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() */
14 #if !defined(HAVE_STRUCT_TM_TM_GMTOFF)
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;
93 /* tm_year is always "year - 1900". So we correct for this. */
94 tw.tw_year = tm->tm_year + 1900;
95 tw.tw_wday = tm->tm_wday;
96 tw.tw_yday = tm->tm_yday;
98 tw.tw_flags = TW_NULL;
100 tw.tw_flags |= TW_DST;
102 #ifdef HAVE_STRUCT_TM_TM_GMTOFF
103 tw.tw_zone = tm->tm_gmtoff / 60;
104 if (tm->tm_isdst) /* if DST is in effect */
105 tw.tw_zone -= 60; /* reset to normal offset */
108 tw.tw_zone = -(timezone / 60);
111 tw.tw_flags &= ~TW_SDAY;
112 tw.tw_flags |= TW_SEXP;
113 tw.tw_flags &= ~TW_SZONE;
114 tw.tw_flags |= TW_SZEXP;
116 tw.tw_clock = *clock;
123 ** Take clock value and return pointer to nmh time
124 ** structure containing "broken-down" time. Time is
125 ** expressed in UTC (Coordinated Universal Time).
129 dgmtime(time_t *clock)
131 static struct tws tw;
139 tw.tw_sec = tm->tm_sec;
140 tw.tw_min = tm->tm_min;
141 tw.tw_hour = tm->tm_hour;
142 tw.tw_mday = tm->tm_mday;
143 tw.tw_mon = tm->tm_mon;
145 /* tm_year is always "year - 1900". 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 -0700
196 ** for the current time, as specified by rfc822 and rfc1123.
204 return dtime(&clock);
209 ** Using a local calendar time value, produce
210 ** a date/time string of the form
212 ** Mon, 16 Jun 1992 15:30:48 -0700
214 ** as specified by rfc822 and rfc1123.
219 return dasctime(dlocaltime(clock));
224 ** Using a nmh "broken-down" time structure, produce
225 ** a date/time string of the form
227 ** Mon, 16 Jun 1992 15:30:48 -0700
229 ** as specified by rfc822 and rfc1123.
232 dasctime(struct tws *tw)
235 static char result[80];
240 /* Display timezone if known */
241 if ((tw->tw_flags & TW_SZONE) == TW_SZNIL)
244 snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags));
246 snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s",
247 tw->tw_mday, tw_moty[tw->tw_mon],
248 tw->tw_year < 100 ? 2 : 4, tw->tw_year,
249 tw->tw_hour, tw->tw_min, tw->tw_sec, result);
251 if ((tw->tw_flags & TW_SDAY) == TW_SEXP)
252 snprintf(result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer);
254 if ((tw->tw_flags & TW_SDAY) == TW_SNIL)
255 strncpy(result, buffer, sizeof(result));
257 snprintf(result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]);
264 ** Get the timezone for given offset as numeric value.
267 dtimezone(int offset, int flags)
270 static char buffer[10];
273 mins = -((-offset) % 60);
274 hours = -((-offset) / 60);
280 #ifdef ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST
283 #endif /* ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST */
284 snprintf(buffer, sizeof(buffer), "%s%02d%02d",
285 offset < 0 ? "-" : "+", abs(hours), abs(mins));
291 ** Convert nmh time structure for local "broken-down"
292 ** time to calendar time (clock value). This routine
293 ** is based on the gtime() routine written by Steven Shafer
294 ** at CMU. It was forwarded to MTR by Jay Lepreau at Utah-CS.
298 dmktime(struct tws *tw)
300 int i, sec, min, hour, mday, mon, year;
303 if (tw->tw_clock != 0)
306 if ((sec = tw->tw_sec) < 0 || sec > 61
307 || (min = tw->tw_min) < 0 || min > 59
308 || (hour = tw->tw_hour) < 0 || hour > 23
309 || (mday = tw->tw_mday) < 1 || mday > 31
310 || (mon = tw->tw_mon + 1) < 1 || mon > 12)
311 return (tw->tw_clock = (time_t) -1);
322 for (i = 1970; i < year; i++)
324 if (dysize(year) == 366 && mon >= 3)
327 result += dmsize[mon - 1];
329 result = 24 * result + hour;
330 result = 60 * result + min;
331 result = 60 * result + sec;
332 result -= 60 * tw->tw_zone;
333 if (tw->tw_flags & TW_DST)
336 return (tw->tw_clock = result);
341 ** Simple calculation of day of the week. Algorithm
342 ** used is Zeller's congruence. We assume that
343 ** if tw->tw_year < 100, then the century = 19.
347 set_dotw(struct tws *tw)
349 int month, day, year, century;
351 month = tw->tw_mon - 1;
353 year = tw->tw_year % 100;
354 century = tw->tw_year < 100 ? 19 : tw->tw_year / 100;
364 tw->tw_wday = ((26 * month - 2) / 10 + day + year + year / 4
365 - 3 * century / 4 + 1) % 7;
369 tw->tw_flags &= ~TW_SDAY, tw->tw_flags |= TW_SIMP;
374 ** Copy nmh time structure
378 twscopy(struct tws *tb, struct tws *tw)
380 *tb = *tw; /* struct copy */
385 ** Compare two nmh time structures
389 twsort(struct tws *tw1, struct tws *tw2)
393 if (tw1->tw_clock == 0)
395 if (tw2->tw_clock == 0)
398 return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
399 : c1 == c2 ? 0 : -1);