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SYSENTER/SYSCALL support
[minix.git] / commands / tar / getdate.c
blobffaa679ba1a33e25602f3014e87f9bd11f12a56f
1 /*
2 * This code is in the public domain and has no copyright.
3 *
4 * This is a plain C recursive-descent translation of an old
5 * public-domain YACC grammar that has been used for parsing dates in
6 * very many open-source projects.
7 *
8 * Since the original authors were generous enough to donate their
9 * work to the public domain, I feel compelled to match their
10 * generosity.
11 *
12 * Tim Kientzle, February 2009.
13 */
14
15 /*
16 * Header comment from original getdate.y:
17 */
18
19 /*
20 ** Originally written by Steven M. Bellovin <smb@research.att.com> while
21 ** at the University of North Carolina at Chapel Hill. Later tweaked by
22 ** a couple of people on Usenet. Completely overhauled by Rich $alz
23 ** <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
24 **
25 ** This grammar has 10 shift/reduce conflicts.
26 **
27 ** This code is in the public domain and has no copyright.
28 */
29
30 #ifdef __FreeBSD__
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 #endif
34
35 #include <ctype.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <time.h>
40
41 /* This file defines a single public function. */
42 time_t get_date(time_t now, char *);
43
44 /* Basic time units. */
45 #define EPOCH 1970
46 #define MINUTE (60L)
47 #define HOUR (60L * MINUTE)
48 #define DAY (24L * HOUR)
49
50 /* Daylight-savings mode: on, off, or not yet known. */
51 enum DSTMODE { DSTon, DSToff, DSTmaybe };
52 /* Meridian: am or pm. */
53 enum { tAM, tPM };
54 /* Token types returned by nexttoken() */
55 enum { tAGO = 260, tDAY, tDAYZONE, tAMPM, tMONTH, tMONTH_UNIT, tSEC_UNIT,
56 tUNUMBER, tZONE, tDST };
57 struct token { int token; time_t value; };
58
59 /*
60 * Parser state.
61 */
62 struct gdstate {
63 struct token *tokenp; /* Pointer to next token. */
64 /* HaveXxxx counts how many of this kind of phrase we've seen;
65 * it's a fatal error to have more than one time, zone, day,
66 * or date phrase. */
67 int HaveYear;
68 int HaveMonth;
69 int HaveDay;
70 int HaveWeekDay; /* Day of week */
71 int HaveTime; /* Hour/minute/second */
72 int HaveZone; /* timezone and/or DST info */
73 int HaveRel; /* time offset; we can have more than one */
74 /* Absolute time values. */
75 time_t Timezone; /* Seconds offset from GMT */
76 time_t Day;
77 time_t Hour;
78 time_t Minutes;
79 time_t Month;
80 time_t Seconds;
81 time_t Year;
82 /* DST selection */
83 enum DSTMODE DSTmode;
84 /* Day of week accounting, e.g., "3rd Tuesday" */
85 time_t DayOrdinal; /* "3" in "3rd Tuesday" */
86 time_t DayNumber; /* "Tuesday" in "3rd Tuesday" */
87 /* Relative time values: hour/day/week offsets are measured in
88 * seconds, month/year are counted in months. */
89 time_t RelMonth;
90 time_t RelSeconds;
91 };
92
93 /*
94 * A series of functions that recognize certain common time phrases.
95 * Each function returns 1 if it managed to make sense of some of the
96 * tokens, zero otherwise.
97 */
98
99 /*
100 * hour:minute or hour:minute:second with optional AM, PM, or numeric
101 * timezone offset
102 */
103 static int
104 timephrase(struct gdstate *gds)
105 {
106 if (gds->tokenp[0].token == tUNUMBER
107 && gds->tokenp[1].token == ':'
108 && gds->tokenp[2].token == tUNUMBER
109 && gds->tokenp[3].token == ':'
110 && gds->tokenp[4].token == tUNUMBER) {
111 /* "12:14:18" or "22:08:07" */
112 ++gds->HaveTime;
113 gds->Hour = gds->tokenp[0].value;
114 gds->Minutes = gds->tokenp[2].value;
115 gds->Seconds = gds->tokenp[4].value;
116 gds->tokenp += 5;
117 }
118 else if (gds->tokenp[0].token == tUNUMBER
119 && gds->tokenp[1].token == ':'
120 && gds->tokenp[2].token == tUNUMBER) {
121 /* "12:14" or "22:08" */
122 ++gds->HaveTime;
123 gds->Hour = gds->tokenp[0].value;
124 gds->Minutes = gds->tokenp[2].value;
125 gds->Seconds = 0;
126 gds->tokenp += 3;
127 }
128 else if (gds->tokenp[0].token == tUNUMBER
129 && gds->tokenp[1].token == tAMPM) {
130 /* "7" is a time if it's followed by "am" or "pm" */
131 ++gds->HaveTime;
132 gds->Hour = gds->tokenp[0].value;
133 gds->Minutes = gds->Seconds = 0;
134 /* We'll handle the AM/PM below. */
135 gds->tokenp += 1;
136 } else {
137 /* We can't handle this. */
138 return 0;
139 }
140
141 if (gds->tokenp[0].token == tAMPM) {
142 /* "7:12pm", "12:20:13am" */
143 if (gds->Hour == 12)
144 gds->Hour = 0;
145 if (gds->tokenp[0].value == tPM)
146 gds->Hour += 12;
147 gds->tokenp += 1;
148 }
149 if (gds->tokenp[0].token == '+'
150 && gds->tokenp[1].token == tUNUMBER) {
151 /* "7:14+0700" */
152 gds->HaveZone++;
153 gds->DSTmode = DSToff;
154 gds->Timezone = - ((gds->tokenp[1].value / 100) * HOUR
155 + (gds->tokenp[1].value % 100) * MINUTE);
156 gds->tokenp += 2;
157 }
158 if (gds->tokenp[0].token == '-'
159 && gds->tokenp[1].token == tUNUMBER) {
160 /* "19:14:12-0530" */
161 gds->HaveZone++;
162 gds->DSTmode = DSToff;
163 gds->Timezone = + ((gds->tokenp[1].value / 100) * HOUR
164 + (gds->tokenp[1].value % 100) * MINUTE);
165 gds->tokenp += 2;
166 }
167 return 1;
168 }
169
170 /*
171 * Timezone name, possibly including DST.
