strftime.c revision 22993 
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#ifdef LIBC_RCS
19static const char rcsid[] =
20	"$Id$";
21#endif
22
23#ifndef lint
24#ifndef NOID
25static const char	elsieid[] = "@(#)strftime.c	7.38";
26/*
27** Based on the UCB version with the ID appearing below.
28** This is ANSIish only when "multibyte character == plain character".
29*/
30#endif /* !defined NOID */
31#endif /* !defined lint */
32
33#include "private.h"
34
35#ifndef LIBC_SCCS
36#ifndef lint
37static const char	sccsid[] = "@(#)strftime.c	5.4 (Berkeley) 3/14/89";
38#endif /* !defined lint */
39#endif /* !defined LIBC_SCCS */
40
41#include "tzfile.h"
42#include <fcntl.h>
43#include <locale.h>
44#include <sys/stat.h>
45#include "setlocale.h"
46
47struct lc_time_T {
48	const char *	mon[12];
49	const char *	month[12];
50	const char *	wday[7];
51	const char *	weekday[7];
52	const char *	X_fmt;
53	const char *	x_fmt;
54	const char *	c_fmt;
55	const char *	am;
56	const char *	pm;
57	const char *	date_fmt;
58};
59
60static struct lc_time_T		localebuf;
61static int using_locale;
62
63#define Locale	(using_locale ? &localebuf : &C_time_locale)
64
65static const struct lc_time_T	C_time_locale = {
66	{
67		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
68		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
69	}, {
70		"January", "February", "March", "April", "May", "June",
71		"July", "August", "September", "October", "November", "December"
72	}, {
73		"Sun", "Mon", "Tue", "Wed",
74		"Thu", "Fri", "Sat"
75	}, {
76		"Sunday", "Monday", "Tuesday", "Wednesday",
77		"Thursday", "Friday", "Saturday"
78	},
79
80	/* X_fmt */
81	"%H:%M:%S",
82
83	/*
84	** x_fmt
85	** Since the C language standard calls for
86	** "date, using locale's date format," anything goes.
87	** Using just numbers (as here) makes Quakers happier;
88	** it's also compatible with SVR4.
89	*/
90	"%m/%d/%y",
91
92	/*
93	** c_fmt (ctime-compatible)
94	** Note that
95	**	"%a %b %d %H:%M:%S %Y"
96	** is used by Solaris 2.3.
97	*/
98	"%a %b %e %X %Y",
99
100	/* am */
101	"AM",
102
103	/* pm */
104	"PM",
105
106	/* date_fmt */
107	"%a %b %e %X %Z %Y"
108};
109
110static char *	_add P((const char *, char *, const char *));
111static char *	_conv P((int, const char *, char *, const char *));
112static char *	_fmt P((const char *, const struct tm *, char *, const char *));
113static char *   _secs P((const struct tm *, char *, const char *));
114
115size_t strftime P((char *, size_t, const char *, const struct tm *));
116
117extern char *	tzname[];
118
119size_t
120strftime(s, maxsize, format, t)
121	char *const s;
122	const size_t maxsize;
123	const char *const format;
124	const struct tm *const t;
125{
126	char *p;
127
128	tzset();
129	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize);
130	if (p == s + maxsize)
131		return 0;
132	*p = '\0';
133	return p - s;
134}
135
136static char *
137_fmt(format, t, pt, ptlim)
138	const char *format;
139	const struct tm *const t;
140	char *pt;
141	const char *const ptlim;
142{
143	for ( ; *format; ++format) {
144		if (*format == '%') {
145label:
146			switch (*++format) {
147			case '\0':
148				--format;
149				break;
150			case 'A':
151				pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
152					"?" : Locale->weekday[t->tm_wday],
153					pt, ptlim);
154				continue;
155			case 'a':
156				pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
157					"?" : Locale->wday[t->tm_wday],
158					pt, ptlim);
159				continue;
160			case 'B':
161				pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
162					"?" : Locale->month[t->tm_mon],
163					pt, ptlim);
164				continue;
165			case 'b':
166			case 'h':
167				pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
168					"?" : Locale->mon[t->tm_mon],
169					pt, ptlim);
170				continue;
171			case 'C':
172				/*
173				** %C used to do a...
