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[apple/libc.git] / stdtime / FreeBSD / strftime.c
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.c 7.64";
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 1.40 2004/06/14 10:31:52 stefanf 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 *, int *);
46
47 size_t strftime(char * __restrict, size_t, const char * __restrict,
48 const struct tm * __restrict);
49
50 extern char * tzname[];
51
52 #ifndef YEAR_2000_NAME
53 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
54 #endif /* !defined YEAR_2000_NAME */
55
56
57 #define IN_NONE 0
58 #define IN_SOME 1
59 #define IN_THIS 2
60 #define IN_ALL 3
61
62 size_t
63 strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
64 const struct tm * __restrict t)
65 {
66 char * p;
67 int warn;
68
69 tzset();
70 warn = IN_NONE;
71 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
72 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
73 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
74 (void) fprintf(stderr, "\n");
75 if (format == NULL)
76 (void) fprintf(stderr, "NULL strftime format ");
77 else (void) fprintf(stderr, "strftime format \"%s\" ",
78 format);
79 (void) fprintf(stderr, "yields only two digits of years in ");
80 if (warn == IN_SOME)
81 (void) fprintf(stderr, "some locales");
82 else if (warn == IN_THIS)
83 (void) fprintf(stderr, "the current locale");
84 else (void) fprintf(stderr, "all locales");
85 (void) fprintf(stderr, "\n");
86 }
87 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
88 if (p == s + maxsize)
89 return 0;
90 *p = '\0';
91 return p - s;
92 }
93
94 static char *
95 _fmt(format, t, pt, ptlim, warnp)
96 const char * format;
97 const struct tm * const t;
98 char * pt;
99 const char * const ptlim;
100 int * warnp;
101 {
102 int Ealternative, Oalternative;
103 struct lc_time_T *tptr = __get_current_time_locale();
104
105 for ( ; *format; ++format) {
106 if (*format == '%') {
107 Ealternative = 0;
108 Oalternative = 0;
109 label:
110 switch (*++format) {
111 case '\0':
112 --format;
113 break;
114 case 'A':
115 pt = _add((t->tm_wday < 0 ||
116 t->tm_wday >= DAYSPERWEEK) ?
117 "?" : tptr->weekday[t->tm_wday],
118 pt, ptlim);
119 continue;
120 case 'a':
121 pt = _add((t->tm_wday < 0 ||
122 t->tm_wday >= DAYSPERWEEK) ?
123 "?" : tptr->wday[t->tm_wday],
124 pt, ptlim);
125 continue;
126 case 'B':
127 pt = _add((t->tm_mon < 0 ||
128 t->tm_mon >= MONSPERYEAR) ?
129 "?" : (Oalternative ? tptr->alt_month :
130 tptr->month)[t->tm_mon],
131 pt, ptlim);
132 continue;
133 case 'b':
134 case 'h':
135 pt = _add((t->tm_mon < 0 ||
136 t->tm_mon >= MONSPERYEAR) ?
137 "?" : tptr->mon[t->tm_mon],
138 pt, ptlim);
139 continue;
140 case 'C':
141 /*
142 ** %C used to do a...
143 ** _fmt("%a %b %e %X %Y", t);
144 ** ...whereas now POSIX 1003.2 calls for
145 ** something completely different.
146 ** (ado, 1993-05-24)
147 */
148 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
149 "%02d", pt, ptlim);
150 continue;
151 case 'c':
152 {
153 int warn2 = IN_SOME;
154
155 pt = _fmt(tptr->c_fmt, t, pt, ptlim, warnp);
156 if (warn2 == IN_ALL)
157 warn2 = IN_THIS;
158 if (warn2 > *warnp)
159 *warnp = warn2;
160 }
161 continue;
162 case 'D':
163 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
164 continue;
165 case 'd':
166 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
167 continue;
168 case 'E':
169 if (Ealternative || Oalternative)
170 break;
171 Ealternative++;
172 goto label;
173 case 'O':
174 /*
175 ** C99 locale modifiers.
176 ** The sequences
177 ** %Ec %EC %Ex %EX %Ey %EY
178 ** %Od %oe %OH %OI %Om %OM
179 ** %OS %Ou %OU %OV %Ow %OW %Oy
180 ** are supposed to provide alternate
181 ** representations.
182 **
183 ** FreeBSD extension
184 ** %OB
185 */
186 if (Ealternative || Oalternative)
187 break;
188 Oalternative++;
189 goto label;
190 case 'e':
191 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
192 continue;
193 case 'F':
194 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
195 continue;
196 case 'H':
197 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
198 continue;
199 case 'I':
200 pt = _conv((t->tm_hour % 12) ?
201 (t->tm_hour % 12) : 12,
202 "%02d", pt, ptlim);
203 continue;
204 case 'j':
205 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
206 continue;
207 case 'k':
208 /*
209 ** This used to be...
210 ** _conv(t->tm_hour % 12 ?