172 */
173 static int
174 zonephrase(struct gdstate *gds)
175 {
176 if (gds->tokenp[0].token == tZONE
177 && gds->tokenp[1].token == tDST) {
178 gds->HaveZone++;
179 gds->Timezone = gds->tokenp[0].value;
180 gds->DSTmode = DSTon;
181 gds->tokenp += 1;
182 return 1;
183 }
184
185 if (gds->tokenp[0].token == tZONE) {
186 gds->HaveZone++;
187 gds->Timezone = gds->tokenp[0].value;
188 gds->DSTmode = DSToff;
189 gds->tokenp += 1;
190 return 1;
191 }
192
193 if (gds->tokenp[0].token == tDAYZONE) {
194 gds->HaveZone++;
195 gds->Timezone = gds->tokenp[0].value;
196 gds->DSTmode = DSTon;
197 gds->tokenp += 1;
198 return 1;
199 }
200 return 0;
201 }
202
203 /*
204 * Year/month/day in various combinations.
205 */
206 static int
207 datephrase(struct gdstate *gds)
208 {
209 if (gds->tokenp[0].token == tUNUMBER
210 && gds->tokenp[1].token == '/'
211 && gds->tokenp[2].token == tUNUMBER
212 && gds->tokenp[3].token == '/'
213 && gds->tokenp[4].token == tUNUMBER) {
214 gds->HaveYear++;
215 gds->HaveMonth++;
216 gds->HaveDay++;
217 if (gds->tokenp[0].value >= 13) {
218 /* First number is big: 2004/01/29, 99/02/17 */
219 gds->Year = gds->tokenp[0].value;
220 gds->Month = gds->tokenp[2].value;
221 gds->Day = gds->tokenp[4].value;
222 } else if ((gds->tokenp[4].value >= 13)
223 || (gds->tokenp[2].value >= 13)) {
224 /* Last number is big: 01/07/98 */
225 /* Middle number is big: 01/29/04 */
226 gds->Month = gds->tokenp[0].value;
227 gds->Day = gds->tokenp[2].value;
228 gds->Year = gds->tokenp[4].value;
229 } else {
230 /* No significant clues: 02/03/04 */
231 gds->Month = gds->tokenp[0].value;
232 gds->Day = gds->tokenp[2].value;
233 gds->Year = gds->tokenp[4].value;
234 }
235 gds->tokenp += 5;
236 return 1;
237 }
238
239 if (gds->tokenp[0].token == tUNUMBER
240 && gds->tokenp[1].token == '/'
241 && gds->tokenp[2].token == tUNUMBER) {
242 /* "1/15" */
243 gds->HaveMonth++;
244 gds->HaveDay++;
245 gds->Month = gds->tokenp[0].value;
246 gds->Day = gds->tokenp[2].value;
247 gds->tokenp += 3;
248 return 1;
249 }
250
251 if (gds->tokenp[0].token == tUNUMBER
252 && gds->tokenp[1].token == '-'
253 && gds->tokenp[2].token == tUNUMBER
254 && gds->tokenp[3].token == '-'
255 && gds->tokenp[4].token == tUNUMBER) {
256 /* ISO 8601 format. yyyy-mm-dd. */
257 gds->HaveYear++;
258 gds->HaveMonth++;
259 gds->HaveDay++;
260 gds->Year = gds->tokenp[0].value;
261 gds->Month = gds->tokenp[2].value;
262 gds->Day = gds->tokenp[4].value;
263 gds->tokenp += 5;
264 return 1;
265 }
266
267 if (gds->tokenp[0].token == tUNUMBER
268 && gds->tokenp[1].token == '-'
269 && gds->tokenp[2].token == tMONTH
270 && gds->tokenp[3].token == '-'
271 && gds->tokenp[4].token == tUNUMBER) {
272 gds->HaveYear++;
273 gds->HaveMonth++;
274 gds->HaveDay++;
275 if (gds->tokenp[0].value > 31) {
276 /* e.g. 1992-Jun-17 */
277 gds->Year = gds->tokenp[0].value;
278 gds->Month = gds->tokenp[2].value;
279 gds->Day = gds->tokenp[4].value;
280 } else {
281 /* e.g. 17-JUN-1992. */
282 gds->Day = gds->tokenp[0].value;
283 gds->Month = gds->tokenp[2].value;
284 gds->Year = gds->tokenp[4].value;
285 }
286 gds->tokenp += 5;
287 return 1;
288 }
289
290 if (gds->tokenp[0].token == tMONTH
291 && gds->tokenp[1].token == tUNUMBER
292 && gds->tokenp[2].token == ','
293 && gds->tokenp[3].token == tUNUMBER) {
