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 int daylight;
  17 extern long timezone;
  18 extern char *tzname[];
  19 #endif
  20
  21 #ifndef abs
  22 # define abs(a) (a >= 0 ? a : -a)
  23 #endif
  24
  25 /*
  26  * The number of days in the year, accounting for leap years
  27  */
  28 #define dysize(y)       \
  29         (((y) % 4) ? 365 : (((y) % 100) ? 366 : (((y) % 400) ? 365 : 366)))
  30
  31 char *tw_moty[] = {
  32     "Jan", "Feb", "Mar", "Apr",
  33     "May", "Jun", "Jul", "Aug",
  34     "Sep", "Oct", "Nov", "Dec",
  35     NULL
  36 };
  37
  38 char *tw_dotw[] = {
  39     "Sun", "Mon", "Tue",
  40     "Wed", "Thu", "Fri",
  41     "Sat", NULL
  42 };
  43
  44 char *tw_ldotw[] = {
  45     "Sunday",    "Monday",   "Tuesday",
  46     "Wednesday", "Thursday", "Friday",
  47     "Saturday",  NULL
  48 };
  49
  50 struct zone {
  51     char *std;
  52     char *dst;
  53     int shift;
  54 };
  55
  56 static struct zone zones[] = {
  57     { "GMT", "BST", 0 },
  58     { "EST", "EDT", -5 },
  59     { "CST", "CDT", -6 },
  60     { "MST", "MDT", -7 },
  61     { "PST", "PDT", -8 },
  62 #if 0
  63 /* RFC1123 specifies do not use military TZs */
  64     { "A", NULL, -1 },
  65     { "B", NULL, -2 },
  66     { "C", NULL, -3 },
  67     { "D", NULL, -4 },
  68     { "E", NULL, -5 },
  69     { "F", NULL, -6 },
  70     { "G", NULL, -7 },
  71     { "H", NULL, -8 },
  72     { "I", NULL, -9 },
  73     { "K", NULL, -10 },
  74     { "L", NULL, -11 },
  75     { "M", NULL, -12 },
  76     { "N", NULL, 1 },
  77 #ifndef HUJI
  78     { "O", NULL, 2 },
  79 #else
  80     { "JST", "JDT", 2 },
  81 #endif
  82     { "P", NULL, 3 },
  83     { "Q", NULL, 4 },
  84     { "R", NULL, 5 },
  85     { "S", NULL, 6 },
  86     { "T", NULL, 7 },
  87     { "U", NULL, 8 },
  88     { "V", NULL, 9 },
  89     { "W", NULL, 10 },
  90     { "X", NULL, 11 },
  91     { "Y", NULL, 12 },
  92 #endif
  93     { NULL, NULL, 0 }
  94 };
  95
  96 static int dmsize[] = {
  97     31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
  98 };
  99
 100
 101 /*
 102  * Get current time (adjusted for local time
 103  * zone and daylight savings time) expressed
 104  * as nmh "broken-down" time structure.
 105  */
 106
 107 struct tws *
 108 dlocaltimenow (void)
 109 {
 110     time_t clock;
 111
 112     time (&clock);
 113     return dlocaltime (&clock);
 114 }
 115
 116
 117 /*
 118  * Take clock value and return pointer to nmh time structure
 119  * containing "broken-down" time.  The time is adjusted for
 120  * local time zone and daylight savings time.
 121  */
 122
 123 struct tws *
 124 dlocaltime (time_t *clock)
 125 {
 126     static struct tws tw;
 127     struct tm *tm;
 128
 129     if (!clock)
 130         return NULL;
 131
 132     tm = localtime (clock);
 133
 134     tw.tw_sec  = tm->tm_sec;
 135     tw.tw_min  = tm->tm_min;
 136     tw.tw_hour = tm->tm_hour;
 137     tw.tw_mday = tm->tm_mday;
 138     tw.tw_mon  = tm->tm_mon;
 139
 140     /*
 141      * tm_year is always "year - 1900".
