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kernel -- Remove unused vfscache structure.
[dragonfly.git] / lib / libc / stdtime / strftime.c
blob3fe24b67d6373b18eac78f714c71956644d1dd4b
1 /*
2 * @(#)strftime.c 8.3
3 * $NetBSD: strftime.c,v 1.19 2009/01/11 02:46:30 christos Exp $
4 * $DragonFly: src/lib/libc/stdtime/strftime.c,v 1.7 2008/10/19 20:15:58 swildner Exp $
5 */
6
7 /*
8 ** Based on the UCB version with the ID appearing below.
9 ** This is ANSIish only when "multibyte character == plain character".
10 */
11
12 /*
13 ** We don't use these extensions in strftime operation even when
14 ** supported by the local tzcode configuration. A strictly
15 ** conforming C application may leave them in undefined state.
16 */
17
18 #ifdef _LIBC
19 #undef TM_ZONE
20 #undef TM_GMTOFF
21 #endif
22
23 /*
24 ** Copyright (c) 1989, 1993
25 ** The Regents of the University of California. All rights reserved.
26 **
27 ** Redistribution and use in source and binary forms, with or without
28 ** modification, are permitted provided that the following conditions
29 ** are met:
30 ** 1. Redistributions of source code must retain the above copyright
31 ** notice, this list of conditions and the following disclaimer.
32 ** 2. Redistributions in binary form must reproduce the above copyright
33 ** notice, this list of conditions and the following disclaimer in the
34 ** documentation and/or other materials provided with the distribution.
35 ** 3. All advertising materials mentioning features or use of this software
36 ** must display the following acknowledgement:
37 ** This product includes software developed by the University of
38 ** California, Berkeley and its contributors.
39 ** 4. Neither the name of the University nor the names of its contributors
40 ** may be used to endorse or promote products derived from this software
41 ** without specific prior written permission.
42 **
43 ** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
44 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 ** ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
47 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 ** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 ** SUCH DAMAGE.
54 */
55
56 #include <sys/localedef.h>
57 #include <fcntl.h>
58 #include <locale.h>
59 #include <time.h>
60
61 #include "private.h"
62 #include "tzfile.h"
63
64 #define Locale _CurrentTimeLocale
65
66 static char * _add(const char *, char *, const char *);
67 static char * _conv(int, const char *, char *, const char *);
68 static char * _fmt(const char *, const struct tm *, char *,
69 const char *, int *);
70 static char * _yconv(int, int, int, int, char *, const char *);
71
72 #define NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
73
74 #ifndef YEAR_2000_NAME
75 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
76 #endif /* !defined YEAR_2000_NAME */
77
78 #define IN_NONE 0
79 #define IN_SOME 1
80 #define IN_THIS 2
81 #define IN_ALL 3
82
83 size_t
84 strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
85 const struct tm * __restrict t)
86 {
87 char * p;
88 int warn;
89
90 tzset();
91 warn = IN_NONE;
92 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
93 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
94 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
95 fprintf(stderr, "\n");
96 if (format == NULL)
97 fprintf(stderr, "NULL strftime format ");
98 else fprintf(stderr, "strftime format \"%s\" ",
99 format);
100 fprintf(stderr, "yields only two digits of years in ");
101 if (warn == IN_SOME)
102 fprintf(stderr, "some locales");
103 else if (warn == IN_THIS)
104 fprintf(stderr, "the current locale");
105 else fprintf(stderr, "all locales");
106 fprintf(stderr, "\n");
107 }
108 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
109 if (p == s + maxsize)
110 return 0;
111 *p = '\0';
112 return p - s;
113 }
114
115 static char *
116 _fmt(const char *format, const struct tm * const t, char *pt,
117 const char * const ptlim, int * warnp)
118 {
119 for ( ; *format; ++format) {
120 if (*format == '%') {
121 label:
122 switch (*++format) {
123 case '\0':
124 --format;
125 break;
126 case 'A':
127 pt = _add((t->tm_wday < 0 ||
128 t->tm_wday >= DAYSPERWEEK) ?
129 "?" : Locale->day[t->tm_wday],
130 pt, ptlim);
131 continue;
132 case 'a':
133 pt = _add((t->tm_wday < 0 ||
134 t->tm_wday >= DAYSPERWEEK) ?
135 "?" : Locale->abday[t->tm_wday],
136 pt, ptlim);
137 continue;
138 case 'B':
139 pt = _add((t->tm_mon < 0 ||
140 t->tm_mon >= MONSPERYEAR) ?
