diplodocus.org Git - nmh/blob - sbr/dtime.c

   1
   2 /*
   3  * dtime.c -- time/date routines
   4  *
   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.
   8  */
   9
  10 #include <h/mh.h>   /* for snprintf() */
  11 #include <h/nmh.h>
  12 #include <h/tws.h>
  13 #include <time.h>
  14
  15 #if !defined(HAVE_STRUCT_TM_TM_GMTOFF)
  16 extern long timezone;
  17 #endif
  18
  19 /*
  20  * The number of days in the year, accounting for leap years
  21  */
  22 #define dysize(y)       \
  23         (((y) % 4) ? 365 : (((y) % 100) ? 366 : (((y) % 400) ? 365 : 366)))
  24
  25 char *tw_moty[] = {
  26     "Jan", "Feb", "Mar", "Apr",
  27     "May", "Jun", "Jul", "Aug",
  28     "Sep", "Oct", "Nov", "Dec",
  29     NULL
  30 };
  31
  32 char *tw_dotw[] = {
  33     "Sun", "Mon", "Tue",
  34     "Wed", "Thu", "Fri",
  35     "Sat", NULL
  36 };
  37
  38 char *tw_ldotw[] = {
  39     "Sunday",    "Monday",   "Tuesday",
  40     "Wednesday", "Thursday", "Friday",
  41     "Saturday",  NULL
  42 };
  43
  44 struct zone {
  45     char *std;
  46     char *dst;
  47     int shift;
  48 };
  49
  50 static int dmsize[] = {
  51     31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
  52 };
  53
  54
  55 /*
  56  * Get current time (adjusted for local time
  57  * zone and daylight savings time) expressed
  58  * as nmh "broken-down" time structure.
  59  */
  60
  61 struct tws *
  62 dlocaltimenow (void)
  63 {
  64     time_t clock;
  65
  66     time (&clock);
  67     return dlocaltime (&clock);
  68 }
  69
  70
  71 /*
  72  * Take clock value and return pointer to nmh time structure
  73  * containing "broken-down" time.  The time is adjusted for
  74  * local time zone and daylight savings time.
  75  */
  76
  77 struct tws *
  78 dlocaltime (time_t *clock)
  79 {
  80     static struct tws tw;
  81     struct tm *tm;
  82
  83     if (!clock)
  84         return NULL;
  85
  86     tm = localtime (clock);
  87
  88     tw.tw_sec  = tm->tm_sec;
  89     tw.tw_min  = tm->tm_min;
  90     tw.tw_hour = tm->tm_hour;
  91     tw.tw_mday = tm->tm_mday;
  92     tw.tw_mon  = tm->tm_mon;
  93
  94     /*
  95      * tm_year is always "year - 1900".
  96      * So we correct for this.
  97      */
  98     tw.tw_year = tm->tm_year + 1900;
  99     tw.tw_wday = tm->tm_wday;
 100     tw.tw_yday = tm->tm_yday;
 101
 102     tw.tw_flags = TW_NULL;
 103     if (tm->tm_isdst)
 104         tw.tw_flags |= TW_DST;
 105
 106 #ifdef HAVE_STRUCT_TM_TM_GMTOFF
 107     tw.tw_zone = tm->tm_gmtoff / 60;
 108     if (tm->tm_isdst)                   /* if DST is in effect */
 109         tw.tw_zone -= 60;               /* reset to normal offset */
 110 #else
 111     tzset();
 112     tw.tw_zone = -(timezone / 60);
 113 #endif
 114
 115     tw.tw_flags &= ~TW_SDAY;
 116     tw.tw_flags |= TW_SEXP;
 117     tw.tw_flags &= ~TW_SZONE;
 118     tw.tw_flags |= TW_SZEXP;
 119
 120     tw.tw_clock = *clock;
 121
 122     return (&tw);
 123 }
 124
 125
 126 /*
 127  * Take clock value and return pointer to nmh time
 128  * structure containing "broken-down" time.  Time is
 129  * expressed in UTC (Coordinated Universal Time).
 130  */
 131
 132 struct tws *
 133 dgmtime (time_t *clock)
 134 {
 135     static struct tws tw;
 136     struct tm *tm;
 137
 138     if (!clock)
 139         return NULL;
 140
 141     tm = gmtime (clock);
 142
 143     tw.tw_sec  = tm->tm_sec;
 144     tw.tw_min  = tm->tm_min;
 145     tw.tw_hour = tm->tm_hour;
 146     tw.tw_mday = tm->tm_mday;
 147     tw.tw_mon  = tm->tm_mon;
 148
 149     /*
 150      * tm_year is always "year - 1900"
 151      * So we correct for this.