 142      * So we correct for this.
 143      */
 144     tw.tw_year = tm->tm_year + 1900;
 145     tw.tw_wday = tm->tm_wday;
 146     tw.tw_yday = tm->tm_yday;
 147
 148     tw.tw_flags = TW_NULL;
 149     if (tm->tm_isdst)
 150         tw.tw_flags |= TW_DST;
 151
 152 #ifdef HAVE_STRUCT_TM_TM_GMTOFF
 153     tw.tw_zone = tm->tm_gmtoff / 60;
 154     if (tm->tm_isdst)                   /* if DST is in effect */
 155         tw.tw_zone -= 60;               /* reset to normal offset */
 156 #else
 157     tzset();
 158     tw.tw_zone = -(timezone / 60);
 159 #endif
 160
 161     tw.tw_flags &= ~TW_SDAY;
 162     tw.tw_flags |= TW_SEXP;
 163     tw.tw_flags &= ~TW_SZONE;
 164     tw.tw_flags |= TW_SZEXP;
 165
 166     tw.tw_clock = *clock;
 167
 168     return (&tw);
 169 }
 170
 171
 172 /*
 173  * Take clock value and return pointer to nmh time
 174  * structure containing "broken-down" time.  Time is
 175  * expressed in UTC (Coordinated Universal Time).
 176  */
 177
 178 struct tws *
 179 dgmtime (time_t *clock)
 180 {
 181     static struct tws tw;
 182     struct tm *tm;
 183
 184     if (!clock)
 185         return NULL;
 186
 187     tm = gmtime (clock);
 188
 189     tw.tw_sec  = tm->tm_sec;
 190     tw.tw_min  = tm->tm_min;
 191     tw.tw_hour = tm->tm_hour;
 192     tw.tw_mday = tm->tm_mday;
 193     tw.tw_mon  = tm->tm_mon;
 194
 195     /*
 196      * tm_year is always "year - 1900"
 197      * So we correct for this.
 198      */
 199     tw.tw_year = tm->tm_year + 1900;
 200     tw.tw_wday = tm->tm_wday;
 201     tw.tw_yday = tm->tm_yday;
 202
 203     tw.tw_flags = TW_NULL;
 204     if (tm->tm_isdst)
 205         tw.tw_flags |= TW_DST;
 206
 207     tw.tw_zone = 0;
 208
 209     tw.tw_flags &= ~TW_SDAY;
 210     tw.tw_flags |= TW_SEXP;
 211     tw.tw_flags &= ~TW_SZONE;
 212     tw.tw_flags |= TW_SZEXP;
 213
 214     tw.tw_clock = *clock;
 215
 216     return (&tw);
 217 }
 218
 219
 220 /*
 221  * Using a nmh "broken-down" time structure,
 222  * produce a 26-byte date/time string, such as
 223  *
 224  *      Tue Jan 14 17:49:03 1992\n\0
 225  */
 226
 227 char *
 228 dctime (struct tws *tw)
 229 {
 230     static char buffer[26];
 231
 232     if (!tw)
 233         return NULL;
 234
 235     snprintf (buffer, sizeof(buffer), "%.3s %.3s %02d %02d:%02d:%02d %.4d\n",
 236             tw_dotw[tw->tw_wday], tw_moty[tw->tw_mon], tw->tw_mday,
 237             tw->tw_hour, tw->tw_min, tw->tw_sec,
 238             tw->tw_year < 100 ? tw->tw_year + 1900 : tw->tw_year);
 239
 240     return buffer;
 241 }
 242
 243
 244 /*
 245  * Produce a date/time string of the form
 246  *
 247  *      Mon, 16 Jun 1992 15:30:48 -700 (or)
 248  *      Mon, 16 Jun 1992 15:30:48 EDT
 249  *
 250  * for the current time, as specified by rfc822.
 251  * The first form is required by rfc1123.
