Correct math and limerick.
[dragonfly.git] / usr.bin / at / parsetime.c
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1 /*
2 * parsetime.c - parse time for at(1)
3 * Copyright (C) 1993, 1994 Thomas Koenig
5 * modifications for English-language times
6 * Copyright (C) 1993 David Parsons
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. The name of the author(s) may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
29 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
30 * |NOON | |[TOMORROW] |
31 * |MIDNIGHT | |[DAY OF WEEK] |
32 * \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
33 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
35 * $FreeBSD: src/usr.bin/at/parsetime.c,v 1.27 2005/08/18 08:18:02 stefanf Exp $
36 * $DragonFly: src/usr.bin/at/parsetime.c,v 1.6 2007/08/26 16:12:27 pavalos Exp $
39 /* System Headers */
41 #include <sys/types.h>
42 #include <ctype.h>
43 #include <err.h>
44 #include <errno.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <time.h>
49 #include <unistd.h>
51 /* Local headers */
53 #include "at.h"
54 #include "panic.h"
55 #include "parsetime.h"
58 /* Structures and unions */
60 enum { /* symbols */
61 MIDNIGHT, NOON, TEATIME,
62 PM, AM, TOMORROW, TODAY, NOW,
63 MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
64 NUMBER, PLUS, DOT, SLASH, ID, JUNK,
65 JAN, FEB, MAR, APR, MAY, JUN,
66 JUL, AUG, SEP, OCT, NOV, DEC,
67 SUN, MON, TUE, WED, THU, FRI, SAT
70 /* parse translation table - table driven parsers can be your FRIEND!
72 struct {
73 const char *name; /* token name */
74 int value; /* token id */
75 int plural; /* is this plural? */
76 } Specials[] = {
77 { "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */
78 { "noon", NOON,0 }, /* 12:00:00 of today or tomorrow */
79 { "teatime", TEATIME,0 }, /* 16:00:00 of today or tomorrow */
80 { "am", AM,0 }, /* morning times for 0-12 clock */
81 { "pm", PM,0 }, /* evening times for 0-12 clock */
82 { "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */
83 { "today", TODAY, 0 }, /* execute today - don't advance time */
84 { "now", NOW,0 }, /* opt prefix for PLUS */
86 { "minute", MINUTES,0 }, /* minutes multiplier */
87 { "minutes", MINUTES,1 }, /* (pluralized) */
88 { "hour", HOURS,0 }, /* hours ... */
89 { "hours", HOURS,1 }, /* (pluralized) */
90 { "day", DAYS,0 }, /* days ... */
91 { "days", DAYS,1 }, /* (pluralized) */
92 { "week", WEEKS,0 }, /* week ... */
93 { "weeks", WEEKS,1 }, /* (pluralized) */
94 { "month", MONTHS,0 }, /* month ... */
95 { "months", MONTHS,1 }, /* (pluralized) */
96 { "year", YEARS,0 }, /* year ... */
97 { "years", YEARS,1 }, /* (pluralized) */
98 { "jan", JAN,0 },
99 { "feb", FEB,0 },
100 { "mar", MAR,0 },
101 { "apr", APR,0 },
102 { "may", MAY,0 },
103 { "jun", JUN,0 },
104 { "jul", JUL,0 },
105 { "aug", AUG,0 },
106 { "sep", SEP,0 },
107 { "oct", OCT,0 },
108 { "nov", NOV,0 },
109 { "dec", DEC,0 },
110 { "january", JAN,0 },
111 { "february", FEB,0 },
112 { "march", MAR,0 },
113 { "april", APR,0 },
