xref: /dflybsd-src/lib/libc/stdtime/strptime.c (revision b88e86541fe9061d2e24b73dac338830db307d3f)
1 /*-
2  * Copyright (c) 2014 Gary Mills
3  * Copyright 2011, Nexenta Systems, Inc.  All rights reserved.
4  * Copyright (c) 1994 Powerdog Industries.  All rights reserved.
5  *
6  * Copyright (c) 2011 The FreeBSD Foundation
7  * All rights reserved.
8  * Portions of this software were developed by David Chisnall
9  * under sponsorship from the FreeBSD Foundation.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer
18  *    in the documentation and/or other materials provided with the
19  *    distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY POWERDOG INDUSTRIES ``AS IS'' AND ANY
22  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE POWERDOG INDUSTRIES BE
25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
30  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
31  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  *
33  * The views and conclusions contained in the software and documentation
34  * are those of the authors and should not be interpreted as representing
35  * official policies, either expressed or implied, of Powerdog Industries.
36  *
37  * @(#)strptime.c	0.1 (Powerdog) 94/03/27
38  * @(#) Copyright (c) 1994 Powerdog Industries.  All rights reserved.
39  * $FreeBSD: head/lib/libc/stdtime/strptime.c 272679 2014-10-07 06:34:05Z ache $
40  */
41 
42 #include "namespace.h"
43 #include <time.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <pthread.h>
49 #include "un-namespace.h"
50 #include "libc_private.h"
51 #include "timelocal.h"
52 #include "tzfile.h"
53 
54 static char * _strptime(const char *, const char *, struct tm *, int *, locale_t);
55 
56 #define	asizeof(a)	(sizeof(a) / sizeof((a)[0]))
57 
58 #define	FLAG_NONE	(1 << 0)
59 #define	FLAG_YEAR	(1 << 1)
60 #define	FLAG_MONTH	(1 << 2)
61 #define	FLAG_YDAY	(1 << 3)
62 #define	FLAG_MDAY	(1 << 4)
63 #define	FLAG_WDAY	(1 << 5)
64 
65 /*
66  * Calculate the week day of the first day of a year. Valid for
67  * the Gregorian calendar, which began Sept 14, 1752 in the UK
68  * and its colonies. Ref:
69  * http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week
70  */
71 
72 static int
73 first_wday_of(int year)
74 {
75 	return (((2 * (3 - (year / 100) % 4)) + (year % 100) +
76 		((year % 100) / 4) + (isleap(year) ? 6 : 0) + 1) % 7);
77 }
78 
79 static char *
80 _strptime(const char *buf, const char *fmt, struct tm *tm, int *GMTp,
81 		locale_t locale)
82 {
83 	char	c;
84 	const char *ptr;
85 	int	day_offset = -1, wday_offset;
86 	int week_offset;
87 	int	i, len;
88 	int flags;
89 	int Ealternative, Oalternative;
90 	const struct lc_time_T *tptr = __get_current_time_locale(locale);
91 	static int start_of_month[2][13] = {
92 		{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
93 		{0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
94 	};
95 
96 	flags = FLAG_NONE;
97 
98 	ptr = fmt;
99 	while (*ptr != 0) {
100 		c = *ptr++;
101 
102 		if (c != '%') {
103 			if (isspace_l((unsigned char)c, locale))
104 				while (*buf != 0 &&
105 				       isspace_l((unsigned char)*buf, locale))
106 					buf++;
107 			else if (c != *buf++)
108 				return (NULL);
109 			continue;
110 		}
111 
112 		Ealternative = 0;
113 		Oalternative = 0;
114 label:
115 		c = *ptr++;
116 		switch (c) {
117 		case '%':
118 			if (*buf++ != '%')
119 				return (NULL);
120 			break;
121 
122 		case '+':
123 			buf = _strptime(buf, tptr->date_fmt, tm, GMTp, locale);
124 			if (buf == NULL)
125 				return (NULL);