294 /* "June 17, 2001" */
295 gds->HaveYear++;
296 gds->HaveMonth++;
297 gds->HaveDay++;
298 gds->Month = gds->tokenp[0].value;
299 gds->Day = gds->tokenp[1].value;
300 gds->Year = gds->tokenp[3].value;
301 gds->tokenp += 4;
302 return 1;
303 }
304
305 if (gds->tokenp[0].token == tMONTH
306 && gds->tokenp[1].token == tUNUMBER) {
307 /* "May 3" */
308 gds->HaveMonth++;
309 gds->HaveDay++;
310 gds->Month = gds->tokenp[0].value;
311 gds->Day = gds->tokenp[1].value;
312 gds->tokenp += 2;
313 return 1;
314 }
315
316 if (gds->tokenp[0].token == tUNUMBER
317 && gds->tokenp[1].token == tMONTH
318 && gds->tokenp[2].token == tUNUMBER) {
319 /* "12 Sept 1997" */
320 gds->HaveYear++;
321 gds->HaveMonth++;
322 gds->HaveDay++;
323 gds->Day = gds->tokenp[0].value;
324 gds->Month = gds->tokenp[1].value;
325 gds->Year = gds->tokenp[2].value;
326 gds->tokenp += 3;
327 return 1;
328 }
329
330 if (gds->tokenp[0].token == tUNUMBER
331 && gds->tokenp[1].token == tMONTH) {
332 /* "12 Sept" */
333 gds->HaveMonth++;
334 gds->HaveDay++;
335 gds->Day = gds->tokenp[0].value;
336 gds->Month = gds->tokenp[1].value;
337 gds->tokenp += 2;
338 return 1;
339 }
340
341 return 0;
342 }
343
344 /*
345 * Relative time phrase: "tomorrow", "yesterday", "+1 hour", etc.
346 */
347 static int
348 relunitphrase(struct gdstate *gds)
349 {
350 if (gds->tokenp[0].token == '-'
351 && gds->tokenp[1].token == tUNUMBER
352 && gds->tokenp[2].token == tSEC_UNIT) {
353 /* "-3 hours" */
354 gds->HaveRel++;
355 gds->RelSeconds -= gds->tokenp[1].value * gds->tokenp[2].value;
356 gds->tokenp += 3;
357 return 1;
358 }
359 if (gds->tokenp[0].token == '+'
360 && gds->tokenp[1].token == tUNUMBER
361 && gds->tokenp[2].token == tSEC_UNIT) {
362 /* "+1 minute" */
363 gds->HaveRel++;
364 gds->RelSeconds += gds->tokenp[1].value * gds->tokenp[2].value;
365 gds->tokenp += 3;
366 return 1;
367 }
368 if (gds->tokenp[0].token == tUNUMBER
369 && gds->tokenp[1].token == tSEC_UNIT) {
370 /* "1 day" */
371 gds->HaveRel++;
372 gds->RelSeconds += gds->tokenp[1].value * gds->tokenp[2].value;
373 gds->tokenp += 3;
374 return 1;
375 }
376 if (gds->tokenp[0].token == '-'
377 && gds->tokenp[1].token == tUNUMBER
378 && gds->tokenp[2].token == tMONTH_UNIT) {
379 /* "-3 months" */
380 gds->HaveRel++;
381 gds->RelMonth -= gds->tokenp[1].value * gds->tokenp[2].value;
382 gds->tokenp += 3;
383 return 1;
384 }
385 if (gds->tokenp[0].token == '+'
386 && gds->tokenp[1].token == tUNUMBER
387 && gds->tokenp[2].token == tMONTH_UNIT) {
388 /* "+5 years" */
389 gds->HaveRel++;
390 gds->RelMonth += gds->tokenp[1].value * gds->tokenp[2].value;
391 gds->tokenp += 3;
392 return 1;
393 }
394 if (gds->tokenp[0].token == tUNUMBER
395 && gds->tokenp[1].token == tMONTH_UNIT) {
396 /* "2 years" */
397 gds->HaveRel++;
398 gds->RelMonth += gds->tokenp[0].value * gds->tokenp[1].value;
399 gds->tokenp += 2;
400 return 1;
401 }
402 if (gds->tokenp[0].token == tSEC_UNIT) {
403 /* "now", "tomorrow" */
404 gds->HaveRel++;
405 gds->RelSeconds += gds->tokenp[0].value;
406 ++gds->tokenp;
407 return 1;
408 }
409 if (gds->tokenp[0].token == tMONTH_UNIT) {
410 /* "month" */
411 gds->HaveRel++;
412 gds->RelMonth += gds->tokenp[0].value;
413 gds->tokenp += 1;
414 return 1;
415 }
416 return 0;
417 }
418
419 /*
420 * Day of the week specification.