 152      */
 153     tw.tw_year = tm->tm_year + 1900;
 154     tw.tw_wday = tm->tm_wday;
 155     tw.tw_yday = tm->tm_yday;
 156
 157     tw.tw_flags = TW_NULL;
 158     if (tm->tm_isdst)
 159         tw.tw_flags |= TW_DST;
 160
 161     tw.tw_zone = 0;
 162
 163     tw.tw_flags &= ~TW_SDAY;
 164     tw.tw_flags |= TW_SEXP;
 165     tw.tw_flags &= ~TW_SZONE;
 166     tw.tw_flags |= TW_SZEXP;
 167
 168     tw.tw_clock = *clock;
 169
 170     return (&tw);
 171 }
 172
 173
 174 /*
 175  * Using a nmh "broken-down" time structure,
 176  * produce a 26-byte date/time string, such as
 177  *
 178  *      Tue Jan 14 17:49:03 1992\n\0
 179  */
 180
 181 char *
 182 dctime (struct tws *tw)
 183 {
 184     static char buffer[26];
 185
 186     if (!tw)
 187         return NULL;
 188
 189     snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %.4d\n",
 190             tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday,
 191             tw->tw_hour, tw->tw_min, tw->tw_sec,
 192             tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year);
 193
 194     return buffer;
 195 }
 196
 197
 198 /*
 199  * Produce a date/time string of the form
 200  *
 201  *      Mon, 16 Jun 1992 15:30:48 -700 (or)
 202  *      Mon, 16 Jun 1992 15:30:48 EDT
 203  *
 204  * for the current time, as specified by rfc822.
 205  * The first form is required by rfc1123.
 206  */
 207
 208 char *
 209 dtimenow (int alpha_timezone)
 210 {
 211     time_t clock;
 212
 213     time (&clock);
 214     return dtime (&clock, alpha_timezone);
 215 }
 216
 217
 218 /*
 219  * Using a local calendar time value, produce
 220  * a date/time string of the form
 221  *
 222  *      Mon, 16 Jun 1992 15:30:48 -700  (or)
 223  *      Mon, 16 Jun 1992 15:30:48 EDT
 224  *
 225  * as specified by rfc822.  The first form is required
 226  * by rfc1123 for outgoing messages.
 227  */
 228
 229 char *
 230 dtime (time_t *clock, int alpha_timezone)
 231 {
 232     if (alpha_timezone)
 233         /* use alpha-numeric timezones */
 234         return dasctime (dlocaltime (clock), TW_NULL);
 235     else
 236         /* use numeric timezones */
 237         return dasctime (dlocaltime (clock), TW_ZONE);
 238 }
 239
 240
 241 /*
 242  * Using a nmh "broken-down" time structure, produce
 243  * a date/time string of the form
 244  *
 245  *      Mon, 16 Jun 1992 15:30:48 -0700
 246  *
 247  * as specified by rfc822 and rfc1123.
 248  */
 249
 250 char *
 251 dasctime (struct tws *tw, int flags)
 252 {
 253     char buffer[80];
 254     static char result[80];
 255
 256     if (!tw)
 257         return NULL;
 258
 259     /* Display timezone if known */
 260     if ((tw->tw_flags & TW_SZONE) == TW_SZNIL)
 261         result[0] = '\0';
 262     else
 263         snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags | flags));
 264
 265     snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s",
 266             tw->tw_mday, tw_moty[tw->tw_mon],
 267             tw->tw_year < 100 ? 2 : 4, tw->tw_year,
 268             tw->tw_hour, tw->tw_min, tw->tw_sec, result);
 269
 270     if ((tw->tw_flags & TW_SDAY) == TW_SEXP)
 271         snprintf (result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer);
 272     else
 273         if ((tw->tw_flags & TW_SDAY) == TW_SNIL)
 274             strncpy (result, buffer, sizeof(result));
 275         else
 276             snprintf (result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]);
 277
 278     return result;
 279 }
 280
 281
 282 /*
 283  * Get the timezone for given offset.
