/* dtime.c -- time/date routines * * This code is Copyright (c) 2002, by the authors of nmh. See the * COPYRIGHT file in the root directory of the nmh distribution for * complete copyright information. */ #include /* for snprintf() */ #include #include #include #include #if !defined(HAVE_STRUCT_TM_TM_GMTOFF) extern long timezone; #endif /* * The number of days in the year, accounting for leap years */ #define dysize(y) \ (((y) % 4) ? 365 : (((y) % 100) ? 366 : (((y) % 400) ? 365 : 366))) char *tw_moty[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL }; char *tw_dotw[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", NULL }; char *tw_ldotw[] = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", NULL }; static int dmsize[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; /* * Get current time (adjusted for local time * zone and daylight savings time) expressed * as nmh "broken-down" time structure. */ struct tws * dlocaltimenow (void) { time_t clock; time (&clock); return dlocaltime (&clock); } /* * Take clock value and return pointer to nmh time structure * containing "broken-down" time. The time is adjusted for * local time zone and daylight savings time. */ struct tws * dlocaltime (time_t *clock) { static struct tws tw; struct tm *tm; if (!clock) return NULL; tm = localtime (clock); tw.tw_sec = tm->tm_sec; tw.tw_min = tm->tm_min; tw.tw_hour = tm->tm_hour; tw.tw_mday = tm->tm_mday; tw.tw_mon = tm->tm_mon; /* * tm_year is always "year - 1900". * So we correct for this. */ tw.tw_year = tm->tm_year + 1900; tw.tw_wday = tm->tm_wday; tw.tw_yday = tm->tm_yday; tw.tw_flags = TW_NULL; if (tm->tm_isdst) tw.tw_flags |= TW_DST; #ifdef HAVE_STRUCT_TM_TM_GMTOFF tw.tw_zone = tm->tm_gmtoff / 60; if (tm->tm_isdst) /* if DST is in effect */ tw.tw_zone -= 60; /* reset to normal offset */ #else { static bool deja_vu; if (!deja_vu) { deja_vu = true; tzset(); } } tw.tw_zone = -(timezone / 60); #endif tw.tw_flags &= ~TW_SDAY; tw.tw_flags |= TW_SEXP; tw.tw_flags |= TW_SZEXP; tw.tw_clock = *clock; return (&tw); } /* * Take clock value and return pointer to nmh time * structure containing "broken-down" time. Time is * expressed in UTC (Coordinated Universal Time). */ struct tws * dgmtime (time_t *clock) { static struct tws tw; struct tm *tm; if (!clock) return NULL; tm = gmtime (clock); tw.tw_sec = tm->tm_sec; tw.tw_min = tm->tm_min; tw.tw_hour = tm->tm_hour; tw.tw_mday = tm->tm_mday; tw.tw_mon = tm->tm_mon; /* * tm_year is always "year - 1900" * So we correct for this. */ tw.tw_year = tm->tm_year + 1900; tw.tw_wday = tm->tm_wday; tw.tw_yday = tm->tm_yday; tw.tw_flags = TW_NULL; if (tm->tm_isdst) tw.tw_flags |= TW_DST; tw.tw_zone = 0; tw.tw_flags &= ~TW_SDAY; tw.tw_flags |= TW_SEXP; tw.tw_flags |= TW_SZEXP; tw.tw_clock = *clock; return (&tw); } /* * Using a nmh "broken-down" time structure, * produce a 26-byte date/time string, such as * * Tue Jan 14 17:49:03 1992\n\0 */ char * dctime (struct tws *tw) { static char buffer[26]; if (!tw) return NULL; snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %s\n", tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday, tw->tw_hour, tw->tw_min, tw->tw_sec, m_strn(tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year, 4)); return buffer; } /* * Produce a date/time string of the form * * Mon, 16 Jun 1992 15:30:48 -700 (or) * Mon, 16 Jun 1992 15:30:48 EDT * * for the current time, as specified by RFC 822. * The first form is required by RFC 1123. */ char * dtimenow (int alpha_timezone) { time_t clock; time (&clock); return dtime (&clock, alpha_timezone); } /* * Using a local calendar time value, produce * a date/time string of the form * * Mon, 16 Jun 1992 15:30:48 -700 (or) * Mon, 16 Jun 1992 15:30:48 EDT * * as specified by RFC 822. The first form