strftime.c revision 21673 
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	"$FreeBSD: head/lib/libc/stdtime/strftime.c 21673 1997-01-14 07:20:47Z jkh $";
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
46struct lc_time_T {
47	const char *	mon[12];
48	const char *	month[12];
49	const char *	wday[7];
50	const char *	weekday[7];
51	const char *	X_fmt;
52	const char *	x_fmt;
53	const char *	c_fmt;
54	const char *	am;
55	const char *	pm;
56	const char *	date_fmt;
57};
58
59static struct lc_time_T		localebuf;
60static int using_locale;
61
62#define Locale	(using_locale ? &localebuf : &C_time_locale)
63
64static const struct lc_time_T	C_time_locale = {
65	{
66		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
67		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
68	}, {
69		"January", "February", "March", "April", "May", "June",
70		"July", "August", "September", "October", "November", "December"
71	}, {
72		"Sun", "Mon", "Tue", "Wed",
73		"Thu", "Fri", "Sat"
74	}, {
75		"Sunday", "Monday", "Tuesday", "Wednesday",
76		"Thursday", "Friday", "Saturday"
77	},
78
79	/* X_fmt */
80	"%H:%M:%S",
81
82	/*
83	** x_fmt
84	** Since the C language standard calls for
85	** "date, using locale's date format," anything goes.
86	** Using just numbers (as here) makes Quakers happier;
87	** it's also compatible with SVR4.
88	*/
89	"%m/%d/%y",
90
91	/*
92	** c_fmt (ctime-compatible)
93	** Note that
94	**	"%a %b %d %H:%M:%S %Y"
95	** is used by Solaris 2.3.
96	*/
97	"%a %b %e %X %Y",
98
99	/* am */
100	"AM",
101
102	/* pm */
103	"PM",
104
105	/* date_fmt */
106	"%a %b %e %X %Z %Y"
107};
108
109static char *	_add P((const char *, char *, const char *));
110static char *	_conv P((int, const char *, char *, const char *));
111static char *	_fmt P((const char *, const struct tm *, char *, const char *));
112static char *   _secs P((const struct tm *, char *, const char *));
113
114size_t strftime P((char *, size_t, const char *, const struct tm *));
115
116extern char *	tzname[];
117
118size_t
119strftime(s, maxsize, format, t)
120	char *const s;
121	const size_t maxsize;
122	const char *const format;
123	const struct tm *const t;
124{
125	char *p;
126
127	tzset();
128	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize);
129	if (p == s + maxsize)
130		return 0;
131	*p = '\0';
132	return p - s;
133}
134
135static char *
136_fmt(format, t, pt, ptlim)
137	const char *format;
138	const struct tm *const t;
139	char *pt;
140	const char *const ptlim;
141{
142	for ( ; *format; ++format) {
143		if (*format == '%') {
144label:
145			switch (*++format) {
146			case '\0':
147				--format;
148				break;
149			case 'A':
150				pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
151					"?" : Locale->weekday[t->tm_wday],
152					pt, ptlim);
153				continue;
154			case 'a':
155				pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
156					"?" : Locale->wday[t->tm_wday],
157					pt, ptlim);
158				continue;
159			case 'B':
160				pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
161					"?" : Locale->month[t->tm_mon],
162					pt, ptlim);
163				continue;
164			case 'b':
165			case 'h':
166				pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
167					"?" : Locale->mon[t->tm_mon],
168					pt, ptlim);
169				continue;
170			case 'C':
171				/*
172				** %C used to do a...
173				**	_fmt("%a %b %e %X %Y", t);
174				** ...whereas now POSIX 1003.2 calls for
175				** something completely different.
176				** (ado, 5/24/93)
177				*/
178				pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
179					"%02d", pt, ptlim);
180				continue;
181			case 'c':
182				pt = _fmt(Locale->c_fmt, t, pt, ptlim);
183				continue;
184			case 'D':
185				pt = _fmt("%m/%d/%y", t, pt, ptlim);
186				continue;
187			case 'd':
188				pt = _conv(t->tm_mday, "%02d", pt, ptlim);
189				continue;
190			case 'E':
191			case 'O':
192				/*
193				** POSIX locale extensions, a la
194				** Arnold Robbins' strftime version 3.0.