126 			flags |= FLAG_WDAY | FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
127 			break;
128 
129 		case 'C':
130 			if (!isdigit_l((unsigned char)*buf, locale))
131 				return (NULL);
132 
133 			/* XXX This will break for 3-digit centuries. */
134 			len = 2;
135 			for (i = 0; len && *buf != 0 &&
136 			     isdigit_l((unsigned char)*buf, locale); buf++) {
137 				i *= 10;
138 				i += *buf - '0';
139 				len--;
140 			}
141 			if (i < 19)
142 				return (NULL);
143 
144 			tm->tm_year = i * 100 - TM_YEAR_BASE;
145 			flags |= FLAG_YEAR;
146 
147 			break;
148 
149 		case 'c':
150 			buf = _strptime(buf, tptr->c_fmt, tm, GMTp, locale);
151 			if (buf == NULL)
152 				return (NULL);
153 			flags |= FLAG_WDAY | FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
154 			break;
155 
156 		case 'D':
157 			buf = _strptime(buf, "%m/%d/%y", tm, GMTp, locale);
158 			if (buf == NULL)
159 				return (NULL);
160 			flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
161 			break;
162 
163 		case 'E':
164 			if (Ealternative || Oalternative)
165 				break;
166 			Ealternative++;
167 			goto label;
168 
169 		case 'O':
170 			if (Ealternative || Oalternative)
171 				break;
172 			Oalternative++;
173 			goto label;
174 
175 		case 'F':
176 			buf = _strptime(buf, "%Y-%m-%d", tm, GMTp, locale);
177 			if (buf == NULL)
178 				return (NULL);
179 			flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
180 			break;
181 
182 		case 'R':
183 			buf = _strptime(buf, "%H:%M", tm, GMTp, locale);
184 			if (buf == NULL)
185 				return (NULL);
186 			break;
187 
188 		case 'r':
189 			buf = _strptime(buf, tptr->ampm_fmt, tm, GMTp, locale);
190 			if (buf == NULL)
191 				return (NULL);
192 			break;
193 
194 		case 'T':
195 			buf = _strptime(buf, "%H:%M:%S", tm, GMTp, locale);
196 			if (buf == NULL)
197 				return (NULL);
198 			break;
199 
200 		case 'X':
201 			buf = _strptime(buf, tptr->X_fmt, tm, GMTp, locale);
202 			if (buf == NULL)
203 				return (NULL);
204 			break;
205 
206 		case 'x':
207 			buf = _strptime(buf, tptr->x_fmt, tm, GMTp, locale);
208 			if (buf == NULL)
209 				return (NULL);
210 			flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
211 			break;
212 
213 		case 'j':
214 			if (!isdigit_l((unsigned char)*buf, locale))
215 				return (NULL);
216 
217 			len = 3;
218 			for (i = 0; len && *buf != 0 &&
219 			     isdigit_l((unsigned char)*buf, locale); buf++){
220 				i *= 10;
221 				i += *buf - '0';
222 				len--;
223 			}
224 			if (i < 1 || i > 366)
225 				return (NULL);
226 
227 			tm->tm_yday = i - 1;
228 			flags |= FLAG_YDAY;
229 
230 			break;
231 
232 		case 'M':
233 		case 'S':
234 			if (*buf == 0 ||
235 				isspace_l((unsigned char)*buf, locale))
236 				break;
237 
238 			if (!isdigit_l((unsigned char)*buf, locale))
239 				return (NULL);
240 
241 			len = 2;
242 			for (i = 0; len && *buf != 0 &&
243 				isdigit_l((unsigned char)*buf, locale); buf++){
244 				i *= 10;
245 				i += *buf - '0';
246 				len--;
247 			}
248 
249 			if (c == 'M') {
250 				if (i > 59)
251 					return (NULL);
252 				tm->tm_min = i;
253 			} else {
254 				if (i > 60)
255 					return (NULL);
256 				tm->tm_sec = i;
257 			}
258 
259 			break;
260 
261 		case 'H':
262 		case 'I':
263 		case 'k':
264 		case 'l':
265 			/*
266 			 * Of these, %l is the only specifier explicitly
267 			 * documented as not being zero-padded.  However,
268 			 * there is no harm in allowing zero-padding.
269 			 *
270 			 * XXX The %l specifier may gobble one too many
271 			 * digits if used incorrectly.
