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#include <err.h>
29#include <time.h>
30#include <stdint.h>
31#include <string.h>
32#include <stdlib.h>
33#include "vary.h"
34
35struct trans {
36  int64_t val;
37  const char *str;
38};
39
40static struct trans trans_mon[] = {
41  { 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
42  { 5, "may"}, { 6, "june" }, { 7, "july" }, { 8, "august" },
43  { 9, "september" }, { 10, "october" }, { 11, "november" }, { 12, "december" },
44  { -1, NULL }
45};
46
47static struct trans trans_wday[] = {
48  { 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
49  { 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
50  { -1, NULL }
51};
52
53static char digits[] = "0123456789";
54static int adjhour(struct tm *, char, int64_t, int);
55
56static int
57domktime(struct tm *t, char type)
58{
59  time_t ret;
60
61  while ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
62    /* While mktime() fails, adjust by an hour */
63    adjhour(t, type == '-' ? type : '+', 1, 0);
64
65  return ret;
66}
67
68static int
69trans(const struct trans t[], const char *arg)
70{
71  int f;
72
73  for (f = 0; t[f].val != -1; f++)
74    if (!strncasecmp(t[f].str, arg, 3) ||
75        !strncasecmp(t[f].str, arg, strlen(t[f].str)))
76      return t[f].val;
77
78  return -1;
79}
80
81struct vary *
82vary_append(struct vary *v, char *arg)
83{
84  struct vary *result, **nextp;
85
86  if (v) {
87    result = v;
88    while (v->next)
89      v = v->next;
90    nextp = &v->next;
91  } else
92    nextp = &result;
93
94  if ((*nextp = (struct vary *)malloc(sizeof(struct vary))) == NULL)
95    err(1, "malloc");
96  (*nextp)->arg = arg;
97  (*nextp)->next = NULL;
98  return result;
99}
100
101static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
102
103static int
104daysinmonth(const struct tm *t)
105{
106  int year;
107
108  year = t->tm_year + 1900;
109
110  if (t->tm_mon == 1)
111    if (!(year % 400))
112      return 29;
113    else if (!(year % 100))
114      return 28;
115    else if (!(year % 4))
116      return 29;
117    else
118      return 28;
119  else if (t->tm_mon >= 0 && t->tm_mon < 12)
120    return mdays[t->tm_mon];
121
122  return 0;
123}
124
125
126static int
127adjyear(struct tm *t, char type, int64_t val, int mk)
128{
129  switch (type) {
130    case '+':
131      t->tm_year += val;
132      break;
133    case '-':
134      t->tm_year -= val;
135      break;
136    default:
137      t->tm_year = val;
138      if (t->tm_year < 69)
139      	t->tm_year += 100;		/* as per date.c */
140      else if (t->tm_year > 1900)
141        t->tm_year -= 1900;             /* struct tm holds years since 1900 */
142      break;
143  }
144  return !mk || domktime(t, type) != -1;
145}
146
147static int
148adjmon(struct tm *t, char type, int64_t val, int istext, int mk)
149{
150  int lmdays;
151
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
207static int
208adjday(struct tm *t, char type, int64_t val, int mk)
209{
210  int lmdays;
211
212  switch (type) {
213    case '+':
214      while (val) {
215        lmdays = daysinmonth(t);
216        if (val > lmdays - t->tm_mday) {
217          val -= lmdays - 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
251static int
252adjwday(struct tm *t, char type, int64_t 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
287static int
288adjhour(struct tm *t, char type, int64_t 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
332static int
333adjmin(struct tm *t, char type, int64_t 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
373static int
374adjsec(struct tm *t, char type, int64_t 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
414const struct vary *
415vary_apply(const struct vary *v, struct tm *t)
416{
417  char type;
418  char which;
419  char *arg;
420  size_t len;
421  int64_t 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
495void
496vary_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}
506