xref: /netbsd-src/lib/libc/time/strptime.c (revision e5717105ade4bc7f7499d88acc69bdc21cc771d4)
1 /*	$NetBSD: strptime.c,v 1.67 2024/06/07 13:53:23 riastradh Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 2005, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code was contributed to The NetBSD Foundation by Klaus Klein.
8  * Heavily optimised by David Laight
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: strptime.c,v 1.67 2024/06/07 13:53:23 riastradh Exp $");
35 #endif
36 
37 #include "namespace.h"
38 #include <sys/localedef.h>
39 #include <sys/types.h>
40 #include <ctype.h>
41 #include <locale.h>
42 #include <string.h>
43 #include <time.h>
44 #include <tzfile.h>
45 #include "private.h"
46 #include "setlocale_local.h"
47 
48 #ifdef __weak_alias
49 __weak_alias(strptime,_strptime)
50 __weak_alias(strptime_l, _strptime_l)
51 #endif
52 
53 static const u_char *conv_num(const unsigned char *, int *, uint, uint);
54 static const u_char *find_string(const u_char *, int *, const char * const *,
55 	const char * const *, int);
56 
57 #define _TIME_LOCALE(loc) \
58     ((_TimeLocale *)((loc)->part_impl[LC_TIME]))
59 
60 /*
61  * We do not implement alternate representations. However, we always
62  * check whether a given modifier is allowed for a certain conversion.
63  */
64 #define ALT_E			0x01
65 #define ALT_O			0x02
66 #define LEGAL_ALT(x)		{ if (alt_format & ~(x)) return NULL; }
67 
68 #define S_YEAR			(1 << 0)
69 #define S_MON			(1 << 1)
70 #define S_YDAY			(1 << 2)
71 #define S_MDAY			(1 << 3)
72 #define S_WDAY			(1 << 4)
73 #define S_HOUR			(1 << 5)
74 
75 #define HAVE_MDAY(s)		(s & S_MDAY)
76 #define HAVE_MON(s)		(s & S_MON)
77 #define HAVE_WDAY(s)		(s & S_WDAY)
78 #define HAVE_YDAY(s)		(s & S_YDAY)
79 #define HAVE_YEAR(s)		(s & S_YEAR)
80 #define HAVE_HOUR(s)		(s & S_HOUR)
81 
82 static char utc[] = { "UTC" };
83 /* RFC-822/RFC-2822 */
84 static const char * const nast[5] = {
85        "EST",    "CST",    "MST",    "PST",    "\0\0\0"
86 };
87 static const char * const nadt[5] = {
88        "EDT",    "CDT",    "MDT",    "PDT",    "\0\0\0"
89 };
90 
91 /*
92  * Table to determine the ordinal date for the start of a month.
93  * Ref: http://en.wikipedia.org/wiki/ISO_week_date
94  */
95 static const int start_of_month[2][13] = {
96 	/* non-leap year */
97 	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
98 	/* leap year */
99 	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
100 };
101 
102 /*
103  * Calculate the week day of the first day of a year. Valid for
104  * the Gregorian calendar, which began Sept 14, 1752 in the UK
105  * and its colonies. Ref:
106  * http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week
107  */
108 
109 static int
first_wday_of(int yr)110 first_wday_of(int yr)
111 {
112 	return ((2 * (3 - (yr / 100) % 4)) + (yr % 100) + ((yr % 100) /  4) +
113 	    (isleap(yr) ? 6 : 0) + 1) % 7;
114 }
115 
116 #define delim(p)	((p) == '\0' || isspace((unsigned char)(p)))
117 
118 static int
fromzone(const unsigned char ** bp,struct tm * tm,int mandatory)119 fromzone(const unsigned char **bp, struct tm *tm, int mandatory)
120 {
121 	timezone_t tz;
122 	char buf[512], *p;
123 	const unsigned char *rp;
124 
125 	for (p = buf, rp = *bp; !delim(*rp) && p < &buf[sizeof(buf) - 1]; rp++)
126 		*p++ = *rp;
127 	*p = '\0';
128 
129 	if (mandatory)
130 		*bp = rp;
131 	if (!isalnum((unsigned char)*buf))
