xref: /openbsd-src/usr.bin/cal/cal.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*	$OpenBSD: cal.c,v 1.6 1998/04/25 01:09:15 deraadt Exp $	*/
2 /*	$NetBSD: cal.c,v 1.6 1995/03/26 03:10:24 glass Exp $	*/
3 
4 /*
5  * Copyright (c) 1989, 1993, 1994
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Kim Letkeman.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the University of
22  *	California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 #ifndef lint
41 static char copyright[] =
42 "@(#) Copyright (c) 1989, 1993, 1994\n\
43 	The Regents of the University of California.  All rights reserved.\n";
44 #endif /* not lint */
45 
46 #ifndef lint
47 #if 0
48 static char sccsid[] = "@(#)cal.c	8.4 (Berkeley) 4/2/94";
49 #else
50 static char rcsid[] = "$OpenBSD: cal.c,v 1.6 1998/04/25 01:09:15 deraadt Exp $";
51 #endif
52 #endif /* not lint */
53 
54 #include <sys/types.h>
55 
56 #include <ctype.h>
57 #include <err.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <time.h>
62 #include <tzfile.h>
63 #include <unistd.h>
64 
65 #define	THURSDAY		4		/* for reformation */
66 #define	SATURDAY 		6		/* 1 Jan 1 was a Saturday */
67 
68 #define	FIRST_MISSING_DAY 	639799		/* 3 Sep 1752 */
69 #define	NUMBER_MISSING_DAYS 	11		/* 11 day correction */
70 
71 #define	MAXDAYS			42		/* max slots in a month array */
72 #define	SPACE			-1		/* used in day array */
73 
74 static int days_in_month[2][13] = {
75 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
76 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
77 };
78 
79 int sep1752[MAXDAYS] = {
80 	SPACE,	SPACE,	1,	2,	14,	15,	16,
81 	17,	18,	19,	20,	21,	22,	23,
82 	24,	25,	26,	27,	28,	29,	30,
83 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
84 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
85 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
86 }, j_sep1752[MAXDAYS] = {
87 	SPACE,	SPACE,	245,	246,	258,	259,	260,
88 	261,	262,	263,	264,	265,	266,	267,
89 	268,	269,	270,	271,	272,	273,	274,
90 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
91 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
92 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
93 }, empty[MAXDAYS] = {
94 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
95 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
96 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
97 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
98 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
99 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
100 };
101 
102 char *month_names[12] = {
103 	"January", "February", "March", "April", "May", "June",
104 	"July", "August", "September", "October", "November", "December",
105 };
106 
107 char *day_headings = "Su Mo Tu We Th Fr Sa";
108 char *j_day_headings = " Su  Mo  Tu  We  Th  Fr  Sa";
109 
110 /* leap year -- account for gregorian reformation in 1752 */
111 #define	leap_year(yr) \
112 	((yr) <= 1752 ? !((yr) % 4) : \
113 	(!((yr) % 4) && ((yr) % 100)) || !((yr) % 400))
114 
115 /* number of centuries since 1700, not inclusive */
116 #define	centuries_since_1700(yr) \
117 	((yr) > 1700 ? (yr) / 100 - 17 : 0)
118 
119 /* number of centuries since 1700 whose modulo of 400 is 0 */
120 #define	quad_centuries_since_1700(yr) \
121 	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
122 
123 /* number of leap years between year 1 and this year, not inclusive */
124 #define	leap_years_since_year_1(yr) \
125 	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
126 
127 int julian;
128 
129 void	ascii_day __P((char *, int));
130 void	center __P((char *, int, int));
131 void	day_array __P((int, int, int *));
132 int	day_in_week __P((int, int, int));
133 int	day_in_year __P((int, int, int));
134 void	j_yearly __P((int));
135 void	monthly __P((int, int));
136 void	trim_trailing_spaces __P((char *));
137 void	usage __P((void));
138 void	yearly __P((int));
139 
140 int
141 main(argc, argv)
142 	int argc;
143 	char **argv;
144 {
145 	struct tm *local_time;
146 	time_t now;
147 	int ch, month, year, yflag;
148 
149 	yflag = year = 0;
150 	while ((ch = getopt(argc, argv, "jy")) != -1)
151 		switch(ch) {
152 		case 'j':
153 			julian = 1;
154 			break;
155 		case 'y':
156 			yflag = 1;
157 			break;
158 		case '?':
159 		default:
160 			usage();
161 		}
162 	argc -= optind;