195				** The sequences
196				**	%Ec %EC %Ex %Ey %EY
197				**	%Od %oe %OH %OI %Om %OM
198				**	%OS %Ou %OU %OV %Ow %OW %Oy
199				** are supposed to provide alternate
200				** representations.
201				** (ado, 5/24/93)
202				*/
203				goto label;
204			case 'e':
205				pt = _conv(t->tm_mday, "%2d", pt, ptlim);
206				continue;
207			case 'H':
208				pt = _conv(t->tm_hour, "%02d", pt, ptlim);
209				continue;
210			case 'I':
211				pt = _conv((t->tm_hour % 12) ?
212					(t->tm_hour % 12) : 12,
213					"%02d", pt, ptlim);
214				continue;
215			case 'j':
216				pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
217				continue;
218			case 'k':
219				/*
220				** This used to be...
221				**	_conv(t->tm_hour % 12 ?
222				**		t->tm_hour % 12 : 12, 2, ' ');
223				** ...and has been changed to the below to
224				** match SunOS 4.1.1 and Arnold Robbins'
225				** strftime version 3.0.  That is, "%k" and
226				** "%l" have been swapped.
227				** (ado, 5/24/93)
228				*/
229				pt = _conv(t->tm_hour, "%2d", pt, ptlim);
230				continue;
231#ifdef KITCHEN_SINK
232			case 'K':
233				/*
234				** After all this time, still unclaimed!
235				*/
236				pt = _add("kitchen sink", pt, ptlim);
237				continue;
238#endif /* defined KITCHEN_SINK */
239			case 'l':
240				/*
241				** This used to be...
242				**	_conv(t->tm_hour, 2, ' ');
243				** ...and has been changed to the below to
244				** match SunOS 4.1.1 and Arnold Robbin's
245				** strftime version 3.0.  That is, "%k" and
246				** "%l" have been swapped.
247				** (ado, 5/24/93)
248				*/
249				pt = _conv((t->tm_hour % 12) ?
250					(t->tm_hour % 12) : 12,
251					"%2d", pt, ptlim);
252				continue;
253			case 'M':
254				pt = _conv(t->tm_min, "%02d", pt, ptlim);
255				continue;
256			case 'm':
257				pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
258				continue;
259			case 'n':
260				pt = _add("\n", pt, ptlim);
261				continue;
262			case 'p':
263				pt = _add((t->tm_hour >= 12) ?
264					Locale->pm :
265					Locale->am,
266					pt, ptlim);
267				continue;
268			case 'R':
269				pt = _fmt("%H:%M", t, pt, ptlim);
270				continue;
271			case 'r':
272				pt = _fmt("%I:%M:%S %p", t, pt, ptlim);
273				continue;
274			case 'S':
275				pt = _conv(t->tm_sec, "%02d", pt, ptlim);
276				continue;
277			case 's':
278				pt = _secs(t, pt, ptlim);
279				continue;
280			case 'T':
281				pt = _fmt("%H:%M:%S", t, pt, ptlim);
282				continue;
283			case 't':
284				pt = _add("\t", pt, ptlim);
285				continue;
286			case 'U':
287				pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7,
288					"%02d", pt, ptlim);
289				continue;
290			case 'u':
291				/*
292				** From Arnold Robbins' strftime version 3.0:
293				** "ISO 8601: Weekday as a decimal number
294				** [1 (Monday) - 7]"
295				** (ado, 5/24/93)
296				*/
297				pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
298					"%d", pt, ptlim);
299				continue;
300			case 'V':
301				/*
302				** From Arnold Robbins' strftime version 3.0:
303				** "the week number of the year (the first
304				** Monday as the first day of week 1) as a
305				** decimal number (01-53).  The method for
306				** determining the week number is as specified
307				** by ISO 8601 (to wit: if the week containing
308				** January 1 has four or more days in the new
309				** year, then it is week 1, otherwise it is
310				** week 53 of the previous year and the next
311				** week is week 1)."