132 		return 0;
133 	tz = tzalloc(buf);
134 	if (tz == NULL)
135 		return 0;
136 
137 	*bp = rp;
138 	tm->tm_isdst = 0;	/* XXX */
139 #ifdef TM_GMTOFF
140 	tm->TM_GMTOFF = tzgetgmtoff(tz, tm->tm_isdst);
141 #endif
142 #ifdef TM_ZONE
143 	// Can't use tzgetname() here because we are going to free()
144 	tm->TM_ZONE = NULL; /* XXX */
145 #endif
146 	tzfree(tz);
147 	return 1;
148 }
149 
150 char *
strptime(const char * buf,const char * fmt,struct tm * tm)151 strptime(const char *buf, const char *fmt, struct tm *tm)
152 {
153 	return strptime_l(buf, fmt, tm, _current_locale());
154 }
155 
156 char *
strptime_l(const char * buf,const char * fmt,struct tm * tm,locale_t loc)157 strptime_l(const char *buf, const char *fmt, struct tm *tm, locale_t loc)
158 {
159 	unsigned char c;
160 	const unsigned char *bp, *ep, *zname;
161 	int alt_format, i, split_year = 0, neg = 0, state = 0,
162 	    day_offset = -1, week_offset = 0, offs, mandatory;
163 	const char *new_fmt;
164 
165 	bp = (const u_char *)buf;
166 
167 	while (bp != NULL && (c = *fmt++) != '\0') {
168 		/* Clear `alternate' modifier prior to new conversion. */
169 		alt_format = 0;
170 		i = 0;
171 
172 		/* Eat up white-space. */
173 		if (isspace(c)) {
174 			while (isspace(*bp))
175 				bp++;
176 			continue;
177 		}
178 
179 		if (c != '%')
180 			goto literal;
181 
182 
183 again:		switch (c = *fmt++) {
184 		case '%':	/* "%%" is converted to "%". */
185 literal:
186 			if (c != *bp++)
187 				return NULL;
188 			LEGAL_ALT(0);
189 			continue;
190 
191 		/*
192 		 * "Alternative" modifiers. Just set the appropriate flag
193 		 * and start over again.
194 		 */
195 		case 'E':	/* "%E?" alternative conversion modifier. */
196 			LEGAL_ALT(0);
197 			alt_format |= ALT_E;
198 			goto again;
199 
200 		case 'O':	/* "%O?" alternative conversion modifier. */
201 			LEGAL_ALT(0);
202 			alt_format |= ALT_O;
203 			goto again;
204 
205 		/*
206 		 * "Complex" conversion rules, implemented through recursion.
207 		 */
208 		case 'c':	/* Date and time, using the locale's format. */
209 			new_fmt = _TIME_LOCALE(loc)->d_t_fmt;
210 			state |= S_WDAY | S_MON | S_MDAY | S_YEAR;
211 			goto recurse;
212 
213 		case 'D':	/* The date as "%m/%d/%y". */
214 			new_fmt = "%m/%d/%y";
215 			LEGAL_ALT(0);
216 			state |= S_MON | S_MDAY | S_YEAR;
217 			goto recurse;
218 
219 		case 'F':	/* The date as "%Y-%m-%d". */
220 			new_fmt = "%Y-%m-%d";
221 			LEGAL_ALT(0);
222 			state |= S_MON | S_MDAY | S_YEAR;
223 			goto recurse;
224 
225 		case 'R':	/* The time as "%H:%M". */
226 			new_fmt = "%H:%M";
227 			LEGAL_ALT(0);
228 			goto recurse;
229 
230 		case 'r':	/* The time in 12-hour clock representation. */
231 			new_fmt = _TIME_LOCALE(loc)->t_fmt_ampm;
232 			LEGAL_ALT(0);
233 			goto recurse;
234 
235 		case 'T':	/* The time as "%H:%M:%S". */
236 			new_fmt = "%H:%M:%S";
237 			LEGAL_ALT(0);
238 			goto recurse;
239 
240 		case 'X':	/* The time, using the locale's format. */
241 			new_fmt = _TIME_LOCALE(loc)->t_fmt;
242 			goto recurse;
243 
244 		case 'x':	/* The date, using the locale's format. */
245 			new_fmt = _TIME_LOCALE(loc)->d_fmt;
246 			state |= S_MON | S_MDAY | S_YEAR;
247 		    recurse:
248 			bp = (const u_char *)strptime((const char *)bp,
249 							    new_fmt, tm);
250 			LEGAL_ALT(ALT_E);
251 			continue;
252 
253 		/*
254 		 * "Elementary" conversion rules.