174				**	_fmt("%a %b %e %X %Y", t);
175				** ...whereas now POSIX 1003.2 calls for
176				** something completely different.
177				** (ado, 5/24/93)
178				*/
179				pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
180					"%02d", pt, ptlim);
181				continue;
182			case 'c':
183				pt = _fmt(Locale->c_fmt, t, pt, ptlim);
184				continue;
185			case 'D':
186				pt = _fmt("%m/%d/%y", t, pt, ptlim);
187				continue;
188			case 'd':
189				pt = _conv(t->tm_mday, "%02d", pt, ptlim);
190				continue;
191			case 'E':
192			case 'O':
193				/*
194				** POSIX locale extensions, a la
195				** Arnold Robbins' strftime version 3.0.
196				** The sequences
197				**	%Ec %EC %Ex %Ey %EY
198				**	%Od %oe %OH %OI %Om %OM
199				**	%OS %Ou %OU %OV %Ow %OW %Oy
200				** are supposed to provide alternate
201				** representations.
202				** (ado, 5/24/93)
203				*/
204				goto label;
205			case 'e':
206				pt = _conv(t->tm_mday, "%2d", pt, ptlim);
207				continue;
208			case 'H':
209				pt = _conv(t->tm_hour, "%02d", pt, ptlim);
210				continue;
211			case 'I':
212				pt = _conv((t->tm_hour % 12) ?
213					(t->tm_hour % 12) : 12,
214					"%02d", pt, ptlim);
215				continue;
216			case 'j':
217				pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
218				continue;
219			case 'k':
220				/*
221				** This used to be...
222				**	_conv(t->tm_hour % 12 ?
223				**		t->tm_hour % 12 : 12, 2, ' ');
224				** ...and has been changed to the below to
225				** match SunOS 4.1.1 and Arnold Robbins'
226				** strftime version 3.0.  That is, "%k" and
227				** "%l" have been swapped.
228				** (ado, 5/24/93)
229				*/
230				pt = _conv(t->tm_hour, "%2d", pt, ptlim);
231				continue;
232#ifdef KITCHEN_SINK
233			case 'K':
234				/*
235				** After all this time, still unclaimed!
236				*/
237				pt = _add("kitchen sink", pt, ptlim);
238				continue;
239#endif /* defined KITCHEN_SINK */
240			case 'l':
241				/*
242				** This used to be...
243				**	_conv(t->tm_hour, 2, ' ');
244				** ...and has been changed to the below to
245				** match SunOS 4.1.1 and Arnold Robbin's
246				** strftime version 3.0.  That is, "%k" and
247				** "%l" have been swapped.
248				** (ado, 5/24/93)
249				*/
250				pt = _conv((t->tm_hour % 12) ?
251					(t->tm_hour % 12) : 12,
252					"%2d", pt, ptlim);
253				continue;
254			case 'M':
255				pt = _conv(t->tm_min, "%02d", pt, ptlim);
256				continue;
257			case 'm':
258				pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
259				continue;
260			case 'n':
261				pt = _add("\n", pt, ptlim);
262				continue;
263			case 'p':
264				pt = _add((t->tm_hour >= 12) ?
265					Locale->pm :
266					Locale->am,
267					pt, ptlim);
268				continue;
269			case 'R':
270				pt = _fmt("%H:%M", t, pt, ptlim);
271				continue;
272			case 'r':
273				pt = _fmt("%I:%M:%S %p", t, pt, ptlim);
274				continue;
275			case 'S':
276				pt = _conv(t->tm_sec, "%02d", pt, ptlim);
277				continue;
278			case 's':
279				pt = _secs(t, pt, ptlim);
280				continue;
281			case 'T':
282				pt = _fmt("%H:%M:%S", t, pt, ptlim);
283				continue;
284			case 't':
285				pt = _add("\t", pt, ptlim);
286				continue;
287			case 'U':
288				pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7,
289					"%02d", pt, ptlim);
290				continue;
291			case 'u':
292				/*
293				** From Arnold Robbins' strftime version 3.0:
294				** "ISO 8601: Weekday as a decimal number
295				** [1 (Monday) - 7]"
296				** (ado, 5/24/93)
297				*/
298				pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
299					"%d", pt, ptlim);
300				continue;
301			case 'V':
302				/*
303				** From Arnold Robbins' strftime version 3.0:
304				** "the week number of the year (the first
305				** Monday as the first day of week 1) as a
306				** decimal number (01-53).  The method for
307				** determining the week number is as specified
308				** by ISO 8601 (to wit: if the week containing
309				** January 1 has four or more days in the new
310				** year, then it is week 1, otherwise it is
311				** week 53 of the previous year and the next
312				** week is week 1)."
