xref: /openbsd/usr.bin/cvs/date.y (revision dda28197)
1 %{
2 /*	$OpenBSD: date.y,v 1.26 2017/07/20 13:39:11 okan Exp $	*/
3 
4 /*
5 **  Originally written by Steven M. Bellovin <smb@research.att.com> while
6 **  at the University of North Carolina at Chapel Hill.  Later tweaked by
7 **  a couple of people on Usenet.  Completely overhauled by Rich $alz
8 **  <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
9 **
10 **  This grammar has 10 shift/reduce conflicts.
11 **
12 **  This code is in the public domain and has no copyright.
13 */
14 /* SUPPRESS 287 on yaccpar_sccsid *//* Unused static variable */
15 /* SUPPRESS 288 on yyerrlab *//* Label unused */
16 
17 #include <ctype.h>
18 #include <string.h>
19 #include <time.h>
20 
21 #include "cvs.h"
22 
23 #define YEAR_EPOCH	1970
24 #define YEAR_TMORIGIN	1900
25 #define HOUR(x)		((time_t)(x) * 60)
26 #define SECSPERDAY	(24L * 60L * 60L)
27 
28 
29 /* An entry in the lexical lookup table */
30 typedef struct _TABLE {
31 	char	*name;
32 	int	type;
33 	time_t	value;
34 } TABLE;
35 
36 
37 /*  Daylight-savings mode:  on, off, or not yet known. */
38 typedef enum _DSTMODE {
39 	DSTon, DSToff, DSTmaybe
40 } DSTMODE;
41 
42 /*  Meridian:  am, pm, or 24-hour style. */
43 typedef enum _MERIDIAN {
44 	MERam, MERpm, MER24
45 } MERIDIAN;
46 
47 
48 /*
49  *  Global variables.  We could get rid of most of these by using a good
50  *  union as the yacc stack.  (This routine was originally written before
51  *  yacc had the %union construct.)  Maybe someday; right now we only use
52  *  the %union very rarely.
53  */
54 static const char	*yyInput;
55 static DSTMODE	yyDSTmode;
56 static time_t	yyDayOrdinal;
57 static time_t	yyDayNumber;
58 static int	yyHaveDate;
59 static int	yyHaveDay;
60 static int	yyHaveRel;
61 static int	yyHaveTime;
62 static int	yyHaveZone;
63 static time_t	yyTimezone;
64 static time_t	yyDay;
65 static time_t	yyHour;
66 static time_t	yyMinutes;
67 static time_t	yyMonth;
68 static time_t	yySeconds;
69 static time_t	yyYear;
70 static MERIDIAN	yyMeridian;
71 static time_t	yyRelMonth;
72 static time_t	yyRelSeconds;
73 
74 
75 static int	yyerror(const char *);
76 static int	yylex(void);
77 static int	yyparse(void);
78 static int	lookup(char *);
79 
80 %}
81 
82 %union {
83 	time_t		Number;
84 	enum _MERIDIAN	Meridian;
85 }
86 
87 %token	tAGO tDAY tDAYZONE tID tMERIDIAN tMINUTE_UNIT tMONTH tMONTH_UNIT
88 %token	tSEC_UNIT tSNUMBER tUNUMBER tZONE tDST
89 
90 %type	<Number>	tDAY tDAYZONE tMINUTE_UNIT tMONTH tMONTH_UNIT
91 %type	<Number>	tSEC_UNIT tSNUMBER tUNUMBER tZONE
92 %type	<Meridian>	tMERIDIAN o_merid
93 
94 %%
95 
96 spec	: /* NULL */
97 	| spec item
98 	;
99 
100 item	: time {
101 		yyHaveTime++;
102 	}
103 	| zone {
104 		yyHaveZone++;
105 	}
106 	| date {
107 		yyHaveDate++;
108 	}
109 	| day {
110 		yyHaveDay++;
111 	}
112 	| rel {
113 		yyHaveRel++;
114 	}
115 	| number
116 	;
117 
118 time	: tUNUMBER tMERIDIAN {
119 		yyHour = $1;
120 		yyMinutes = 0;
