3 * dtime.c -- time/date routines
5 * This code is Copyright (c) 2002, by the authors of nmh. See the
6 * COPYRIGHT file in the root directory of the nmh distribution for
7 * complete copyright information.
10 #include <h/mh.h> /* for snprintf() */
15 #if !defined(HAVE_STRUCT_TM_TM_GMTOFF)
18 extern char *tzname[];
22 # define abs(a) (a >= 0 ? a : -a)
26 * The number of days in the year, accounting for leap years
29 (((y) % 4) ? 365 : (((y) % 100) ? 366 : (((y) % 400) ? 365 : 366)))
32 "Jan", "Feb", "Mar", "Apr",
33 "May", "Jun", "Jul", "Aug",
34 "Sep", "Oct", "Nov", "Dec",
45 "Sunday", "Monday", "Tuesday",
46 "Wednesday", "Thursday", "Friday",
56 static int dmsize[] = {
57 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
62 * Get current time (adjusted for local time
63 * zone and daylight savings time) expressed
64 * as nmh "broken-down" time structure.
73 return dlocaltime (&clock);
78 * Take clock value and return pointer to nmh time structure
79 * containing "broken-down" time. The time is adjusted for
80 * local time zone and daylight savings time.
84 dlocaltime (time_t *clock)
92 tm = localtime (clock);
94 tw.tw_sec = tm->tm_sec;
95 tw.tw_min = tm->tm_min;
96 tw.tw_hour = tm->tm_hour;
97 tw.tw_mday = tm->tm_mday;
98 tw.tw_mon = tm->tm_mon;
101 * tm_year is always "year - 1900".
102 * So we correct for this.
104 tw.tw_year = tm->tm_year + 1900;
105 tw.tw_wday = tm->tm_wday;
106 tw.tw_yday = tm->tm_yday;
108 tw.tw_flags = TW_NULL;
110 tw.tw_flags |= TW_DST;
112 #ifdef HAVE_STRUCT_TM_TM_GMTOFF
113 tw.tw_zone = tm->tm_gmtoff / 60;
114 if (tm->tm_isdst) /* if DST is in effect */
115 tw.tw_zone -= 60; /* reset to normal offset */
118 tw.tw_zone = -(timezone / 60);
121 tw.tw_flags &= ~TW_SDAY;
122 tw.tw_flags |= TW_SEXP;
123 tw.tw_flags &= ~TW_SZONE;
124 tw.tw_flags |= TW_SZEXP;
126 tw.tw_clock = *clock;
133 * Take clock value and return pointer to nmh time
134 * structure containing "broken-down" time. Time is
135 * expressed in UTC (Coordinated Universal Time).
139 dgmtime (time_t *clock)
141 static struct tws tw;
149 tw.tw_sec = tm->tm_sec;
150 tw.tw_min = tm->tm_min;
151 tw.tw_hour = tm->tm_hour;
152 tw.tw_mday = tm->tm_mday;
153 tw.tw_mon = tm->tm_mon;
156 * tm_year is always "year - 1900"
157 * So we correct for this.
159 tw.tw_year = tm->tm_year + 1900;
160 tw.tw_wday = tm->tm_wday;
161 tw.tw_yday = tm->tm_yday;
163 tw.tw_flags = TW_NULL;
165 tw.tw_flags |= TW_DST;
169 tw.tw_flags &= ~TW_SDAY;
170 tw.tw_flags |= TW_SEXP;
171 tw.tw_flags &= ~TW_SZONE;
172 tw.tw_flags |= TW_SZEXP;
174 tw.tw_clock = *clock;
181 * Using a nmh "broken-down" time structure,
182 * produce a 26-byte date/time string, such as
184 * Tue Jan 14 17:49:03 1992\n\0
188 dctime (struct tws *tw)
190 static char buffer[26];
195 snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %.4d\n",
196 tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday,
197 tw->tw_hour, tw->tw_min, tw->tw_sec,
198 tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year);
205 * Produce a date/time string of the form
207 * Mon, 16 Jun 1992 15:30:48 -700 (or)
208 * Mon, 16 Jun 1992 15:30:48 EDT
210 * for the current time, as specified by rfc822.
211 * The first form is required by rfc1123.
215 dtimenow (int alpha_timezone)
220 return dtime (&clock, alpha_timezone);
225 * Using a local calendar time value, produce
226 * a date/time string of the form
228 * Mon, 16 Jun 1992 15:30:48 -700 (or)
229 * Mon, 16 Jun 1992 15:30:48 EDT
231 * as specified by rfc822. The first form is required
232 * by rfc1123 for outgoing messages.
