vary.c revision 60836 
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#ifndef lint
28static const char rcsid[] =
29  "$FreeBSD: head/bin/date/vary.c 60836 2000-05-23 23:58:18Z brian $";
30#endif /* not lint */
31
32#include <time.h>
33#include <string.h>
34#include <stdlib.h>
35#include "vary.h"
36
37struct trans {
38  int val;
39  char *str;
40};
41
42static struct trans trans_mon[] = {
43  { 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
44  { 5, "may"}, { 6, "june" }, { 7, "july" }, { 8, "august" },
45  { 9, "september" }, { 10, "october" }, { 11, "november" }, { 12, "december" },
46  { -1, NULL }
47};
48
49static struct trans trans_wday[] = {
50  { 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
51  { 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
52  { -1, NULL }
53};
54
55static char digits[] = "0123456789";
56static int adjhour(struct tm *, char, int, int);
57
58static int
59domktime(struct tm *t, char type)
60{
61  time_t ret;
62
63  while ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
64    /* While mktime() fails, adjust by an hour */
65    adjhour(t, type == '-' ? type : '+', 1, 0);
66
67  return ret;
68}
69
70static int
71trans(const struct trans t[], const char *arg)
72{
73  int f;
74
75  for (f = 0; t[f].val != -1; f++)
76    if (!strncasecmp(t[f].str, arg, 3) ||
77        !strncasecmp(t[f].str, arg, strlen(t[f].str)))
78      return t[f].val;
79
80  return -1;
81}
82
83struct vary *
84vary_append(struct vary *v, char *arg)
85{
86  struct vary *result, **nextp;
87
88  if (v) {
89    result = v;
90    while (v->next)
91      v = v->next;
92    nextp = &v->next;
93  } else
94    nextp = &result;
95
96  *nextp = (struct vary *)malloc(sizeof(struct vary));
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  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
201static int
202adjday(struct tm *t, char type, int val, int mk)
203{
204  int mdays;
205
206  switch (type) {
207    case '+':
208      while (val) {
209        mdays = daysinmonth(t);
210        if (val > mdays - t->tm_mday) {
211          val -= mdays - 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
245static int
246adjwday(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
281static int
282adjhour(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
326static int
327adjmin(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
367static int
368adjsec(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
408const struct vary *
409vary_apply(const struct vary *v, struct tm *t)
410{
411  char type;
412  char which;
413  char *arg;
414  int 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
489void
490vary_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}
500