313				** (ado, 5/24/93)
314				*/
315				/*
316				** XXX--If January 1 falls on a Friday,
317				** January 1-3 are part of week 53 of the
318				** previous year.  By analogy, if January
319				** 1 falls on a Thursday, are December 29-31
320				** of the PREVIOUS year part of week 1???
321				** (ado 5/24/93)
322				*/
323				/*
324				** You are understood not to expect this.
325				*/
326				{
327					int	i;
328
329					i = (t->tm_yday + 10 - (t->tm_wday ?
330						(t->tm_wday - 1) : 6)) / 7;
331					if (i == 0) {
332						/*
333						** What day of the week does
334						** January 1 fall on?
335						*/
336						i = t->tm_wday -
337							(t->tm_yday - 1);
338						/*
339						** Fri Jan 1: 53
340						** Sun Jan 1: 52
341						** Sat Jan 1: 53 if previous
342						**		 year a leap
343						**		 year, else 52
344						*/
345						if (i == TM_FRIDAY)
346							i = 53;
347						else if (i == TM_SUNDAY)
348							i = 52;
349						else	i = isleap(t->tm_year +
350								TM_YEAR_BASE) ?
351								53 : 52;
352#ifdef XPG4_1994_04_09
353						/*
354						** As of 4/9/94, though,
355						** XPG4 calls for 53
356						** unconditionally.
357						*/
358						i = 53;
359#endif /* defined XPG4_1994_04_09 */
360					}
361					pt = _conv(i, "%02d", pt, ptlim);
362				}
363				continue;
364			case 'v':
365				/*
366				** From Arnold Robbins' strftime version 3.0:
367				** "date as dd-bbb-YYYY"
368				** (ado, 5/24/93)
369				*/
370				pt = _fmt("%e-%b-%Y", t, pt, ptlim);
371				continue;
372			case 'W':
373				pt = _conv((t->tm_yday + 7 -
374					(t->tm_wday ?
375					(t->tm_wday - 1) : 6)) / 7,
376					"%02d", pt, ptlim);
377				continue;
378			case 'w':
379				pt = _conv(t->tm_wday, "%d", pt, ptlim);
380				continue;
381			case 'X':
382				pt = _fmt(Locale->X_fmt, t, pt, ptlim);
383				continue;
384			case 'x':
385				pt = _fmt(Locale->x_fmt, t, pt, ptlim);
386				continue;
387			case 'y':
388				pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
389					"%02d", pt, ptlim);
390				continue;
391			case 'Y':
392				pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
393					pt, ptlim);
394				continue;
395			case 'Z':
396				if (t->tm_zone != NULL)
397					pt = _add(t->tm_zone, pt, ptlim);
398				else
399				if (t->tm_isdst == 0 || t->tm_isdst == 1) {
400					pt = _add(tzname[t->tm_isdst],
401						pt, ptlim);
402				} else  pt = _add("?", pt, ptlim);
403				continue;
404			case '+':
405				pt = _fmt(Locale->date_fmt, t, pt, ptlim);
406				continue;
407			case '%':
408			/*
409			 * X311J/88-090 (4.12.3.5): if conversion char is
410			 * undefined, behavior is undefined.  Print out the
411			 * character itself as printf(3) also does.