312				** (ado, 5/24/93)
313				*/
314				/*
315				** XXX--If January 1 falls on a Friday,
316				** January 1-3 are part of week 53 of the
317				** previous year.  By analogy, if January
318				** 1 falls on a Thursday, are December 29-31
319				** of the PREVIOUS year part of week 1???
320				** (ado 5/24/93)
321				*/
322				/*
323				** You are understood not to expect this.
324				*/
325				{
326					int	i;
327
328					i = (t->tm_yday + 10 - (t->tm_wday ?
329						(t->tm_wday - 1) : 6)) / 7;
330					if (i == 0) {
331						/*
332						** What day of the week does
333						** January 1 fall on?
334						*/
335						i = t->tm_wday -
336							(t->tm_yday - 1);
337						/*
338						** Fri Jan 1: 53
339						** Sun Jan 1: 52
340						** Sat Jan 1: 53 if previous
341						**		 year a leap
342						**		 year, else 52
343						*/
344						if (i == TM_FRIDAY)
345							i = 53;
346						else if (i == TM_SUNDAY)
347							i = 52;
348						else	i = isleap(t->tm_year +
349								TM_YEAR_BASE) ?
350								53 : 52;
351#ifdef XPG4_1994_04_09
352						/*
353						** As of 4/9/94, though,
354						** XPG4 calls for 53
355						** unconditionally.
356						*/
357						i = 53;
358#endif /* defined XPG4_1994_04_09 */
359					}
360					pt = _conv(i, "%02d", pt, ptlim);
361				}
362				continue;
363			case 'v':
364				/*
365				** From Arnold Robbins' strftime version 3.0:
366				** "date as dd-bbb-YYYY"
367				** (ado, 5/24/93)
368				*/
369				pt = _fmt("%e-%b-%Y", t, pt, ptlim);
370				continue;
371			case 'W':
372				pt = _conv((t->tm_yday + 7 -
373					(t->tm_wday ?
374					(t->tm_wday - 1) : 6)) / 7,
375					"%02d", pt, ptlim);
376				continue;
377			case 'w':
378				pt = _conv(t->tm_wday, "%d", pt, ptlim);
379				continue;
380			case 'X':
381				pt = _fmt(Locale->X_fmt, t, pt, ptlim);
382				continue;
383			case 'x':
384				pt = _fmt(Locale->x_fmt, t, pt, ptlim);
385				continue;
386			case 'y':
387				pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
388					"%02d", pt, ptlim);
389				continue;
390			case 'Y':
391				pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
392					pt, ptlim);
393				continue;
394			case 'Z':
395				if (t->tm_zone != NULL)
396					pt = _add(t->tm_zone, pt, ptlim);
397				else
398				if (t->tm_isdst == 0 || t->tm_isdst == 1) {
399					pt = _add(tzname[t->tm_isdst],
400						pt, ptlim);
401				} else  pt = _add("?", pt, ptlim);
402				continue;
403			case '+':
404				pt = _fmt(Locale->date_fmt, t, pt, ptlim);
405				continue;
406			case '%':
407			/*
408			 * X311J/88-090 (4.12.3.5): if conversion char is
409			 * undefined, behavior is undefined.  Print out the
410			 * character itself as printf(3) also does.