121 		yySeconds = 0;
122 		yyMeridian = $2;
123 	}
124 	| tUNUMBER ':' tUNUMBER o_merid {
125 		yyHour = $1;
126 		yyMinutes = $3;
127 		yySeconds = 0;
128 		yyMeridian = $4;
129 	}
130 	| tUNUMBER ':' tUNUMBER tSNUMBER {
131 		yyHour = $1;
132 		yyMinutes = $3;
133 		yyMeridian = MER24;
134 		yyDSTmode = DSToff;
135 		yyTimezone = - ($4 % 100 + ($4 / 100) * 60);
136 	}
137 	| tUNUMBER ':' tUNUMBER ':' tUNUMBER o_merid {
138 		yyHour = $1;
139 		yyMinutes = $3;
140 		yySeconds = $5;
141 		yyMeridian = $6;
142 	}
143 	| tUNUMBER ':' tUNUMBER ':' tUNUMBER tSNUMBER {
144 		yyHour = $1;
145 		yyMinutes = $3;
146 		yySeconds = $5;
147 		yyMeridian = MER24;
148 		yyDSTmode = DSToff;
149 		yyTimezone = - ($6 % 100 + ($6 / 100) * 60);
150 	}
151 	;
152 
153 zone	: tZONE {
154 		yyTimezone = $1;
155 		yyDSTmode = DSToff;
156 	}
157 	| tDAYZONE {
158 		yyTimezone = $1;
159 		yyDSTmode = DSTon;
160 	}
161 	| tZONE tDST {
162 		yyTimezone = $1;
163 		yyDSTmode = DSTon;
164 	}
165 	;
166 
167 day	: tDAY {
168 		yyDayOrdinal = 1;
169 		yyDayNumber = $1;
170 	}
171 	| tDAY ',' {
172 		yyDayOrdinal = 1;
173 		yyDayNumber = $1;
174 	}
175 	| tUNUMBER tDAY {
176 		yyDayOrdinal = $1;
177 		yyDayNumber = $2;
178 	}
179 	;
180 
181 date	: tUNUMBER '/' tUNUMBER {
182 		yyMonth = $1;
183 		yyDay = $3;
184 	}
185 	| tUNUMBER '/' tUNUMBER '/' tUNUMBER {
186 		if ($1 >= 100) {
187 			yyYear = $1;
188 			yyMonth = $3;
189 			yyDay = $5;
190 		} else {
191 			yyMonth = $1;
192 			yyDay = $3;
193 			yyYear = $5;
194 		}
195 	}
196 	| tUNUMBER tSNUMBER tSNUMBER {
197 		/* ISO 8601 format.  yyyy-mm-dd.  */
198 		yyYear = $1;
199 		yyMonth = -$2;
200 		yyDay = -$3;
201 	}
202 	| tUNUMBER tMONTH tSNUMBER {
203 		/* e.g. 17-JUN-1992.  */
204 		yyDay = $1;
205 		yyMonth = $2;
206 		yyYear = -$3;
207 	}
208 	| tMONTH tUNUMBER {
209 		yyMonth = $1;
210 		yyDay = $2;
211 	}
212 	| tMONTH tUNUMBER ',' tUNUMBER {
213 		yyMonth = $1;
214 		yyDay = $2;
215 		yyYear = $4;
216 	}
217 	| tUNUMBER tMONTH {
218 		yyMonth = $2;
219 		yyDay = $1;
220 	}
221 	| tUNUMBER tMONTH tUNUMBER {
222 		yyMonth = $2;
223 		yyDay = $1;
224 		yyYear = $3;
225 	}
226 	;
227 
228 rel	: relunit tAGO {
229 		yyRelSeconds = -yyRelSeconds;
230 		yyRelMonth = -yyRelMonth;
231 	}
232 	| relunit
233 	;
234 
235 relunit	: tUNUMBER tMINUTE_UNIT {
236 		yyRelSeconds += $1 * $2 * 60L;
237 	}
238 	| tSNUMBER tMINUTE_UNIT {
239 		yyRelSeconds += $1 * $2 * 60L;
240 	}
241 	| tMINUTE_UNIT {
242 		yyRelSeconds += $1 * 60L;
243 	}
244 	| tSNUMBER tSEC_UNIT {
245 		yyRelSeconds += $1;
246 	}
247 	| tUNUMBER tSEC_UNIT {
248 		yyRelSeconds += $1;
249 	}
250 	| tSEC_UNIT {
251 		yyRelSeconds++;
252 	}
253 	| tSNUMBER tMONTH_UNIT {
254 		yyRelMonth += $1 * $2;
255 	}
256 	| tUNUMBER tMONTH_UNIT {
257 		yyRelMonth += $1 * $2;
258 	}
259 	| tMONTH_UNIT {
260 		yyRelMonth += $1;
261 	}
262 	;
263 
264 number	: tUNUMBER {
265 		if (yyHaveTime && yyHaveDate && !yyHaveRel)
266 			yyYear = $1;
267 		else {
