bin/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  * $FreeBSD: src/bin/date/vary.c,v 1.8.2.2 2000/12/08 11:42:53 brian Exp $
  27  * $DragonFly: src/bin/date/vary.c,v 1.3 2004/03/19 17:30:59 cpressey Exp $
  28  */
  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   if (val < 0)
 152     return 0;
 153
 154   switch (type) {
 155     case '+':
 156       if (istext) {
 157         if (val <= t->tm_mon)
 158           val += 11 - t->tm_mon;        /* early next year */
 159         else
 160           val -= t->tm_mon + 1;         /* later this year */
 161       }
 162       if (val) {
 163         if (!adjyear(t, '+', (t->tm_mon + val) / 12, 0))
 164           return 0;
 165         val %= 12;
 166         t->tm_mon += val;
 167         if (t->tm_mon > 11)
 168           t->tm_mon -= 12;
 169       }
 170       break;
 171
 172     case '-':
 173       if (istext) {
 174         if (val-1 > t->tm_mon)
 175           val = 13 - val + t->tm_mon;   /* later last year */
 176         else
 177           val = t->tm_mon - val + 1;    /* early this year */
 178       }
 179       if (val) {
 180         if (!adjyear(t, '-', val / 12, 0))
 181           return 0;
 182         val %= 12;
 183         if (val > t->tm_mon) {
 184           if (!adjyear(t, '-', 1, 0))
 185             return 0;
 186           val -= 12;
 187         }
 188         t->tm_mon -= val;
 189       }
 190       break;
 191
 192     default:
 193       if (val > 12 || val < 1)
 194         return 0;
 195       t->tm_mon = --val;
 196   }
 197
 198   return !mk || domktime(t, type) != -1;
 199 }
 200
 201 static int
 202 adjday(struct tm *t, char type, int val, int mk)
 203 {
 204   int daycount;
 205
 206   switch (type) {
 207     case '+':
 208       while (val) {
 209         daycount = daysinmonth(t);
 210         if (val > daycount - t->tm_mday) {
 211           val -= daycount - t->tm_mday + 1;
 212           t->tm_mday = 1;
 213           if (!adjmon(t, '+', 1, 0, 0))
 214             return 0;
 215         } else {
 216           t->tm_mday += val;
 217           val = 0;
 218         }
 219       }
 220       break;
 221     case '-':
 222       while (val)
 223         if (val >= t->tm_mday) {
 224           val -= t->tm_mday;
 225           t->tm_mday = 1;
 226           if (!adjmon(t, '-', 1, 0, 0))
 227             return 0;
 228           t->tm_mday = daysinmonth(t);
 229         } else {
 230           t->tm_mday -= val;
 231           val = 0;
 232         }
 233       break;
 234     default:
 235       if (val > 0 && val <= daysinmonth(t))
 236         t->tm_mday = val;
 237       else
 238         return 0;
 239       break;
 240   }
 241
 242   return !mk || domktime(t, type) != -1;
 243 }
 244
 245 static int
 246 adjwday(struct tm *t, char type, int val, int istext, int mk)
 247 {
 248   if (val < 0)
 249     return 0;
 250
 251   switch (type) {
 252     case '+':
 253       if (istext)
 254         if (val < t->tm_wday)
 255           val = 7 - t->tm_wday + val;  /* early next week */
 256         else
 257           val -= t->tm_wday;           /* later this week */
 258       else
 259         val *= 7;                      /* "-v+5w" == "5 weeks in the future" */
 260       return !val || adjday(t, '+', val, mk);
 261     case '-':
 262       if (istext) {
 263         if (val > t->tm_wday)
 264           val = 7 - val + t->tm_wday;  /* later last week */
 265         else
 266           val = t->tm_wday - val;      /* early this week */
 267       } else
 268         val *= 7;                      /* "-v-5w" == "5 weeks ago" */
 269       return !val || adjday(t, '-', val, mk);
 270     default:
 271       if (val < t->tm_wday)
 272         return adjday(t, '-', t->tm_wday - val, mk);
 273       else if (val > 6)
 274         return 0;
 275       else if (val > t->tm_wday)
 276         return adjday(t, '+', val - t->tm_wday, mk);
 277   }
 278   return 1;
 279 }
 280
 281 static int
 282 adjhour(struct tm *t, char type, int val, int mk)
 283 {
 284   if (val < 0)
 285     return 0;
 286
 287   switch (type) {
 288     case '+':
 289       if (val) {
 290         int days;
 291
 292         days = (t->tm_hour + val) / 24;
 293         val %= 24;
 294         t->tm_hour += val;
 295         t->tm_hour %= 24;
 296         if (!adjday(t, '+', days, 0))
 297           return 0;
 298       }
 299       break;
 300
 301     case '-':
 302       if (val) {
 303         int days;
 304
 305         days = val / 24;
 306         val %= 24;