421 */
422 static int
423 dayphrase(struct gdstate *gds)
424 {
425 if (gds->tokenp[0].token == tDAY) {
426 /* "tues", "wednesday," */
427 gds->HaveWeekDay++;
428 gds->DayOrdinal = 1;
429 gds->DayNumber = gds->tokenp[0].value;
430 gds->tokenp += 1;
431 if (gds->tokenp[0].token == ',')
432 gds->tokenp += 1;
433 return 1;
434 }
435 if (gds->tokenp[0].token == tUNUMBER
436 && gds->tokenp[1].token == tDAY) {
437 /* "second tues" "3 wed" */
438 gds->HaveWeekDay++;
439 gds->DayOrdinal = gds->tokenp[0].value;
440 gds->DayNumber = gds->tokenp[1].value;
441 gds->tokenp += 2;
442 return 1;
443 }
444 return 0;
445 }
446
447 /*
448 * Try to match a phrase using one of the above functions.
449 * This layer also deals with a couple of generic issues.
450 */
451 static int
452 phrase(struct gdstate *gds)
453 {
454 if (timephrase(gds))
455 return 1;
456 if (zonephrase(gds))
457 return 1;
458 if (datephrase(gds))
459 return 1;
460 if (dayphrase(gds))
461 return 1;
462 if (relunitphrase(gds)) {
463 if (gds->tokenp[0].token == tAGO) {
464 gds->RelSeconds = -gds->RelSeconds;
465 gds->RelMonth = -gds->RelMonth;
466 gds->tokenp += 1;
467 }
468 return 1;
469 }
470
471 /* Bare numbers sometimes have meaning. */
472 if (gds->tokenp[0].token == tUNUMBER) {
473 if (gds->HaveTime && !gds->HaveYear && !gds->HaveRel) {
474 gds->HaveYear++;
475 gds->Year = gds->tokenp[0].value;
476 gds->tokenp += 1;
477 return 1;
478 }
479
480 if(gds->tokenp[0].value > 10000) {
481 /* "20040301" */
482 gds->HaveYear++;
483 gds->HaveMonth++;
484 gds->HaveDay++;
485 gds->Day= (gds->tokenp[0].value)%100;
486 gds->Month= (gds->tokenp[0].value/100)%100;
487 gds->Year = gds->tokenp[0].value/10000;
488 gds->tokenp += 1;
489 return 1;
490 }
491
492 if (gds->tokenp[0].value < 24) {
493 gds->HaveTime++;
494 gds->Hour = gds->tokenp[0].value;
495 gds->Minutes = 0;
496 gds->Seconds = 0;
497 gds->tokenp += 1;
498 return 1;
499 }
500
501 if ((gds->tokenp[0].value / 100 < 24)
502 && (gds->tokenp[0].value % 100 < 60)) {
503 /* "513" is same as "5:13" */
504 gds->Hour = gds->tokenp[0].value / 100;
505 gds->Minutes = gds->tokenp[0].value % 100;
506 gds->Seconds = 0;
507 gds->tokenp += 1;
508 return 1;
509 }
510 }
511
512 return 0;
513 }
514
515 /*
516 * A dictionary of time words.
517 */
518 static struct LEXICON {
519 size_t abbrev;
520 const char *name;
521 int type;
522 time_t value;
523 } const TimeWords[] = {
524 /* am/pm */
525 { 0, "am", tAMPM, tAM },
526 { 0, "pm", tAMPM, tPM },
527
528 /* Month names. */
529 { 3, "january", tMONTH, 1 },
530 { 3, "february", tMONTH, 2 },
531 { 3, "march", tMONTH, 3 },
532 { 3, "april", tMONTH, 4 },
533 { 3, "may", tMONTH, 5 },
534 { 3, "june", tMONTH, 6 },
535 { 3, "july", tMONTH, 7 },
536 { 3, "august", tMONTH, 8 },
537 { 3, "september", tMONTH, 9 },
538 { 3, "october", tMONTH, 10 },
539 { 3, "november", tMONTH, 11 },
540 { 3, "december", tMONTH, 12 },
541
542 /* Days of the week. */
543 { 2, "sunday", tDAY, 0 },
544 { 3, "monday", tDAY, 1 },
545 { 2, "tuesday", tDAY, 2 },
546 { 3, "wednesday", tDAY, 3 },