is required * by RFC 1123 for outgoing messages. */ char * dtime (time_t *clock, int alpha_timezone) { if (alpha_timezone) /* use alpha-numeric timezones */ return dasctime (dlocaltime (clock), TW_NULL); /* use numeric timezones */ return dasctime (dlocaltime (clock), TW_ZONE); } /* * Using a nmh "broken-down" time structure, produce * a date/time string of the form * * Mon, 16 Jun 1992 15:30:48 -0700 * * as specified by RFC 822 and RFC 1123. */ char * dasctime (struct tws *tw, int flags) { char buffer[80]; static char result[80]; int twf; if (!tw) return NULL; /* Display timezone if known */ if (tw->tw_flags & TW_SZEXP) snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags | flags)); else result[0] = '\0'; snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s", tw->tw_mday, tw_moty[tw->tw_mon], tw->tw_year < 100 ? 2 : 4, tw->tw_year, tw->tw_hour, tw->tw_min, tw->tw_sec, result); if ((twf = tw->tw_flags & TW_SDAY)) { if (twf == TW_SEXP) snprintf(result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer); else snprintf(result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]); } else strncpy(result, buffer, sizeof(result)); return result; } /* * Get the timezone for given offset. * This used to return a three-letter abbreviation for some offset * values. But not many. Until there's a good way to do that, * return the string representation of the numeric offset. */ char *dtimezone(int offset, int flags) { static char buffer[sizeof "+3579139459"]; /* 2,147,483,648 / 60 = 35,791,394 */ bool pos; unsigned os, hours, mins; pos = offset >= 0; os = pos ? offset : ~offset + 1; /* abs(3) undefined on INT_MIN. */ hours = os / 60; mins = os % 60; if (flags & TW_DST) /* Shift towards +infinity. */ hours += pos ? 1 : -1; snprintf(buffer, sizeof(buffer), "%c%02u%02u", pos ? '+' : '-', hours, mins); return buffer; } /* * Convert nmh time structure for local "broken-down" * time to calendar time (clock value). This routine * is based on the gtime() routine written by Steven Shafer * at CMU. It was forwarded to MTR by Jay Lepreau at Utah-CS. */ time_t dmktime (struct tws *tw) { int i, sec, min, hour, mday, mon, year; time_t result; if (tw->tw_clock != 0) return tw->tw_clock; if ((sec = tw->tw_sec) < 0 || sec > 61 || (min = tw->tw_min) < 0 || min > 59 || (hour = tw->tw_hour) < 0 || hour > 23 || (mday = tw->tw_mday) < 1 || mday > 31 || (mon = tw->tw_mon + 1) < 1 || mon > 12) return (tw->tw_clock = (time_t) -1); year = tw->tw_year; result = 0; if (year < 1970) year += 1900; if (year < 1970) year += 100; for (i = 1970; i < year; i++) result += dysize (i); if (dysize (year) == 366 && mon >= 3) result++; while (--mon) result += dmsize[mon - 1]; result += mday - 1; result = 24 * result + hour; result = 60 * result + min; result = 60 * result + sec; result -= 60 * tw->tw_zone; if (tw->tw_flags & TW_DST) result -= 60 * 60; return (tw->tw_clock = result); } /* * Simple calculation of day of the week. Algorithm * used is Zeller's congruence. We assume that * if tw->tw_year < 100, then the century = 19. */ void set_dotw (struct tws *tw) { int month, day, year, century; month = tw->tw_mon - 1; day = tw->tw_mday; year = tw->tw_year % 100; century = tw->tw_year < 100 ? 19 : tw->tw_year / 100; if (month <= 0) { month += 12; if (--year < 0) { year += 100; century--; } } tw->tw_wday = ((26 * month - 2) / 10 + day + year + year / 4 - 3 * century / 4 + 1) % 7; if (tw->tw_wday < 0) tw->tw_wday += 7; tw->tw_flags &= ~TW_SDAY; tw->tw_flags |= TW_SIMP; } /* * Compare two nmh time structures */ int twsort (struct tws *tw1, struct tws *tw2) { time_t c1, c2; if (tw1->tw_clock == 0) dmktime (tw1); if (tw2->tw_clock == 0) dmktime (tw2); return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1 : c1 == c2 ? 0 : -1); }