268 			if ($1 > 10000) {
269 				yyHaveDate++;
270 				yyDay= ($1)%100;
271 				yyMonth= ($1/100)%100;
272 				yyYear = $1/10000;
273 			} else {
274 				yyHaveTime++;
275 				if ($1 < 100) {
276 					yyHour = $1;
277 					yyMinutes = 0;
278 				} else {
279 					yyHour = $1 / 100;
280 					yyMinutes = $1 % 100;
281 				}
282 				yySeconds = 0;
283 				yyMeridian = MER24;
284 			}
285 		}
286 	}
287 	;
288 
289 o_merid	: /* NULL */ {
290 		$$ = MER24;
291 	}
292 	| tMERIDIAN {
293 		$$ = $1;
294 	}
295 	;
296 
297 %%
298 
299 /* Month and day table. */
300 static TABLE const MonthDayTable[] = {
301 	{ "january",	tMONTH,	1 },
302 	{ "february",	tMONTH,	2 },
303 	{ "march",	tMONTH,	3 },
304 	{ "april",	tMONTH,	4 },
305 	{ "may",	tMONTH,	5 },
306 	{ "june",	tMONTH,	6 },
307 	{ "july",	tMONTH,	7 },
308 	{ "august",	tMONTH,	8 },
309 	{ "september",	tMONTH,	9 },
310 	{ "sept",	tMONTH,	9 },
311 	{ "october",	tMONTH,	10 },
312 	{ "november",	tMONTH,	11 },
313 	{ "december",	tMONTH,	12 },
314 	{ "sunday",	tDAY,	0 },
315 	{ "monday",	tDAY,	1 },
316 	{ "tuesday",	tDAY,	2 },
317 	{ "tues",	tDAY,	2 },
318 	{ "wednesday",	tDAY,	3 },
319 	{ "wednes",	tDAY,	3 },
320 	{ "thursday",	tDAY,	4 },
321 	{ "thur",	tDAY,	4 },
322 	{ "thurs",	tDAY,	4 },
323 	{ "friday",	tDAY,	5 },
324 	{ "saturday",	tDAY,	6 },
325 	{ NULL }
326 };
327 
328 /* Time units table. */
329 static TABLE const UnitsTable[] = {
330 	{ "year",	tMONTH_UNIT,	12 },
331 	{ "month",	tMONTH_UNIT,	1 },
332 	{ "fortnight",	tMINUTE_UNIT,	14 * 24 * 60 },
333 	{ "week",	tMINUTE_UNIT,	7 * 24 * 60 },
334 	{ "day",	tMINUTE_UNIT,	1 * 24 * 60 },
335 	{ "hour",	tMINUTE_UNIT,	60 },
336 	{ "minute",	tMINUTE_UNIT,	1 },
337 	{ "min",	tMINUTE_UNIT,	1 },
338 	{ "second",	tSEC_UNIT,	1 },
339 	{ "sec",	tSEC_UNIT,	1 },
340 	{ NULL }
341 };
342 
343 /* Assorted relative-time words. */
344 static TABLE const OtherTable[] = {
345 	{ "tomorrow",	tMINUTE_UNIT,	1 * 24 * 60 },
346 	{ "yesterday",	tMINUTE_UNIT,	-1 * 24 * 60 },
347 	{ "today",	tMINUTE_UNIT,	0 },
348 	{ "now",	tMINUTE_UNIT,	0 },
349 	{ "last",	tUNUMBER,	-1 },
350 	{ "this",	tMINUTE_UNIT,	0 },
351 	{ "next",	tUNUMBER,	2 },
352 	{ "first",	tUNUMBER,	1 },
353 /*  { "second",		tUNUMBER,	2 }, */
354 	{ "third",	tUNUMBER,	3 },
355 	{ "fourth",	tUNUMBER,	4 },
356 	{ "fifth",	tUNUMBER,	5 },
357 	{ "sixth",	tUNUMBER,	6 },
358 	{ "seventh",	tUNUMBER,	7 },
359 	{ "eighth",	tUNUMBER,	8 },
360 	{ "ninth",	tUNUMBER,	9 },
361 	{ "tenth",	tUNUMBER,	10 },
362 	{ "eleventh",	tUNUMBER,	11 },
363 	{ "twelfth",	tUNUMBER,	12 },
364 	{ "ago",	tAGO,	1 },
365 	{ NULL }
366 };
367 
368 /* The timezone table. */
369 /* Some of these are commented out because a time_t can't store a float. */
370 static TABLE const TimezoneTable[] = {
371 	{ "gmt",	tZONE,     HOUR( 0) },	/* Greenwich Mean */
372 	{ "ut",		tZONE,     HOUR( 0) },	/* Universal (Coordinated) */
373 	{ "utc",	tZONE,     HOUR( 0) },
374 	{ "wet",	tZONE,     HOUR( 0) },	/* Western European */