272 			 */
273 			if (!isdigit_l((unsigned char)*buf, locale))
274 				return (NULL);
275 
276 			len = 2;
277 			for (i = 0; len && *buf != 0 &&
278 			     isdigit_l((unsigned char)*buf, locale); buf++) {
279 				i *= 10;
280 				i += *buf - '0';
281 				len--;
282 			}
283 			if (c == 'H' || c == 'k') {
284 				if (i > 23)
285 					return (NULL);
286 			} else if (i > 12)
287 				return (NULL);
288 
289 			tm->tm_hour = i;
290 
291 			break;
292 
293 		case 'p':
294 			/*
295 			 * XXX This is bogus if parsed before hour-related
296 			 * specifiers.
297 			 */
298 			len = strlen(tptr->am);
299 			if (strncasecmp_l(buf, tptr->am, len, locale) == 0) {
300 				if (tm->tm_hour > 12)
301 					return (NULL);
302 				if (tm->tm_hour == 12)
303 					tm->tm_hour = 0;
304 				buf += len;
305 				break;
306 			}
307 
308 			len = strlen(tptr->pm);
309 			if (strncasecmp_l(buf, tptr->pm, len, locale) == 0) {
310 				if (tm->tm_hour > 12)
311 					return (NULL);
312 				if (tm->tm_hour != 12)
313 					tm->tm_hour += 12;
314 				buf += len;
315 				break;
316 			}
317 
318 			return (NULL);
319 
320 		case 'A':
321 		case 'a':
322 			for (i = 0; i < asizeof(tptr->weekday); i++) {
323 				len = strlen(tptr->weekday[i]);
324 				if (strncasecmp_l(buf, tptr->weekday[i],
325 						len, locale) == 0)
326 					break;
327 				len = strlen(tptr->wday[i]);
328 				if (strncasecmp_l(buf, tptr->wday[i],
329 						len, locale) == 0)
330 					break;
331 			}
332 			if (i == asizeof(tptr->weekday))
333 				return (NULL);
334 
335 			buf += len;
336 			tm->tm_wday = i;
337 			flags |= FLAG_WDAY;
338 			break;
339 
340 		case 'U':
341 		case 'W':
342 			/*
343 			 * XXX This is bogus, as we can not assume any valid
344 			 * information present in the tm structure at this
345 			 * point to calculate a real value, so just check the
346 			 * range for now.
347 			 */
348 			if (!isdigit_l((unsigned char)*buf, locale))
349 				return (NULL);
350 
351 			len = 2;
352 			for (i = 0; len && *buf != 0 &&
353 			     isdigit_l((unsigned char)*buf, locale); buf++) {
354 				i *= 10;
355 				i += *buf - '0';
356 				len--;
357 			}
358 			if (i > 53)
359 				return (NULL);
360 
361 			if (c == 'U')
362 				day_offset = TM_SUNDAY;
363 			else
364 				day_offset = TM_MONDAY;
365 
366 
367 			week_offset = i;
368 
369 			break;
370 
371 		case 'w':
372 			if (!isdigit_l((unsigned char)*buf, locale))
373 				return (NULL);
374 
375 			i = *buf - '0';
376 			if (i > 6)
377 				return (NULL);
378 
379 			tm->tm_wday = i;
380 			flags |= FLAG_WDAY;
381 
382 			break;
383 
384 		case 'e':
385 			/*
386 			 * With %e format, our strftime(3) adds a blank space
387 			 * before single digits.
388 			 */
389 			if (*buf != 0 &&
390 			    isspace_l((unsigned char)*buf, locale))
391 			       buf++;
392 			/* FALLTHROUGH */
393 		case 'd':
394 			/*
395 			 * The %e specifier was once explicitly documented as
396 			 * not being zero-padded but was later changed to
397 			 * equivalent to %d.  There is no harm in allowing
398 			 * such padding.
399 			 *
400 			 * XXX The %e specifier may gobble one too many
401 			 * digits if used incorrectly.
402 			 */
403 			if (!isdigit_l((unsigned char)*buf, locale))
404 				return (NULL);
405 
406 			len = 2;
407 			for (i = 0; len && *buf != 0 &&
408 			     isdigit_l((unsigned char)*buf, locale); buf++) {
409 				i *= 10;
410 				i += *buf - '0';
411 				len--;
412 			}
413 			if (i > 31)
414 				return (NULL);
415 
416 			tm->tm_mday = i;
417 			flags |= FLAG_MDAY;
418 
419 			break;
420 
421 		case 'B':
422 		case 'b':
423 		case 'h':
424 			for (i = 0; i < asizeof(tptr->month); i++) {
425 				if (Oalternative) {
426 					if (c == 'B') {
427 						len = strlen(tptr->alt_month[i]);
428 						if (strncasecmp_l(buf,
429 								tptr->alt_month[i],
430 								len, locale) == 0)
431 							break;
432 					}
433 				} else {
434 					len = strlen(tptr->month[i]);
435 					if (strncasecmp_l(buf, tptr->month[i],
436 							len, locale) == 0)
437 						break;
438 				}
439 			}
440 			/*
441 			 * Try the abbreviated month name if the full name
442 			 * wasn't found and Oalternative was not requested.