255 		 */
256 		case 'A':	/* The day of week, using the locale's form. */
257 		case 'a':
258 			bp = find_string(bp, &tm->tm_wday,
259 			    _TIME_LOCALE(loc)->day, _TIME_LOCALE(loc)->abday, 7);
260 			LEGAL_ALT(0);
261 			state |= S_WDAY;
262 			continue;
263 
264 		case 'B':	/* The month, using the locale's form. */
265 		case 'b':
266 		case 'h':
267 			bp = find_string(bp, &tm->tm_mon,
268 			    _TIME_LOCALE(loc)->mon, _TIME_LOCALE(loc)->abmon,
269 			    12);
270 			LEGAL_ALT(0);
271 			state |= S_MON;
272 			continue;
273 
274 		case 'C':	/* The century number. */
275 			i = 20;
276 			bp = conv_num(bp, &i, 0, 99);
277 
278 			i = i * 100 - TM_YEAR_BASE;
279 			if (split_year)
280 				i += tm->tm_year % 100;
281 			split_year = 1;
282 			tm->tm_year = i;
283 			LEGAL_ALT(ALT_E);
284 			state |= S_YEAR;
285 			continue;
286 
287 		case 'd':	/* The day of month. */
288 		case 'e':
289 			bp = conv_num(bp, &tm->tm_mday, 1, 31);
290 			LEGAL_ALT(ALT_O);
291 			state |= S_MDAY;
292 			continue;
293 
294 		case 'k':	/* The hour (24-hour clock representation). */
295 			LEGAL_ALT(0);
296 			/* FALLTHROUGH */
297 		case 'H':
298 			bp = conv_num(bp, &tm->tm_hour, 0, 23);
299 			LEGAL_ALT(ALT_O);
300 			state |= S_HOUR;
301 			continue;
302 
303 		case 'l':	/* The hour (12-hour clock representation). */
304 			LEGAL_ALT(0);
305 			/* FALLTHROUGH */
306 		case 'I':
307 			bp = conv_num(bp, &tm->tm_hour, 1, 12);
308 			if (tm->tm_hour == 12)
309 				tm->tm_hour = 0;
310 			LEGAL_ALT(ALT_O);
311 			state |= S_HOUR;
312 			continue;
313 
314 		case 'j':	/* The day of year. */
315 			i = 1;
316 			bp = conv_num(bp, &i, 1, 366);
317 			tm->tm_yday = i - 1;
318 			LEGAL_ALT(0);
319 			state |= S_YDAY;
320 			continue;
321 
322 		case 'M':	/* The minute. */
323 			bp = conv_num(bp, &tm->tm_min, 0, 59);
324 			LEGAL_ALT(ALT_O);
325 			continue;
326 
327 		case 'm':	/* The month. */
328 			i = 1;
329 			bp = conv_num(bp, &i, 1, 12);
330 			tm->tm_mon = i - 1;
331 			LEGAL_ALT(ALT_O);
332 			state |= S_MON;
333 			continue;
334 
335 		case 'p':	/* The locale's equivalent of AM/PM. */
336 			bp = find_string(bp, &i, _TIME_LOCALE(loc)->am_pm,
337 			    NULL, 2);