211 ** t->tm_hour % 12 : 12, 2, ' ');
212 ** ...and has been changed to the below to
213 ** match SunOS 4.1.1 and Arnold Robbins'
214 ** strftime version 3.0. That is, "%k" and
215 ** "%l" have been swapped.
216 ** (ado, 1993-05-24)
217 */
218 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
219 continue;
220 #ifdef KITCHEN_SINK
221 case 'K':
222 /*
223 ** After all this time, still unclaimed!
224 */
225 pt = _add("kitchen sink", pt, ptlim);
226 continue;
227 #endif /* defined KITCHEN_SINK */
228 case 'l':
229 /*
230 ** This used to be...
231 ** _conv(t->tm_hour, 2, ' ');
232 ** ...and has been changed to the below to
233 ** match SunOS 4.1.1 and Arnold Robbin's
234 ** strftime version 3.0. That is, "%k" and
235 ** "%l" have been swapped.
236 ** (ado, 1993-05-24)
237 */
238 pt = _conv((t->tm_hour % 12) ?
239 (t->tm_hour % 12) : 12,
240 "%2d", pt, ptlim);
241 continue;
242 case 'M':
243 pt = _conv(t->tm_min, "%02d", pt, ptlim);
244 continue;
245 case 'm':
246 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
247 continue;
248 case 'n':
249 pt = _add("\n", pt, ptlim);
250 continue;
251 case 'p':
252 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
253 tptr->pm :
254 tptr->am,
255 pt, ptlim);
256 continue;
257 case 'R':
258 pt = _fmt("%H:%M", t, pt, ptlim, warnp);
259 continue;
260 case 'r':
261 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim,
262 warnp);
263 continue;
264 case 'S':
265 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
266 continue;
267 case 's':
268 {
269 struct tm tm;
270 char buf[INT_STRLEN_MAXIMUM(
271 time_t) + 1];
272 time_t mkt;
273
274 tm = *t;
275 mkt = mktime(&tm);
276 if (TYPE_SIGNED(time_t))
277 (void) sprintf(buf, "%ld",
278 (long) mkt);
279 else (void) sprintf(buf, "%lu",
280 (unsigned long) mkt);
281 pt = _add(buf, pt, ptlim);
282 }
283 continue;
284 case 'T':
285 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
286 continue;
287 case 't':
288 pt = _add("\t", pt, ptlim);
289 continue;
290 case 'U':
291 pt = _conv((t->tm_yday + DAYSPERWEEK -
292 t->tm_wday) / DAYSPERWEEK,
293 "%02d", pt, ptlim);
294 continue;
295 case 'u':
296 /*
297 ** From Arnold Robbins' strftime version 3.0:
298 ** "ISO 8601: Weekday as a decimal number
299 ** [1 (Monday) - 7]"
300 ** (ado, 1993-05-24)
301 */
302 pt = _conv((t->tm_wday == 0) ?
303 DAYSPERWEEK : t->tm_wday,
304 "%d", pt, ptlim);
305 continue;
306 case 'V': /* ISO 8601 week number */
307 case 'G': /* ISO 8601 year (four digits) */
308 case 'g': /* ISO 8601 year (two digits) */
309 /*
310 ** From Arnold Robbins' strftime version 3.0: "the week number of the
311 ** year (the first Monday as the first day of week 1) as a decimal number
312 ** (01-53)."
313 ** (ado, 1993-05-24)
314 **
315 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
316 ** "Week 01 of a year is per definition the first week which has the
317 ** Thursday in this year, which is equivalent to the week which contains
318 ** the fourth day of January. In other words, the first week of a new year
319 ** is the week which has the majority of its days in the new year. Week 01
320 ** might also contain days from the previous year and the week before week
321 ** 01 of a year is the last week (52 or 53) of the previous year even if
322 ** it contains days from the new year. A week starts with Monday (day 1)
323 ** and ends with Sunday (day 7). For example, the first week of the year
324 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
325 ** (ado, 1996-01-02)
326 */
327 {
328 int year;
329 int yday;
330 int wday;
331 int w;
332
333 year = t->tm_year + TM_YEAR_BASE;
334 yday = t->tm_yday;
335 wday = t->tm_wday;
336 for ( ; ; ) {
337 int len;
338 int bot;
339 int top;
340
341 len = isleap(year) ?
342 DAYSPERLYEAR :
343 DAYSPERNYEAR;
344 /*
345 ** What yday (-3 ... 3) does
346 ** the ISO year begin on?
347 */
348 bot = ((yday + 11 - wday) %
349 DAYSPERWEEK) - 3;
350 /*
351 ** What yday does the NEXT
352 ** ISO year begin on?
353 */
354 top = bot -
355 (len % DAYSPERWEEK);
356 if (top < -3)
357 top += DAYSPERWEEK;
358 top += len;
359 if (yday >= top) {
360 ++year;
361 w = 1;
362 break;
363 }
364 if (yday >= bot) {
365 w = 1 + ((yday - bot) /
366 DAYSPERWEEK);
367 break;
368 }
369 --year;
370 yday += isleap(year) ?