412			 */
413			default:
414				break;
415			}
416		}
417		if (pt == ptlim)
418			break;
419		*pt++ = *format;
420	}
421	return pt;
422}
423
424static char *
425_conv(n, format, pt, ptlim)
426	const int n;
427	const char *const format;
428	char *const pt;
429	const char *const ptlim;
430{
431	char	buf[INT_STRLEN_MAXIMUM(int) + 1];
432
433	(void) sprintf(buf, format, n);
434	return _add(buf, pt, ptlim);
435}
436
437static char *
438_secs(t, pt, ptlim)
439	const struct tm *t;
440	char *pt;
441	const char *ptlim;
442{
443	char    buf[INT_STRLEN_MAXIMUM(int) + 1];
444	register time_t s;
445	struct tm tmp;
446
447	/* Make a copy, mktime(3) modifies the tm struct. */
448	tmp = *t;
449	s = mktime(&tmp);
450	(void) sprintf(buf, "%ld", s);
451	return _add(buf, pt, ptlim);
452}
453
454static char *
455_add(str, pt, ptlim)
456	const char *str;
457	char *pt;
458	const char *const ptlim;
459{
460	while (pt < ptlim && (*pt = *str++) != '\0')
461		++pt;
462	return pt;
463}
464
465int
466__time_load_locale(const char *name)
467{
468	static char *		locale_buf;
469	static char		locale_buf_C[] = "C";
470
471	int			fd;
472	char *			lbuf;
473	char *			p;
474	const char **		ap;
475	const char *		plim;
476	char                    filename[PATH_MAX];
477	struct stat		st;
478	size_t			namesize;
479	size_t			bufsize;
480	int                     save_using_locale;
481
482	save_using_locale = using_locale;
483	using_locale = 0;
484
485	if (name == NULL)
486		goto no_locale;
487
488	if (!strcmp(name, "C") || !strcmp(name, "POSIX"))
489		return 0;
490
491	/*
492	** If the locale name is the same as our cache, use the cache.
493	*/
494	lbuf = locale_buf;
495	if (lbuf != NULL && strcmp(name, lbuf) == 0) {
496		p = lbuf;
497		for (ap = (const char **) &localebuf;
498			ap < (const char **) (&localebuf + 1);
499				++ap)
500					*ap = p += strlen(p) + 1;
501		using_locale = 1;
502		return 0;
503	}
504	/*
505	** Slurp the locale file into the cache.
506	*/
507	namesize = strlen(name) + 1;
508
509	if (!_PathLocale)
510		goto no_locale;
511	/* Range checking not needed, 'name' size is limited */
512	strcpy(filename, _PathLocale);
513	strcat(filename, "/");
514	strcat(filename, name);
515	strcat(filename, "/LC_TIME");
516	fd = open(filename, O_RDONLY);
517	if (fd < 0)
518		goto no_locale;
519	if (fstat(fd, &st) != 0)
520		goto bad_locale;
521	if (st.st_size <= 0)
522		goto bad_locale;
523	bufsize = namesize + st.st_size;
524	locale_buf = NULL;
525	lbuf = (lbuf == NULL || lbuf == locale_buf_C) ?
526		malloc(bufsize) : realloc(lbuf, bufsize);
527	if (lbuf == NULL)
528		goto bad_locale;
529	(void) strcpy(lbuf, name);
530	p = lbuf + namesize;
531	plim = p + st.st_size;
532	if (read(fd, p, (size_t) st.st_size) != st.st_size)
533		goto bad_lbuf;
534	if (close(fd) != 0)
535		goto bad_lbuf;
536	/*
537	** Parse the locale file into localebuf.
538	*/
539	if (plim[-1] != '\n')
540		goto bad_lbuf;
541	for (ap = (const char **) &localebuf;
542		ap < (const char **) (&localebuf + 1);
543			++ap) {
544				if (p == plim)
545					goto reset_locale;
546				*ap = p;
547				while (*p != '\n')
548					++p;
549				*p++ = '\0';
550	}
551	/*
552	** Record the successful parse in the cache.
553	*/
554	locale_buf = lbuf;
555
556	using_locale = 1;
557	return 0;
558
559reset_locale:
560	/*
561	 * XXX - This may not be the correct thing to do in this case.
562	 * setlocale() assumes that we left the old locale alone.
563	 */
564	locale_buf = locale_buf_C;
565	localebuf = C_time_locale;
566	save_using_locale = 0;
567bad_lbuf:
568	free(lbuf);
569bad_locale:
570	(void) close(fd);
571no_locale:
572	using_locale = save_using_locale;
573	return -1;
574}
575