163 	argv += optind;
164 
165 	month = 0;
166 	switch(argc) {
167 	case 2:
168 		if ((month = atoi(*argv++)) < 1 || month > 12)
169 			errx(1, "illegal month value: use 1-12");
170 		/* FALLTHROUGH */
171 	case 1:
172 		if ((year = atoi(*argv)) < 1 || year > 9999)
173 			errx(1, "illegal year value: use 1-9999");
174 		break;
175 	case 0:
176 		(void)time(&now);
177 		local_time = localtime(&now);
178 		year = local_time->tm_year + TM_YEAR_BASE;
179 		if (!yflag)
180 			month = local_time->tm_mon + 1;
181 		break;
182 	default:
183 		usage();
184 	}
185 
186 	if (month)
187 		monthly(month, year);
188 	else if (julian)
189 		j_yearly(year);
190 	else
191 		yearly(year);
192 	exit(0);
193 }
194 
195 #define	DAY_LEN		3		/* 3 spaces per day */
196 #define	J_DAY_LEN	4		/* 4 spaces per day */
197 #define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
198 #define	J_WEEK_LEN	27		/* 7 * 4 - one space at the end */
199 #define	HEAD_SEP	2		/* spaces between day headings */
200 #define	J_HEAD_SEP	2
201 
202 void
203 monthly(month, year)
204 	int month, year;
205 {
206 	int col, row, len, days[MAXDAYS];
207 	char *p, lineout[30];
208 
209 	day_array(month, year, days);
210 	len = sprintf(lineout, "%s %d", month_names[month - 1], year);
211 	(void)printf("%*s%s\n%s\n",
212 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
213 	    lineout, julian ? j_day_headings : day_headings);
214 	for (row = 0; row < 6; row++) {
215 		for (col = 0, p = lineout; col < 7; col++,
216 		    p += julian ? J_DAY_LEN : DAY_LEN)
217 			ascii_day(p, days[row * 7 + col]);
218 		*p = '\0';
219 		trim_trailing_spaces(lineout);
220 		(void)printf("%s\n", lineout);
221 	}
222 }
223 
224 void
225 j_yearly(year)
226 	int year;
227 {
228 	int col, *dp, i, month, row, which_cal;
229 	int days[12][MAXDAYS];
230 	char *p, lineout[80];
231 
232 	(void)sprintf(lineout, "%d", year);
233 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
234 	(void)printf("\n\n");
235 	for (i = 0; i < 12; i++)
236 		day_array(i + 1, year, days[i]);
237 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
238 	lineout[sizeof(lineout) - 1] = '\0';
239 	for (month = 0; month < 12; month += 2) {
240 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
241 		center(month_names[month + 1], J_WEEK_LEN, 0);
242 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
243 		    j_day_headings);
244 		for (row = 0; row < 6; row++) {
245 			for (which_cal = 0; which_cal < 2; which_cal++) {
246 				p = lineout + which_cal * (J_WEEK_LEN + 2);
247 				dp = &days[month + which_cal][row * 7];
248 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
249 					ascii_day(p, *dp++);
250 			}
251 			*p = '\0';
252 			trim_trailing_spaces(lineout);
253 			(void)printf("%s\n", lineout);
254 		}
255 	}
256 	(void)printf("\n");
257 }
258 
259 void
260 yearly(year)
261 	int year;
262 {
263 	int col, *dp, i, month, row, which_cal;
264 	int days[12][MAXDAYS];
265 	char *p, lineout[80];
266 
267 	(void)sprintf(lineout, "%d", year);
268 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
269 	(void)printf("\n\n");
270 	for (i = 0; i < 12; i++)
271 		day_array(i + 1, year, days[i]);
272 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
273 	lineout[sizeof(lineout) - 1] = '\0';
274 	for (month = 0; month < 12; month += 3) {
275 		center(month_names[month], WEEK_LEN, HEAD_SEP);
276 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
277 		center(month_names[month + 2], WEEK_LEN, 0);
278 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
279 		    "", day_headings, HEAD_SEP, "", day_headings);
280 		for (row = 0; row < 6; row++) {
281 			for (which_cal = 0; which_cal < 3; which_cal++) {
282 				p = lineout + which_cal * (WEEK_LEN + 2);
283 				dp = &days[month + which_cal][row * 7];
284 				for (col = 0; col < 7; col++, p += DAY_LEN)
285 					ascii_day(p, *dp++);
286 			}
287 			*p = '\0';
288 			trim_trailing_spaces(lineout);
289 			(void)printf("%s\n", lineout);
290 		}
291 	}
292 	(void)printf("\n");
293 }
294 
295 /*
296  * day_array --
297  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
298  *	that you took the (maximum) 6 rows in a calendar and stretched them
299  *	out end to end.  You would have 42 numbers or spaces.  This routine
300  *	builds that array for any month from Jan. 1 through Dec. 9999.