547 { 2, "thursday", tDAY, 4 },
548 { 2, "friday", tDAY, 5 },
549 { 2, "saturday", tDAY, 6 },
550
551 /* Timezones: Offsets are in seconds. */
552 { 0, "gmt", tZONE, 0*HOUR }, /* Greenwich Mean */
553 { 0, "ut", tZONE, 0*HOUR }, /* Universal (Coordinated) */
554 { 0, "utc", tZONE, 0*HOUR },
555 { 0, "wet", tZONE, 0*HOUR }, /* Western European */
556 { 0, "bst", tDAYZONE, 0*HOUR }, /* British Summer */
557 { 0, "wat", tZONE, 1*HOUR }, /* West Africa */
558 { 0, "at", tZONE, 2*HOUR }, /* Azores */
559 /* { 0, "bst", tZONE, 3*HOUR }, */ /* Brazil Standard: Conflict */
560 /* { 0, "gst", tZONE, 3*HOUR }, */ /* Greenland Standard: Conflict*/
561 { 0, "nft", tZONE, 3*HOUR+30*MINUTE }, /* Newfoundland */
562 { 0, "nst", tZONE, 3*HOUR+30*MINUTE }, /* Newfoundland Standard */
563 { 0, "ndt", tDAYZONE, 3*HOUR+30*MINUTE }, /* Newfoundland Daylight */
564 { 0, "ast", tZONE, 4*HOUR }, /* Atlantic Standard */
565 { 0, "adt", tDAYZONE, 4*HOUR }, /* Atlantic Daylight */
566 { 0, "est", tZONE, 5*HOUR }, /* Eastern Standard */
567 { 0, "edt", tDAYZONE, 5*HOUR }, /* Eastern Daylight */
568 { 0, "cst", tZONE, 6*HOUR }, /* Central Standard */
569 { 0, "cdt", tDAYZONE, 6*HOUR }, /* Central Daylight */
570 { 0, "mst", tZONE, 7*HOUR }, /* Mountain Standard */
571 { 0, "mdt", tDAYZONE, 7*HOUR }, /* Mountain Daylight */
572 { 0, "pst", tZONE, 8*HOUR }, /* Pacific Standard */
573 { 0, "pdt", tDAYZONE, 8*HOUR }, /* Pacific Daylight */
574 { 0, "yst", tZONE, 9*HOUR }, /* Yukon Standard */
575 { 0, "ydt", tDAYZONE, 9*HOUR }, /* Yukon Daylight */
576 { 0, "hst", tZONE, 10*HOUR }, /* Hawaii Standard */
577 { 0, "hdt", tDAYZONE, 10*HOUR }, /* Hawaii Daylight */
578 { 0, "cat", tZONE, 10*HOUR }, /* Central Alaska */
579 { 0, "ahst", tZONE, 10*HOUR }, /* Alaska-Hawaii Standard */
580 { 0, "nt", tZONE, 11*HOUR }, /* Nome */
581 { 0, "idlw", tZONE, 12*HOUR }, /* Intl Date Line West */
582 { 0, "cet", tZONE, -1*HOUR }, /* Central European */
583 { 0, "met", tZONE, -1*HOUR }, /* Middle European */
584 { 0, "mewt", tZONE, -1*HOUR }, /* Middle European Winter */
585 { 0, "mest", tDAYZONE, -1*HOUR }, /* Middle European Summer */
586 { 0, "swt", tZONE, -1*HOUR }, /* Swedish Winter */
587 { 0, "sst", tDAYZONE, -1*HOUR }, /* Swedish Summer */
588 { 0, "fwt", tZONE, -1*HOUR }, /* French Winter */
589 { 0, "fst", tDAYZONE, -1*HOUR }, /* French Summer */
590 { 0, "eet", tZONE, -2*HOUR }, /* Eastern Eur, USSR Zone 1 */
591 { 0, "bt", tZONE, -3*HOUR }, /* Baghdad, USSR Zone 2 */
592 { 0, "it", tZONE, -3*HOUR-30*MINUTE },/* Iran */
593 { 0, "zp4", tZONE, -4*HOUR }, /* USSR Zone 3 */
594 { 0, "zp5", tZONE, -5*HOUR }, /* USSR Zone 4 */
595 { 0, "ist", tZONE, -5*HOUR-30*MINUTE },/* Indian Standard */
596 { 0, "zp6", tZONE, -6*HOUR }, /* USSR Zone 5 */
597 /* { 0, "nst", tZONE, -6.5*HOUR }, */ /* North Sumatra: Conflict */
598 /* { 0, "sst", tZONE, -7*HOUR }, */ /* So Sumatra, USSR 6: Conflict */
599 { 0, "wast", tZONE, -7*HOUR }, /* West Australian Standard */
600 { 0, "wadt", tDAYZONE, -7*HOUR }, /* West Australian Daylight */
