about summary refs log tree commit diff
path: root/time/strftime.c
blob: ccc19c72b0d123be893c5a8aebf25f19d3eaec98 (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
/* Extensions for GNU date that are still missing here:
   -
   _
*/

/* Copyright (C) 1991, 1992, 1993, 1994 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.  */

#include <ansidecl.h>
#include <localeinfo.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#ifndef	HAVE_GNU_LD
#define	__tzname	tzname
#define	__daylight	daylight
#define	__timezone	timezone
#endif


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

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

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

  /* Set DL to the day in the year of the last day of the week previous to the
     one containing the day specified in TP.  If DL is negative or zero, the
     day specified in TP is in the first week of the year.  Otherwise,
     calculate the number of complete weeks before our week (DL / 7) and
     add any partial week at the start of the year (DL % 7).  */
  dl = tp->tm_yday - wday;
  return dl <= 0 ? 0 : ((dl / 7) + ((dl % 7) == 0 ? 0 : 1));
}


/* 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
DEFUN(strftime, (s, maxsize, format, tp),
      char *s AND size_t maxsize AND
      CONST char *format AND register CONST struct tm *tp)
{
  CONST char *CONST a_wkday = _time_info->abbrev_wkday[tp->tm_wday];
  CONST char *CONST f_wkday = _time_info->full_wkday[tp->tm_wday];
  CONST char *CONST a_month = _time_info->abbrev_month[tp->tm_mon];
  CONST char *CONST f_month = _time_info->full_month[tp->tm_mon];
  size_t aw_len = strlen(a_wkday);
  size_t am_len = strlen(a_month);
  size_t wkday_len = strlen(f_wkday);
  size_t month_len = strlen(f_month);
  int hour12 = tp->tm_hour;
  CONST char *CONST ampm = _time_info->ampm[hour12 >= 12];
  size_t ap_len = strlen(ampm);
  CONST unsigned int y_week0 = week(tp, 0);
  CONST unsigned int y_week1 = week(tp, 1);
  CONST char *zone;
  size_t zonelen;
  register size_t i = 0;
  register char *p = s;
  register CONST char *f;

  if (tp->tm_isdst < 0)
    {
      zone = "";
      zonelen = 0;
    }
  else
    {
      zone = __tzname[tp->tm_isdst];
      zonelen = strlen(zone);
    }

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

  for (f = format; *f != '\0'; ++f)
    {
      CONST char *subfmt;

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

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

      ++f;
      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':
	  subfmt = _time_info->date_time;
	subformat:
	  {
	    size_t len = strftime (p, maxsize - i, subfmt, tp);
	    add(len, );
	  }
	  break;

	case 'C':
	  fmt (2, (p, "%.2d", (1900 + tp->tm_year) / 100));
	  break;

	case 'D':		/* GNU extension.  */
	  subfmt = "%m/%d/%y";
	  goto subformat;

	case 'd':
	  fmt(2, (p, "%.2d", tp->tm_mday));
	  break;

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

	case 'H':
	  fmt(2, (p, "%.2d", tp->tm_hour));
	  break;

	case 'I':
	  fmt(2, (p, "%.2d", hour12));
	  break;

	case 'k':		/* GNU extension.  */
	  fmt(2, (p, "%2d", tp->tm_hour));
	  break;

	case 'l':		/* GNU extension.  */
	  fmt(2, (p, "%2d", hour12));
	  break;

	case 'j':
	  fmt(3, (p, "%.3d", 1 + tp->tm_yday));
	  break;

	case 'M':
	  fmt(2, (p, "%.2d", tp->tm_min));
	  break;

	case 'm':
	  fmt(2, (p, "%.2d", tp->tm_mon + 1));
	  break;

	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':
	  fmt(2, (p, "%.2d", tp->tm_sec));
	  break;

	case 'T':		/* GNU extenstion.  */
	  subfmt = "%H:%M:%S";
	  goto subformat;

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

	case 'U':
	  fmt(2, (p, "%.2u", y_week0));
	  break;

	case 'W':
	  fmt(2, (p, "%.2u", y_week1));
	  break;

	case 'w':
	  fmt(2, (p, "%.2d", tp->tm_wday));
	  break;

	case 'X':
	  subfmt = _time_info->time;
	  goto subformat;

	case 'x':
	  subfmt = _time_info->date;
	  goto subformat;

	case 'Y':
	  fmt(4, (p, "%.4d", 1900 + tp->tm_year));
	  break;

	case 'y':
	  fmt(2, (p, "%.2d", tp->tm_year));
	  break;

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

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

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