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1 /*
2 * Copyright (c) 1989 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
6 * provided that the above copyright notice and this paragraph are
7 * duplicated in all such forms and that any documentation,
8 * advertising materials, and other materials related to such
9 * distribution and use acknowledge that the software was developed
10 * by the University of California, Berkeley. The name of the
11 * University may not be used to endorse or promote products derived
12 * from this software without specific prior written permission.
13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16 */
17
18 #ifndef lint
19 #ifndef NOID
20 static const char elsieid[] = "@(#)strftime.3 8.3";
21 /*
22 ** Based on the UCB version with the ID appearing below.
23 ** This is ANSIish only when "multibyte character == plain character".
24 */
25 #endif /* !defined NOID */
26 #endif /* !defined lint */
27
28 #include "namespace.h"
29 #include "private.h"
30
31 #if defined(LIBC_SCCS) && !defined(lint)
32 static const char sccsid[] = "@(#)strftime.c 5.4 (Berkeley) 3/14/89";
33 #endif /* LIBC_SCCS and not lint */
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: src/lib/libc/stdtime/strftime.c,v 1.44 2009/06/09 09:02:58 delphij Exp $");
36
37 #include "tzfile.h"
38 #include <fcntl.h>
39 #include <sys/stat.h>
40 #include "un-namespace.h"
41 #include "timelocal.h"
42
43 static char * _add(const char *, char *, const char *);
44 static char * _conv(int, const char *, char *, const char *);
45 static char * _fmt(const char *, const struct tm *, char *, const char *,
46 int *);
47 static char * _yconv(int, int, int, int, char *, const char *);
48
49 extern char * tzname[];
50
51 #ifndef YEAR_2000_NAME
52 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
53 #endif /* !defined YEAR_2000_NAME */
54
55 #define IN_NONE 0
56 #define IN_SOME 1
57 #define IN_THIS 2
58 #define IN_ALL 3
59
60 #define PAD_DEFAULT 0
61 #define PAD_LESS 1
62 #define PAD_SPACE 2
63 #define PAD_ZERO 3
64
65 static const char* fmt_padding[][4] = {
66 /* DEFAULT, LESS, SPACE, ZERO */
67 #define PAD_FMT_MONTHDAY 0
68 #define PAD_FMT_HMS 0
69 #define PAD_FMT_CENTURY 0
70 #define PAD_FMT_SHORTYEAR 0
71 #define PAD_FMT_MONTH 0
72 #define PAD_FMT_WEEKOFYEAR 0
73 #define PAD_FMT_DAYOFMONTH 0
74 { "%02d", "%d", "%2d", "%02d" },
75 #define PAD_FMT_SDAYOFMONTH 1
76 #define PAD_FMT_SHMS 1
77 { "%2d", "%d", "%2d", "%02d" },
78 #define PAD_FMT_DAYOFYEAR 2
79 { "%03d", "%d", "%3d", "%03d" },
80 #define PAD_FMT_YEAR 3
81 { "%04d", "%d", "%4d", "%04d" }
82 };
83
84 size_t
85 strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
86 const struct tm * __restrict t)
87 {
88 char * p;
89 int warn;
90
91 tzset();
92 warn = IN_NONE;
93 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
94 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
95 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
96 (void) fprintf(stderr, "\n");
97 if (format == NULL)
98 (void) fprintf(stderr, "NULL strftime format ");
99 else (void) fprintf(stderr, "strftime format \"%s\" ",
100 format);
101 (void) fprintf(stderr, "yields only two digits of years in ");
102 if (warn == IN_SOME)
103 (void) fprintf(stderr, "some locales");
104 else if (warn == IN_THIS)
105 (void) fprintf(stderr, "the current locale");
106 else (void) fprintf(stderr, "all locales");
107 (void) fprintf(stderr, "\n");
108 }
109 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
110 if (p == s + maxsize)
111 return 0;
112 *p = '\0';
113 return p - s;
114 }
115
116 static char *
117 _fmt(format, t, pt, ptlim, warnp)
118 const char * format;
119 const struct tm * const t;
120 char * pt;
121 const char * const ptlim;
122 int * warnp;
123 {
124 int Ealternative, Oalternative, PadIndex;
125 struct lc_time_T *tptr = __get_current_time_locale();
126
127 for ( ; *format; ++format) {
128 if (*format == '%') {
129 Ealternative = 0;
130 Oalternative = 0;
131 PadIndex = PAD_DEFAULT;
132 label:
133 switch (*++format) {
134 case '\0':
135 --format;
136 break;
137 case 'A':
138 pt = _add((t->tm_wday < 0 ||
139 t->tm_wday >= DAYSPERWEEK) ?