141 "?" : Locale->mon[t->tm_mon],
142 pt, ptlim);
143 continue;
144 case 'b':
145 case 'h':
146 pt = _add((t->tm_mon < 0 ||
147 t->tm_mon >= MONSPERYEAR) ?
148 "?" : Locale->abmon[t->tm_mon],
149 pt, ptlim);
150 continue;
151 case 'C':
152 /*
153 ** %C used to do a...
154 ** _fmt("%a %b %e %X %Y", t);
155 ** ...whereas now POSIX 1003.2 calls for
156 ** something completely different.
157 ** (ado, 1993-05-24)
158 */
159 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
160 pt, ptlim);
161 continue;
162 case 'c':
163 {
164 int warn2 = IN_SOME;
165
166 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, &warn2);
167 if (warn2 == IN_ALL)
168 warn2 = IN_THIS;
169 if (warn2 > *warnp)
170 *warnp = warn2;
171 }
172 continue;
173 case 'D':
174 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
175 continue;
176 case 'd':
177 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
178 continue;
179 case 'E':
180 case 'O':
181 /*
182 ** C99 locale modifiers.
183 ** The sequences
184 ** %Ec %EC %Ex %EX %Ey %EY
185 ** %Od %oe %OH %OI %Om %OM
186 ** %OS %Ou %OU %OV %Ow %OW %Oy
187 ** are supposed to provide alternate
188 ** representations.
189 */
190 goto label;
191 case 'e':
192 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
193 continue;
194 case 'F':
195 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
196 continue;
197 case 'H':
198 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
199 continue;
200 case 'I':
201 pt = _conv((t->tm_hour % 12) ?
202 (t->tm_hour % 12) : 12,
203 "%02d", pt, ptlim);
204 continue;
205 case 'j':
206 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
207 continue;
208 case 'k':
209 /*
210 ** This used to be...
211 ** _conv(t->tm_hour % 12 ?
212 ** t->tm_hour % 12 : 12, 2, ' ');
213 ** ...and has been changed to the below to
214 ** match SunOS 4.1.1 and Arnold Robbins'
215 ** strftime version 3.0. That is, "%k" and
216 ** "%l" have been swapped.
217 ** (ado, 1993-05-24)
218 */
219 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
220 continue;
221 #ifdef KITCHEN_SINK
222 case 'K':
223 /*
224 ** After all this time, still unclaimed!
225 */
226 pt = _add("kitchen sink", pt, ptlim);
227 continue;
228 #endif /* defined KITCHEN_SINK */
229 case 'l':
230 /*
231 ** This used to be...
232 ** _conv(t->tm_hour, 2, ' ');
233 ** ...and has been changed to the below to
234 ** match SunOS 4.1.1 and Arnold Robbin's
235 ** strftime version 3.0. That is, "%k" and
236 ** "%l" have been swapped.
237 ** (ado, 1993-05-24)
238 */
239 pt = _conv((t->tm_hour % 12) ?
240 (t->tm_hour % 12) : 12,
241 "%2d", pt, ptlim);
242 continue;
243 case 'M':
244 pt = _conv(t->tm_min, "%02d", pt, ptlim);
245 continue;
246 case 'm':
247 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
248 continue;
249 case 'n':
250 pt = _add("\n", pt, ptlim);
251 continue;
252 case 'p':
253 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
254 Locale->am_pm[1] :
255 Locale->am_pm[0],
256 pt, ptlim);
257 continue;
258 case 'R':
259 pt = _fmt("%H:%M", t, pt, ptlim, warnp);
260 continue;
261 case 'r':
262 pt = _fmt(Locale->t_fmt_ampm, t, pt, ptlim,
263 warnp);
264 continue;
265 case 'S':
266 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
267 continue;
268 case 's':
269 {
270 struct tm tm;
271 char buf[INT_STRLEN_MAXIMUM(
272 time_t) + 1];
273 time_t mkt;
274
275 tm = *t;
276 mkt = mktime(&tm);
277 /* CONSTCOND */
278 if (TYPE_SIGNED(time_t))
279 snprintf(buf, sizeof(buf),
280 "%ld", (long) mkt);
281 else snprintf(buf, sizeof(buf),
282 "%lu", (unsigned long)
283 mkt);
284 pt = _add(buf, pt, ptlim);
285 }
286 continue;
287 case 'T':
288 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
289 continue;
290 case 't':
291 pt = _add("\t", pt, ptlim);
292 continue;
293 case 'U':
294 pt = _conv((t->tm_yday + DAYSPERWEEK -
295 t->tm_wday) / DAYSPERWEEK,
296 "%02d", pt, ptlim);
297 continue;
298 case 'u':
299 /*
300 ** From Arnold Robbins' strftime version 3.0:
301 ** "ISO 8601: Weekday as a decimal number
302 ** [1 (Monday) - 7]"
303 ** (ado, 1993-05-24)
304 */
305 pt = _conv((t->tm_wday == 0) ?