601 { 0, "jt", tZONE, -7*HOUR-30*MINUTE },/* Java (3pm in Cronusland!)*/
602 { 0, "cct", tZONE, -8*HOUR }, /* China Coast, USSR Zone 7 */
603 { 0, "jst", tZONE, -9*HOUR }, /* Japan Std, USSR Zone 8 */
604 { 0, "cast", tZONE, -9*HOUR-30*MINUTE },/* Ctrl Australian Std */
605 { 0, "cadt", tDAYZONE, -9*HOUR-30*MINUTE },/* Ctrl Australian Daylt */
606 { 0, "east", tZONE, -10*HOUR }, /* Eastern Australian Std */
607 { 0, "eadt", tDAYZONE, -10*HOUR }, /* Eastern Australian Daylt */
608 { 0, "gst", tZONE, -10*HOUR }, /* Guam Std, USSR Zone 9 */
609 { 0, "nzt", tZONE, -12*HOUR }, /* New Zealand */
610 { 0, "nzst", tZONE, -12*HOUR }, /* New Zealand Standard */
611 { 0, "nzdt", tDAYZONE, -12*HOUR }, /* New Zealand Daylight */
612 { 0, "idle", tZONE, -12*HOUR }, /* Intl Date Line East */
613
614 { 0, "dst", tDST, 0 },
615
616 /* Time units. */
617 { 4, "years", tMONTH_UNIT, 12 },
618 { 5, "months", tMONTH_UNIT, 1 },
619 { 9, "fortnights", tSEC_UNIT, 14 * DAY },
620 { 4, "weeks", tSEC_UNIT, 7 * DAY },
621 { 3, "days", tSEC_UNIT, DAY },
622 { 4, "hours", tSEC_UNIT, HOUR },
623 { 3, "minutes", tSEC_UNIT, MINUTE },
624 { 3, "seconds", tSEC_UNIT, 1 },
625
626 /* Relative-time words. */
627 { 0, "tomorrow", tSEC_UNIT, DAY },
628 { 0, "yesterday", tSEC_UNIT, -DAY },
629 { 0, "today", tSEC_UNIT, 0 },
630 { 0, "now", tSEC_UNIT, 0 },
631 { 0, "last", tUNUMBER, -1 },
632 { 0, "this", tSEC_UNIT, 0 },
633 { 0, "next", tUNUMBER, 2 },
634 { 0, "first", tUNUMBER, 1 },
635 { 0, "1st", tUNUMBER, 1 },
636 /* { 0, "second", tUNUMBER, 2 }, */
637 { 0, "2nd", tUNUMBER, 2 },
638 { 0, "third", tUNUMBER, 3 },
639 { 0, "3rd", tUNUMBER, 3 },
640 { 0, "fourth", tUNUMBER, 4 },
641 { 0, "4th", tUNUMBER, 4 },
642 { 0, "fifth", tUNUMBER, 5 },
643 { 0, "5th", tUNUMBER, 5 },
644 { 0, "sixth", tUNUMBER, 6 },
645 { 0, "seventh", tUNUMBER, 7 },
646 { 0, "eighth", tUNUMBER, 8 },
647 { 0, "ninth", tUNUMBER, 9 },
648 { 0, "tenth", tUNUMBER, 10 },
649 { 0, "eleventh", tUNUMBER, 11 },
650 { 0, "twelfth", tUNUMBER, 12 },
651 { 0, "ago", tAGO, 1 },
652
653 /* Military timezones. */
654 { 0, "a", tZONE, 1*HOUR },
655 { 0, "b", tZONE, 2*HOUR },
656 { 0, "c", tZONE, 3*HOUR },
657 { 0, "d", tZONE, 4*HOUR },
658 { 0, "e", tZONE, 5*HOUR },
659 { 0, "f", tZONE, 6*HOUR },
660 { 0, "g", tZONE, 7*HOUR },
661 { 0, "h", tZONE, 8*HOUR },
662 { 0, "i", tZONE, 9*HOUR },
663 { 0, "k", tZONE, 10*HOUR },
664 { 0, "l", tZONE, 11*HOUR },
665 { 0, "m", tZONE, 12*HOUR },
666 { 0, "n", tZONE, -1*HOUR },
667 { 0, "o", tZONE, -2*HOUR },
668 { 0, "p", tZONE, -3*HOUR },
669 { 0, "q", tZONE, -4*HOUR },
670 { 0, "r", tZONE, -5*HOUR },
671 { 0, "s", tZONE, -6*HOUR },
672 { 0, "t", tZONE, -7*HOUR },
673 { 0, "u", tZONE, -8*HOUR },
674 { 0, "v", tZONE, -9*HOUR },
675 { 0, "w", tZONE, -10*HOUR },
676 { 0, "x", tZONE, -11*HOUR },
677 { 0, "y", tZONE, -12*HOUR },
678 { 0, "z", tZONE, 0*HOUR },
679
680 /* End of table. */
681 { 0, NULL, 0, 0 }
682 };
683
684 /*
685 * Year is either:
686 * = A number from 0 to 99, which means a year from 1970 to 2069, or
687 * = The actual year (>=100).