236 dtime (time_t *clock, int alpha_timezone)
239 /* use alpha-numeric timezones */
240 return dasctime (dlocaltime (clock), TW_NULL);
242 /* use numeric timezones */
243 return dasctime (dlocaltime (clock), TW_ZONE);
248 * Using a nmh "broken-down" time structure, produce
249 * a date/time string of the form
251 * Mon, 16 Jun 1992 15:30:48 -0700
253 * as specified by rfc822 and rfc1123.
257 dasctime (struct tws *tw, int flags)
260 static char result[80];
265 /* Display timezone if known */
266 if ((tw->tw_flags & TW_SZONE) == TW_SZNIL)
269 snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags | flags));
271 snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s",
272 tw->tw_mday, tw_moty[tw->tw_mon],
273 tw->tw_year < 100 ? 2 : 4, tw->tw_year,
274 tw->tw_hour, tw->tw_min, tw->tw_sec, result);
276 if ((tw->tw_flags & TW_SDAY) == TW_SEXP)
277 snprintf (result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer);
279 if ((tw->tw_flags & TW_SDAY) == TW_SNIL)
280 strncpy (result, buffer, sizeof(result));
282 snprintf (result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]);
289 * Get the timezone for given offset
293 dtimezone (int offset, int flags)
296 static char buffer[10];
299 mins = -((-offset) % 60);
300 hours = -((-offset) / 60);
306 if (!(flags & TW_ZONE) && mins == 0) {
308 return ((flags & TW_DST) ? tzname[1] : tzname[0]);
311 #ifdef ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST
314 #endif /* ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST */
315 snprintf (buffer, sizeof(buffer), "%s%02d%02d",
316 offset < 0 ? "-" : "+", abs (hours), abs (mins));
322 * Convert nmh time structure for local "broken-down"
323 * time to calendar time (clock value). This routine
324 * is based on the gtime() routine written by Steven Shafer
325 * at CMU. It was forwarded to MTR by Jay Lepreau at Utah-CS.
329 dmktime (struct tws *tw)
331 int i, sec, min, hour, mday, mon, year;
334 if (tw->tw_clock != 0)
337 if ((sec = tw->tw_sec) < 0 || sec > 61
338 || (min = tw->tw_min) < 0 || min > 59
339 || (hour = tw->tw_hour) < 0 || hour > 23
340 || (mday = tw->tw_mday) < 1 || mday > 31
341 || (mon = tw->tw_mon + 1) < 1 || mon > 12)
342 return (tw->tw_clock = (time_t) -1);
353 for (i = 1970; i < year; i++)
354 result += dysize (i);
355 if (dysize (year) == 366 && mon >= 3)
358 result += dmsize[mon - 1];
360 result = 24 * result + hour;
361 result = 60 * result + min;
362 result = 60 * result + sec;
363 result -= 60 * tw->tw_zone;
364 if (tw->tw_flags & TW_DST)
367 return (tw->tw_clock = result);
372 * Simple calculation of day of the week. Algorithm
373 * used is Zeller's congruence. We assume that
374 * if tw->tw_year < 100, then the century = 19.
378 set_dotw (struct tws *tw)
380 int month, day, year, century;
382 month = tw->tw_mon - 1;
384 year = tw->tw_year % 100;
385 century = tw->tw_year < 100 ? 19 : tw->tw_year / 100;
396 ((26 * month - 2) / 10 + day + year + year / 4
397 - 3 * century / 4 + 1) % 7;
401 tw->tw_flags &= ~TW_SDAY, tw->tw_flags |= TW_SIMP;
406 * Copy nmh time structure
410 twscopy (struct tws *tb, struct tws *tw)
412 *tb = *tw; /* struct copy */
415 tb->tw_sec = tw->tw_sec;
416 tb->tw_min = tw->tw_min;
417 tb->tw_hour = tw->tw_hour;
418 tb->tw_mday = tw->tw_mday;
419 tb->tw_mon = tw->tw_mon;
420 tb->tw_year = tw->tw_year;
421 tb->tw_wday = tw->tw_wday;
422 tb->tw_yday = tw->tw_yday;
423 tb->tw_zone = tw->tw_zone;
424 tb->tw_clock = tw->tw_clock;
425 tb->tw_flags = tw->tw_flags;
431 * Compare two nmh time structures
435 twsort (struct tws *tw1, struct tws *tw2)
439 if (tw1->tw_clock == 0)
441 if (tw2->tw_clock == 0)
444 return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
445 : c1 == c2 ? 0 : -1);