date/vary.c

   1 /*-
   2  * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <err.h>
  31 #include <time.h>
  32 #include <string.h>
  33 #include <stdlib.h>
  34 #include "vary.h"
  35
  36 struct trans {
  37   int val;
  38   const char *str;
  39 };
  40
  41 static struct trans trans_mon[] = {
  42   { 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
  43   { 5, "may"}, { 6, "june" }, { 7, "july" }, { 8, "august" },
  44   { 9, "september" }, { 10, "october" }, { 11, "november" }, { 12, "december" },
  45   { -1, NULL }
  46 };
  47
  48 static struct trans trans_wday[] = {
  49   { 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
  50   { 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
  51   { -1, NULL }
  52 };
  53
  54 static char digits[] = "0123456789";
  55 static int adjhour(struct tm *, char, int, int);
  56
  57 static int
  58 domktime(struct tm *t, char type)
  59 {
  60   time_t ret;
  61
  62   while ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
  63     /* While mktime() fails, adjust by an hour */
  64     adjhour(t, type == '-' ? type : '+', 1, 0);
  65
  66   return ret;
  67 }
  68
  69 static int
  70 trans(const struct trans t[], const char *arg)
  71 {
  72   int f;
  73
  74   for (f = 0; t[f].val != -1; f++)
  75     if (!strncasecmp(t[f].str, arg, 3) ||
  76         !strncasecmp(t[f].str, arg, strlen(t[f].str)))
  77       return t[f].val;
  78
  79   return -1;
  80 }
  81
  82 struct vary *
  83 vary_append(struct vary *v, char *arg)
  84 {
  85   struct vary *result, **nextp;
  86
  87   if (v) {
  88     result = v;
  89     while (v->next)
  90       v = v->next;
  91     nextp = &v->next;
  92   } else
  93     nextp = &result;
  94
  95   if ((*nextp = (struct vary *)malloc(sizeof(struct vary))) == NULL)
  96     err(1, "malloc");
  97   (*nextp)->arg = arg;
  98   (*nextp)->next = NULL;
  99   return result;
 100 }
 101
 102 static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 103
 104 static int
 105 daysinmonth(const struct tm *t)
 106 {
 107   int year;
 108
 109   year = t->tm_year + 1900;
 110
 111   if (t->tm_mon == 1)
 112     if (!(year % 400))
 113       return 29;
 114     else if (!(year % 100))
 115       return 28;
 116     else if (!(year % 4))
 117       return 29;
 118     else
 119       return 28;
 120   else if (t->tm_mon >= 0 && t->tm_mon < 12)
 121     return mdays[t->tm_mon];
 122
 123   return 0;
 124 }
 125
 126
 127 static int
 128 adjyear(struct tm *t, char type, int val, int mk)
 129 {
 130   switch (type) {
 131     case '+':
 132       t->tm_year += val;
 133       break;
 134     case '-':
 135       t->tm_year -= val;
 136       break;
 137     default:
 138       t->tm_year = val;
 139       if (t->tm_year < 69)
 140         t->tm_year += 100;              /* as per date.c */
 141       else if (t->tm_year > 1900)
 142         t->tm_year -= 1900;             /* struct tm holds years since 1900 */
 143       break;
 144   }
 145   return !mk || domktime(t, type) != -1;
 146 }
 147
 148 static int
 149 adjmon(struct tm *t, char type, int val, int istext, int mk)
 150 {
 151   int lmdays;
 152
 153   if (val < 0)
 154     return 0;
 155
 156   switch (type) {
 157     case '+':
 158       if (istext) {
 159         if (val <= t->tm_mon)
 160           val += 11 - t->tm_mon;        /* early next year */
 161         else
 162           val -= t->tm_mon + 1;         /* later this year */
 163       }
 164       if (val) {
 165         if (!adjyear(t, '+', (t->tm_mon + val) / 12, 0))
 166           return 0;
 167         val %= 12;
 168         t->tm_mon += val;
 169         if (t->tm_mon > 11)
 170           t->tm_mon -= 12;
 171       }
 172       break;
 173
 174     case '-':
 175       if (istext) {
 176         if (val-1 > t->tm_mon)
 177           val = 13 - val + t->tm_mon;   /* later last year */
 178         else
 179           val = t->tm_mon - val + 1;    /* early this year */
 180       }
 181       if (val) {
 182         if (!adjyear(t, '-', val / 12, 0))