306 DAYSPERWEEK : t->tm_wday,
307 "%d", pt, ptlim);
308 continue;
309 case 'V': /* ISO 8601 week number */
310 case 'G': /* ISO 8601 year (four digits) */
311 case 'g': /* ISO 8601 year (two digits) */
312 /*
313 ** From Arnold Robbins' strftime version 3.0: "the week number of the
314 ** year (the first Monday as the first day of week 1) as a decimal number
315 ** (01-53)."
316 ** (ado, 1993-05-24)
317 **
318 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
319 ** "Week 01 of a year is per definition the first week which has the
320 ** Thursday in this year, which is equivalent to the week which contains
321 ** the fourth day of January. In other words, the first week of a new year
322 ** is the week which has the majority of its days in the new year. Week 01
323 ** might also contain days from the previous year and the week before week
324 ** 01 of a year is the last week (52 or 53) of the previous year even if
325 ** it contains days from the new year. A week starts with Monday (day 1)
326 ** and ends with Sunday (day 7). For example, the first week of the year
327 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
328 ** (ado, 1996-01-02)
329 */
330 {
331 int year;
332 int base;
333 int yday;
334 int wday;
335 int w;
336
337 year = t->tm_year;
338 base = TM_YEAR_BASE;
339 yday = t->tm_yday;
340 wday = t->tm_wday;
341 for ( ; ; ) {
342 int len;
343 int bot;
344 int top;
345
346 len = isleap_sum(year, base) ?
347 DAYSPERLYEAR :
348 DAYSPERNYEAR;
349 /*
350 ** What yday (-3 ... 3) does
351 ** the ISO year begin on?
352 */
353 bot = ((yday + 11 - wday) %
354 DAYSPERWEEK) - 3;
355 /*
356 ** What yday does the NEXT
357 ** ISO year begin on?
358 */
359 top = bot -
360 (len % DAYSPERWEEK);
361 if (top < -3)
362 top += DAYSPERWEEK;
363 top += len;
364 if (yday >= top) {
365 ++base;
366 w = 1;
367 break;
368 }
369 if (yday >= bot) {
370 w = 1 + ((yday - bot) /
371 DAYSPERWEEK);
372 break;
373 }
374 --base;
375 yday += isleap_sum(year, base) ?
376 DAYSPERLYEAR :
377 DAYSPERNYEAR;
378 }
379 #ifdef XPG4_1994_04_09
380 if ((w == 52 &&
381 t->tm_mon == TM_JANUARY) ||
382 (w == 1 &&
383 t->tm_mon == TM_DECEMBER))
384 w = 53;
385 #endif /* defined XPG4_1994_04_09 */
386 if (*format == 'V')
387 pt = _conv(w, "%02d",
388 pt, ptlim);
389 else if (*format == 'g') {
390 *warnp = IN_ALL;
391 pt = _yconv(year, base, 0, 1,
392 pt, ptlim);
393 } else pt = _yconv(year, base, 1, 1,
394 pt, ptlim);
395 }
396 continue;
397 case 'v':
398 /*
399 ** From Arnold Robbins' strftime version 3.0:
400 ** "date as dd-bbb-YYYY"
401 ** (ado, 1993-05-24)
402 */
403 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
404 continue;
405 case 'W':
406 pt = _conv((t->tm_yday + DAYSPERWEEK -
407 (t->tm_wday ?
408 (t->tm_wday - 1) :
409 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
410 "%02d", pt, ptlim);
411 continue;
412 case 'w':
413 pt = _conv(t->tm_wday, "%d", pt, ptlim);
414 continue;
415 case 'X':
416 pt = _fmt(Locale->t_fmt, t, pt, ptlim, warnp);
417 continue;
418 case 'x':
419 {
420 int warn2 = IN_SOME;
421
422 pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2);
423 if (warn2 == IN_ALL)
424 warn2 = IN_THIS;
425 if (warn2 > *warnp)
426 *warnp = warn2;
427 }
428 continue;
429 case 'y':
430 *warnp = IN_ALL;
431 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
432 pt, ptlim);
433 continue;
434 case 'Y':
435 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
436 pt, ptlim);
437 continue;
438 case 'Z':
439 #ifdef TM_ZONE
440 if (t->TM_ZONE != NULL)
441 pt = _add(t->TM_ZONE, pt, ptlim);
442 else
443 #endif /* defined TM_ZONE */
444 if (t->tm_isdst >= 0)
445 pt = _add(tzname[t->tm_isdst != 0],
446 pt, ptlim);
447 /*
448 ** C99 says that %Z must be replaced by the
449 ** empty string if the time zone is not
450 ** determinable.