 252  */
 253
 254 char *
 255 dtimenow (int alpha_timezone)
 256 {
 257     time_t clock;
 258
 259     time (&clock);
 260     return dtime (&clock, alpha_timezone);
 261 }
 262
 263
 264 /*
 265  * Using a local calendar time value, produce
 266  * a date/time string of the form
 267  *
 268  *      Mon, 16 Jun 1992 15:30:48 -700  (or)
 269  *      Mon, 16 Jun 1992 15:30:48 EDT
 270  *
 271  * as specified by rfc822.  The first form is required
 272  * by rfc1123 for outgoing messages.
 273  */
 274
 275 char *
 276 dtime (time_t *clock, int alpha_timezone)
 277 {
 278     if (alpha_timezone)
 279         /* use alpha-numeric timezones */
 280         return dasctime (dlocaltime (clock), TW_NULL);
 281     else
 282         /* use numeric timezones */
 283         return dasctime (dlocaltime (clock), TW_ZONE);
 284 }
 285
 286
 287 /*
 288  * Using a nmh "broken-down" time structure, produce
 289  * a date/time string of the form
 290  *
 291  *      Mon, 16 Jun 1992 15:30:48 -0700
 292  *
 293  * as specified by rfc822 and rfc1123.
 294  */
 295
 296 char *
 297 dasctime (struct tws *tw, int flags)
 298 {
 299     char buffer[80];
 300     static char result[80];
 301
 302     if (!tw)
 303         return NULL;
 304
 305     /* Display timezone if known */
 306     if ((tw->tw_flags & TW_SZONE) == TW_SZNIL)
 307         result[0] = '\0';
 308     else
 309         snprintf(result, sizeof(result), " %s", dtimezone(tw->tw_zone, tw->tw_flags | flags));
 310
 311     snprintf(buffer, sizeof(buffer), "%02d %s %0*d %02d:%02d:%02d%s",
 312             tw->tw_mday, tw_moty[tw->tw_mon],
 313             tw->tw_year < 100 ? 2 : 4, tw->tw_year,
 314             tw->tw_hour, tw->tw_min, tw->tw_sec, result);
 315
 316     if ((tw->tw_flags & TW_SDAY) == TW_SEXP)
 317         snprintf (result, sizeof(result), "%s, %s", tw_dotw[tw->tw_wday], buffer);
 318     else
 319         if ((tw->tw_flags & TW_SDAY) == TW_SNIL)
 320             strncpy (result, buffer, sizeof(result));
 321         else
 322             snprintf (result, sizeof(result), "%s (%s)", buffer, tw_dotw[tw->tw_wday]);
 323
 324     return result;
 325 }
 326
 327
 328 /*
 329  * Get the timezone for given offset
 330  */
 331
 332 char *
 333 dtimezone (int offset, int flags)
 334 {
 335     int hours, mins;
 336     struct zone *z;
 337     static char buffer[10];
 338
 339     if (offset < 0) {
 340         mins = -((-offset) % 60);
 341         hours = -((-offset) / 60);
 342     } else {
 343         mins = offset % 60;
 344         hours = offset / 60;
 345     }
 346
 347     if (!(flags & TW_ZONE) && mins == 0) {
 348         tzset();
 349         return ((flags & TW_DST) ? tzname[1] : tzname[0]);
 350     }
 351
 352 #ifdef ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST
 353     if (flags & TW_DST)
 354         hours += 1;
 355 #endif /* ADJUST_NUMERIC_ONLY_TZ_OFFSETS_WRT_DST */
 356     snprintf (buffer, sizeof(buffer), "%s%02d%02d",
 357                 offset < 0 ? "-" : "+", abs (hours), abs (mins));
 358     return buffer;
 359 }
 360
 361
 362 /*
 363  * Convert nmh time structure for local "broken-down"
 364  * time to calendar time (clock value).  This routine
 365  * is based on the gtime() routine written by Steven Shafer
 366  * at CMU.  It was forwarded to MTR by Jay Lepreau at Utah-CS.