338 			if (HAVE_HOUR(state) && tm->tm_hour > 11)
339 				return NULL;
340 			tm->tm_hour += i * 12;
341 			LEGAL_ALT(0);
342 			continue;
343 
344 		case 'S':	/* The seconds. */
345 			bp = conv_num(bp, &tm->tm_sec, 0, 61);
346 			LEGAL_ALT(ALT_O);
347 			continue;
348 
349 		case 's': {	/* seconds since the epoch */
350 			const time_t TIME_MAX = __type_max(time_t);
351 			time_t sse, d;
352 
353 			if (*bp < '0' || *bp > '9') {
354 				bp = NULL;
355 				continue;
356 			}
357 
358 			sse = *bp++ - '0';
359 			while (*bp >= '0' && *bp <= '9') {
360 				d = *bp++ - '0';
361 				if (sse > TIME_MAX/10) {
362 					bp = NULL;
363 					break;
364 				}
365 				sse *= 10;
366 				if (sse > TIME_MAX - d) {
367 					bp = NULL;
368 					break;
369 				}
370 				sse += d;
371 			}
372 			if (bp == NULL)
373 				continue;
374 
375 			if (localtime_r(&sse, tm) == NULL)
376 				bp = NULL;
377 			else
378 				state |= S_YDAY | S_WDAY |
379 				    S_MON | S_MDAY | S_YEAR;
380 			continue;
381 		}
382 
383 		case 'U':	/* The week of year, beginning on sunday. */
384 		case 'W':	/* The week of year, beginning on monday. */
385 			/*
386 			 * This is bogus, as we can not assume any valid
387 			 * information present in the tm structure at this
388 			 * point to calculate a real value, so save the
389 			 * week for now in case it can be used later.
390 			 */
391 			bp = conv_num(bp, &i, 0, 53);
392 			LEGAL_ALT(ALT_O);
393 			if (c == 'U')
394 				day_offset = TM_SUNDAY;
395 			else
396 				day_offset = TM_MONDAY;
397 			week_offset = i;
398 			continue;
399 
400 		case 'w':	/* The day of week, beginning on sunday. */
401 			bp = conv_num(bp, &tm->tm_wday, 0, 6);
402 			LEGAL_ALT(ALT_O);
403 			state |= S_WDAY;
404 			continue;
405 
406 		case 'u':	/* The day of week, monday = 1. */
407 			bp = conv_num(bp, &i, 1, 7);
408 			tm->tm_wday = i % 7;
409 			LEGAL_ALT(ALT_O);
410 			state |= S_WDAY;
411 			continue;
412 
413 		case 'g':	/* The year corresponding to the ISO week
414 				 * number but without the century.
415 				 */
416 			bp = conv_num(bp, &i, 0, 99);
417 			continue;
418 
419 		case 'G':	/* The year corresponding to the ISO week
420 				 * number with century.