114 { "may", MAY,0 },
115 { "june", JUN,0 },
116 { "july", JUL,0 },
117 { "august", AUG,0 },
118 { "september", SEP,0 },
119 { "october", OCT,0 },
120 { "november", NOV,0 },
121 { "december", DEC,0 },
122 { "sunday", SUN, 0 },
123 { "sun", SUN, 0 },
124 { "monday", MON, 0 },
125 { "mon", MON, 0 },
126 { "tuesday", TUE, 0 },
127 { "tue", TUE, 0 },
128 { "wednesday", WED, 0 },
129 { "wed", WED, 0 },
130 { "thursday", THU, 0 },
131 { "thu", THU, 0 },
132 { "friday", FRI, 0 },
133 { "fri", FRI, 0 },
134 { "saturday", SAT, 0 },
135 { "sat", SAT, 0 },
138 /* File scope variables */
140 static char **scp; /* scanner - pointer at arglist */
141 static char scc; /* scanner - count of remaining arguments */
142 static char *sct; /* scanner - next char pointer in current argument */
143 static int need; /* scanner - need to advance to next argument */
145 static char *sc_token; /* scanner - token buffer */
146 static size_t sc_len; /* scanner - length of token buffer */
147 static int sc_tokid; /* scanner - token id */
148 static int sc_tokplur; /* scanner - is token plural? */
150 /* Local functions */
153 * parse a token, checking if it's something special to us
155 static int
156 parse_token(char *arg)
158 size_t i;
160 for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
161 if (strcasecmp(Specials[i].name, arg) == 0) {
162 sc_tokplur = Specials[i].plural;
163 return sc_tokid = Specials[i].value;
166 /* not special - must be some random id */
167 return ID;
168 } /* parse_token */
172 * init_scanner() sets up the scanner to eat arguments
174 static void
175 init_scanner(int argc, char **argv)
177 scp = argv;
178 scc = argc;
179 need = 1;
180 sc_len = 1;
181 while (argc-- > 0)
182 sc_len += strlen(*argv++);
184 if ((sc_token = malloc(sc_len)) == NULL)
185 errx(EXIT_FAILURE, "virtual memory exhausted");
186 } /* init_scanner */
189 * token() fetches a token from the input stream
191 static int
192 token(void)
194 int idx;
196 while (1) {
197 memset(sc_token, 0, sc_len);
198 sc_tokid = EOF;
199 sc_tokplur = 0;
200 idx = 0;
202 /* if we need to read another argument, walk along the argument list;
203 * when we fall off the arglist, we'll just return EOF forever
205 if (need) {
206 if (scc < 1)
207 return sc_tokid;
208 sct = *scp;
209 scp++;
210 scc--;
211 need = 0;
213 /* eat whitespace now - if we walk off the end of the argument,
214 * we'll continue, which puts us up at the top of the while loop
215 * to fetch the next argument in
217 while (isspace(*sct))
218 ++sct;
219 if (!*sct) {
220 need = 1;
221 continue;
224 /* preserve the first character of the new token
226 sc_token[0] = *sct++;
228 /* then see what it is
230 if (isdigit(sc_token[0])) {
231 while (isdigit(*sct))
232 sc_token[++idx] = *sct++;
233 sc_token[++idx] = 0;
234 return sc_tokid = NUMBER;
236 else if (isalpha(sc_token[0])) {
237 while (isalpha(*sct))
238 sc_token[++idx] = *sct++;
239 sc_token[++idx] = 0;
240 return parse_token(sc_token);
242 else if (sc_token[0] == ':' || sc_token[0] == '.')
