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
36struct trans {
37  int val;
38  const char *str;
39};
40
41static 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
48static 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
54static char digits[] = "0123456789";
55static int adjhour(struct tm *, char, int, int);
56
57static int
58domktime(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
69static int
70trans(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
82struct vary *
83vary_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
102static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
103
104static int
105daysinmonth(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
127static int
128adjyear(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
148static int
149adjmon(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
208static int
209adjday(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
252static int
253adjwday(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
288static int
289adjhour(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
333static int
334adjmin(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
374static int
375adjsec(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
415const struct vary *
416vary_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
496void
497vary_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}
507