140 "?" : tptr->weekday[t->tm_wday],
141 pt, ptlim);
142 continue;
143 case 'a':
144 pt = _add((t->tm_wday < 0 ||
145 t->tm_wday >= DAYSPERWEEK) ?
146 "?" : tptr->wday[t->tm_wday],
147 pt, ptlim);
148 continue;
149 case 'B':
150 pt = _add((t->tm_mon < 0 ||
151 t->tm_mon >= MONSPERYEAR) ?
152 "?" : (Oalternative ? tptr->alt_month :
153 tptr->month)[t->tm_mon],
154 pt, ptlim);
155 continue;
156 case 'b':
157 case 'h':
158 pt = _add((t->tm_mon < 0 ||
159 t->tm_mon >= MONSPERYEAR) ?
160 "?" : tptr->mon[t->tm_mon],
161 pt, ptlim);
162 continue;
163 case 'C':
164 /*
165 ** %C used to do a...
166 ** _fmt("%a %b %e %X %Y", t);
167 ** ...whereas now POSIX 1003.2 calls for
168 ** something completely different.
169 ** (ado, 1993-05-24)
170 */
171 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
172 pt, ptlim);
173 continue;
174 case 'c':
175 {
176 int warn2 = IN_SOME;
177
178 pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2);
179 if (warn2 == IN_ALL)
180 warn2 = IN_THIS;
181 if (warn2 > *warnp)
182 *warnp = warn2;
183 }
184 continue;
185 case 'D':
186 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
187 continue;
188 case 'd':
189 pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex],
190 pt, ptlim);
191 continue;
192 case 'E':
193 if (Ealternative || Oalternative)
194 break;
195 Ealternative++;
196 goto label;
197 case 'O':
198 /*
199 ** C99 locale modifiers.
200 ** The sequences
201 ** %Ec %EC %Ex %EX %Ey %EY
202 ** %Od %oe %OH %OI %Om %OM
203 ** %OS %Ou %OU %OV %Ow %OW %Oy
204 ** are supposed to provide alternate
205 ** representations.
206 **
207 ** FreeBSD extension
208 ** %OB
209 */
210 if (Ealternative || Oalternative)
211 break;
212 Oalternative++;
213 goto label;
214 case 'e':
215 pt = _conv(t->tm_mday,
216 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim);
217 continue;
218 case 'F':
219 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
220 continue;
221 case 'H':
222 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex],
223 pt, ptlim);
224 continue;
225 case 'I':
226 pt = _conv((t->tm_hour % 12) ?
227 (t->tm_hour % 12) : 12,
228 fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim);
229 continue;
230 case 'j':
231 pt = _conv(t->tm_yday + 1,
232 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim);
233 continue;
234 case 'k':
235 /*
236 ** This used to be...
237 ** _conv(t->tm_hour % 12 ?
238 ** t->tm_hour % 12 : 12, 2, ' ');
239 ** ...and has been changed to the below to
240 ** match SunOS 4.1.1 and Arnold Robbins'
241 ** strftime version 3.0. That is, "%k" and
242 ** "%l" have been swapped.
