summary refs log tree commit diff
path: root/time/strftime.c
blob: c781841c6a1d4c7752ff2fbf52714bfdf33ec3f9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
/* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#ifdef _LIBC
# define HAVE_LIMITS_H 1
# define HAVE_MBLEN 1
# define HAVE_TM_ZONE 1
# define STDC_HEADERS 1
# include <ansidecl.h>
# include "../locale/localeinfo.h"
#endif

#include <stdio.h>
#include <sys/types.h>		/* Some systems define `time_t' here.  */

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#if HAVE_MBLEN
# include <ctype.h>
#endif

#if HAVE_LIMITS_H
# include <limits.h>
#endif

#if STDC_HEADERS
# include <stddef.h>
# include <stdlib.h>
# include <string.h>
#else
# define memcpy(d, s, n) bcopy (s, d, n)
#endif

#ifndef __P
#if defined (__GNUC__) || (defined (__STDC__) && __STDC__)
#define __P(args) args
#else
#define __P(args) ()
#endif  /* GCC.  */
#endif  /* Not __P.  */

#ifndef PTR
#ifdef __STDC__
#define PTR void *
#else
#define PTR char *
#endif
#endif

static unsigned int week __P((const struct tm *const, int, int));


#define	add(n, f)							      \
  do									      \
    {									      \
      i += (n);								      \
      if (i >= maxsize)							      \
	return 0;							      \
      else								      \
	if (p)								      \
	  {								      \
	    f;								      \
	    p += (n);							      \
	  }								      \
    } while (0)
#define	cpy(n, s)	add((n), memcpy((PTR) p, (PTR) (s), (n)))

#ifdef _LIBC
#define	fmt(n, args)	add((n), if (sprintf args != (n)) return 0)
#else
#define	fmt(n, args)	add((n), sprintf args; if (strlen (p) != (n)) return 0)
#endif



/* Return the week in the year specified by TP,
   with weeks starting on STARTING_DAY.  */
#ifdef	__GNUC__
inline
#endif
static unsigned int
week (tp, starting_day, max_preceding)
      const struct tm *const tp;
      int starting_day;
      int max_preceding;
{
  int wday, dl, base;

  wday = tp->tm_wday - starting_day;
  if (wday < 0)
    wday += 7;

  /* Set DL to the day in the year of the first day of the week
     containing the day specified in TP.  */
  dl = tp->tm_yday - wday;

  /* For the computation following ISO 8601:1988 we set the number of
     the week containing January 1st to 1 if this week has more than
     MAX_PRECEDING days in the new year.  For ISO 8601 this number is
     3, for the other representation it is 7 (i.e., not to be
     fulfilled).  */
  base = ((dl + 7) % 7) > max_preceding ? 1 : 0;

  /* If DL is negative we compute the result as 0 unless we have to
     compute it according ISO 8601.  In this case we have to return 53
     or 1 if the week containing January 1st has less than 4 days in
     the new year or not.  If DL is not negative we calculate the
     number of complete weeks for our week (DL / 7) plus 1 (because
     only for DL < 0 we are in week 0/53 and plus the number of the
     first week computed in the last step.  */
  return dl < 0 ? (dl < -max_preceding ? 53 : base)
		: base + 1 + dl / 7;
}

#ifndef _NL_CURRENT
static char const weekday_name[][10] =
  {
    "Sunday", "Monday", "Tuesday", "Wednesday",
    "Thursday", "Friday", "Saturday"
  };
static char const month_name[][10] =
  {
    "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
  };
#endif

