2 * $NetBSD: strftime.c,v 1.19 2009/01/11 02:46:30 christos Exp $
6 ** We don't use these extensions in strftime operation even when
7 ** supported by the local tzcode configuration. A strictly
8 ** conforming C application may leave them in undefined state.
17 ** Copyright (c) 1989, 1993
18 ** The Regents of the University of California. All rights reserved.
20 ** Redistribution and use in source and binary forms, with or without
21 ** modification, are permitted provided that the following conditions
23 ** 1. Redistributions of source code must retain the above copyright
24 ** notice, this list of conditions and the following disclaimer.
25 ** 2. Redistributions in binary form must reproduce the above copyright
26 ** notice, this list of conditions and the following disclaimer in the
27 ** documentation and/or other materials provided with the distribution.
28 ** 3. All advertising materials mentioning features or use of this software
29 ** must display the following acknowledgement:
30 ** This product includes software developed by the University of
31 ** California, Berkeley and its contributors.
32 ** 4. Neither the name of the University nor the names of its contributors
33 ** may be used to endorse or promote products derived from this software
34 ** without specific prior written permission.
36 ** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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41 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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43 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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49 #include <sys/localedef.h>
57 #define Locale _CurrentTimeLocale
59 static char * _add(const char *, char *, const char *);
60 static char * _conv(int, const char *, char *, const char *);
61 static char * _fmt(const char *, const struct tm *, char *,
63 static char * _yconv(int, int, int, int, char *, const char *);
65 #define NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
67 #ifndef YEAR_2000_NAME
68 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
69 #endif /* !defined YEAR_2000_NAME */
77 strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
78 const struct tm * __restrict t)
85 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
86 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
87 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
88 fprintf(stderr, "\n");
90 fprintf(stderr, "NULL strftime format ");
91 else fprintf(stderr, "strftime format \"%s\" ",
93 fprintf(stderr, "yields only two digits of years in ");
95 fprintf(stderr, "some locales");
96 else if (warn == IN_THIS)
97 fprintf(stderr, "the current locale");
98 else fprintf(stderr, "all locales");
99 fprintf(stderr, "\n");
101 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
102 if (p == s + maxsize)
109 _fmt(const char *format, const struct tm * const t, char *pt,
110 const char * const ptlim, int * warnp)
112 for ( ; *format; ++format) {
113 if (*format == '%') {
120 pt = _add((t->tm_wday < 0 ||
121 t->tm_wday >= DAYSPERWEEK) ?
122 "?" : Locale->day[t->tm_wday],
126 pt = _add((t->tm_wday < 0 ||
127 t->tm_wday >= DAYSPERWEEK) ?
128 "?" : Locale->abday[t->tm_wday],
132 pt = _add((t->tm_mon < 0 ||
133 t->tm_mon >= MONSPERYEAR) ?
134 "?" : Locale->mon[t->tm_mon],
139 pt = _add((t->tm_mon < 0 ||
140 t->tm_mon >= MONSPERYEAR) ?
141 "?" : Locale->abmon[t->tm_mon],
146 ** %C used to do a...
147 ** _fmt("%a %b %e %X %Y", t);
148 ** ...whereas now POSIX 1003.2 calls for
149 ** something completely different.
152 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
159 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, &warn2);
167 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
170 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
175 ** C99 locale modifiers.
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
185 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
188 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
191 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
194 pt = _conv((t->tm_hour % 12) ?
195 (t->tm_hour % 12) : 12,
199 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
203 ** This used to be...
204 ** _conv(t->tm_hour % 12 ?
205 ** t->tm_hour % 12 : 12, 2, ' ');
206 ** ...and has been changed to the below to
207 ** match SunOS 4.1.1 and Arnold Robbins'
208 ** strftime version 3.0. That is, "%k" and
209 ** "%l" have been swapped.
212 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
217 ** After all this time, still unclaimed!
219 pt = _add("kitchen sink", pt, ptlim);
221 #endif /* defined KITCHEN_SINK */
224 ** This used to be...
225 ** _conv(t->tm_hour, 2, ' ');
226 ** ...and has been changed to the below to
227 ** match SunOS 4.1.1 and Arnold Robbin's
228 ** strftime version 3.0. That is, "%k" and
229 ** "%l" have been swapped.
232 pt = _conv((t->tm_hour % 12) ?
233 (t->tm_hour % 12) : 12,
237 pt = _conv(t->tm_min, "%02d", pt, ptlim);
240 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
243 pt = _add("\n", pt, ptlim);
246 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
252 pt = _fmt("%H:%M", t, pt, ptlim, warnp);
255 pt = _fmt(Locale->t_fmt_ampm, t, pt, ptlim,
259 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
264 char buf[INT_STRLEN_MAXIMUM(
271 if (TYPE_SIGNED(time_t))
272 snprintf(buf, sizeof(buf),
274 else snprintf(buf, sizeof(buf),
275 "%lu", (unsigned long)
277 pt = _add(buf, pt, ptlim);
281 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
284 pt = _add("\t", pt, ptlim);
287 pt = _conv((t->tm_yday + DAYSPERWEEK -
288 t->tm_wday) / DAYSPERWEEK,
293 ** From Arnold Robbins' strftime version 3.0:
294 ** "ISO 8601: Weekday as a decimal number
298 pt = _conv((t->tm_wday == 0) ?