375 	{ "bst",	tDAYZONE,  HOUR( 0) },	/* British Summer */
376 	{ "wat",	tZONE,     HOUR( 1) },	/* West Africa */
377 	{ "at",		tZONE,     HOUR( 2) },	/* Azores */
378 #if	0
379 	/* For completeness.  BST is also British Summer, and GST is
380 	 * also Guam Standard. */
381 	{ "bst",	tZONE,     HOUR( 3) },	/* Brazil Standard */
382 	{ "gst",	tZONE,     HOUR( 3) },	/* Greenland Standard */
383 #endif
384 #if 0
385 	{ "nft",	tZONE,     HOUR(3.5) },	/* Newfoundland */
386 	{ "nst",	tZONE,     HOUR(3.5) },	/* Newfoundland Standard */
387 	{ "ndt",	tDAYZONE,  HOUR(3.5) },	/* Newfoundland Daylight */
388 #endif
389 	{ "ast",	tZONE,     HOUR( 4) },	/* Atlantic Standard */
390 	{ "adt",	tDAYZONE,  HOUR( 4) },	/* Atlantic Daylight */
391 	{ "est",	tZONE,     HOUR( 5) },	/* Eastern Standard */
392 	{ "edt",	tDAYZONE,  HOUR( 5) },	/* Eastern Daylight */
393 	{ "cst",	tZONE,     HOUR( 6) },	/* Central Standard */
394 	{ "cdt",	tDAYZONE,  HOUR( 6) },	/* Central Daylight */
395 	{ "mst",	tZONE,     HOUR( 7) },	/* Mountain Standard */
396 	{ "mdt",	tDAYZONE,  HOUR( 7) },	/* Mountain Daylight */
397 	{ "pst",	tZONE,     HOUR( 8) },	/* Pacific Standard */
398 	{ "pdt",	tDAYZONE,  HOUR( 8) },	/* Pacific Daylight */
399 	{ "yst",	tZONE,     HOUR( 9) },	/* Yukon Standard */
400 	{ "ydt",	tDAYZONE,  HOUR( 9) },	/* Yukon Daylight */
401 	{ "hst",	tZONE,     HOUR(10) },	/* Hawaii Standard */
402 	{ "hdt",	tDAYZONE,  HOUR(10) },	/* Hawaii Daylight */
403 	{ "cat",	tZONE,     HOUR(10) },	/* Central Alaska */
404 	{ "ahst",	tZONE,     HOUR(10) },	/* Alaska-Hawaii Standard */
405 	{ "nt",		tZONE,     HOUR(11) },	/* Nome */
406 	{ "idlw",	tZONE,     HOUR(12) },	/* International Date Line West */
407 	{ "cet",	tZONE,     -HOUR(1) },	/* Central European */
408 	{ "met",	tZONE,     -HOUR(1) },	/* Middle European */
409 	{ "mewt",	tZONE,     -HOUR(1) },	/* Middle European Winter */
410 	{ "mest",	tDAYZONE,  -HOUR(1) },	/* Middle European Summer */
411 	{ "swt",	tZONE,     -HOUR(1) },	/* Swedish Winter */
412 	{ "sst",	tDAYZONE,  -HOUR(1) },	/* Swedish Summer */
413 	{ "fwt",	tZONE,     -HOUR(1) },	/* French Winter */
414 	{ "fst",	tDAYZONE,  -HOUR(1) },	/* French Summer */
415 	{ "eet",	tZONE,     -HOUR(2) },	/* Eastern Europe, USSR Zone 1 */
416 	{ "bt",		tZONE,     -HOUR(3) },	/* Baghdad, USSR Zone 2 */
417 #if 0
418 	{ "it",		tZONE,     -HOUR(3.5) },/* Iran */
419 #endif
420 	{ "zp4",	tZONE,     -HOUR(4) },	/* USSR Zone 3 */
421 	{ "zp5",	tZONE,     -HOUR(5) },	/* USSR Zone 4 */
422 #if 0
423 	{ "ist",	tZONE,     -HOUR(5.5) },/* Indian Standard */
424 #endif
425 	{ "zp6",	tZONE,     -HOUR(6) },	/* USSR Zone 5 */
426 #if	0
427 	/* For completeness.  NST is also Newfoundland Stanard, and SST is
428 	 * also Swedish Summer. */
429 	{ "nst",	tZONE,     -HOUR(6.5) },/* North Sumatra */
430 	{ "sst",	tZONE,     -HOUR(7) },	/* South Sumatra, USSR Zone 6 */
431 #endif	/* 0 */
432 	{ "wast",	tZONE,     -HOUR(7) },	/* West Australian Standard */