688 */
689 static time_t
690 Convert(time_t Month, time_t Day, time_t Year,
691 time_t Hours, time_t Minutes, time_t Seconds,
692 time_t Timezone, enum DSTMODE DSTmode)
693 {
694 static int DaysInMonth[12] = {
695 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
696 };
697 time_t Julian;
698 int i;
699
700 if (Year < 69)
701 Year += 2000;
702 else if (Year < 100)
703 Year += 1900;
704 DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
705 ? 29 : 28;
706 /* Checking for 2038 bogusly assumes that time_t is 32 bits. But
707 I'm too lazy to try to check for time_t overflow in another way. */
708 if (Year < EPOCH || Year > 2038
709 || Month < 1 || Month > 12
710 /* Lint fluff: "conversion from long may lose accuracy" */
711 || Day < 1 || Day > DaysInMonth[(int)--Month]
712 || Hours < 0 || Hours > 23
713 || Minutes < 0 || Minutes > 59
714 || Seconds < 0 || Seconds > 59)
715 return -1;
716
717 Julian = Day - 1;
718 for (i = 0; i < Month; i++)
719 Julian += DaysInMonth[i];
720 for (i = EPOCH; i < Year; i++)
721 Julian += 365 + (i % 4 == 0);
722 Julian *= DAY;
723 Julian += Timezone;
724 Julian += Hours * HOUR + Minutes * MINUTE + Seconds;
725 if (DSTmode == DSTon
726 || (DSTmode == DSTmaybe && localtime(&Julian)->tm_isdst))
727 Julian -= HOUR;
728 return Julian;
729 }
730
731
732 static time_t
733 DSTcorrect(time_t Start, time_t Future)
734 {
735 time_t StartDay;
736 time_t FutureDay;
737
738 StartDay = (localtime(&Start)->tm_hour + 1) % 24;
739 FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
740 return (Future - Start) + (StartDay - FutureDay) * HOUR;
741 }
742
743
744 static time_t
745 RelativeDate(time_t Start, time_t zone, int dstmode,
746 time_t DayOrdinal, time_t DayNumber)
747 {
748 struct tm *tm;
749 time_t t, now;
750
751 t = Start - zone;
752 tm = gmtime(&t);
753 now = Start;
754 now += DAY * ((DayNumber - tm->tm_wday + 7) % 7);
755 now += 7 * DAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
756 if (dstmode == DSTmaybe)
757 return DSTcorrect(Start, now);
758 return now - Start;
759 }
760
761
762 static time_t
763 RelativeMonth(time_t Start, time_t Timezone, time_t RelMonth)
764 {
765 struct tm *tm;
766 time_t Month;
767 time_t Year;
768
769 if (RelMonth == 0)
770 return 0;
771 tm = localtime(&Start);
772 Month = 12 * (tm->tm_year + 1900) + tm->tm_mon + RelMonth;
773 Year = Month / 12;
774 Month = Month % 12 + 1;
775 return DSTcorrect(Start,
776 Convert(Month, (time_t)tm->tm_mday, Year,
777 (time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
778 Timezone, DSTmaybe));
779 }
780
781 /*
782 * Tokenizer.
783 */
784 static int
785 nexttoken(char **in, time_t *value)
786 {
787 char c;
788 char buff[64];
789
790 for ( ; ; ) {
791 while (isspace((unsigned char)**in))
792 ++*in;
793
794 /* Skip parenthesized comments. */
795 if (**in == '(') {
796 int Count = 0;
797 do {
798 c = *(*in)++;
799 if (c == '\0')
800 return c;
801 if (c == '(')
802 Count++;
803 else if (c == ')')
804 Count--;
805 } while (Count > 0);
806 continue;
807 }
808
809 /* Try the next token in the word table first. */
810 /* This allows us to match "2nd", for example. */
811 {
812 char *src = *in;
813 const struct LEXICON *tp;
814 unsigned i = 0;
815
816 /* Force to lowercase and strip '.' characters. */
817 while (*src != '\0'
818 && (isalnum((unsigned char)*src) || *src == '.')
819 && i < sizeof(buff)-1) {
820 if (*src != '.') {
821 if (isupper((unsigned char)*src))
822 buff[i++] = tolower((unsigned char)*src);
823 else
824 buff[i++] = *src;
825 }
826 src++;
827 }
828 buff[i] = '\0';
829
830 /*
831 * Find the first match. If the word can be
832 * abbreviated, make sure we match at least
833 * the minimum abbreviation.
834 */
835 for (tp = TimeWords; tp->name; tp++) {
836 size_t abbrev = tp->abbrev;
837 if (abbrev == 0)
838 abbrev = strlen(tp->name);
839 if (strlen(buff) >= abbrev
840 && strncmp(tp->name, buff, strlen(buff))
841 == 0) {
842 /* Skip over token. */
843 *in = src;
844 /* Return the match. */
845 *value = tp->value;
846 return tp->type;
847 }
848 }
849 }
850
851 /*
852 * Not in the word table, maybe it's a number. Note:
853 * Because '-' and '+' have other special meanings, I
854 * don't deal with signed numbers here.
855 */
856 if (isdigit((unsigned char)(c = **in))) {
857 for (*value = 0; isdigit((unsigned char)(c = *(*in)++)); )
858 *value = 10 * *value + c - '0';
859 (*in)--;
860 return (tUNUMBER);
861 }
862
863 return *(*in)++;
864 }
865 }
866
867 #define TM_YEAR_ORIGIN 1900
868
869 /* Yield A - B, measured in seconds. */
870 static long
871 difftm (struct tm *a, struct tm *b)
872 {
873 int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
874 int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
875 int days = (
876 /* difference in day of year */
877 a->tm_yday - b->tm_yday
878 /* + intervening leap days */
879 + ((ay >> 2) - (by >> 2))
880 - (ay/100 - by/100)
881 + ((ay/100 >> 2) - (by/100 >> 2))
882 /* + difference in years * 365 */
883 + (long)(ay-by) * 365
884 );
885 return (days * DAY + (a->tm_hour - b->tm_hour) * HOUR
886 + (a->tm_min - b->tm_min) * MINUTE
887 + (a->tm_sec - b->tm_sec));
888 }
889
890 /*
891 *
892 * The public function.