 284  * This used to return a three-letter abbreviation for some offset
 285  * values.  But not many.  Until there's a good way to do that,
 286  * return the string representation of the numeric offset.
 287  */
 288
 289 char *
 290 dtimezone (int offset, int flags)
 291 {
 292     int hours, mins;
 293     static char buffer[10];
 294
 295     if (offset < 0) {
 296         mins = -((-offset) % 60);
 297         hours = -((-offset) / 60);
 298     } else {
 299         mins = offset % 60;
 300         hours = offset / 60;
 301     }
 302
 303 #ifdef ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST
 304     if (flags & TW_DST)
 305         hours += 1;
 306 #endif /* ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST */
 307     snprintf (buffer, sizeof(buffer), "%s%02d%02d",
 308                 offset < 0 ? "-" : "+", abs (hours), abs (mins));
 309     return buffer;
 310 }
 311
 312
 313 /*
 314  * Convert nmh time structure for local "broken-down"
 315  * time to calendar time (clock value).  This routine
 316  * is based on the gtime() routine written by Steven Shafer
 317  * at CMU.  It was forwarded to MTR by Jay Lepreau at Utah-CS.
 318  */
 319
 320 time_t
 321 dmktime (struct tws *tw)
 322 {
 323     int i, sec, min, hour, mday, mon, year;
 324     time_t result;
 325
 326     if (tw->tw_clock != 0)
 327         return tw->tw_clock;
 328
 329     if ((sec = tw->tw_sec) < 0 || sec > 61
 330             || (min = tw->tw_min) < 0 || min > 59
 331             || (hour = tw->tw_hour) < 0 || hour > 23
 332             || (mday = tw->tw_mday) < 1 || mday > 31
 333             || (mon = tw->tw_mon + 1) < 1 || mon > 12)
 334         return (tw->tw_clock = (time_t) -1);
 335
 336     year = tw->tw_year;
 337
 338     result = 0;
 339     if (year < 1970)
 340       year += 1900;
 341
 342     if (year < 1970)
 343       year += 100;
 344
 345     for (i = 1970; i < year; i++)
 346         result += dysize (i);
 347     if (dysize (year) == 366 && mon >= 3)
 348         result++;
 349     while (--mon)
 350         result += dmsize[mon - 1];
 351     result += mday - 1;
 352     result = 24 * result + hour;
 353     result = 60 * result + min;
 354     result = 60 * result + sec;
 355     result -= 60 * tw->tw_zone;
 356     if (tw->tw_flags & TW_DST)
 357         result -= 60 * 60;
 358
 359     return (tw->tw_clock = result);
 360 }
 361
 362
 363 /*
 364  * Simple calculation of day of the week.  Algorithm
 365  * used is Zeller's congruence.  We assume that
 366  * if tw->tw_year < 100, then the century = 19.
 367  */
 368
 369 void
 370 set_dotw (struct tws *tw)
 371 {
 372     int month, day, year, century;
 373
 374     month = tw->tw_mon - 1;
 375     day = tw->tw_mday;
 376     year = tw->tw_year % 100;
 377     century = tw->tw_year < 100 ? 19 : tw->tw_year / 100;
 378
 379     if (month <= 0) {
 380         month += 12;
 381         if (--year < 0) {
 382             year += 100;
 383             century--;
 384         }
 385     }
 386
 387     tw->tw_wday =
 388         ((26 * month - 2) / 10 + day + year + year / 4
 389             - 3 * century / 4 + 1) % 7;
 390     if (tw->tw_wday < 0)
 391         tw->tw_wday += 7;
 392
 393     tw->tw_flags &= ~TW_SDAY, tw->tw_flags |= TW_SIMP;
 394 }
 395
 396
 397 /*
 398  * Copy nmh time structure
 399  */
 400
 401 void
 402 twscopy (struct tws *tb, struct tws *tw)
 403 {
 404     *tb = *tw;  /* struct copy */
 405 }
 406
 407
 408 /*
 409  * Compare two nmh time structures
 410  */
 411
 412 int
 413 twsort (struct tws *tw1, struct tws *tw2)
 414 {
 415     time_t c1, c2;
 416
 417     if (tw1->tw_clock == 0)
 418         dmktime (tw1);
 419     if (tw2->tw_clock == 0)
 420         dmktime (tw2);
 421
 422     return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
 423             : c1 == c2 ? 0 : -1);
 424 }