451 */
452 continue;
453 case 'z':
454 {
455 int diff;
456 char const * sign;
457
458 if (t->tm_isdst < 0)
459 continue;
460 #ifdef TM_GMTOFF
461 diff = (int)t->TM_GMTOFF;
462 #else /* !defined TM_GMTOFF */
463 /*
464 ** C99 says that the UTC offset must
465 ** be computed by looking only at
466 ** tm_isdst. This requirement is
467 ** incorrect, since it means the code
468 ** must rely on magic (in this case
469 ** altzone and timezone), and the
470 ** magic might not have the correct
471 ** offset. Doing things correctly is
472 ** tricky and requires disobeying C99;
473 ** see GNU C strftime for details.
474 ** For now, punt and conform to the
475 ** standard, even though it's incorrect.
476 **
477 ** C99 says that %z must be replaced by the
478 ** empty string if the time zone is not
479 ** determinable, so output nothing if the
480 ** appropriate variables are not available.
481 */
482 {
483 struct tm tmp;
484 time_t lct, gct;
485
486 /*
487 ** Get calendar time from t
488 ** being treated as local.
489 */
490 tmp = *t; /* mktime discards const */
491 lct = mktime(&tmp);
492
493 if (lct == (time_t)-1)
494 continue;
495
496 /*
497 ** Get calendar time from t
498 ** being treated as GMT.
499 **/
500 tmp = *t; /* mktime discards const */
501 gct = timegm(&tmp);
502
503 if (gct == (time_t)-1)
504 continue;
505
506 /* LINTED difference will fit int */
507 diff = (intmax_t)gct - (intmax_t)lct;
508 }
509 #endif /* !defined TM_GMTOFF */
510 if (diff < 0) {
511 sign = "-";
512 diff = -diff;
513 } else sign = "+";
514 pt = _add(sign, pt, ptlim);
515 diff /= SECSPERMIN;
516 diff = (diff / MINSPERHOUR) * 100 +
517 (diff % MINSPERHOUR);
518 pt = _conv(diff, "%04d", pt, ptlim);
519 }
520 continue;
521 case '+':
522 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim,
523 warnp);
524 continue;
525 case '%':
526 /*
527 ** X311J/88-090 (4.12.3.5): if conversion char is
528 ** undefined, behavior is undefined. Print out the
529 ** character itself as printf(3) also does.
530 */
531 default:
532 break;
533 }
534 }
535 if (pt == ptlim)
536 break;
537 *pt++ = *format;
538 }
539 return pt;
540 }
541
542 static char *
543 _conv(const int n, const char * const format, char * const pt,
544 const char * const ptlim)
545 {
546 char buf[INT_STRLEN_MAXIMUM(int) + 1];
547
548 snprintf(buf, sizeof(buf), format, n);
549 return _add(buf, pt, ptlim);
550 }
551
552 static char *
553 _add(const char *str, char *pt, const char * const ptlim)
554 {
555 while (pt < ptlim && (*pt = *str++) != '\0')
556 ++pt;
557 return pt;
558 }
559
560 /*
561 ** POSIX and the C Standard are unclear or inconsistent about
562 ** what %C and %y do if the year is negative or exceeds 9999.
563 ** Use the convention that %C concatenated with %y yields the
564 ** same output as %Y, and that %Y contains at least 4 bytes,
565 ** with more only if necessary.
566 */
567
568 static char *
569 _yconv(const int a, const int b, const int convert_top, const int convert_yy,
570 char *pt, const char * const ptlim)
571 {
572 int lead;
573 int trail;
574
575 #define DIVISOR 100
576 trail = a % DIVISOR + b % DIVISOR;
577 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
578 trail %= DIVISOR;
579 if (trail < 0 && lead > 0) {
580 trail += DIVISOR;
581 --lead;
582 } else if (lead < 0 && trail > 0) {
583 trail -= DIVISOR;
584 ++lead;
585 }
586 if (convert_top) {
587 if (lead == 0 && trail < 0)
588 pt = _add("-0", pt, ptlim);
589 else pt = _conv(lead, "%02d", pt, ptlim);
590 }
591 if (convert_yy)
592 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
593 return pt;
594 }
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