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      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
    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
    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 *
    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 *
    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 *
    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 *
    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