243 ** (ado, 1993-05-24)
244 */
245 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex],
246 pt, ptlim);
247 continue;
248 #ifdef KITCHEN_SINK
249 case 'K':
250 /*
251 ** After all this time, still unclaimed!
252 */
253 pt = _add("kitchen sink", pt, ptlim);
254 continue;
255 #endif /* defined KITCHEN_SINK */
256 case 'l':
257 /*
258 ** This used to be...
259 ** _conv(t->tm_hour, 2, ' ');
260 ** ...and has been changed to the below to
261 ** match SunOS 4.1.1 and Arnold Robbin's
262 ** strftime version 3.0. That is, "%k" and
263 ** "%l" have been swapped.
264 ** (ado, 1993-05-24)
265 */
266 pt = _conv((t->tm_hour % 12) ?
267 (t->tm_hour % 12) : 12,
268 fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim);
269 continue;
270 case 'M':
271 pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex],
272 pt, ptlim);
273 continue;
274 case 'm':
275 pt = _conv(t->tm_mon + 1,
276 fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim);
277 continue;
278 case 'n':
279 pt = _add("\n", pt, ptlim);
280 continue;
281 case 'p':
282 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
283 tptr->pm :
284 tptr->am,
285 pt, ptlim);
286 continue;
287 case 'R':
288 pt = _fmt("%H:%M", t, pt, ptlim, warnp);
289 continue;
290 case 'r':
291 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim,
292 warnp);
293 continue;
294 case 'S':
295 pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex],
296 pt, ptlim);
297 continue;
298 case 's':
299 {
300 struct tm tm;
301 char buf[INT_STRLEN_MAXIMUM(
302 time_t) + 1];
303 time_t mkt;
304
305 tm = *t;
306 mkt = mktime(&tm);
307 if (TYPE_SIGNED(time_t))
308 (void) sprintf(buf, "%ld",
309 (long) mkt);
310 else (void) sprintf(buf, "%lu",
311 (unsigned long) mkt);
312 pt = _add(buf, pt, ptlim);
313 }
314 continue;
315 case 'T':
316 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
317 continue;
318 case 't':
319 pt = _add("\t", pt, ptlim);
320 continue;
321 case 'U':
322 pt = _conv((t->tm_yday + DAYSPERWEEK -
323 t->tm_wday) / DAYSPERWEEK,
324 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim);
325 continue;
326 case 'u':
327 /*
328 ** From Arnold Robbins' strftime version 3.0:
329 ** "ISO 8601: Weekday as a decimal number
330 ** [1 (Monday) - 7]"
331 ** (ado, 1993-05-24)
332 */
333 pt = _conv((t->tm_wday == 0) ?
334 DAYSPERWEEK : t->tm_wday,
335 "%d", pt, ptlim);
336 continue;
337 case 'V': /* ISO 8601 week number */
338 case 'G': /* ISO 8601 year (four digits) */
339 case 'g': /* ISO 8601 year (two digits) */
340 /*
341 ** From Arnold Robbins' strftime version 3.0: "the week number of the
342 ** year (the first Monday as the first day of week 1) as a decimal number
343 ** (01-53)."
344 ** (ado, 1993-05-24)
345 **
346 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
347 ** "Week 01 of a year is per definition the first week which has the
348 ** Thursday in this year, which is equivalent to the week which contains
349 ** the fourth day of January. In other words, the first week of a new year
350 ** is the week which has the majority of its days in the new year. Week 01
351 ** might also contain days from the previous year and the week before week
352 ** 01 of a year is the last week (52 or 53) of the previous year even if
353 ** it contains days from the new year. A week starts with Monday (day 1)
354 ** and ends with Sunday (day 7). For example, the first week of the year
355 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
356 ** (ado, 1996-01-02)
357 */
358 {
359 int year;
360 int base;
361 int yday;
362 int wday;
363 int w;
364
365 year = t->tm_year;
366 base = TM_YEAR_BASE;
367 yday = t->tm_yday;
368 wday = t->tm_wday;
369 for ( ; ; ) {
370 int len;
371 int bot;
372 int top;
373
374 len = isleap_sum(year, base) ?