443 			 */
444 			if (i == asizeof(tptr->month) && !Oalternative) {
445 				for (i = 0; i < asizeof(tptr->month); i++) {
446 					len = strlen(tptr->mon[i]);
447 					if (strncasecmp_l(buf, tptr->mon[i],
448 							len, locale) == 0)
449 						break;
450 				}
451 			}
452 			if (i == asizeof(tptr->month))
453 				return (NULL);
454 
455 			tm->tm_mon = i;
456 			buf += len;
457 			flags |= FLAG_MONTH;
458 
459 			break;
460 
461 		case 'm':
462 			if (!isdigit_l((unsigned char)*buf, locale))
463 				return (NULL);
464 
465 			len = 2;
466 			for (i = 0; len && *buf != 0 &&
467 			     isdigit_l((unsigned char)*buf, locale); buf++) {
468 				i *= 10;
469 				i += *buf - '0';
470 				len--;
471 			}
472 			if (i < 1 || i > 12)
473 				return (NULL);
474 
475 			tm->tm_mon = i - 1;
476 			flags |= FLAG_MONTH;
477 
478 			break;
479 
480 		case 's':
481 			{
482 			char *cp;
483 			int sverrno;
484 			long n;
485 			time_t t;
486 
487 			sverrno = errno;
488 			errno = 0;
489 			n = strtol_l(buf, &cp, 10, locale);
490 			if (errno == ERANGE || (long)(t = n) != n) {
491 				errno = sverrno;
492 				return (NULL);
493 			}
494 			errno = sverrno;
495 			buf = cp;
496 			if (gmtime_r(&t, tm) == NULL)
497 				return (NULL);
498 			*GMTp = 1;
499 			flags |= FLAG_YDAY | FLAG_WDAY | FLAG_MONTH |
500 			    FLAG_MDAY | FLAG_YEAR;
501 			}
502 			break;
503 
504 		case 'Y':
505 		case 'y':
506 			if (*buf == 0 ||
507 			    isspace_l((unsigned char)*buf, locale))
508 				break;
509 
510 			if (!isdigit_l((unsigned char)*buf, locale))
511 				return (NULL);
512 
513 			len = (c == 'Y') ? 4 : 2;
514 			for (i = 0; len && *buf != 0 &&
515 			     isdigit_l((unsigned char)*buf, locale); buf++) {
516 				i *= 10;
517 				i += *buf - '0';
518 				len--;
519 			}
520 			if (c == 'Y')
521 				i -= TM_YEAR_BASE;
522 			if (c == 'y' && i < 69)
523 				i += 100;
524 			if (i < 0)
525 				return (NULL);
526 
527 			tm->tm_year = i;
528 			flags |= FLAG_YEAR;
529 
530 			break;
531 
532 		case 'Z':
533 			{
534 			const char *cp;
535 			char *zonestr;
536 
537 			for (cp = buf; *cp &&
538 			     isupper_l((unsigned char)*cp, locale); ++cp) {
539 				/*empty*/}
540 			if (cp - buf) {
541 				zonestr = alloca(cp - buf + 1);
542 				strncpy(zonestr, buf, cp - buf);
543 				zonestr[cp - buf] = '\0';
544 				tzset();
545 				if (0 == strcmp(zonestr, "GMT") ||
546 				    0 == strcmp(zonestr, "UTC")) {
547 				    *GMTp = 1;
548 				} else if (0 == strcmp(zonestr, tzname[0])) {
549 				    tm->tm_isdst = 0;
550 				} else if (0 == strcmp(zonestr, tzname[1])) {
551 				    tm->tm_isdst = 1;
552 				} else {
553 				    return (NULL);
554 				}
555 				buf += cp - buf;
556 			}
557 			}
558 			break;
559 
560 		case 'z':
561 			{
562 			int sign = 1;
563 
564 			if (*buf != '+') {
565 				if (*buf == '-')
566 					sign = -1;
567 				else
568 					return (NULL);