243 return sc_tokid = DOT;
244 else if (sc_token[0] == '+')
245 return sc_tokid = PLUS;
246 else if (sc_token[0] == '/')
247 return sc_tokid = SLASH;
248 else
249 return sc_tokid = JUNK;
250 } /* while (1) */
251 } /* token */
255 * plonk() gives an appropriate error message if a token is incorrect
257 static void
258 plonk(int tok)
260 panic((tok == EOF) ? "incomplete time"
261 : "garbled time");
262 } /* plonk */
266 * expect() gets a token and dies most horribly if it's not the token we want
268 static void
269 expect(int desired)
271 if (token() != desired)
272 plonk(sc_tokid); /* and we die here... */
273 } /* expect */
277 * plus() parses a now + time
279 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
283 static void
284 plus(struct tm *tm)
286 int delay;
287 int expectplur;
289 expect(NUMBER);
291 delay = atoi(sc_token);
292 expectplur = (delay != 1) ? 1 : 0;
294 switch (token()) {
295 case YEARS:
296 tm->tm_year += delay;
297 break;
298 case MONTHS:
299 tm->tm_mon += delay;
300 break;
301 case WEEKS:
302 delay *= 7;
303 case DAYS:
304 tm->tm_mday += delay;
305 break;
306 case HOURS:
307 tm->tm_hour += delay;
308 break;
309 case MINUTES:
310 tm->tm_min += delay;
311 break;
312 default:
313 plonk(sc_tokid);
314 break;
317 if (expectplur != sc_tokplur)
318 warnx("pluralization is wrong");
320 tm->tm_isdst = -1;
321 if (mktime(tm) < 0)
322 plonk(sc_tokid);
324 } /* plus */
328 * tod() computes the time of day
329 * [NUMBER [DOT NUMBER] [AM|PM]]
331 static void
332 tod(struct tm *tm)
334 int hour, minute = 0;
335 int tlen;
337 hour = atoi(sc_token);
338 tlen = strlen(sc_token);
340 /* first pick out the time of day - if it's 4 digits, we assume
341 * a HHMM time, otherwise it's HH DOT MM time
343 if (token() == DOT) {
344 expect(NUMBER);
345 minute = atoi(sc_token);
346 if (minute > 59)
347 panic("garbled time");
348 token();
350 else if (tlen == 4) {
351 minute = hour%100;
352 if (minute > 59)
353 panic("garbled time");
354 hour = hour/100;
357 /* check if an AM or PM specifier was given
359 if (sc_tokid == AM || sc_tokid == PM) {
360 if (hour > 12)
361 panic("garbled time");
363 if (sc_tokid == PM) {
364 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
365 hour += 12;
366 } else {
367 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
368 hour = 0;
370 token();
372 else if (hour > 23)
373 panic("garbled time");
375 /* if we specify an absolute time, we don't want to bump the day even
376 * if we've gone past that time - but if we're specifying a time plus
377 * a relative offset, it's okay to bump things
379 if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
380 tm->tm_mday++;
381 tm->tm_wday++;
384 tm->tm_hour = hour;
385 tm->tm_min = minute;
386 if (tm->tm_hour == 24) {
387 tm->tm_hour = 0;
388 tm->tm_mday++;
390 } /* tod */
394 * assign_date() assigns a date, wrapping to next year if needed
396 static void
397 assign_date(struct tm *tm, long mday, long mon, long year)
401 * Convert year into tm_year format (year - 1900).
402 * We may be given the year in 2 digit, 4 digit, or tm_year format.
404 if (year != -1) {
405 if (year >= 1900)
406 year -= 1900; /* convert from 4 digit year */
407 else if (year < 100) {
408 /* convert from 2 digit year */
409 struct tm *lt;
410 time_t now;
412 time(&now);
413 lt = localtime(&now);
415 /* Convert to tm_year assuming current century */
416 year += (lt->tm_year / 100) * 100;
418 if (year == lt->tm_year - 1) year++;
419 else if (year < lt->tm_year)
420 year += 100; /* must be in next century */
424 if (year < 0 &&
425 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
426 year = tm->tm_year + 1;
428 tm->tm_mday = mday;
429 tm->tm_mon = mon;
431 if (year >= 0)
432 tm->tm_year = year;
433 } /* assign_date */
437 * month() picks apart a month specification
439 * /[<month> NUMBER [NUMBER]] \
440 * |[TOMORROW] |
441 * |[DAY OF WEEK] |