 183           return 0;
 184         val %= 12;
 185         if (val > t->tm_mon) {
 186           if (!adjyear(t, '-', 1, 0))
 187             return 0;
 188           val -= 12;
 189         }
 190         t->tm_mon -= val;
 191       }
 192       break;
 193
 194     default:
 195       if (val > 12 || val < 1)
 196         return 0;
 197       t->tm_mon = --val;
 198   }
 199
 200   /* e.g., -v-1m on March, 31 is the last day of February in common sense */
 201   lmdays = daysinmonth(t);
 202   if (t->tm_mday > lmdays)
 203     t->tm_mday = lmdays;
 204
 205   return !mk || domktime(t, type) != -1;
 206 }
 207
 208 static int
 209 adjday(struct tm *t, char type, int val, int mk)
 210 {
 211   int lmdays;
 212
 213   switch (type) {
 214     case '+':
 215       while (val) {
 216         lmdays = daysinmonth(t);
 217         if (val > lmdays - t->tm_mday) {
 218           val -= lmdays - t->tm_mday + 1;
 219           t->tm_mday = 1;
 220           if (!adjmon(t, '+', 1, 0, 0))
 221             return 0;
 222         } else {
 223           t->tm_mday += val;
 224           val = 0;
 225         }
 226       }
 227       break;
 228     case '-':
 229       while (val)
 230         if (val >= t->tm_mday) {
 231           val -= t->tm_mday;
 232           t->tm_mday = 1;
 233           if (!adjmon(t, '-', 1, 0, 0))
 234             return 0;
 235           t->tm_mday = daysinmonth(t);
 236         } else {
 237           t->tm_mday -= val;
 238           val = 0;
 239         }
 240       break;
 241     default:
 242       if (val > 0 && val <= daysinmonth(t))
 243         t->tm_mday = val;
 244       else
 245         return 0;
 246       break;
 247   }
 248
 249   return !mk || domktime(t, type) != -1;
 250 }
 251
 252 static int
 253 adjwday(struct tm *t, char type, int val, int istext, int mk)
 254 {
 255   if (val < 0)
 256     return 0;
 257
 258   switch (type) {
 259     case '+':
 260       if (istext)
 261         if (val < t->tm_wday)
 262           val = 7 - t->tm_wday + val;  /* early next week */
 263         else
 264           val -= t->tm_wday;           /* later this week */
 265       else
 266         val *= 7;                      /* "-v+5w" == "5 weeks in the future" */
 267       return !val || adjday(t, '+', val, mk);
 268     case '-':
 269       if (istext) {
 270         if (val > t->tm_wday)
 271           val = 7 - val + t->tm_wday;  /* later last week */
 272         else
 273           val = t->tm_wday - val;      /* early this week */
 274       } else
 275         val *= 7;                      /* "-v-5w" == "5 weeks ago" */
 276       return !val || adjday(t, '-', val, mk);
 277     default:
 278       if (val < t->tm_wday)
 279         return adjday(t, '-', t->tm_wday - val, mk);
 280       else if (val > 6)
 281         return 0;
 282       else if (val > t->tm_wday)
 283         return adjday(t, '+', val - t->tm_wday, mk);
 284   }
 285   return 1;
 286 }
 287
 288 static int
 289 adjhour(struct tm *t, char type, int val, int mk)
 290 {
 291   if (val < 0)
 292     return 0;
 293
 294   switch (type) {
 295     case '+':
 296       if (val) {
 297         int days;
 298
 299         days = (t->tm_hour + val) / 24;
 300         val %= 24;
 301         t->tm_hour += val;
 302         t->tm_hour %= 24;
 303         if (!adjday(t, '+', days, 0))
 304           return 0;
 305       }
 306       break;
 307
 308     case '-':
 309       if (val) {
 310         int days;
 311
 312         days = val / 24;
 313         val %= 24;
 314         if (val > t->tm_hour) {
 315           days++;
 316           val -= 24;
 317         }
 318         t->tm_hour -= val;
 319         if (!adjday(t, '-', days, 0))
 320           return 0;
 321       }
 322       break;
 323
 324     default:
 325       if (val > 23)
 326         return 0;
 327       t->tm_hour = val;
 328   }
 329
 330   return !mk || domktime(t, type) != -1;
 331 }
 332
 333 static int
 334 adjmin(struct tm *t, char type, int val, int mk)
 335 {
 336   if (val < 0)