421 				 */
422 			do
423 				bp++;
424 			while (isdigit(*bp));
425 			continue;
426 
427 		case 'V':	/* The ISO 8601:1988 week number as decimal */
428 			bp = conv_num(bp, &i, 1, 53);
429 			continue;
430 
431 		case 'Y':	/* The year. */
432 			i = TM_YEAR_BASE;	/* just for data sanity... */
433 			bp = conv_num(bp, &i, 0, 9999);
434 			tm->tm_year = i - TM_YEAR_BASE;
435 			LEGAL_ALT(ALT_E);
436 			state |= S_YEAR;
437 			continue;
438 
439 		case 'y':	/* The year within 100 years of the epoch. */
440 			/* LEGAL_ALT(ALT_E | ALT_O); */
441 			bp = conv_num(bp, &i, 0, 99);
442 
443 			if (split_year)
444 				/* preserve century */
445 				i += (tm->tm_year / 100) * 100;
446 			else {
447 				split_year = 1;
448 				if (i <= 68)
449 					i = i + 2000 - TM_YEAR_BASE;
450 				else
451 					i = i + 1900 - TM_YEAR_BASE;
452 			}
453 			tm->tm_year = i;
454 			state |= S_YEAR;
455 			continue;
456 
457 		case 'Z':
458 		case 'z':
459 			tzset();
460 			mandatory = c == 'z';
461 			/*
462 			 * We recognize all ISO 8601 formats:
463 			 * Z	= Zulu time/UTC
464 			 * [+-]hhmm
465 			 * [+-]hh:mm
466 			 * [+-]hh
467 			 * We recognize all RFC-822/RFC-2822 formats:
468 			 * UT|GMT
469 			 *          North American : UTC offsets
470 			 * E[DS]T = Eastern : -4 | -5
471 			 * C[DS]T = Central : -5 | -6
472 			 * M[DS]T = Mountain: -6 | -7
473 			 * P[DS]T = Pacific : -7 | -8
474 			 *          Nautical/Military
475 			 * [A-IL-M] = -1 ... -9 (J not used)
476 			 * [N-Y]  = +1 ... +12
477 			 * Note: J maybe used to denote non-nautical
478 			 *       local time
479 			 */
480 			if (mandatory)
481 				while (isspace(*bp))
482 					bp++;
483 
484 			zname = bp;
485 			switch (*bp++) {
486 			case 'G':
487 				if (*bp++ != 'M')
488 					goto namedzone;
489 				/*FALLTHROUGH*/
490 			case 'U':
491 				if (*bp++ != 'T')
492 					goto namedzone;
493 				else if (!delim(*bp) && *bp++ != 'C')
494 					goto namedzone;
495 				/*FALLTHROUGH*/
496 			case 'Z':
497 				if (!delim(*bp))
498 					goto namedzone;
499 				tm->tm_isdst = 0;
500 #ifdef TM_GMTOFF
501 				tm->TM_GMTOFF = 0;
502 #endif
503 #ifdef TM_ZONE
504 				tm->TM_ZONE = utc;
505 #endif
506 				continue;
507 			case '+':
508 				neg = 0;
509 				break;
510 			case '-':
511 				neg = 1;
512 				break;
513 			default:
514 namedzone:
515 				bp = zname;
516 
517 				/* Nautical / Military style */
518 				if (delim(bp[1]) &&
519 				    ((*bp >= 'A' && *bp <= 'I') ||
520 				     (*bp >= 'L' && *bp <= 'Y'))) {
521 #ifdef TM_GMTOFF
522 					/* Argh! No 'J'! */
523 					if (*bp >= 'A' && *bp <= 'I')
524 						tm->TM_GMTOFF =
525 						    (int)*bp - ('A' - 1);
526 					else if (*bp >= 'L' && *bp <= 'M')
527 						tm->TM_GMTOFF = (int)*bp - 'A';
528 					else if (*bp >= 'N' && *bp <= 'Y')
529 						tm->TM_GMTOFF = 'M' - (int)*bp;
530 					tm->TM_GMTOFF *= SECSPERHOUR;
531 #endif
532 #ifdef TM_ZONE
533 					tm->TM_ZONE = NULL; /* XXX */
534 #endif
535 					bp++;
536 					continue;
537 				}
538 				/* 'J' is local time */
539 				if (delim(bp[1]) && *bp == 'J') {
540 #ifdef TM_GMTOFF
541 					tm->TM_GMTOFF = -timezone;
542 #endif
543 #ifdef TM_ZONE
544 					tm->TM_ZONE = NULL; /* XXX */
545 #endif
546 					bp++;