433 	{ "wadt",	tDAYZONE,  -HOUR(7) },	/* West Australian Daylight */
434 #if 0
435 	{ "jt",		tZONE,     -HOUR(7.5) },/* Java (3pm in Cronusland!) */
436 #endif
437 	{ "cct",	tZONE,     -HOUR(8) },	/* China Coast, USSR Zone 7 */
438 	{ "jst",	tZONE,     -HOUR(9) },	/* Japan Standard, USSR Zone 8 */
439 #if 0
440 	{ "cast",	tZONE,     -HOUR(9.5) },/* Central Australian Standard */
441 	{ "cadt",	tDAYZONE,  -HOUR(9.5) },/* Central Australian Daylight */
442 #endif
443 	{ "east",	tZONE,     -HOUR(10) },	/* Eastern Australian Standard */
444 	{ "eadt",	tDAYZONE,  -HOUR(10) },	/* Eastern Australian Daylight */
445 	{ "gst",	tZONE,     -HOUR(10) },	/* Guam Standard, USSR Zone 9 */
446 	{ "nzt",	tZONE,     -HOUR(12) },	/* New Zealand */
447 	{ "nzst",	tZONE,     -HOUR(12) },	/* New Zealand Standard */
448 	{ "nzdt",	tDAYZONE,  -HOUR(12) },	/* New Zealand Daylight */
449 	{ "idle",	tZONE,     -HOUR(12) },	/* International Date Line East */
450 	{  NULL  }
451 };
452 
453 /* Military timezone table. */
454 static TABLE const MilitaryTable[] = {
455 	{ "a",	tZONE,	HOUR(  1) },
456 	{ "b",	tZONE,	HOUR(  2) },
457 	{ "c",	tZONE,	HOUR(  3) },
458 	{ "d",	tZONE,	HOUR(  4) },
459 	{ "e",	tZONE,	HOUR(  5) },
460 	{ "f",	tZONE,	HOUR(  6) },
461 	{ "g",	tZONE,	HOUR(  7) },
462 	{ "h",	tZONE,	HOUR(  8) },
463 	{ "i",	tZONE,	HOUR(  9) },
464 	{ "k",	tZONE,	HOUR( 10) },
465 	{ "l",	tZONE,	HOUR( 11) },
466 	{ "m",	tZONE,	HOUR( 12) },
467 	{ "n",	tZONE,	HOUR(- 1) },
468 	{ "o",	tZONE,	HOUR(- 2) },
469 	{ "p",	tZONE,	HOUR(- 3) },
470 	{ "q",	tZONE,	HOUR(- 4) },
471 	{ "r",	tZONE,	HOUR(- 5) },
472 	{ "s",	tZONE,	HOUR(- 6) },
473 	{ "t",	tZONE,	HOUR(- 7) },
474 	{ "u",	tZONE,	HOUR(- 8) },
475 	{ "v",	tZONE,	HOUR(- 9) },
476 	{ "w",	tZONE,	HOUR(-10) },
477 	{ "x",	tZONE,	HOUR(-11) },
478 	{ "y",	tZONE,	HOUR(-12) },
479 	{ "z",	tZONE,	HOUR(  0) },
480 	{ NULL }
481 };
482 
483 
484 static int
485 yyerror(const char *s)
486 {
487 #if !defined(TEST)
488 	char *str;
489 
490 	(void)xasprintf(&str, "parsing date string: %s", s);
491 	cvs_log(LP_ERR, "%s", str);
492 	free(str);
493 #endif
494 	return (0);
495 }
496 
497 
498 static time_t
499 ToSeconds(time_t Hours, time_t Minutes, time_t	Seconds, MERIDIAN Meridian)
500 {
501 	if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59)
502 		return (-1);
503 
504 	switch (Meridian) {
505 	case MER24:
506 		if (Hours < 0 || Hours > 23)
507 			return (-1);
508 		return (Hours * 60L + Minutes) * 60L + Seconds;
509 	case MERam:
510 		if (Hours < 1 || Hours > 12)
511 			return (-1);
512 		if (Hours == 12)
513 			Hours = 0;
514 		return (Hours * 60L + Minutes) * 60L + Seconds;
515 	case MERpm:
516 		if (Hours < 1 || Hours > 12)
517 			return (-1);
518 		if (Hours == 12)
519 			Hours = 0;
520 		return ((Hours + 12) * 60L + Minutes) * 60L + Seconds;
521 	default:
522 		return (-1);
523 	}
524 	/* NOTREACHED */
525 }
526 
527 
528 /* Year is either
529  * A negative number, which means to use its absolute value (why?)