301  */
302 void
303 day_array(month, year, days)
304 	int month, year;
305 	int *days;
306 {
307 	int day, dw, dm;
308 
309 	if (month == 9 && year == 1752) {
310 		memmove(days,
311 			julian ? j_sep1752 : sep1752, MAXDAYS * sizeof(int));
312 		return;
313 	}
314 	memmove(days, empty, MAXDAYS * sizeof(int));
315 	dm = days_in_month[leap_year(year)][month];
316 	dw = day_in_week(1, month, year);
317 	day = julian ? day_in_year(1, month, year) : 1;
318 	while (dm--)
319 		days[dw++] = day++;
320 }
321 
322 /*
323  * day_in_year --
324  *	return the 1 based day number within the year
325  */
326 int
327 day_in_year(day, month, year)
328 	int day, month, year;
329 {
330 	int i, leap;
331 
332 	leap = leap_year(year);
333 	for (i = 1; i < month; i++)
334 		day += days_in_month[leap][i];
335 	return (day);
336 }
337 
338 /*
339  * day_in_week
340  *	return the 0 based day number for any date from 1 Jan. 1 to
341  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
342  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
343  *	missing days.
344  */
345 int
346 day_in_week(day, month, year)
347 	int day, month, year;
348 {
349 	long temp;
350 
351 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
352 	    + day_in_year(day, month, year);
353 	if (temp < FIRST_MISSING_DAY)
354 		return ((temp - 1 + SATURDAY) % 7);
355 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
356 		return (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
357 	return (THURSDAY);
358 }
359 
360 void
361 ascii_day(p, day)
362 	char *p;
363 	int day;
364 {
365 	int display, val;
366 	static char *aday[] = {
367 		"",
368 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
369 		" 8", " 9", "10", "11", "12", "13", "14",
370 		"15", "16", "17", "18", "19", "20", "21",
371 		"22", "23", "24", "25", "26", "27", "28",
372 		"29", "30", "31",
373 	};
374 
375 	if (day == SPACE) {
376 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
377 		return;
378 	}
379 	if (julian) {
380 		val = day / 100;
381 		if (val) {
382 			day %= 100;
383 			*p++ = val + '0';
384 			display = 1;
385 		} else {
386 			*p++ = ' ';
387 			display = 0;
388 		}
389 		val = day / 10;
390 		if (val || display)
391 			*p++ = val + '0';
392 		else
393 			*p++ = ' ';
394 		*p++ = day % 10 + '0';
395 	} else {
396 		*p++ = aday[day][0];
397 		*p++ = aday[day][1];
398 	}
399 	*p = ' ';
400 }
401 
402 void
403 trim_trailing_spaces(s)
404 	char *s;
405 {
406 	char *p;
407 
408 	for (p = s; *p; ++p)
409 		continue;
410 	while (p > s && isspace(*--p))
411 		continue;
412 	if (p > s)
413 		++p;
414 	*p = '\0';
415 }
416 
417 void
418 center(str, len, separate)
419 	char *str;
420 	int len;
421 	int separate;
422 {
423 
424 	len -= strlen(str);
425 	(void)printf("%*s%s%*s", len / 2, "", str, len / 2 + len % 2, "");
426 	if (separate)
427 		(void)printf("%*s", separate, "");
428 }
429 
430 void
431 usage()
432 {
433 
434 	(void)fprintf(stderr, "usage: cal [-jy] [[month] year]\n");
435 	exit(1);
436 }
437