547 					continue;
548 				}
549 
550 				/*
551 				 * From our 3 letter hard-coded table
552 				 * XXX: Can be removed, handled by tzload()
553 				 */
554 				if (delim(bp[0]) || delim(bp[1]) ||
555 				    delim(bp[2]) || !delim(bp[3]))
556 					goto loadzone;
557 				ep = find_string(bp, &i, nast, NULL, 4);
558 				if (ep != NULL) {
559 #ifdef TM_GMTOFF
560 					tm->TM_GMTOFF = (-5 - i) * SECSPERHOUR;
561 #endif
562 #ifdef TM_ZONE
563 					tm->TM_ZONE = __UNCONST(nast[i]);
564 #endif
565 					bp = ep;
566 					continue;
567 				}
568 				ep = find_string(bp, &i, nadt, NULL, 4);
569 				if (ep != NULL) {
570 					tm->tm_isdst = 1;
571 #ifdef TM_GMTOFF
572 					tm->TM_GMTOFF = (-4 - i) * SECSPERHOUR;
573 #endif
574 #ifdef TM_ZONE
575 					tm->TM_ZONE = __UNCONST(nadt[i]);
576 #endif
577 					bp = ep;
578 					continue;
579 				}
580 				/*
581 				 * Our current timezone
582 				 */
583 				ep = find_string(bp, &i,
584 					       	 (const char * const *)tzname,
585 					       	  NULL, 2);
586 				if (ep != NULL) {
587 					tm->tm_isdst = i;
588 #ifdef TM_GMTOFF
589 					tm->TM_GMTOFF = -timezone;
590 #endif
591 #ifdef TM_ZONE
592 					tm->TM_ZONE = tzname[i];
593 #endif
594 					bp = ep;
595 					continue;
596 				}
597 loadzone:
598 				/*
599 				 * The hard way, load the zone!
600 				 */
601 				if (fromzone(&bp, tm, mandatory))
602 					continue;
603 				goto out;
604 			}
605 			offs = 0;
606 			for (i = 0; i < 4; ) {
607 				if (isdigit(*bp)) {
608 					offs = offs * 10 + (*bp++ - '0');
609 					i++;
610 					continue;
611 				}
612 				if (i == 2 && *bp == ':') {
613 					bp++;
614 					continue;
615 				}
616 				break;
617 			}
618 			if (isdigit(*bp))
619 				goto out;
620 			switch (i) {
621 			case 2:
622 				offs *= SECSPERHOUR;
623 				break;
624 			case 4:
625 				i = offs % 100;
626 				offs /= 100;
627 				if (i >= SECSPERMIN)
628 					goto out;
629 				/* Convert minutes into decimal */
630 				offs = offs * SECSPERHOUR + i * SECSPERMIN;
631 				break;
632 			default:
633 			out:
634 				if (mandatory)
635 					return NULL;
636 				bp = zname;
637 				continue;
638 			}
639 			/* ISO 8601 & RFC 3339 limit to 23:59 max */
640 			if (offs >= (HOURSPERDAY * SECSPERHOUR))
641 				goto out;
642 			if (neg)
643 				offs = -offs;
644 			tm->tm_isdst = 0;	/* XXX */
645 #ifdef TM_GMTOFF
646 			tm->TM_GMTOFF = offs;
647 #endif
648 #ifdef TM_ZONE
649 			tm->TM_ZONE = NULL;	/* XXX */
650 #endif
651 			continue;
652 
653 		/*
654 		 * Miscellaneous conversions.
655 		 */
656 		case 'n':	/* Any kind of white-space. */
657 		case 't':
658 			while (isspace(*bp))
659 				bp++;
660 			LEGAL_ALT(0);
661 			continue;
662 
663 
664 		default:	/* Unknown/unsupported conversion. */
665 			return NULL;
666 		}
667 	}
668 
669 	if (!HAVE_YDAY(state) && HAVE_YEAR(state)) {
670 		if (HAVE_MON(state) && HAVE_MDAY(state)) {
671 			/* calculate day of year (ordinal date) */
672 			tm->tm_yday =  start_of_month[isleap_sum(tm->tm_year,
673 			    TM_YEAR_BASE)][tm->tm_mon] + (tm->tm_mday - 1);
674 			state |= S_YDAY;
675 		} else if (day_offset != -1) {
676 			/*
677 			 * Set the date to the first Sunday (or Monday)
678 			 * of the specified week of the year.