530  * A number from 0 to 99, which means a year from 1900 to 1999, or
531  * The actual year (>=100).
532  */
533 static time_t
534 Convert(time_t Month, time_t Day, time_t Year, time_t Hours, time_t Minutes,
535     time_t Seconds, MERIDIAN Meridian, DSTMODE DSTmode)
536 {
537 	static int DaysInMonth[12] = {
538 		31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
539 	};
540 	time_t	tod;
541 	time_t	julian;
542 	int	i;
543 
544 	if (Year < 0)
545 		Year = -Year;
546 	if (Year < 69)
547 		Year += 2000;
548 	else if (Year < 100) {
549 		Year += 1900;
550 		if (Year < YEAR_EPOCH)
551 			Year += 100;
552 	}
553 	DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
554 	    ? 29 : 28;
555 	/* XXX Sloppily check for 2038 if time_t is 32 bits */
556 	if (Year < YEAR_EPOCH ||
557 	    (sizeof(time_t) == sizeof(int) && Year > 2038) ||
558 	    Month < 1 || Month > 12 ||
559 	    /* Lint fluff:  "conversion from long may lose accuracy" */
560 	     Day < 1 || Day > DaysInMonth[(int)--Month])
561 		return (-1);
562 
563 	for (julian = Day - 1, i = 0; i < Month; i++)
564 		julian += DaysInMonth[i];
565 
566 	for (i = YEAR_EPOCH; i < Year; i++)
567 		julian += 365 + (i % 4 == 0);
568 	julian *= SECSPERDAY;
569 	julian += yyTimezone * 60L;
570 
571 	if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
572 		return (-1);
573 	julian += tod;
574 	if ((DSTmode == DSTon) ||
575 	    (DSTmode == DSTmaybe && localtime(&julian)->tm_isdst))
576 	julian -= 60 * 60;
577 	return (julian);
578 }
579 
580 
581 static time_t
582 DSTcorrect(time_t Start, time_t Future)
583 {
584 	time_t	StartDay;
585 	time_t	FutureDay;
586 
587 	StartDay = (localtime(&Start)->tm_hour + 1) % 24;
588 	FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
589 	return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
590 }
591 
592 
593 static time_t
594 RelativeDate(time_t Start, time_t DayOrdinal, time_t DayNumber)
595 {
596 	struct tm	*tm;
597 	time_t	now;
598 
599 	now = Start;
600 	tm = localtime(&now);
601 	now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
602 	now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
603 	return DSTcorrect(Start, now);
604 }
605 
606 
607 static time_t
608 RelativeMonth(time_t Start, time_t RelMonth)
609 {
610 	struct tm	*tm;
611 	time_t	Month;
612 	time_t	Year;
613 
614 	if (RelMonth == 0)
615 		return (0);
616 	tm = localtime(&Start);
617 	Month = 12 * (tm->tm_year + 1900) + tm->tm_mon + RelMonth;
618 	Year = Month / 12;
619 	Month = Month % 12 + 1;
620 	return DSTcorrect(Start,
621 	    Convert(Month, (time_t)tm->tm_mday, Year,
622 	    (time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
623 	    MER24, DSTmaybe));
624 }
625 
626 
627 static int
628 lookup(char *buff)
629 {
630 	size_t		len;
631 	char		*p, *q;
632 	int		i, abbrev;
633 	const TABLE	*tp;
634 
635 	/* Make it lowercase. */
636 	for (p = buff; *p; p++)
637 		if (isupper(*p))
638 			*p = tolower(*p);
639 
640 	if (strcmp(buff, "am") == 0 || strcmp(buff, "a.m.") == 0) {
641 		yylval.Meridian = MERam;
642 		return (tMERIDIAN);
643 	}