375 DAYSPERLYEAR :
376 DAYSPERNYEAR;
377 /*
378 ** What yday (-3 ... 3) does
379 ** the ISO year begin on?
380 */
381 bot = ((yday + 11 - wday) %
382 DAYSPERWEEK) - 3;
383 /*
384 ** What yday does the NEXT
385 ** ISO year begin on?
386 */
387 top = bot -
388 (len % DAYSPERWEEK);
389 if (top < -3)
390 top += DAYSPERWEEK;
391 top += len;
392 if (yday >= top) {
393 ++base;
394 w = 1;
395 break;
396 }
397 if (yday >= bot) {
398 w = 1 + ((yday - bot) /
399 DAYSPERWEEK);
400 break;
401 }
402 --base;
403 yday += isleap_sum(year, base) ?
404 DAYSPERLYEAR :
405 DAYSPERNYEAR;
406 }
407 #ifdef XPG4_1994_04_09
408 if ((w == 52 &&
409 t->tm_mon == TM_JANUARY) ||
410 (w == 1 &&
411 t->tm_mon == TM_DECEMBER))
412 w = 53;
413 #endif /* defined XPG4_1994_04_09 */
414 if (*format == 'V')
415 pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
416 pt, ptlim);
417 else if (*format == 'g') {
418 *warnp = IN_ALL;
419 pt = _yconv(year, base, 0, 1,
420 pt, ptlim);
421 } else pt = _yconv(year, base, 1, 1,
422 pt, ptlim);
423 }
424 continue;
425 case 'v':
426 /*
427 ** From Arnold Robbins' strftime version 3.0:
428 ** "date as dd-bbb-YYYY"
429 ** (ado, 1993-05-24)
430 */
431 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
432 continue;
433 case 'W':
434 pt = _conv((t->tm_yday + DAYSPERWEEK -
435 (t->tm_wday ?
436 (t->tm_wday - 1) :
437 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
438 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim);
439 continue;
440 case 'w':
441 pt = _conv(t->tm_wday, "%d", pt, ptlim);
442 continue;
443 case 'X':
444 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp);
445 continue;
446 case 'x':
447 {
448 int warn2 = IN_SOME;
449
450 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2);
451 if (warn2 == IN_ALL)
452 warn2 = IN_THIS;
453 if (warn2 > *warnp)
454 *warnp = warn2;
455 }
456 continue;
457 case 'y':
458 *warnp = IN_ALL;
459 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
460 pt, ptlim);
461 continue;
462 case 'Y':
463 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
464 pt, ptlim);
465 continue;
466 case 'Z':
467 #ifdef TM_ZONE
468 if (t->TM_ZONE != NULL)
469 pt = _add(t->TM_ZONE, pt, ptlim);
470 else
471 #endif /* defined TM_ZONE */
472 if (t->tm_isdst >= 0)
473 pt = _add(tzname[t->tm_isdst != 0],
474 pt, ptlim);
475 /*
476 ** C99 says that %Z must be replaced by the
477 ** empty string if the time zone is not
478 ** determinable.
479 */
480 continue;
481 case 'z':
482 {
483 int diff;
484 char const * sign;
485
486 if (t->tm_isdst < 0)
487 continue;
488 #ifdef TM_GMTOFF
489 diff = t->TM_GMTOFF;
490 #else /* !defined TM_GMTOFF */
491 /*
492 ** C99 says that the UTC offset must
493 ** be computed by looking only at
494 ** tm_isdst. This requirement is
495 ** incorrect, since it means the code
496 ** must rely on magic (in this case
497 ** altzone and timezone), and the
498 ** magic might not have the correct
499 ** offset. Doing things correctly is
500 ** tricky and requires disobeying C99;
501 ** see GNU C strftime for details.
