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 1.16 2004/08/09 13:43:39 yar Exp $
  27  * $DragonFly: src/bin/date/vary.c,v 1.4 2005/07/20 06:10:51 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   int lmdays;
 152   if (val < 0)
 153     return 0;
 154
 155   switch (type) {
 156     case '+':
 157       if (istext) {
 158         if (val <= t->tm_mon)
 159           val += 11 - t->tm_mon;        /* early next year */
 160         else
 161           val -= t->tm_mon + 1;         /* later this year */
 162       }
 163       if (val) {
 164         if (!adjyear(t, '+', (t->tm_mon + val) / 12, 0))
 165           return 0;
 166         val %= 12;
 167         t->tm_mon += val;
 168         if (t->tm_mon > 11)
 169           t->tm_mon -= 12;
 170       }
 171       break;
 172
 173     case '-':
 174       if (istext) {
 175         if (val-1 > t->tm_mon)
 176           val = 13 - val + t->tm_mon;   /* later last year */
 177         else
 178           val = t->tm_mon - val + 1;    /* early this year */
 179       }
 180       if (val) {
 181         if (!adjyear(t, '-', val / 12, 0))
 182           return 0;
 183         val %= 12;
 184         if (val > t->tm_mon) {
 185           if (!adjyear(t, '-', 1, 0))
 186             return 0;
 187           val -= 12;
 188         }
 189         t->tm_mon -= val;
 190       }
 191       break;
 192
 193     default:
 194       if (val > 12 || val < 1)
 195         return 0;
 196       t->tm_mon = --val;
 197   }
 198
 199   /* e.g., -v-1m on March, 31 is the last day of February in common sense */
 200   lmdays = daysinmonth(t);
 201   if (t->tm_mday > lmdays)
 202     t->tm_mday = lmdays;
 203
 204   return !mk || domktime(t, type) != -1;
 205 }
 206
 207 static int
 208 adjday(struct tm *t, char type, int val, int mk)
 209 {
 210   int daycount;
 211
 212   switch (type) {
 213     case '+':
 214       while (val) {
 215         daycount = daysinmonth(t);
 216         if (val > daycount - t->tm_mday) {
 217           val -= daycount - t->tm_mday + 1;
 218           t->tm_mday = 1;
 219           if (!adjmon(t, '+', 1, 0, 0))
 220             return 0;
 221         } else {
 222           t->tm_mday += val;
 223           val = 0;
 224         }
 225       }
 226       break;
 227     case '-':
 228       while (val)
 229         if (val >= t->tm_mday) {
 230           val -= t->tm_mday;
 231           t->tm_mday = 1;
 232           if (!adjmon(t, '-', 1, 0, 0))
 233             return 0;
 234           t->tm_mday = daysinmonth(t);
 235         } else {
 236           t->tm_mday -= val;
 237           val = 0;
 238         }
 239       break;
 240     default:
 241       if (val > 0 && val <= daysinmonth(t))
 242         t->tm_mday = val;
 243       else
 244         return 0;
 245       break;
 246   }
 247
 248   return !mk || domktime(t, type) != -1;
 249 }
 250
 251 static int
 252 adjwday(struct tm *t, char type, int val, int istext, int mk)
 253 {
 254   if (val < 0)
 255     return 0;
 256
 257   switch (type) {
 258     case '+':
 259       if (istext)
 260         if (val < t->tm_wday)
 261           val = 7 - t->tm_wday + val;  /* early next week */
 262         else
 263           val -= t->tm_wday;           /* later this week */
 264       else
 265         val *= 7;                      /* "-v+5w" == "5 weeks in the future" */
 266       return !val || adjday(t, '+', val, mk);
 267     case '-':
 268       if (istext) {
 269         if (val > t->tm_wday)
 270           val = 7 - val + t->tm_wday;  /* later last week */
 271         else
 272           val = t->tm_wday - val;      /* early this week */
 273       } else
 274         val *= 7;                      /* "-v-5w" == "5 weeks ago" */
 275       return !val || adjday(t, '-', val, mk);
 276     default:
 277       if (val < t->tm_wday)
 278         return adjday(t, '-', t->tm_wday - val, mk);
 279       else if (val > 6)
 280         return 0;
 281       else if (val > t->tm_wday)
 282         return adjday(t, '+', val - t->tm_wday, mk);
 283   }
 284   return 1;
 285 }
 286
 287 static int
 288 adjhour(struct tm *t, char type, int val, int mk)
 289 {
 290   if (val < 0)
 291     return 0;
 292
 293   switch (type) {
 294     case '+':
 295       if (val) {
 296         int days;
 297
 298         days = (t->tm_hour + val) / 24;
 299         val %= 24;
 300         t->tm_hour += val;
 301         t->tm_hour %= 24;
 302         if (!adjday(t, '+', days, 0))
 303           return 0;
 304       }
 305       break;
 306
 307     case '-':
 308       if (val) {
 309         int days;
 310
