1 /* strftime - custom formatting of date and/or time
2 Copyright (C) 1989, 1991, 1992 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
18 /* Note: this version of strftime lacks locale support,
21 Performs `%' substitutions similar to those in printf. Except
22 where noted, substituted fields have a fixed size; numeric fields are
23 padded if necessary. Padding is with zeros by default; for fields
24 that display a single number, padding can be changed or inhibited by
25 following the `%' with one of the modifiers described below. Unknown
26 field specifiers are copied as normal characters. All other
27 characters are copied to the output without change.
29 Supports a superset of the ANSI C field specifiers.
31 Literal character fields:
36 Numeric modifiers (a nonstandard extension):
37 - do not pad the field
38 _ pad the field with spaces
47 %r time, 12-hour (hh:mm:ss [AP]M)
48 %R time, 24-hour (hh:mm)
49 %s time in seconds since 00:00:00, Jan 1, 1970 (a nonstandard extension)
51 %T time, 24-hour (hh:mm:ss)
52 %X locale's time representation (%H:%M:%S)
53 %Z time zone (EDT), or nothing if no time zone is determinable
56 %a locale's abbreviated weekday name (Sun..Sat)
57 %A locale's full weekday name, variable length (Sunday..Saturday)
58 %b locale's abbreviated month name (Jan..Dec)
59 %B locale's full month name, variable length (January..December)
60 %c locale's date and time (Sat Nov 04 12:02:33 EST 1989)
62 %d day of month (01..31)
63 %e day of month ( 1..31)
66 %j day of year (001..366)
68 %U week number of year with Sunday as first day of week (00..53)
70 %W week number of year with Monday as first day of week (00..53)
71 %x locale's date representation (mm/dd/yy)
72 %y last two digits of year (00..99)
75 David MacKenzie <djm@gnu.ai.mit.edu> */
78 #if defined (CONFIG_BROKETS)
79 /* We use <config.h> instead of "config.h" so that a compilation
80 using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
81 (which it would do because it found this file in $srcdir). */
89 #include <sys/types.h>
90 #if defined(TM_IN_SYS_TIME) || (!defined(HAVE_TM_ZONE) && !defined(HAVE_TZNAME))
100 #if defined(HAVE_TZNAME)
101 extern char *tzname[2];
104 /* Types of padding for numbers in date and time. */
110 static char const* const days[] =
112 "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
115 static char const * const months[] =
117 "January", "February", "March", "April", "May", "June",
118 "July", "August", "September", "October", "November", "December"
121 /* Add character C to STRING and increment LENGTH,
122 unless LENGTH would exceed MAX. */
124 #define add_char(c) \
127 if (length + 1 <= max) \
128 string[length++] = (c); \
132 /* Add a 2 digit number to STRING, padding if specified.
133 Return the number of characters added, up to MAX. */
136 add_num2 (string, num, max, pad)
145 if (top == 0 && pad == blank)
147 else if (top != 0 || pad == zero)
148 add_char (top + '0');
149 add_char (num % 10 + '0');
153 /* Add a 3 digit number to STRING, padding if specified.
154 Return the number of characters added, up to MAX. */
157 add_num3 (string, num, max, pad)
164 int mid = (num - top * 100) / 10;
167 if (top == 0 && pad == blank)
169 else if (top != 0 || pad == zero)
170 add_char (top + '0');
171 if (mid == 0 && top == 0 && pad == blank)
173 else if (mid != 0 || top != 0 || pad == zero)
174 add_char (mid + '0');
175 add_char (num % 10 + '0');
179 /* Like strncpy except return the number of characters copied. */
182 add_str (to, from, max)
189 for (i = 0; from[i] && i <= max; ++i)
195 add_num_time_t (string, max, num)
200 /* This buffer is large enough to hold the character representation
201 (including the trailing NUL) of any unsigned decimal quantity
202 whose binary representation fits in 128 bits. */
206 if (sizeof (num) > 16)
208 sprintf (buf, "%lu", (unsigned long) num);
209 length = add_str (string, buf, max);
213 /* Return the week in the year of the time in TM, with the weeks
214 starting on Sundays. */
222 /* Set `dl' to the day in the year of the last day of the week previous
223 to the one containing the day specified in TM. If the day specified
224 in TM is in the first week of the year, `dl' will be negative or 0.