411			 */
412			default:
413				break;
414			}
415		}
416		if (pt == ptlim)
417			break;
418		*pt++ = *format;
419	}
420	return pt;
421}
422
423static char *
424_conv(n, format, pt, ptlim)
425	const int n;
426	const char *const format;
427	char *const pt;
428	const char *const ptlim;
429{
430	char	buf[INT_STRLEN_MAXIMUM(int) + 1];
431
432	(void) sprintf(buf, format, n);
433	return _add(buf, pt, ptlim);
434}
435
436static char *
437_secs(t, pt, ptlim)
438	const struct tm *t;
439	char *pt;
440	const char *ptlim;
441{
442	char    buf[INT_STRLEN_MAXIMUM(int) + 1];
443	register time_t s;
444	struct tm tmp;
445
446	/* Make a copy, mktime(3) modifies the tm struct. */
447	tmp = *t;
448	s = mktime(&tmp);
449	(void) sprintf(buf, "%ld", s);
450	return _add(buf, pt, ptlim);
451}
452
453static char *
454_add(str, pt, ptlim)
455	const char *str;
456	char *pt;
457	const char *const ptlim;
458{
459	while (pt < ptlim && (*pt = *str++) != '\0')
460		++pt;
461	return pt;
462}
463
464extern char *_PathLocale;
465
466int
467__time_load_locale(const char *name)
468{
469	static char *		locale_buf;
470	static char		locale_buf_C[] = "C";
471
472	int			fd;
473	char *			lbuf;
474	char *			p;
475	const char **		ap;
476	const char *		plim;
477	char                    filename[PATH_MAX];
478	struct stat		st;
479	size_t			namesize;
480	size_t			bufsize;
481	int                     save_using_locale;
482
483	save_using_locale = using_locale;
484	using_locale = 0;
485
486	if (name == NULL)
487		goto no_locale;
488
489	if (!strcmp(name, "C") || !strcmp(name, "POSIX"))
490		return 0;
491
492	/*
493	** If the locale name is the same as our cache, use the cache.
494	*/
495	lbuf = locale_buf;
496	if (lbuf != NULL && strcmp(name, lbuf) == 0) {
497		p = lbuf;
498		for (ap = (const char **) &localebuf;
499			ap < (const char **) (&localebuf + 1);
500				++ap)
501					*ap = p += strlen(p) + 1;
502		using_locale = 1;
503		return 0;
504	}
505	/*
506	** Slurp the locale file into the cache.
507	*/
508	namesize = strlen(name) + 1;
509
510	if (!_PathLocale)
511		goto no_locale;
512	/* Range checking already done at upper level caller */
513	strcpy(filename, _PathLocale);
514	strcat(filename, "/");
515	strcat(filename, name);
516	strcat(filename, "/LC_TIME");
517	fd = open(filename, O_RDONLY);
518	if (fd < 0)
519		goto no_locale;
520	if (fstat(fd, &st) != 0)
521		goto bad_locale;
522	if (st.st_size <= 0)
523		goto bad_locale;
524	bufsize = namesize + st.st_size;
525	locale_buf = NULL;
526	lbuf = (lbuf == NULL || lbuf == locale_buf_C) ?
527		malloc(bufsize) : realloc(lbuf, bufsize);
528	if (lbuf == NULL)
529		goto bad_locale;
530	(void) strcpy(lbuf, name);
531	p = lbuf + namesize;
532	plim = p + st.st_size;
533	if (read(fd, p, (size_t) st.st_size) != st.st_size)
534		goto bad_lbuf;
535	if (close(fd) != 0)
536		goto bad_lbuf;
537	/*
538	** Parse the locale file into localebuf.
539	*/
540	if (plim[-1] != '\n')
541		goto bad_lbuf;
542	for (ap = (const char **) &localebuf;
543		ap < (const char **) (&localebuf + 1);
544			++ap) {
545				if (p == plim)
546					goto reset_locale;
547				*ap = p;
548				while (*p != '\n')
549					++p;
550				*p++ = '\0';
551	}
552	/*
553	** Record the successful parse in the cache.
554	*/
555	locale_buf = lbuf;
556
557	using_locale = 1;
558	return 0;
559
560reset_locale:
561	/*
562	 * XXX - This may not be the correct thing to do in this case.
563	 * setlocale() assumes that we left the old locale alone.
564	 */
565	locale_buf = locale_buf_C;
566	localebuf = C_time_locale;
567	save_using_locale = 0;
568bad_lbuf:
569	free(lbuf);
570bad_locale:
571	(void) close(fd);
572no_locale:
573	using_locale = save_using_locale;
574	return -1;
575}
576