/* Write information from TP into S according to the format
   string FORMAT, writing no more that MAXSIZE characters
   (including the terminating '\0') and returning number of
   characters written.  If S is NULL, nothing will be written
   anywhere, so to determine how many characters would be
   written, use NULL for S and (size_t) UINT_MAX for MAXSIZE.  */
size_t
strftime (s, maxsize, format, tp)
      char *s;
      size_t maxsize;
      const char *format;
      register const struct tm *tp;
{
  int hour12 = tp->tm_hour;
#ifdef _NL_CURRENT
  const char *const a_wkday = _NL_CURRENT (LC_TIME, ABDAY_1 + tp->tm_wday);
  const char *const f_wkday = _NL_CURRENT (LC_TIME, DAY_1 + tp->tm_wday);
  const char *const a_month = _NL_CURRENT (LC_TIME, ABMON_1 + tp->tm_mon);
  const char *const f_month = _NL_CURRENT (LC_TIME, MON_1 + tp->tm_mon);
  const char *const ampm = _NL_CURRENT (LC_TIME,
					hour12 > 11 ? PM_STR : AM_STR);
  size_t aw_len = strlen(a_wkday);
  size_t am_len = strlen(a_month);
  size_t ap_len = strlen (ampm);
#else
  const char *const f_wkday = weekday_name[tp->tm_wday];
  const char *const f_month = month_name[tp->tm_mon];
  const char *const a_wkday = f_wkday;
  const char *const a_month = f_month;
  const char *const ampm = "AMPM" + 2 * (hour12 > 11);
  size_t aw_len = 3;
  size_t am_len = 3;
  size_t ap_len = 2;
#endif
  size_t wkday_len = strlen(f_wkday);
  size_t month_len = strlen(f_month);
  const unsigned int y_week0 = week (tp, 0, 7);
  const unsigned int y_week1 = week (tp, 1, 7);
  const unsigned int y_week2 = week (tp, 1, 3);
  const char *zone;
  size_t zonelen;
  register size_t i = 0;
  register char *p = s;
  register const char *f;
  char number_fmt[5];

  /* Initialize the buffer we will use for the sprintf format for numbers.  */
  number_fmt[0] = '%';

  zone = 0;
#if HAVE_TM_ZONE
  zone = (const char *) tp->tm_zone;
#endif
#if HAVE_TZNAME
  if (!(zone && *zone) && tp->tm_isdst >= 0)
    zone = tzname[tp->tm_isdst];
#endif
  if (!(zone && *zone))
    zone = "???";

  zonelen = strlen (zone);

  if (hour12 > 12)
    hour12 -= 12;
  else
    if (hour12 == 0) hour12 = 12;

  for (f = format; *f != '\0'; ++f)
    {
      enum { pad_zero, pad_space, pad_none } pad; /* Padding for number.  */
      unsigned int maxdigits;	/* Max digits for numeric format.  */
      unsigned int number_value; /* Numeric value to be printed.  */
      const char *subfmt;

#if HAVE_MBLEN
      if (!isascii(*f))
	{
	  /* Non-ASCII, may be a multibyte.  */
	  int len = mblen(f, strlen(f));
	  if (len > 0)
	    {
	      cpy(len, f);
	      continue;
	    }
	}
#endif

      if (*f != '%')
	{
	  add(1, *p = *f);
	  continue;
	}

      /* Check for flags that can modify a number format.  */
      ++f;
      switch (*f)
	{
	case '_':
	  pad = pad_space;
	  ++f;
	  break;
	case '-':
	  pad = pad_none;
	  ++f;
	  break;
	default:
	  pad = pad_zero;
	  break;
	}

      /* Now do the specified format.  */
      switch (*f)
	{
	case '\0':
	case '%':
	  add(1, *p = *f);
	  break;

	case 'a':
	  cpy(aw_len, a_wkday);
	  break;

	case 'A':
	  cpy(wkday_len, f_wkday);
	  break;

	case 'b':
	case 'h':		/* GNU extension.  */
	  cpy(am_len, a_month);
	  break;

	case 'B':
	  cpy(month_len, f_month);
	  break;

	case 'c':
#ifdef _NL_CURRENT
	  subfmt = _NL_CURRENT (LC_TIME, D_T_FMT);
#else
	  subfmt = "%a %b %d %H:%M:%S %Z %Y";
#endif
	subformat:
	  {
	    size_t len = strftime (p, maxsize - i, subfmt, tp);
	    if (len == 0 && *subfmt)
	      return 0;
	    add(len, );
	  }
	  break;