299 DAYSPERWEEK : t->tm_wday,
302 case 'V': /* ISO 8601 week number */
303 case 'G': /* ISO 8601 year (four digits) */
304 case 'g': /* ISO 8601 year (two digits) */
306 ** From Arnold Robbins' strftime version 3.0: "the week number of the
307 ** year (the first Monday as the first day of week 1) as a decimal number
311 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
312 ** "Week 01 of a year is per definition the first week which has the
313 ** Thursday in this year, which is equivalent to the week which contains
314 ** the fourth day of January. In other words, the first week of a new year
315 ** is the week which has the majority of its days in the new year. Week 01
316 ** might also contain days from the previous year and the week before week
317 ** 01 of a year is the last week (52 or 53) of the previous year even if
318 ** it contains days from the new year. A week starts with Monday (day 1)
319 ** and ends with Sunday (day 7). For example, the first week of the year
320 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
339 len = isleap_sum(year, base) ?
343 ** What yday (-3 ... 3) does
344 ** the ISO year begin on?
346 bot = ((yday + 11 - wday) %
349 ** What yday does the NEXT
350 ** ISO year begin on?
363 w = 1 + ((yday - bot) /
368 yday += isleap_sum(year, base) ?
372 #ifdef XPG4_1994_04_09
374 t->tm_mon == TM_JANUARY) ||
376 t->tm_mon == TM_DECEMBER))
378 #endif /* defined XPG4_1994_04_09 */
380 pt = _conv(w, "%02d",
382 else if (*format == 'g') {
384 pt = _yconv(year, base, 0, 1,
386 } else pt = _yconv(year, base, 1, 1,
392 ** From Arnold Robbins' strftime version 3.0:
393 ** "date as dd-bbb-YYYY"
396 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
399 pt = _conv((t->tm_yday + DAYSPERWEEK -
402 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
406 pt = _conv(t->tm_wday, "%d", pt, ptlim);
409 pt = _fmt(Locale->t_fmt, t, pt, ptlim, warnp);
415 pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2);
424 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
428 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
433 if (t->TM_ZONE != NULL)
434 pt = _add(t->TM_ZONE, pt, ptlim);
436 #endif /* defined TM_ZONE */
437 if (t->tm_isdst >= 0)
438 pt = _add(tzname[t->tm_isdst != 0],
441 ** C99 says that %Z must be replaced by the
442 ** empty string if the time zone is not
454 diff = (int)t->TM_GMTOFF;
455 #else /* !defined TM_GMTOFF */
457 ** C99 says that the UTC offset must
458 ** be computed by looking only at
459 ** tm_isdst. This requirement is
460 ** incorrect, since it means the code
461 ** must rely on magic (in this case
462 ** altzone and timezone), and the
463 ** magic might not have the correct
464 ** offset. Doing things correctly is
465 ** tricky and requires disobeying C99;
466 ** see GNU C strftime for details.
467 ** For now, punt and conform to the
468 ** standard, even though it's incorrect.
470 ** C99 says that %z must be replaced by the
471 ** empty string if the time zone is not
472 ** determinable, so output nothing if the
473 ** appropriate variables are not available.
480 ** Get calendar time from t
481 ** being treated as local.
483 tmp = *t; /* mktime discards const */
486 if (lct == (time_t)-1)
490 ** Get calendar time from t
491 ** being treated as GMT.
493 tmp = *t; /* mktime discards const */
496 if (gct == (time_t)-1)
499 /* LINTED difference will fit int */
500 diff = (intmax_t)gct - (intmax_t)lct;
502 #endif /* !defined TM_GMTOFF */
507 pt = _add(sign, pt, ptlim);
509 diff = (diff / MINSPERHOUR) * 100 +
510 (diff % MINSPERHOUR);
511 pt = _conv(diff, "%04d", pt, ptlim);
515 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim,
520 ** X311J/88-090 (4.12.3.5): if conversion char is
521 ** undefined, behavior is undefined. Print out the
522 ** character itself as printf(3) also does.
536 _conv(const int n, const char * const format, char * const pt,
537 const char * const ptlim)
539 char buf[INT_STRLEN_MAXIMUM(int) + 1];
541 snprintf(buf, sizeof(buf), format, n);
542 return _add(buf, pt, ptlim);
546 _add(const char *str, char *pt, const char * const ptlim)
548 while (pt < ptlim && (*pt = *str++) != '\0')
554 ** POSIX and the C Standard are unclear or inconsistent about
555 ** what %C and %y do if the year is negative or exceeds 9999.
556 ** Use the convention that %C concatenated with %y yields the
557 ** same output as %Y, and that %Y contains at least 4 bytes,
558 ** with more only if necessary.
562 _yconv(const int a, const int b, const int convert_top, const int convert_yy,
563 char *pt, const char * const ptlim)
569 trail = a % DIVISOR + b % DIVISOR;
570 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
572 if (trail < 0 && lead > 0) {
575 } else if (lead < 0 && trail > 0) {
580 if (lead == 0 && trail < 0)
581 pt = _add("-0", pt, ptlim);
582 else pt = _conv(lead, "%02d", pt, ptlim);
585 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);