502 ** For now, punt and conform to the
503 ** standard, even though it's incorrect.
504 **
505 ** C99 says that %z must be replaced by the
506 ** empty string if the time zone is not
507 ** determinable, so output nothing if the
508 ** appropriate variables are not available.
509 */
510 if (t->tm_isdst == 0)
511 #ifdef USG_COMPAT
512 diff = -timezone;
513 #else /* !defined USG_COMPAT */
514 continue;
515 #endif /* !defined USG_COMPAT */
516 else
517 #ifdef ALTZONE
518 diff = -altzone;
519 #else /* !defined ALTZONE */
520 continue;
521 #endif /* !defined ALTZONE */
522 #endif /* !defined TM_GMTOFF */
523 if (diff < 0) {
524 sign = "-";
525 diff = -diff;
526 } else sign = "+";
527 pt = _add(sign, pt, ptlim);
528 diff /= SECSPERMIN;
529 diff = (diff / MINSPERHOUR) * 100 +
530 (diff % MINSPERHOUR);
531 pt = _conv(diff,
532 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim);
533 }
534 continue;
535 case '+':
536 pt = _fmt(tptr->date_fmt, t, pt, ptlim,
537 warnp);
538 continue;
539 case '-':
540 if (PadIndex != PAD_DEFAULT)
541 break;
542 PadIndex = PAD_LESS;
543 goto label;
544 case '_':
545 if (PadIndex != PAD_DEFAULT)
546 break;
547 PadIndex = PAD_SPACE;
548 goto label;
549 case '0':
550 if (PadIndex != PAD_DEFAULT)
551 break;
552 PadIndex = PAD_ZERO;
553 goto label;
554 case '%':
555 /*
556 ** X311J/88-090 (4.12.3.5): if conversion char is
557 ** undefined, behavior is undefined. Print out the
558 ** character itself as printf(3) also does.
559 */
560 default:
561 break;
562 }
563 }
564 if (pt == ptlim)
565 break;
566 *pt++ = *format;
567 }
568 return pt;
569 }
570
571 static char *
572 _conv(n, format, pt, ptlim)
573 const int n;
574 const char * const format;
575 char * const pt;
576 const char * const ptlim;
577 {
578 char buf[INT_STRLEN_MAXIMUM(int) + 1];
579
580 (void) sprintf(buf, format, n);
581 return _add(buf, pt, ptlim);
582 }
583
584 static char *
585 _add(str, pt, ptlim)
586 const char * str;
587 char * pt;
588 const char * const ptlim;
589 {
590 while (pt < ptlim && (*pt = *str++) != '\0')
591 ++pt;
592 return pt;
593 }
594
595 /*
596 ** POSIX and the C Standard are unclear or inconsistent about
597 ** what %C and %y do if the year is negative or exceeds 9999.
598 ** Use the convention that %C concatenated with %y yields the
599 ** same output as %Y, and that %Y contains at least 4 bytes,
600 ** with more only if necessary.
601 */
602
603 static char *
604 _yconv(a, b, convert_top, convert_yy, pt, ptlim)
605 const int a;
606 const int b;
607 const int convert_top;
608 const int convert_yy;
609 char * pt;
610 const char * const ptlim;
611 {
612 register int lead;
613 register int trail;
614
615 #define DIVISOR 100
616 trail = a % DIVISOR + b % DIVISOR;
617 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
618 trail %= DIVISOR;
619 if (trail < 0 && lead > 0) {
620 trail += DIVISOR;
621 --lead;
622 } else if (lead < 0 && trail > 0) {
623 trail -= DIVISOR;
624 ++lead;
625 }
626 if (convert_top) {
627 if (lead == 0 && trail < 0)
628 pt = _add("-0", pt, ptlim);
629 else pt = _conv(lead, "%02d", pt, ptlim);
630 }
631 if (convert_yy)
632 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
633 return pt;
634 }
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