 	** so we return an adjacent second.
   1612 	*/
   1613 	x = t + leapcorr(&t);
   1614 	y = x - leapcorr(&x);
   1615 	if (y < t) {
   1616 		do {
   1617 			x++;
   1618 			y = x - leapcorr(&x);
   1619 		} while (y < t);
   1620 		if (t != y)
   1621 			return x - 1;
   1622 	} else if (y > t) {
   1623 		do {
   1624 			--x;
   1625 			y = x - leapcorr(&x);
   1626 		} while (y > t);
   1627 		if (t != y)
   1628 			return x + 1;
   1629 	}
   1630 	return x;
   1631 }
   1632 
   1633 #endif /* defined STD_INSPIRED */
   1634