 337     return 0;
 338
 339   switch (type) {
 340     case '+':
 341       if (val) {
 342         if (!adjhour(t, '+', (t->tm_min + val) / 60, 0))
 343           return 0;
 344         val %= 60;
 345         t->tm_min += val;
 346         if (t->tm_min > 59)
 347           t->tm_min -= 60;
 348       }
 349       break;
 350
 351     case '-':
 352       if (val) {
 353         if (!adjhour(t, '-', val / 60, 0))
 354           return 0;
 355         val %= 60;
 356         if (val > t->tm_min) {
 357           if (!adjhour(t, '-', 1, 0))
 358             return 0;
 359           val -= 60;
 360         }
 361         t->tm_min -= val;
 362       }
 363       break;
 364
 365     default:
 366       if (val > 59)
 367         return 0;
 368       t->tm_min = val;
 369   }
 370
 371   return !mk || domktime(t, type) != -1;
 372 }
 373
 374 static int
 375 adjsec(struct tm *t, char type, int val, int mk)
 376 {
 377   if (val < 0)
 378     return 0;
 379
 380   switch (type) {
 381     case '+':
 382       if (val) {
 383         if (!adjmin(t, '+', (t->tm_sec + val) / 60, 0))
 384           return 0;
 385         val %= 60;
 386         t->tm_sec += val;
 387         if (t->tm_sec > 59)
 388           t->tm_sec -= 60;
 389       }
 390       break;
 391
 392     case '-':
 393       if (val) {
 394         if (!adjmin(t, '-', val / 60, 0))
 395           return 0;
 396         val %= 60;
 397         if (val > t->tm_sec) {
 398           if (!adjmin(t, '-', 1, 0))
 399             return 0;
 400           val -= 60;
 401         }
 402         t->tm_sec -= val;
 403       }
 404       break;
 405
 406     default:
 407       if (val > 59)
 408         return 0;
 409       t->tm_sec = val;
 410   }
 411
 412   return !mk || domktime(t, type) != -1;
 413 }
 414
 415 const struct vary *
 416 vary_apply(const struct vary *v, struct tm *t)
 417 {
 418   char type;
 419   char which;
 420   char *arg;
 421   size_t len;
 422   int val;
 423
 424   for (; v; v = v->next) {
 425     type = *v->arg;
 426     arg = v->arg;
 427     if (type == '+' || type == '-')
 428       arg++;
 429     else
 430       type = '\0';
 431     len = strlen(arg);
 432     if (len < 2)
 433       return v;
 434
 435     if (type == '\0')
 436       t->tm_isdst = -1;
 437
 438     if (strspn(arg, digits) != len-1) {
 439       val = trans(trans_wday, arg);
 440       if (val != -1) {
 441           if (!adjwday(t, type, val, 1, 1))
 442             return v;
 443       } else {
 444         val = trans(trans_mon, arg);
 445         if (val != -1) {
 446           if (!adjmon(t, type, val, 1, 1))
 447             return v;
 448         } else
 449           return v;
 450       }
 451     } else {
 452       val = atoi(arg);
 453       which = arg[len-1];
 454
 455       switch (which) {
 456         case 'S':
 457           if (!adjsec(t, type, val, 1))
 458             return v;
 459           break;
 460         case 'M':
 461           if (!adjmin(t, type, val, 1))
 462             return v;
 463           break;
 464         case 'H':
 465           if (!adjhour(t, type, val, 1))
 466             return v;
 467           break;
 468         case 'd':
 469           t->tm_isdst = -1;
 470           if (!adjday(t, type, val, 1))
 471             return v;
 472           break;
 473         case 'w':
 474           t->tm_isdst = -1;
 475           if (!adjwday(t, type, val, 0, 1))
 476             return v;
 477           break;
 478         case 'm':
 479           t->tm_isdst = -1;
 480           if (!adjmon(t, type, val, 0, 1))
 481             return v;
 482           break;
 483         case 'y':
 484           t->tm_isdst = -1;
 485           if (!adjyear(t, type, val, 1))
 486             return v;
 487           break;
 488         default:
 489           return v;
 490       }
 491     }
 492   }
 493   return 0;
 494 }
 495
 496 void
 497 vary_destroy(struct vary *v)
 498 {
 499   struct vary *n;
 500
 501   while (v) {
 502     n = v->next;
 503     free(v);
 504     v = n;
 505   }
 506 }