569 			}
570 
571 			buf++;
572 			i = 0;
573 			for (len = 4; len > 0; len--) {
574 				if (isdigit_l((unsigned char)*buf, locale)) {
575 					i *= 10;
576 					i += *buf - '0';
577 					buf++;
578 				} else
579 					return (NULL);
580 			}
581 
582 			tm->tm_hour -= sign * (i / 100);
583 			tm->tm_min  -= sign * (i % 100);
584 			*GMTp = 1;
585 			}
586 			break;
587 
588 		case 'n':
589 		case 't':
590 			while (isspace_l((unsigned char)*buf, locale))
591 				buf++;
592 			break;
593 
594 		default:
595 			return (NULL);
596 		}
597 	}
598 
599 	if (!(flags & FLAG_YDAY) && (flags & FLAG_YEAR)) {
600 		if ((flags & (FLAG_MONTH | FLAG_MDAY)) ==
601 		    (FLAG_MONTH | FLAG_MDAY)) {
602 			tm->tm_yday = start_of_month[isleap(tm->tm_year +
603 			    TM_YEAR_BASE)][tm->tm_mon] + (tm->tm_mday - 1);
604 			flags |= FLAG_YDAY;
605 		} else if (day_offset != -1) {
606 			/* Set the date to the first Sunday (or Monday)
607 			 * of the specified week of the year.
608 			 */
609 			if (!(flags & FLAG_WDAY)) {
610 				tm->tm_wday = day_offset;
611 				flags |= FLAG_WDAY;
612 			}
613 			tm->tm_yday = (7 -
614 			    first_wday_of(tm->tm_year + TM_YEAR_BASE) +
615 			    day_offset) % 7 + (week_offset - 1) * 7 +
616 			    tm->tm_wday - day_offset;
617 			flags |= FLAG_YDAY;
618 		}
619 	}
620 
621 	if ((flags & (FLAG_YEAR | FLAG_YDAY)) == (FLAG_YEAR | FLAG_YDAY)) {
622 		if (!(flags & FLAG_MONTH)) {
623 			i = 0;
624 			while (tm->tm_yday >=
625 			    start_of_month[isleap(tm->tm_year +
626 			    TM_YEAR_BASE)][i])
627 				i++;
628 			if (i > 12) {
629 				i = 1;
630 				tm->tm_yday -=
631 				    start_of_month[isleap(tm->tm_year +
632 				    TM_YEAR_BASE)][12];
633 				tm->tm_year++;
634 			}
635 			tm->tm_mon = i - 1;
636 			flags |= FLAG_MONTH;
637 		}
638 		if (!(flags & FLAG_MDAY)) {
639 			tm->tm_mday = tm->tm_yday -
640 			    start_of_month[isleap(tm->tm_year + TM_YEAR_BASE)]
641 			    [tm->tm_mon] + 1;
642 			flags |= FLAG_MDAY;
643 		}
644 		if (!(flags & FLAG_WDAY)) {
645 			i = 0;
646 			wday_offset = first_wday_of(tm->tm_year);
647 			while (i++ <= tm->tm_yday) {
648 				if (wday_offset++ >= 6)
649 					wday_offset = 0;
650 			}
651 			tm->tm_wday = wday_offset;
652 			flags |= FLAG_WDAY;
653 		}
654 	}
655 
656 	return ((char *)buf);
657 }
658 
659 char *
660 strptime_l(const char * __restrict buf, const char * __restrict fmt,
661     struct tm * __restrict tm, locale_t loc)
662 {
663 	char *ret;
664 	int gmt;
665 	FIX_LOCALE(loc);
666 
667 	gmt = 0;
668 	ret = _strptime(buf, fmt, tm, &gmt, loc);
669 	if (ret && gmt) {
670 		time_t t = timegm(tm);
671 
672 		localtime_r(&t, tm);
673 	}
674 
675 	return (ret);
676 }
677 
678 char *
679 strptime(const char * __restrict buf, const char * __restrict fmt,
680     struct tm * __restrict tm)
681 {
682 	return strptime_l(buf, fmt, tm, __get_locale());
683 }
684