xref: /netbsd-src/usr.bin/cal/cal.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: cal.c,v 1.7 1997/10/18 12:24:59 lukem Exp $	*/
2 
3 /*
4  * Copyright (c) 1989, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Kim Letkeman.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #ifndef lint
41 __COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\n\
42 	The Regents of the University of California.  All rights reserved.\n");
43 #endif /* not lint */
44 
45 #ifndef lint
46 #if 0
47 static char sccsid[] = "@(#)cal.c	8.4 (Berkeley) 4/2/94";
48 #else
49 __RCSID("$NetBSD: cal.c,v 1.7 1997/10/18 12:24:59 lukem Exp $");
50 #endif
51 #endif /* not lint */
52 
53 #include <sys/types.h>
54 
55 #include <ctype.h>
56 #include <err.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <time.h>
61 #include <unistd.h>
62 
63 #define	THURSDAY		4		/* for reformation */
64 #define	SATURDAY 		6		/* 1 Jan 1 was a Saturday */
65 
66 #define	FIRST_MISSING_DAY 	639799		/* 3 Sep 1752 */
67 #define	NUMBER_MISSING_DAYS 	11		/* 11 day correction */
68 
69 #define	MAXDAYS			42		/* max slots in a month array */
70 #define	SPACE			-1		/* used in day array */
71 
72 static int days_in_month[2][13] = {
73 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
74 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
75 };
76 
77 int sep1752[MAXDAYS] = {
78 	SPACE,	SPACE,	1,	2,	14,	15,	16,
79 	17,	18,	19,	20,	21,	22,	23,
80 	24,	25,	26,	27,	28,	29,	30,
81 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
82 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
83 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
84 }, j_sep1752[MAXDAYS] = {
85 	SPACE,	SPACE,	245,	246,	258,	259,	260,
86 	261,	262,	263,	264,	265,	266,	267,
87 	268,	269,	270,	271,	272,	273,	274,
88 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
89 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
90 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
91 }, empty[MAXDAYS] = {
92 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
93 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
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 };
99 
100 char *month_names[12] = {
101 	"January", "February", "March", "April", "May", "June",
102 	"July", "August", "September", "October", "November", "December",
103 };
104 
105 char *day_headings = " S  M Tu  W Th  F  S";
106 char *j_day_headings = "  S   M  Tu   W  Th   F   S";
107 
108 /* leap year -- account for gregorian reformation in 1752 */
109 #define	leap_year(yr) \
110 	((yr) <= 1752 ? !((yr) % 4) : \
111 	!(((yr) % 4) && ((yr) % 100)) || !((yr) % 400))
112 
113 /* number of centuries since 1700, not inclusive */
114 #define	centuries_since_1700(yr) \
115 	((yr) > 1700 ? (yr) / 100 - 17 : 0)
116 
117 /* number of centuries since 1700 whose modulo of 400 is 0 */
118 #define	quad_centuries_since_1700(yr) \
119 	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
120 
121 /* number of leap years between year 1 and this year, not inclusive */
122 #define	leap_years_since_year_1(yr) \
123 	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
124 
125 int julian;
126 
127 void	ascii_day __P((char *, int));
128 void	center __P((char *, int, int));
129 void	day_array __P((int, int, int *));
130 int	day_in_week __P((int, int, int));
131 int	day_in_year __P((int, int, int));
132 void	j_yearly __P((int));
133 void	monthly __P((int, int));
134 int	main __P((int, char **));
135 void	trim_trailing_spaces __P((char *));
136 void	usage __P((void));
137 void	yearly __P((int));
138 
139 int
140 main(argc, argv)
141 	int argc;
142 	char **argv;
143 {
144 	struct tm *local_time;
145 	time_t now;
146 	int ch, month, year, yflag;
147 
148 	yflag = year = 0;
149 	while ((ch = getopt(argc, argv, "jy")) != -1)
150 		switch(ch) {
151 		case 'j':
152 			julian = 1;
153 			break;
154 		case 'y':
155 			yflag = 1;
156 			break;
157 		case '?':
158 		default:
159 			usage();
160 		}
161 	argc -= optind;
162 	argv += optind;
163 
164 	month = 0;
165 	switch(argc) {
166 	case 2:
167 		if ((month = atoi(*argv++)) < 1 || month > 12)
168 			errx(1, "illegal month value: use 1-12");
169 		/* FALLTHROUGH */
170 	case 1:
171 		if ((year = atoi(*argv)) < 1 || year > 9999)
172 			errx(1, "illegal year value: use 1-9999");
173 		break;
174 	case 0:
175 		(void)time(&now);
176 		local_time = localtime(&now);
177 		year = local_time->tm_year + 1900;
178 		if (!yflag)
179 			month = local_time->tm_mon + 1;
180 		break;
181 	default:
182 		usage();
183 	}
184 
185 	if (month)
186 		monthly(month, year);
187 	else if (julian)
188 		j_yearly(year);
189 	else
190 		yearly(year);
191 	exit(0);
192 }
193 
194 #define	DAY_LEN		3		/* 3 spaces per day */
195 #define	J_DAY_LEN	4		/* 4 spaces per day */
196 #define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
197 #define	J_WEEK_LEN	27		/* 7 * 4 - one space at the end */
