2 ** dtime.c -- time/date routines
4 ** This code is Copyright (c) 2002, by the authors of nmh. See the
5 ** COPYRIGHT file in the root directory of the nmh distribution for
6 ** complete copyright information.
9 #include <h/mh.h> /* for snprintf() */
15 # define abs(a) (a >= 0 ? a : -a)
19 ** The number of days in the year, accounting for leap years
22 (((y) % 4) ? 365 : (((y) % 100) ? 366 : (((y) % 400) ? 365 : 366)))
25 "Jan", "Feb", "Mar", "Apr",
26 "May", "Jun", "Jul", "Aug",
27 "Sep", "Oct", "Nov", "Dec",
38 "Sunday", "Monday", "Tuesday",
39 "Wednesday", "Thursday", "Friday",
49 static int dmsize[] = {
50 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
55 ** Get current time (adjusted for local time
56 ** zone and daylight savings time) expressed
57 ** as nmh "broken-down" time structure.
66 return dlocaltime(&clock);
71 ** Take clock value and return pointer to nmh time structure
72 ** containing "broken-down" time. The time is adjusted for
73 ** local time zone and daylight savings time.
77 dlocaltime(time_t *clock)
85 tm = localtime(clock);
87 tw.tw_sec = tm->tm_sec;
88 tw.tw_min = tm->tm_min;
89 tw.tw_hour = tm->tm_hour;
90 tw.tw_mday = tm->tm_mday;
91 tw.tw_mon = tm->tm_mon;
94 * tm_year is always "year - 1900".
95 * So we correct for this.
97 tw.tw_year = tm->tm_year + 1900;
98 tw.tw_wday = tm->tm_wday;
99 tw.tw_yday = tm->tm_yday;
101 tw.tw_flags = TW_NULL;
103 tw.tw_flags |= TW_DST;
106 tw.tw_zone = -(timezone / 60);
108 tw.tw_flags &= ~TW_SDAY;
109 tw.tw_flags |= TW_SEXP;
110 tw.tw_flags &= ~TW_SZONE;
111 tw.tw_flags |= TW_SZEXP;
113 tw.tw_clock = *clock;
120 ** Take clock value and return pointer to nmh time
121 ** structure containing "broken-down" time. Time is
122 ** expressed in UTC (Coordinated Universal Time).
126 dgmtime(time_t *clock)
128 static struct tws tw;
136 tw.tw_sec = tm->tm_sec;
137 tw.tw_min = tm->tm_min;
138 tw.tw_hour = tm->tm_hour;
139 tw.tw_mday = tm->tm_mday;
140 tw.tw_mon = tm->tm_mon;
143 * tm_year is always "year - 1900"
144 * So we correct for this.
146 tw.tw_year = tm->tm_year + 1900;
147 tw.tw_wday = tm->tm_wday;
148 tw.tw_yday = tm->tm_yday;
150 tw.tw_flags = TW_NULL;
152 tw.tw_flags |= TW_DST;
156 tw.tw_flags &= ~TW_SDAY;
157 tw.tw_flags |= TW_SEXP;
158 tw.tw_flags &= ~TW_SZONE;
159 tw.tw_flags |= TW_SZEXP;
161 tw.tw_clock = *clock;
168 ** Using a nmh "broken-down" time structure,
169 ** produce a 26-byte date/time string, such as
171 ** Tue Jan 14 17:49:03 1992\n\0
175 dctime(struct tws *tw)
177 static char buffer[26];
182 snprintf(buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %.4d\n",
183 tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday,
184 tw->tw_hour, tw->tw_min, tw->tw_sec,
185 tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year);
192 ** Produce a date/time string of the form
194 ** Mon, 16 Jun 1992 15:30:48 -700 (or)
195 ** Mon, 16 Jun 1992 15:30:48 EDT
197 ** for the current time, as specified by rfc822.
198 ** The first form is required by rfc1123.
202 dtimenow(int alpha_timezone)
207 return dtime(&clock, alpha_timezone);
212 ** Using a local calendar time value, produce
213 ** a date/time string of the form
215 ** Mon, 16 Jun 1992 15:30:48 -700 (or)
216 ** Mon, 16 Jun 1992 15:30:48 EDT
218 ** as specified by rfc822. The first form is required
219 ** by rfc1123 for outgoing messages.