893 *
894 * TODO: tokens[] array should be dynamically sized.
895 */
896 time_t
897 get_date(time_t now, char *p)
898 {
899 struct token tokens[256];
900 struct gdstate _gds;
901 struct token *lasttoken;
902 struct gdstate *gds;
903 struct tm local, *tm;
904 struct tm gmt, *gmt_ptr;
905 time_t Start;
906 time_t tod;
907 long tzone;
908
909 /* Clear out the parsed token array. */
910 memset(tokens, 0, sizeof(tokens));
911 /* Initialize the parser state. */
912 memset(&_gds, 0, sizeof(_gds));
913 gds = &_gds;
914
915 /* Look up the current time. */
916 memset(&local, 0, sizeof(local));
917 tm = localtime (&now);
918 if (tm == NULL)
919 return -1;
920 local = *tm;
921
922 /* Look up UTC if we can and use that to determine the current
923 * timezone offset. */
924 memset(&gmt, 0, sizeof(gmt));
925 gmt_ptr = gmtime (&now);
926 if (gmt_ptr != NULL) {
927 /* Copy, in case localtime and gmtime use the same buffer. */
928 gmt = *gmt_ptr;
929 }
930 if (gmt_ptr != NULL)
931 tzone = difftm (&gmt, &local);
932 else
933 /* This system doesn't understand timezones; fake it. */
934 tzone = 0;
935 if(local.tm_isdst)
936 tzone += HOUR;
937
938 /* Tokenize the input string. */
939 lasttoken = tokens;
940 while ((lasttoken->token = nexttoken(&p, &lasttoken->value)) != 0) {
941 ++lasttoken;
942 if (lasttoken > tokens + 255)
943 return -1;
944 }
945 gds->tokenp = tokens;
946
947 /* Match phrases until we run out of input tokens. */
948 while (gds->tokenp < lasttoken) {
949 if (!phrase(gds))
950 return -1;
951 }
952
953 /* Use current local timezone if none was specified. */
954 if (!gds->HaveZone) {
955 gds->Timezone = tzone;
956 gds->DSTmode = DSTmaybe;
957 }
958
959 /* If a timezone was specified, use that for generating the default
960 * time components instead of the local timezone. */
961 if (gds->HaveZone && gmt_ptr != NULL) {
962 now -= gds->Timezone;
963 gmt_ptr = gmtime (&now);
964 if (gmt_ptr != NULL)
965 local = *gmt_ptr;
966 now += gds->Timezone;
967 }
968
969 if (!gds->HaveYear)
970 gds->Year = local.tm_year + 1900;
971 if (!gds->HaveMonth)
972 gds->Month = local.tm_mon + 1;
973 if (!gds->HaveDay)
974 gds->Day = local.tm_mday;
975 /* Note: No default for hour/min/sec; a specifier that just
976 * gives date always refers to 00:00 on that date. */
977
978 /* If we saw more than one time, timezone, weekday, year, month,
979 * or day, then give up. */
980 if (gds->HaveTime > 1 || gds->HaveZone > 1 || gds->HaveWeekDay > 1
981 || gds->HaveYear > 1 || gds->HaveMonth > 1 || gds->HaveDay > 1)
982 return -1;
983
984 /* Compute an absolute time based on whatever absolute information
985 * we collected. */
986 if (gds->HaveYear || gds->HaveMonth || gds->HaveDay
987 || gds->HaveTime || gds->HaveWeekDay) {
988 Start = Convert(gds->Month, gds->Day, gds->Year,
989 gds->Hour, gds->Minutes, gds->Seconds,
990 gds->Timezone, gds->DSTmode);
991 if (Start < 0)
992 return -1;
993 } else {
994 Start = now;
995 if (!gds->HaveRel)
996 Start -= local.tm_hour * HOUR + local.tm_min * MINUTE
997 + local.tm_sec;
998 }
999
1000 /* Add the relative offset. */
1001 Start += gds->RelSeconds;
1002 Start += RelativeMonth(Start, gds->Timezone, gds->RelMonth);
1003
1004 /* Adjust for day-of-week offsets. */
1005 if (gds->HaveWeekDay
1006 && !(gds->HaveYear || gds->HaveMonth || gds->HaveDay)) {
1007 tod = RelativeDate(Start, gds->Timezone,
1008 gds->DSTmode, gds->DayOrdinal, gds->DayNumber);
1009 Start += tod;
1010 }
1011
1012 /* -1 is an error indicator, so return 0 instead of -1 if
1013 * that's the actual time. */
1014 return Start == -1 ? 0 : Start;
1015 }
1016
1017
1018 #if defined(TEST)
1019
1020 /* ARGSUSED */
1021 int
1022 main(int argc, char **argv)
1023 {
1024 time_t d;
1025
1026 while (*++argv != NULL) {
1027 (void)printf("Input: %s\n", *argv);
1028 d = get_date(*argv);
1029 if (d == -1)
1030 (void)printf("Bad format - couldn't convert.\n");
1031 else
1032 (void)printf("Output: %s\n", ctime(&d));
1033 }
1034 exit(0);
1035 /* NOTREACHED */
1036 }
1037 #endif /* defined(TEST) */
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