 311         days = val / 24;
 312         val %= 24;
 313         if (val > t->tm_hour) {
 314           days++;
 315           val -= 24;
 316         }
 317         t->tm_hour -= val;
 318         if (!adjday(t, '-', days, 0))
 319           return 0;
 320       }
 321       break;
 322
 323     default:
 324       if (val > 23)
 325         return 0;
 326       t->tm_hour = val;
 327   }
 328
 329   return !mk || domktime(t, type) != -1;
 330 }
 331
 332 static int
 333 adjmin(struct tm *t, char type, int val, int mk)
 334 {
 335   if (val < 0)
 336     return 0;
 337
 338   switch (type) {
 339     case '+':
 340       if (val) {
 341         if (!adjhour(t, '+', (t->tm_min + val) / 60, 0))
 342           return 0;
 343         val %= 60;
 344         t->tm_min += val;
 345         if (t->tm_min > 59)
 346           t->tm_min -= 60;
 347       }
 348       break;
 349
 350     case '-':
 351       if (val) {
 352         if (!adjhour(t, '-', val / 60, 0))
 353           return 0;
 354         val %= 60;
 355         if (val > t->tm_min) {
 356           if (!adjhour(t, '-', 1, 0))
 357             return 0;
 358           val -= 60;
 359         }
 360         t->tm_min -= val;
 361       }
 362       break;
 363
 364     default:
 365       if (val > 59)
 366         return 0;
 367       t->tm_min = val;
 368   }
 369
 370   return !mk || domktime(t, type) != -1;
 371 }
 372
 373 static int
 374 adjsec(struct tm *t, char type, int val, int mk)
 375 {
 376   if (val < 0)
 377     return 0;
 378
 379   switch (type) {
 380     case '+':
 381       if (val) {
 382         if (!adjmin(t, '+', (t->tm_sec + val) / 60, 0))
 383           return 0;
 384         val %= 60;
 385         t->tm_sec += val;
 386         if (t->tm_sec > 59)
 387           t->tm_sec -= 60;
 388       }
 389       break;
 390
 391     case '-':
 392       if (val) {
 393         if (!adjmin(t, '-', val / 60, 0))
 394           return 0;
 395         val %= 60;
 396         if (val > t->tm_sec) {
 397           if (!adjmin(t, '-', 1, 0))
 398             return 0;
 399           val -= 60;
 400         }
 401         t->tm_sec -= val;
 402       }
 403       break;
 404
 405     default:
 406       if (val > 59)
 407         return 0;
 408       t->tm_sec = val;
 409   }
 410
 411   return !mk || domktime(t, type) != -1;
 412 }
 413
 414 const struct vary *
 415 vary_apply(const struct vary *v, struct tm *t)
 416 {
 417   char type;
 418   char which;
 419   char *arg;
 420   size_t len;
 421   int val;
 422
 423   for (; v; v = v->next) {
 424     type = *v->arg;
 425     arg = v->arg;
 426     if (type == '+' || type == '-')
 427       arg++;
 428     else
 429       type = '\0';
 430     len = strlen(arg);
 431     if (len < 2)
 432       return v;
 433
 434     if (type == '\0')
 435       t->tm_isdst = -1;
 436
 437     if (strspn(arg, digits) != len-1) {
 438       val = trans(trans_wday, arg);
 439       if (val != -1) {
 440           if (!adjwday(t, type, val, 1, 1))
 441             return v;
 442       } else {
 443         val = trans(trans_mon, arg);
 444         if (val != -1) {
 445           if (!adjmon(t, type, val, 1, 1))
 446             return v;
 447         } else
 448           return v;
 449       }
 450     } else {
 451       val = atoi(arg);
 452       which = arg[len-1];
 453
 454       switch (which) {
 455         case 'S':
 456           if (!adjsec(t, type, val, 1))
 457             return v;
 458           break;
 459         case 'M':
 460           if (!adjmin(t, type, val, 1))
 461             return v;
 462           break;
 463         case 'H':
 464           if (!adjhour(t, type, val, 1))
 465             return v;
 466           break;
 467         case 'd':
 468           t->tm_isdst = -1;
 469           if (!adjday(t, type, val, 1))
 470             return v;
 471           break;
 472         case 'w':
 473           t->tm_isdst = -1;
 474           if (!adjwday(t, type, val, 0, 1))
 475             return v;
 476           break;
 477         case 'm':
 478           t->tm_isdst = -1;
 479           if (!adjmon(t, type, val, 0, 1))
 480             return v;
 481           break;
 482         case 'y':
 483           t->tm_isdst = -1;
 484           if (!adjyear(t, type, val, 1))
 485             return v;
 486           break;
 487         default:
 488           return v;
 489       }
 490     }
 491   }
 492   return 0;
 493 }
 494
 495 void
 496 vary_destroy(struct vary *v)
 497 {
 498   struct vary *n;
 499
 500   while (v) {
 501     n = v->next;
 502     free(v);
 503     v = n;
 504   }
 505 }