#define DO_NUMBER(digits, value) \
	  maxdigits = digits; number_value = value; goto do_number
#define DO_NUMBER_NOPAD(digits, value) \
	  maxdigits = digits; number_value = value; goto do_number_nopad

	case 'C':
	  DO_NUMBER (2, (1900 + tp->tm_year) / 100);

	case 'x':
#ifdef _NL_CURRENT
	  subfmt = _NL_CURRENT (LC_TIME, D_FMT);
	  goto subformat;
#endif
	  /* Fall through.  */
	case 'D':		/* GNU extension.  */
	  subfmt = "%m/%d/%y";
	  goto subformat;

	case 'd':
	  DO_NUMBER (2, tp->tm_mday);

	case 'e':		/* GNU extension: %d, but blank-padded.  */
	  DO_NUMBER_NOPAD (2, tp->tm_mday);

	  /* All numeric formats set MAXDIGITS and NUMBER_VALUE and then
	     jump to one of these two labels.  */

	do_number_nopad:
	  /* Force `-' flag.  */
	  pad = pad_none;

	do_number:
	  {
	    /* Format the number according to the PAD flag.  */

	    register char *nf = &number_fmt[1];
	    int printed;

	    switch (pad)
	      {
	      case pad_zero:
		*nf++ = '0';
	      case pad_space:
		*nf++ = '0' + maxdigits;
	      case pad_none:
		*nf++ = 'u';
		*nf = '\0';
	      }

#ifdef _LIBC
	    add (maxdigits, printed = sprintf (p, number_fmt, number_value));
#else
	    add (maxdigits, sprintf (p, number_fmt, number_value);
		 printed = strlen (p));
#endif

	    break;
	  }


	case 'H':
	  DO_NUMBER (2, tp->tm_hour);

	case 'I':
	  DO_NUMBER (2, hour12);

	case 'k':		/* GNU extension.  */
	  DO_NUMBER_NOPAD (2, tp->tm_hour);

	case 'l':		/* GNU extension.  */
	  DO_NUMBER_NOPAD (2, hour12);

	case 'j':
	  DO_NUMBER (3, 1 + tp->tm_yday);

	case 'M':
	  DO_NUMBER (2, tp->tm_min);

	case 'm':
	  DO_NUMBER (2, tp->tm_mon + 1);

	case 'n':		/* GNU extension.  */
	  add (1, *p = '\n');
	  break;

	case 'p':
	  cpy(ap_len, ampm);
	  break;

	case 'R':		/* GNU extension.  */
	  subfmt = "%H:%M";
	  goto subformat;

	case 'r':		/* GNU extension.  */
	  subfmt = "%I:%M:%S %p";
	  goto subformat;

	case 'S':
	  DO_NUMBER (2, tp->tm_sec);

	case 'X':
#ifdef _NL_CURRENT
	  subfmt = _NL_CURRENT (LC_TIME, T_FMT);
	  goto subformat;
#endif
	  /* Fall through.  */
	case 'T':		/* GNU extenstion.  */
	  subfmt = "%H:%M:%S";
	  goto subformat;

	case 't':		/* GNU extenstion.  */
	  add (1, *p = '\t');
	  break;

	case 'U':
	  DO_NUMBER (2, y_week0);

	case 'V':
	  DO_NUMBER (2, y_week2);

	case 'W':
	  DO_NUMBER (2, y_week1);

	case 'w':
	  DO_NUMBER (2, tp->tm_wday);

	case 'Y':
	  DO_NUMBER (4, 1900 + tp->tm_year);

	case 'y':
	  DO_NUMBER (2, tp->tm_year % 100);

	case 'Z':
	  cpy(zonelen, zone);
	  break;

	default:
	  /* Bad format.  */
	  break;
	}
    }

  if (p)
    *p = '\0';
  return i;
}