644 	if (strcmp(buff, "pm") == 0 || strcmp(buff, "p.m.") == 0) {
645 		yylval.Meridian = MERpm;
646 		return (tMERIDIAN);
647 	}
648 
649 	len = strlen(buff);
650 	/* See if we have an abbreviation for a month. */
651 	if (len == 3)
652 		abbrev = 1;
653 	else if (len == 4 && buff[3] == '.') {
654 		abbrev = 1;
655 		buff[3] = '\0';
656 		--len;
657 	} else
658 		abbrev = 0;
659 
660 	for (tp = MonthDayTable; tp->name; tp++) {
661 		if (abbrev) {
662 			if (strncmp(buff, tp->name, 3) == 0) {
663 				yylval.Number = tp->value;
664 				return (tp->type);
665 			}
666 		} else if (strcmp(buff, tp->name) == 0) {
667 			yylval.Number = tp->value;
668 			return (tp->type);
669 		}
670 	}
671 
672 	for (tp = TimezoneTable; tp->name; tp++)
673 		if (strcmp(buff, tp->name) == 0) {
674 			yylval.Number = tp->value;
675 			return (tp->type);
676 		}
677 
678 	if (strcmp(buff, "dst") == 0)
679 		return (tDST);
680 
681 	for (tp = UnitsTable; tp->name; tp++)
682 		if (strcmp(buff, tp->name) == 0) {
683 			yylval.Number = tp->value;
684 			return (tp->type);
685 		}
686 
687 	/* Strip off any plural and try the units table again. */
688 	if (len != 0 && buff[len - 1] == 's') {
689 		buff[len - 1] = '\0';
690 		for (tp = UnitsTable; tp->name; tp++)
691 			if (strcmp(buff, tp->name) == 0) {
692 				yylval.Number = tp->value;
693 				return (tp->type);
694 			}
695 		buff[len - 1] = 's';	/* Put back for "this" in OtherTable. */
696 	}
697 
698 	for (tp = OtherTable; tp->name; tp++)
699 		if (strcmp(buff, tp->name) == 0) {
700 			yylval.Number = tp->value;
701 			return (tp->type);
702 		}
703 
704 	/* Military timezones. */
705 	if (len == 1 && isalpha(*buff)) {
706 		for (tp = MilitaryTable; tp->name; tp++)
707 			if (strcmp(buff, tp->name) == 0) {
708 				yylval.Number = tp->value;
709 				return (tp->type);
710 			}
711 	}
712 
713 	/* Drop out any periods and try the timezone table again. */
714 	for (i = 0, p = q = buff; *q; q++)
715 		if (*q != '.')
716 			*p++ = *q;
717 		else
718 			i++;
719 	*p = '\0';
720 	if (i)
721 		for (tp = TimezoneTable; tp->name; tp++)
722 			if (strcmp(buff, tp->name) == 0) {
723 				yylval.Number = tp->value;
724 				return (tp->type);
725 			}
726 
727 	return (tID);
728 }
729 
730 
731 static int
732 yylex(void)
733 {
734 	char	c, *p, buff[20];
735 	int	count, sign;
736 
737 	for (;;) {
738 		while (isspace(*yyInput))
739 			yyInput++;
740 
741 		if (isdigit(c = *yyInput) || c == '-' || c == '+') {
742 			if (c == '-' || c == '+') {
743 				sign = c == '-' ? -1 : 1;
744 				if (!isdigit(*++yyInput))
745 					/* skip the '-' sign */
746 					continue;
747 			}
748 			else
749 				sign = 0;
750 
751 			for (yylval.Number = 0; isdigit(c = *yyInput++); )
752 				yylval.Number = 10 * yylval.Number + c - '0';
753 			yyInput--;
754 			if (sign < 0)
755 				yylval.Number = -yylval.Number;
756 			return sign ? tSNUMBER : tUNUMBER;
757 		}
758 
759 		if (isalpha(c)) {
760 			for (p = buff; isalpha(c = *yyInput++) || c == '.'; )
761 				if (p < &buff[sizeof buff - 1])
762 					*p++ = c;
763 			*p = '\0';
764 			yyInput--;