 367  */
 368
 369 time_t
 370 dmktime (struct tws *tw)
 371 {
 372     int i, sec, min, hour, mday, mon, year;
 373     time_t result;
 374
 375     if (tw->tw_clock != 0)
 376         return tw->tw_clock;
 377
 378     if ((sec = tw->tw_sec) < 0 || sec > 61
 379             || (min = tw->tw_min) < 0 || min > 59
 380             || (hour = tw->tw_hour) < 0 || hour > 23
 381             || (mday = tw->tw_mday) < 1 || mday > 31
 382             || (mon = tw->tw_mon + 1) < 1 || mon > 12)
 383         return (tw->tw_clock = (time_t) -1);
 384
 385     year = tw->tw_year;
 386
 387     result = 0;
 388     if (year < 1970)
 389       year += 1900;
 390
 391     if (year < 1970)
 392       year += 100;
 393
 394     for (i = 1970; i < year; i++)
 395         result += dysize (i);
 396     if (dysize (year) == 366 && mon >= 3)
 397         result++;
 398     while (--mon)
 399         result += dmsize[mon - 1];
 400     result += mday - 1;
 401     result = 24 * result + hour;
 402     result = 60 * result + min;
 403     result = 60 * result + sec;
 404     result -= 60 * tw->tw_zone;
 405     if (tw->tw_flags & TW_DST)
 406         result -= 60 * 60;
 407
 408     return (tw->tw_clock = result);
 409 }
 410
 411
 412 /*
 413  * Simple calculation of day of the week.  Algorithm
 414  * used is Zeller's congruence.  We assume that
 415  * if tw->tw_year < 100, then the century = 19.
 416  */
 417
 418 void
 419 set_dotw (struct tws *tw)
 420 {
 421     int month, day, year, century;
 422
 423     month = tw->tw_mon - 1;
 424     day = tw->tw_mday;
 425     year = tw->tw_year % 100;
 426     century = tw->tw_year < 100 ? 19 : tw->tw_year / 100;
 427
 428     if (month <= 0) {
 429         month += 12;
 430         if (--year < 0) {
 431             year += 100;
 432             century--;
 433         }
 434     }
 435
 436     tw->tw_wday =
 437         ((26 * month - 2) / 10 + day + year + year / 4
 438             - 3 * century / 4 + 1) % 7;
 439     if (tw->tw_wday < 0)
 440         tw->tw_wday += 7;
 441
 442     tw->tw_flags &= ~TW_SDAY, tw->tw_flags |= TW_SIMP;
 443 }
 444
 445
 446 /*
 447  * Copy nmh time structure
 448  */
 449
 450 void
 451 twscopy (struct tws *tb, struct tws *tw)
 452 {
 453     *tb = *tw;  /* struct copy */
 454
 455 #if 0
 456     tb->tw_sec   = tw->tw_sec;
 457     tb->tw_min   = tw->tw_min;
 458     tb->tw_hour  = tw->tw_hour;
 459     tb->tw_mday  = tw->tw_mday;
 460     tb->tw_mon   = tw->tw_mon;
 461     tb->tw_year  = tw->tw_year;
 462     tb->tw_wday  = tw->tw_wday;
 463     tb->tw_yday  = tw->tw_yday;
 464     tb->tw_zone  = tw->tw_zone;
 465     tb->tw_clock = tw->tw_clock;
 466     tb->tw_flags = tw->tw_flags;
 467 #endif
 468 }
 469
 470
 471 /*
 472  * Compare two nmh time structures
 473  */
 474
 475 int
 476 twsort (struct tws *tw1, struct tws *tw2)
 477 {
 478     time_t c1, c2;
 479
 480     if (tw1->tw_clock == 0)
 481         dmktime (tw1);
 482     if (tw2->tw_clock == 0)
 483         dmktime (tw2);
 484
 485     return ((c1 = tw1->tw_clock) > (c2 = tw2->tw_clock) ? 1
 486             : c1 == c2 ? 0 : -1);
 487 }