225 Otherwise, calculate the number of complete weeks before our week
226 (dl / 7) and add any partial week at the start of the year (dl % 7). */
227 dl = tm->tm_yday - tm->tm_wday;
228 return dl <= 0 ? 0 : dl / 7 + (dl % 7 != 0);
231 /* Return the week in the year of the time in TM, with the weeks
232 starting on Mondays. */
240 if (tm->tm_wday == 0)
243 wday = tm->tm_wday - 1;
244 dl = tm->tm_yday - wday;
245 return dl <= 0 ? 0 : dl / 7 + (dl % 7 != 0);
248 #if !defined(HAVE_TM_ZONE) && !defined(HAVE_TZNAME)
257 gettimeofday (&tv, &tz);
258 return timezone (tz.tz_minuteswest, tp->tm_isdst);
262 /* Format the time given in TM according to FORMAT, and put the
264 Return the number of characters (not including terminating null)
265 that were put into STRING, or 0 if the length would have
269 strftime (string, max, format, tm)
275 enum padding pad; /* Type of padding to apply. */
276 size_t length = 0; /* Characters put in STRING so far. */
278 for (; *format && length < max; ++format)
291 else if (*format == '_')
301 /* Literal character fields: */
320 add_num2 (&string[length], tm->tm_hour, max - length,
321 *format == 'H' ? pad : blank);
328 if (tm->tm_hour == 0)
330 else if (tm->tm_hour > 12)
331 hour12 = tm->tm_hour - 12;
333 hour12 = tm->tm_hour;
335 add_num2 (&string[length], hour12, max - length,
336 *format == 'I' ? pad : blank);
341 add_num2 (&string[length], tm->tm_min, max - length, pad);
344 if (tm->tm_hour < 12)
352 strftime (&string[length], max - length, "%I:%M:%S %p", tm);
356 strftime (&string[length], max - length, "%H:%M", tm);
361 struct tm writable_tm;
363 length += add_num_time_t (&string[length], max - length,
364 mktime (&writable_tm));
370 add_num2 (&string[length], tm->tm_sec, max - length, pad);
374 strftime (&string[length], max - length, "%H:%M:%S", tm);
378 strftime (&string[length], max - length, "%H:%M:%S", tm);
382 length += add_str (&string[length], tm->tm_zone, max - length);
385 if (tm->tm_isdst && tzname[1] && *tzname[1])
386 length += add_str (&string[length], tzname[1], max - length);
388 length += add_str (&string[length], tzname[0], max - length);
390 length += add_str (&string[length], zone_name (tm), max - length);
397 add_char (days[tm->tm_wday][0]);
398 add_char (days[tm->tm_wday][1]);
399 add_char (days[tm->tm_wday][2]);
403 add_str (&string[length], days[tm->tm_wday], max - length);
407 add_char (months[tm->tm_mon][0]);
408 add_char (months[tm->tm_mon][1]);
409 add_char (months[tm->tm_mon][2]);
413 add_str (&string[length], months[tm->tm_mon], max - length);
417 strftime (&string[length], max - length,
418 "%a %b %d %H:%M:%S %Z %Y", tm);
422 add_num2 (&string[length], (tm->tm_year + 1900) / 100,
427 add_num2 (&string[length], tm->tm_mday, max - length, pad);
431 add_num2 (&string[length], tm->tm_mday, max - length, blank);
435 strftime (&string[length], max - length, "%m/%d/%y", tm);
439 add_num3 (&string[length], tm->tm_yday + 1, max - length, pad);
443 add_num2 (&string[length], tm->tm_mon + 1, max - length, pad);
447 add_num2 (&string[length], sun_week (tm), max - length, pad);
450 add_char (tm->tm_wday + '0');
454 add_num2 (&string[length], mon_week (tm), max - length, pad);
458 strftime (&string[length], max - length, "%m/%d/%y", tm);
462 add_num2 (&string[length], tm->tm_year % 100,
466 add_char ((tm->tm_year + 1900) / 1000 + '0');
468 add_num3 (&string[length],
469 (1900 + tm->tm_year) % 1000, max - length, zero);