vary.c revision 69457 
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 69457 2000-12-01 09:59:40Z brian $";
30#endif /* not lint */
31
32#include <err.h>
33#include <time.h>
34#include <string.h>
35#include <stdlib.h>
36#include "vary.h"
37
38struct trans {
39  int val;
40  char *str;
41};
42
43static struct trans trans_mon[] = {
44  { 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
45  { 5, "may"}, { 6, "june" }, { 7, "july" }, { 8, "august" },
46  { 9, "september" }, { 10, "october" }, { 11, "november" }, { 12, "december" },
47  { -1, NULL }
48};
49
50static struct trans trans_wday[] = {
51  { 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
52  { 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
53  { -1, NULL }
54};
55
56static char digits[] = "0123456789";
57static int adjhour(struct tm *, char, int, int);
58
59static int
60domktime(struct tm *t, char type)
61{
62  time_t ret;
63
64  while ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
65    /* While mktime() fails, adjust by an hour */
66    adjhour(t, type == '-' ? type : '+', 1, 0);
67
68  return ret;
69}
70
71static int
72trans(const struct trans t[], const char *arg)
73{
74  int f;
75
76  for (f = 0; t[f].val != -1; f++)
77    if (!strncasecmp(t[f].str, arg, 3) ||
78        !strncasecmp(t[f].str, arg, strlen(t[f].str)))
79      return t[f].val;
80
81  return -1;
82}
83
84struct vary *
85vary_append(struct vary *v, char *arg)
86{
87  struct vary *result, **nextp;
88
89  if (v) {
90    result = v;
91    while (v->next)
92      v = v->next;
93    nextp = &v->next;
94  } else
95    nextp = &result;
96
97  if ((*nextp = (struct vary *)malloc(sizeof(struct vary))) == NULL)
98    err(1, "malloc");
99  (*nextp)->arg = arg;
100  (*nextp)->next = NULL;
101  return result;
102}
103
104static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
105
106static int
107daysinmonth(const struct tm *t)
108{
109  int year;
110
111  year = t->tm_year + 1900;
112
113  if (t->tm_mon == 1)
114    if (!(year % 400))
115      return 29;
116    else if (!(year % 100))
117      return 28;
118    else if (!(year % 4))
119      return 29;
120    else
121      return 28;
122  else if (t->tm_mon >= 0 && t->tm_mon < 12)
123    return mdays[t->tm_mon];
124
125  return 0;
126}
127
128
129static int
130adjyear(struct tm *t, char type, int val, int mk)
131{
132  switch (type) {
133    case '+':
134      t->tm_year += val;
135      break;
136    case '-':
137      t->tm_year -= val;
138      break;
139    default:
140      t->tm_year = val;
141      if (t->tm_year < 69)
142      	t->tm_year += 100;		/* as per date.c */
143      else if (t->tm_year > 1900)
144        t->tm_year -= 1900;             /* struct tm holds years since 1900 */
145      break;
146  }
147  return !mk || domktime(t, type) != -1;
148}
149
150static int
151adjmon(struct tm *t, char type, int val, int istext, int mk)
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  return !mk || domktime(t, type) != -1;
201}
202
203static int
204adjday(struct tm *t, char type, int val, int mk)
205{
206  int mdays;
207
208  switch (type) {
209    case '+':
210      while (val) {
211        mdays = daysinmonth(t);
212        if (val > mdays - t->tm_mday) {
213          val -= mdays - t->tm_mday + 1;
214          t->tm_mday = 1;
215          if (!adjmon(t, '+', 1, 0, 0))
216            return 0;
217        } else {
218          t->tm_mday += val;
219          val = 0;
220        }
221      }
222      break;
223    case '-':
224      while (val)
225        if (val >= t->tm_mday) {
226          val -= t->tm_mday;
227          t->tm_mday = 1;
228          if (!adjmon(t, '-', 1, 0, 0))
229            return 0;
230          t->tm_mday = daysinmonth(t);
231        } else {
232          t->tm_mday -= val;
233          val = 0;
234        }
235      break;
236    default:
237      if (val > 0 && val <= daysinmonth(t))
238        t->tm_mday = val;
239      else
240        return 0;
241      break;
242  }
243
244  return !mk || domktime(t, type) != -1;
245}
246
247static int
248adjwday(struct tm *t, char type, int val, int istext, int mk)
249{
250  if (val < 0)
251    return 0;
252
253  switch (type) {
254    case '+':
255      if (istext)
256        if (val < t->tm_wday)
257          val = 7 - t->tm_wday + val;  /* early next week */
258        else
259          val -= t->tm_wday;           /* later this week */
260      else
261        val *= 7;                      /* "-v+5w" == "5 weeks in the future" */
262      return !val || adjday(t, '+', val, mk);
263    case '-':
264      if (istext) {
265        if (val > t->tm_wday)
266          val = 7 - val + t->tm_wday;  /* later last week */
267        else
268          val = t->tm_wday - val;      /* early this week */
269      } else
270        val *= 7;                      /* "-v-5w" == "5 weeks ago" */
271      return !val || adjday(t, '-', val, mk);
272    default:
273      if (val < t->tm_wday)