223 dtime(time_t *clock, int alpha_timezone)
226 /* use alpha-numeric timezones */
227 return dasctime(dlocaltime(clock), TW_NULL);
229 /* use numeric timezones */
230 return dasctime(dlocaltime(clock), TW_ZONE);
235 ** Using a nmh "broken-down" time structure, produce
236 ** a date/time string of the form
238 ** Mon, 16 Jun 1992 15:30:48 -0700
240 ** as specified by rfc822 and rfc1123.
244 dasctime(struct tws *tw, int flags)
247 static char result[80];
252 /* Display timezone if known */
253 if ((tw->tw_flags & TW_SZONE) == TW_SZNIL)
256 snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags | flags));
258 snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s",
259 tw->tw_mday, tw_moty[tw->tw_mon],
260 tw->tw_year < 100 ? 2 : 4, tw->tw_year,
261 tw->tw_hour, tw->tw_min, tw->tw_sec, result);
263 if ((tw->tw_flags & TW_SDAY) == TW_SEXP)
264 snprintf(result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer);
266 if ((tw->tw_flags & TW_SDAY) == TW_SNIL)
267 strncpy(result, buffer, sizeof(result));
269 snprintf(result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]);
276 ** Get the timezone for given offset
280 dtimezone(int offset, int flags)
283 static char buffer[10];
286 mins = -((-offset) % 60);
287 hours = -((-offset) / 60);
293 if (!(flags & TW_ZONE) && mins == 0) {
295 return ((flags & TW_DST) ? tzname[1] : tzname[0]);
298 #ifdef ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST
301 #endif /* ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST */
302 snprintf(buffer, sizeof(buffer), "%s%02d%02d",
303 offset < 0 ? "-" : "+", abs(hours), abs(mins));
309 ** Convert nmh time structure for local "broken-down"
310 ** time to calendar time (clock value). This routine
311 ** is based on the gtime() routine written by Steven Shafer
312 ** at CMU. It was forwarded to MTR by Jay Lepreau at Utah-CS.
316 dmktime(struct tws *tw)
318 int i, sec, min, hour, mday, mon, year;
321 if (tw->tw_clock != 0)
324 if ((sec = tw->tw_sec) < 0 || sec > 61
325 || (min = tw->tw_min) < 0 || min > 59
326 || (hour = tw->tw_hour) < 0 || hour > 23
327 || (mday = tw->tw_mday) < 1 || mday > 31
328 || (mon = tw->tw_mon + 1) < 1 || mon > 12)
329 return (tw->tw_clock = (time_t) -1);
340 for (i = 1970; i < year; i++)
342 if (dysize(year) == 366 && mon >= 3)
345 result += dmsize[mon - 1];
347 result = 24 * result + hour;
348 result = 60 * result + min;
349 result = 60 * result + sec;
350 result -= 60 * tw->tw_zone;
351 if (tw->tw_flags & TW_DST)
354 return (tw->tw_clock = result);
359 ** Simple calculation of day of the week. Algorithm
360 ** used is Zeller's congruence. We assume that
361 ** if tw->tw_year < 100, then the century = 19.
365 set_dotw(struct tws *tw)
367 int month, day, year, century;
369 month = tw->tw_mon - 1;
371 year = tw->tw_year % 100;
372 century = tw->tw_year < 100 ? 19 : tw->tw_year / 100;
382 tw->tw_wday = ((26 * month - 2) / 10 + day + year + year / 4
383 - 3 * century / 4 + 1) % 7;
387 tw->tw_flags &= ~TW_SDAY, tw->tw_flags |= TW_SIMP;
392 ** Copy nmh time structure
396 twscopy(struct tws *tb, struct tws *tw)
398 *tb = *tw; /* struct copy */
403 ** Compare two nmh time structures
407 twsort(struct tws *tw1, struct tws *tw2)
411 if (tw1->tw_clock == 0)
413 if (tw2->tw_clock == 0)
416 return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
417 : c1 == c2 ? 0 : -1);