442 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
443 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
445 static void
446 month(struct tm *tm)
448 long year= (-1);
449 long mday = 0, wday, mon;
450 int tlen;
452 switch (sc_tokid) {
453 case PLUS:
454 plus(tm);
455 break;
457 case TOMORROW:
458 /* do something tomorrow */
459 tm->tm_mday ++;
460 tm->tm_wday ++;
461 case TODAY: /* force ourselves to stay in today - no further processing */
462 token();
463 break;
465 case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
466 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
467 /* do month mday [year]
469 mon = (sc_tokid-JAN);
470 expect(NUMBER);
471 mday = atol(sc_token);
472 if (token() == NUMBER) {
473 year = atol(sc_token);
474 token();
476 assign_date(tm, mday, mon, year);
477 break;
479 case SUN: case MON: case TUE:
480 case WED: case THU: case FRI:
481 case SAT:
482 /* do a particular day of the week
484 wday = (sc_tokid-SUN);
486 mday = tm->tm_mday;
488 /* if this day is < today, then roll to next week
490 if (wday < tm->tm_wday)
491 mday += 7 - (tm->tm_wday - wday);
492 else
493 mday += (wday - tm->tm_wday);
495 tm->tm_wday = wday;
497 assign_date(tm, mday, tm->tm_mon, tm->tm_year);
498 break;
500 case NUMBER:
501 /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
503 tlen = strlen(sc_token);
504 mon = atol(sc_token);
505 token();
507 if (sc_tokid == SLASH || sc_tokid == DOT) {
508 int sep;
510 sep = sc_tokid;
511 expect(NUMBER);
512 mday = atol(sc_token);
513 if (token() == sep) {
514 expect(NUMBER);
515 year = atol(sc_token);
516 token();
519 /* flip months and days for European timing
521 if (sep == DOT) {
522 int x = mday;
523 mday = mon;
524 mon = x;
527 else if (tlen == 6 || tlen == 8) {
528 if (tlen == 8) {
529 year = (mon % 10000) - 1900;
530 mon /= 10000;
532 else {
533 year = mon % 100;
534 mon /= 100;
536 mday = mon % 100;
537 mon /= 100;
539 else
540 panic("garbled time");
542 mon--;
543 if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
544 panic("garbled time");
546 assign_date(tm, mday, mon, year);
547 break;
548 } /* case */
549 } /* month */
552 /* Global functions */
554 time_t
555 parsetime(int argc, char **argv)
557 /* Do the argument parsing, die if necessary, and return the time the job
558 * should be run.
560 time_t nowtimer, runtimer;
561 struct tm nowtime, runtime;
562 int hr = 0;
563 /* this MUST be initialized to zero for midnight/noon/teatime */
565 nowtimer = time(NULL);
566 nowtime = *localtime(&nowtimer);
568 runtime = nowtime;
569 runtime.tm_sec = 0;
570 runtime.tm_isdst = 0;
572 if (argc <= optind)
573 usage();
575 init_scanner(argc-optind, argv+optind);
577 switch (token()) {
578 case NOW:
579 if (scc < 1) {
580 return nowtimer;
582 /* now is optional prefix for PLUS tree */
583 expect(PLUS);
584 case PLUS:
585 plus(&runtime);
586 break;
588 case NUMBER:
589 tod(&runtime);
590 month(&runtime);
591 break;
593 /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
594 * hr to zero up above, then fall into this case in such a
595 * way so we add +12 +4 hours to it for teatime, +12 hours
596 * to it for noon, and nothing at all for midnight, then
597 * set our runtime to that hour before leaping into the
598 * month scanner
600 case TEATIME:
601 hr += 4;
602 case NOON:
603 hr += 12;
604 case MIDNIGHT:
605 if (runtime.tm_hour >= hr) {
606 runtime.tm_mday++;
607 runtime.tm_wday++;
609 runtime.tm_hour = hr;
610 runtime.tm_min = 0;
611 token();
612 /* FALLTHROUGH to month setting */
613 default:
614 month(&runtime);
615 break;
616 } /* ugly case statement */
617 expect(EOF);
619 /* convert back to time_t
621 runtime.tm_isdst = -1;
622 runtimer = mktime(&runtime);
624 if (runtimer < 0)
625 panic("garbled time");
627 if (nowtimer > runtimer)
628 panic("trying to travel back in time");
630 return runtimer;
631 } /* parsetime */