679 			 */
680 			if (!HAVE_WDAY(state)) {
681 				tm->tm_wday = day_offset;
682 				state |= S_WDAY;
683 			}
684 			tm->tm_yday = (7 -
685 			    first_wday_of(tm->tm_year + TM_YEAR_BASE) +
686 			    day_offset) % 7 + (week_offset - 1) * 7 +
687 			    tm->tm_wday  - day_offset;
688 			state |= S_YDAY;
689 		}
690 	}
691 
692 	if (HAVE_YDAY(state) && HAVE_YEAR(state)) {
693 		int isleap;
694 
695 		if (!HAVE_MON(state)) {
696 			/* calculate month of day of year */
697 			i = 0;
698 			isleap = isleap_sum(tm->tm_year, TM_YEAR_BASE);
699 			while (tm->tm_yday >= start_of_month[isleap][i])
700 				i++;
701 			if (i > 12) {
702 				i = 1;
703 				tm->tm_yday -= start_of_month[isleap][12];
704 				tm->tm_year++;
705 			}
706 			tm->tm_mon = i - 1;
707 			state |= S_MON;
708 		}
709 
710 		if (!HAVE_MDAY(state)) {
711 			/* calculate day of month */
712 			isleap = isleap_sum(tm->tm_year, TM_YEAR_BASE);
713 			tm->tm_mday = tm->tm_yday -
714 			    start_of_month[isleap][tm->tm_mon] + 1;
715 			state |= S_MDAY;
716 		}
717 
718 		if (!HAVE_WDAY(state)) {
719 			/* calculate day of week */
720 			i = 0;
721 			week_offset = first_wday_of(tm->tm_year);
722 			while (i++ <= tm->tm_yday) {
723 				if (week_offset++ >= 6)
724 					week_offset = 0;
725 			}
726 			tm->tm_wday = week_offset;
727 			state |= S_WDAY;
728 		}
729 	}
730 
731 	return __UNCONST(bp);
732 }
733 
734 
735 static const u_char *
conv_num(const unsigned char * buf,int * dest,uint llim,uint ulim)736 conv_num(const unsigned char *buf, int *dest, uint llim, uint ulim)
737 {
738 	uint result = 0;
739 	unsigned char ch;
740 
741 	/* The limit also determines the number of valid digits. */
742 	uint rulim = ulim;
743 
744 	ch = *buf;
745 	if (ch < '0' || ch > '9')
746 		return NULL;
747 
748 	do {
749 		result *= 10;
750 		result += ch - '0';
751 		rulim /= 10;
752 		ch = *++buf;
753 	} while ((result * 10 <= ulim) && rulim && ch >= '0' && ch <= '9');
754 
755 	if (result < llim || result > ulim)
756 		return NULL;
757 
758 	*dest = result;
759 	return buf;
760 }
761 
762 static const u_char *
find_string(const u_char * bp,int * tgt,const char * const * n1,const char * const * n2,int c)763 find_string(const u_char *bp, int *tgt, const char * const *n1,
764 		const char * const *n2, int c)
765 {
766 	int i;
767 	size_t len;
768 
769 	/* check full name - then abbreviated ones */
770 	for (; n1 != NULL; n1 = n2, n2 = NULL) {
771 		for (i = 0; i < c; i++, n1++) {
772 			len = strlen(*n1);
773 			if (strncasecmp(*n1, (const char *)bp, len) == 0) {
774 				*tgt = i;
775 				return bp + len;
776 			}
777 		}
778 	}
779 
780 	/* Nothing matched */
781 	return NULL;
782 }
783