371 DAYSPERLYEAR :
372 DAYSPERNYEAR;
373 }
374 #ifdef XPG4_1994_04_09
375 if ((w == 52
376 && t->tm_mon == TM_JANUARY)
377 || (w == 1
378 && t->tm_mon == TM_DECEMBER))
379 w = 53;
380 #endif /* defined XPG4_1994_04_09 */
381 if (*format == 'V')
382 pt = _conv(w, "%02d",
383 pt, ptlim);
384 else if (*format == 'g') {
385 *warnp = IN_ALL;
386 pt = _conv(year % 100, "%02d",
387 pt, ptlim);
388 } else pt = _conv(year, "%04d",
389 pt, ptlim);
390 }
391 continue;
392 case 'v':
393 /*
394 ** From Arnold Robbins' strftime version 3.0:
395 ** "date as dd-bbb-YYYY"
396 ** (ado, 1993-05-24)
397 */
398 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
399 continue;
400 case 'W':
401 pt = _conv((t->tm_yday + DAYSPERWEEK -
402 (t->tm_wday ?
403 (t->tm_wday - 1) :
404 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
405 "%02d", pt, ptlim);
406 continue;
407 case 'w':
408 pt = _conv(t->tm_wday, "%d", pt, ptlim);
409 continue;
410 case 'X':
411 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp);
412 continue;
413 case 'x':
414 {
415 int warn2 = IN_SOME;
416
417 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2);
418 if (warn2 == IN_ALL)
419 warn2 = IN_THIS;
420 if (warn2 > *warnp)
421 *warnp = warn2;
422 }
423 continue;
424 case 'y':
425 *warnp = IN_ALL;
426 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
427 "%02d", pt, ptlim);
428 continue;
429 case 'Y':
430 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
431 pt, ptlim);
432 continue;
433 case 'Z':
434 #ifdef TM_ZONE
435 if (t->TM_ZONE != NULL)
436 pt = _add(t->TM_ZONE, pt, ptlim);
437 else
438 #endif /* defined TM_ZONE */
439 if (t->tm_isdst >= 0)
440 pt = _add(tzname[t->tm_isdst != 0],
441 pt, ptlim);
442 /*
443 ** C99 says that %Z must be replaced by the
444 ** empty string if the time zone is not
445 ** determinable.
446 */
447 continue;
448 case 'z':
449 {
450 int diff;
451 char const * sign;
452
453 if (t->tm_isdst < 0)
454 continue;
455 #ifdef TM_GMTOFF
456 diff = t->TM_GMTOFF;
457 #else /* !defined TM_GMTOFF */
458 /*
459 ** C99 says that the UTC offset must
460 ** be computed by looking only at
461 ** tm_isdst. This requirement is
462 ** incorrect, since it means the code
463 ** must rely on magic (in this case
464 ** altzone and timezone), and the
465 ** magic might not have the correct
466 ** offset. Doing things correctly is
467 ** tricky and requires disobeying C99;
468 ** see GNU C strftime for details.
469 ** For now, punt and conform to the
470 ** standard, even though it's incorrect.
471 **
472 ** C99 says that %z must be replaced by the
473 ** empty string if the time zone is not
474 ** determinable, so output nothing if the
475 ** appropriate variables are not available.
476 */
477 if (t->tm_isdst == 0)
478 #ifdef USG_COMPAT
479 diff = -timezone;
480 #else /* !defined USG_COMPAT */
481 continue;
482 #endif /* !defined USG_COMPAT */
483 else
484 #ifdef ALTZONE
485 diff = -altzone;
486 #else /* !defined ALTZONE */
487 continue;
488 #endif /* !defined ALTZONE */
489 #endif /* !defined TM_GMTOFF */
490 if (diff < 0) {
491 sign = "-";
492 diff = -diff;
493 } else sign = "+";
494 pt = _add(sign, pt, ptlim);
495 diff /= 60;
496 pt = _conv((diff/60)*100 + diff%60,
497 "%04d", pt, ptlim);
498 }
499 continue;
500 case '+':
501 pt = _fmt(tptr->date_fmt, t, pt, ptlim,
502 warnp);
503 continue;
504 case '%':
505 /*
506 ** X311J/88-090 (4.12.3.5): if conversion char is
507 ** undefined, behavior is undefined. Print out the
508 ** character itself as printf(3) also does.
509 */
510 default:
511 break;
512 }
513 }
514 if (pt == ptlim)
515 break;
516 *pt++ = *format;
517 }
518 return pt;
519 }
520
521 static char *
522 _conv(n, format, pt, ptlim)
523 const int n;
524 const char * const format;
525 char * const pt;
526 const char * const ptlim;
527 {
528 char buf[INT_STRLEN_MAXIMUM(int) + 1];
529
530 (void) sprintf(buf, format, n);
531 return _add(buf, pt, ptlim);
532 }
533
534 static char *
535 _add(str, pt, ptlim)
536 const char * str;
537 char * pt;
538 const char * const ptlim;
539 {
540 while (pt < ptlim && (*pt = *str++) != '\0')
541 ++pt;
542 return pt;
543 }
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