765 			return lookup(buff);
766 		}
767 		if (c != '(')
768 			return *yyInput++;
769 
770 		count = 0;
771 		do {
772 			c = *yyInput++;
773 			if (c == '\0')
774 				return (c);
775 			if (c == '(')
776 				count++;
777 			else if (c == ')')
778 				count--;
779 		} while (count > 0);
780 	}
781 }
782 
783 /* Yield A - B, measured in seconds.  */
784 static long
785 difftm(struct tm *a, struct tm *b)
786 {
787 	int ay = a->tm_year + (YEAR_TMORIGIN - 1);
788 	int by = b->tm_year + (YEAR_TMORIGIN - 1);
789 	int days = (
790 	    /* difference in day of year */
791 	    a->tm_yday - b->tm_yday
792 	    /* + intervening leap days */
793 	    +  ((ay >> 2) - (by >> 2))
794 	    -  (ay/100 - by/100)
795 	    +  ((ay/100 >> 2) - (by/100 >> 2))
796 	    /* + difference in years * 365 */
797 	    +  (long)(ay-by) * 365);
798 	return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
799 	    + (a->tm_min - b->tm_min)) + (a->tm_sec - b->tm_sec));
800 }
801 
802 /*
803  * date_parse()
804  *
805  * Returns the number of seconds since the Epoch corresponding to the date.
806  */
807 time_t
808 date_parse(const char *p)
809 {
810 	struct tm	gmt, tm;
811 	time_t		Start, tod, nowtime, tz;
812 
813 	yyInput = p;
814 
815 	if (time(&nowtime) == -1 || !gmtime_r(&nowtime, &gmt) ||
816 	    !localtime_r(&nowtime, &tm))
817 		return -1;
818 
819 	tz = difftm(&gmt, &tm) / 60;
820 
821 	if (tm.tm_isdst)
822 		tz += 60;
823 
824 	yyYear = tm.tm_year + 1900;
825 	yyMonth = tm.tm_mon + 1;
826 	yyDay = tm.tm_mday;
827 	yyTimezone = tz;
828 	yyDSTmode = DSTmaybe;
829 	yyHour = 0;
830 	yyMinutes = 0;
831 	yySeconds = 0;
832 	yyMeridian = MER24;
833 	yyRelSeconds = 0;
834 	yyRelMonth = 0;
835 	yyHaveDate = 0;
836 	yyHaveDay = 0;
837 	yyHaveRel = 0;
838 	yyHaveTime = 0;
839 	yyHaveZone = 0;
840 
841 	if (yyparse() || yyHaveTime > 1 || yyHaveZone > 1 ||
842 	    yyHaveDate > 1 || yyHaveDay > 1)
843 		return (-1);
844 
845 	if (yyHaveDate || yyHaveTime || yyHaveDay) {
846 		Start = Convert(yyMonth, yyDay, yyYear, yyHour, yyMinutes,
847 		    yySeconds, yyMeridian, yyDSTmode);
848 		if (Start < 0)
849 			return (-1);
850 	} else {
851 		Start = nowtime;
852 		if (!yyHaveRel)
853 			Start -= ((tm.tm_hour * 60L + tm.tm_min) * 60L) +
854 			    tm.tm_sec;
855 	}
856 
857 	Start += yyRelSeconds;
858 	Start += RelativeMonth(Start, yyRelMonth);
859 
860 	if (yyHaveDay && !yyHaveDate) {
861 		tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber);
862 		Start += tod;
863 	}
864 
865 	return Start;
866 }
867 
868 #if defined(TEST)
869 /* ARGSUSED */
870 int
871 main(int argc, char **argv)
872 {
873 	char	buff[128];
874 	time_t	d;
875 
876 	(void)printf("Enter date, or blank line to exit.\n\t> ");
877 	(void)fflush(stdout);
878 	while (fgets(buff, sizeof(buff), stdin) && buff[0]) {
879 		d = date_parse(buff);
880 		if (d == -1)
881 			(void)printf("Bad format - couldn't convert.\n");
882 		else
883 			(void)printf("%s", ctime(&d));
884 		(void)printf("\t> ");
885 		(void)fflush(stdout);
886 	}
887 
888 	return (0);
889 }
890 #endif	/* defined(TEST) */
891