 307         if (val > t->tm_hour) {
 308           days++;
 309           val -= 24;
 310         }
 311         t->tm_hour -= val;
 312         if (!adjday(t, '-', days, 0))
 313           return 0;
 314       }
 315       break;
 316
 317     default:
 318       if (val > 23)
 319         return 0;
 320       t->tm_hour = val;
 321   }
 322
 323   return !mk || domktime(t, type) != -1;
 324 }
 325
 326 static int
 327 adjmin(struct tm *t, char type, int val, int mk)
 328 {
 329   if (val < 0)
 330     return 0;
 331
 332   switch (type) {
 333     case '+':
 334       if (val) {
 335         if (!adjhour(t, '+', (t->tm_min + val) / 60, 0))
 336           return 0;
 337         val %= 60;
 338         t->tm_min += val;
 339         if (t->tm_min > 59)
 340           t->tm_min -= 60;
 341       }
 342       break;
 343
 344     case '-':
 345       if (val) {
 346         if (!adjhour(t, '-', val / 60, 0))
 347           return 0;
 348         val %= 60;
 349         if (val > t->tm_min) {
 350           if (!adjhour(t, '-', 1, 0))
 351             return 0;
 352           val -= 60;
 353         }
 354         t->tm_min -= val;
 355       }
 356       break;
 357
 358     default:
 359       if (val > 59)
 360         return 0;
 361       t->tm_min = val;
 362   }
 363
 364   return !mk || domktime(t, type) != -1;
 365 }
 366
 367 static int
 368 adjsec(struct tm *t, char type, int val, int mk)
 369 {
 370   if (val < 0)
 371     return 0;
 372
 373   switch (type) {
 374     case '+':
 375       if (val) {
 376         if (!adjmin(t, '+', (t->tm_sec + val) / 60, 0))
 377           return 0;
 378         val %= 60;
 379         t->tm_sec += val;
 380         if (t->tm_sec > 59)
 381           t->tm_sec -= 60;
 382       }
 383       break;
 384
 385     case '-':
 386       if (val) {
 387         if (!adjmin(t, '-', val / 60, 0))
 388           return 0;
 389         val %= 60;
 390         if (val > t->tm_sec) {
 391           if (!adjmin(t, '-', 1, 0))
 392             return 0;
 393           val -= 60;
 394         }
 395         t->tm_sec -= val;
 396       }
 397       break;
 398
 399     default:
 400       if (val > 59)
 401         return 0;
 402       t->tm_sec = val;
 403   }
 404
 405   return !mk || domktime(t, type) != -1;
 406 }
 407
 408 const struct vary *
 409 vary_apply(const struct vary *v, struct tm *t)
 410 {
 411   char type;
 412   char which;
 413   char *arg;
 414   size_t len;
 415   int val;
 416
 417   for (; v; v = v->next) {
 418     type = *v->arg;
 419     arg = v->arg;
 420     if (type == '+' || type == '-')
 421       arg++;
 422     else
 423       type = '\0';
 424     len = strlen(arg);
 425     if (len < 2)
 426       return v;
 427
 428     if (type == '\0')
 429       t->tm_isdst = -1;
 430
 431     if (strspn(arg, digits) != len-1) {
 432       val = trans(trans_wday, arg);
 433       if (val != -1) {
 434           if (!adjwday(t, type, val, 1, 1))
 435             return v;
 436       } else {
 437         val = trans(trans_mon, arg);
 438         if (val != -1) {
 439           if (!adjmon(t, type, val, 1, 1))
 440             return v;
 441         } else
 442           return v;
 443       }
 444     } else {
 445       val = atoi(arg);
 446       which = arg[len-1];
 447
 448       switch (which) {
 449         case 'S':
 450           if (!adjsec(t, type, val, 1))
 451             return v;
 452           break;
 453         case 'M':
 454           if (!adjmin(t, type, val, 1))
 455             return v;
 456           break;
 457         case 'H':
 458           if (!adjhour(t, type, val, 1))
 459             return v;
 460           break;
 461         case 'd':
 462           t->tm_isdst = -1;
 463           if (!adjday(t, type, val, 1))
 464             return v;
 465           break;
 466         case 'w':
 467           t->tm_isdst = -1;
 468           if (!adjwday(t, type, val, 0, 1))
 469             return v;
 470           break;
 471         case 'm':
 472           t->tm_isdst = -1;
 473           if (!adjmon(t, type, val, 0, 1))
 474             return v;
 475           break;
 476         case 'y':
 477           t->tm_isdst = -1;
 478           if (!adjyear(t, type, val, 1))
 479             return v;
 480           break;
 481         default:
 482           return v;
 483       }
 484     }
 485   }
 486   return 0;
 487 }
 488
 489 void
 490 vary_destroy(struct vary *v)
 491 {
 492   struct vary *n;
 493
 494   while (v) {
 495     n = v->next;
 496     free(v);
 497     v = n;
 498   }
 499 }