274        return adjday(t, '-', t->tm_wday - val, mk);
275      else if (val > 6)
276        return 0;
277      else if (val > t->tm_wday)
278        return adjday(t, '+', val - t->tm_wday, mk);
279  }
280  return 1;
281}
282
283static int
284adjhour(struct tm *t, char type, int val, int mk)
285{
286  if (val < 0)
287    return 0;
288
289  switch (type) {
290    case '+':
291      if (val) {
292        int days;
293
294        days = (t->tm_hour + val) / 24;
295        val %= 24;
296        t->tm_hour += val;
297        t->tm_hour %= 24;
298        if (!adjday(t, '+', days, 0))
299          return 0;
300      }
301      break;
302
303    case '-':
304      if (val) {
305        int days;
306
307        days = val / 24;
308        val %= 24;
309        if (val > t->tm_hour) {
310          days++;
311          val -= 24;
312        }
313        t->tm_hour -= val;
314        if (!adjday(t, '-', days, 0))
315          return 0;
316      }
317      break;
318
319    default:
320      if (val > 23)
321        return 0;
322      t->tm_hour = val;
323  }
324
325  return !mk || domktime(t, type) != -1;
326}
327
328static int
329adjmin(struct tm *t, char type, int val, int mk)
330{
331  if (val < 0)
332    return 0;
333
334  switch (type) {
335    case '+':
336      if (val) {
337        if (!adjhour(t, '+', (t->tm_min + val) / 60, 0))
338          return 0;
339        val %= 60;
340        t->tm_min += val;
341        if (t->tm_min > 59)
342          t->tm_min -= 60;
343      }
344      break;
345
346    case '-':
347      if (val) {
348        if (!adjhour(t, '-', val / 60, 0))
349          return 0;
350        val %= 60;
351        if (val > t->tm_min) {
352          if (!adjhour(t, '-', 1, 0))
353            return 0;
354          val -= 60;
355        }
356        t->tm_min -= val;
357      }
358      break;
359
360    default:
361      if (val > 59)
362        return 0;
363      t->tm_min = val;
364  }
365
366  return !mk || domktime(t, type) != -1;
367}
368
369static int
370adjsec(struct tm *t, char type, int val, int mk)
371{
372  if (val < 0)
373    return 0;
374
375  switch (type) {
376    case '+':
377      if (val) {
378        if (!adjmin(t, '+', (t->tm_sec + val) / 60, 0))
379          return 0;
380        val %= 60;
381        t->tm_sec += val;
382        if (t->tm_sec > 59)
383          t->tm_sec -= 60;
384      }
385      break;
386
387    case '-':
388      if (val) {
389        if (!adjmin(t, '-', val / 60, 0))
390          return 0;
391        val %= 60;
392        if (val > t->tm_sec) {
393          if (!adjmin(t, '-', 1, 0))
394            return 0;
395          val -= 60;
396        }
397        t->tm_sec -= val;
398      }
399      break;
400
401    default:
402      if (val > 59)
403        return 0;
404      t->tm_sec = val;
405  }
406
407  return !mk || domktime(t, type) != -1;
408}
409
410const struct vary *
411vary_apply(const struct vary *v, struct tm *t)
412{
413  char type;
414  char which;
415  char *arg;
416  int len;
417  int val;
418
419  for (; v; v = v->next) {
420    type = *v->arg;
421    arg = v->arg;
422    if (type == '+' || type == '-')
423      arg++;
424    else
425      type = '\0';
426    len = strlen(arg);
427    if (len < 2)
428      return v;
429
430    if (type == '\0')
431      t->tm_isdst = -1;
432
433    if (strspn(arg, digits) != len-1) {
434      val = trans(trans_wday, arg);
435      if (val != -1) {
436          if (!adjwday(t, type, val, 1, 1))
437            return v;
438      } else {
439        val = trans(trans_mon, arg);
440        if (val != -1) {
441          if (!adjmon(t, type, val, 1, 1))
442            return v;
443        } else
444          return v;
445      }
446    } else {
447      val = atoi(arg);
448      which = arg[len-1];
449
450      switch (which) {
451        case 'S':
452          if (!adjsec(t, type, val, 1))
453            return v;
454          break;
455        case 'M':
456          if (!adjmin(t, type, val, 1))
457            return v;
458          break;
459        case 'H':
460          if (!adjhour(t, type, val, 1))
461            return v;
462          break;
463        case 'd':
464          t->tm_isdst = -1;
465          if (!adjday(t, type, val, 1))
466            return v;
467          break;
468        case 'w':
469          t->tm_isdst = -1;
470          if (!adjwday(t, type, val, 0, 1))
471            return v;
472          break;
473        case 'm':
474          t->tm_isdst = -1;
475          if (!adjmon(t, type, val, 0, 1))
476            return v;
477          break;
478        case 'y':
479          t->tm_isdst = -1;
480          if (!adjyear(t, type, val, 1))
481            return v;
482          break;
483        default:
484          return v;
485      }
486    }
487  }
488  return 0;
489}
490
491void
492vary_destroy(struct vary *v)
493{
494  struct vary *n;
495
496  while (v) {
497    n = v->next;
498    free(v);
499    v = n;
500  }
501}
502