198 #define	HEAD_SEP	2		/* spaces between day headings */
199 #define	J_HEAD_SEP	2
200 
201 void
202 monthly(month, year)
203 	int month, year;
204 {
205 	int col, row, len, days[MAXDAYS];
206 	char *p, lineout[30];
207 
208 	day_array(month, year, days);
209 	len = sprintf(lineout, "%s %d", month_names[month - 1], year);
210 	(void)printf("%*s%s\n%s\n",
211 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
212 	    lineout, julian ? j_day_headings : day_headings);
213 	for (row = 0; row < 6; row++) {
214 		for (col = 0, p = lineout; col < 7; col++,
215 		    p += julian ? J_DAY_LEN : DAY_LEN)
216 			ascii_day(p, days[row * 7 + col]);
217 		*p = '\0';
218 		trim_trailing_spaces(lineout);
219 		(void)printf("%s\n", lineout);
220 	}
221 }
222 
223 void
224 j_yearly(year)
225 	int year;
226 {
227 	int col, *dp, i, month, row, which_cal;
228 	int days[12][MAXDAYS];
229 	char *p, lineout[80];
230 
231 	(void)sprintf(lineout, "%d", year);
232 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
233 	(void)printf("\n\n");
234 	for (i = 0; i < 12; i++)
235 		day_array(i + 1, year, days[i]);
236 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
237 	lineout[sizeof(lineout) - 1] = '\0';
238 	for (month = 0; month < 12; month += 2) {
239 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
240 		center(month_names[month + 1], J_WEEK_LEN, 0);
241 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
242 		    j_day_headings);
243 		for (row = 0; row < 6; row++) {
244 			for (which_cal = 0; which_cal < 2; which_cal++) {
245 				p = lineout + which_cal * (J_WEEK_LEN + 2);
246 				dp = &days[month + which_cal][row * 7];
247 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
248 					ascii_day(p, *dp++);
249 			}
250 			*p = '\0';
251 			trim_trailing_spaces(lineout);
252 			(void)printf("%s\n", lineout);
253 		}
254 	}
255 	(void)printf("\n");
256 }
257 
258 void
259 yearly(year)
260 	int year;
261 {
262 	int col, *dp, i, month, row, which_cal;
263 	int days[12][MAXDAYS];
264 	char *p, lineout[80];
265 
266 	(void)sprintf(lineout, "%d", year);
267 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
268 	(void)printf("\n\n");
269 	for (i = 0; i < 12; i++)
270 		day_array(i + 1, year, days[i]);
271 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
272 	lineout[sizeof(lineout) - 1] = '\0';
273 	for (month = 0; month < 12; month += 3) {
274 		center(month_names[month], WEEK_LEN, HEAD_SEP);
275 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
276 		center(month_names[month + 2], WEEK_LEN, 0);
277 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
278 		    "", day_headings, HEAD_SEP, "", day_headings);
279 		for (row = 0; row < 6; row++) {
280 			for (which_cal = 0; which_cal < 3; which_cal++) {
281 				p = lineout + which_cal * (WEEK_LEN + 2);
282 				dp = &days[month + which_cal][row * 7];
283 				for (col = 0; col < 7; col++, p += DAY_LEN)
284 					ascii_day(p, *dp++);
285 			}
286 			*p = '\0';
287 			trim_trailing_spaces(lineout);
288 			(void)printf("%s\n", lineout);
289 		}
290 	}
291 	(void)printf("\n");
292 }
293 
294 /*
295  * day_array --
296  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
297  *	that you took the (maximum) 6 rows in a calendar and stretched them
298  *	out end to end.  You would have 42 numbers or spaces.  This routine
299  *	builds that array for any month from Jan. 1 through Dec. 9999.
300  */
301 void
302 day_array(month, year, days)
303 	int month, year;
304 	int *days;
305 {
306 	int day, dw, dm;
307 
308 	if (month == 9 && year == 1752) {
309 		memmove(days,
310 			julian ? j_sep1752 : sep1752, MAXDAYS * sizeof(int));
311 		return;
312 	}
313 	memmove(days, empty, MAXDAYS * sizeof(int));
314 	dm = days_in_month[leap_year(year)][month];
315 	dw = day_in_week(1, month, year);
316 	day = julian ? day_in_year(1, month, year) : 1;
317 	while (dm--)
318 		days[dw++] = day++;
319 }
320 
321 /*
322  * day_in_year --
323  *	return the 1 based day number within the year
324  */
325 int
326 day_in_year(day, month, year)
327 	int day, month, year;
328 {
329 	int i, leap;
330 
331 	leap = leap_year(year);
332 	for (i = 1; i < month; i++)
333 		day += days_in_month[leap][i];
334 	return (day);
335 }
336 
337 /*
338  * day_in_week
339  *	return the 0 based day number for any date from 1 Jan. 1 to
340  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
341  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
342  *	missing days.
343  */
344 int
345 day_in_week(day, month, year)
346 	int day, month, year;
347 {
348 	long temp;
349 
350 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
351 	    + day_in_year(day, month, year);
352 	if (temp < FIRST_MISSING_DAY)
353 		return ((temp - 1 + SATURDAY) % 7);
354 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
355 		return (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
356 	return (THURSDAY);
357 }
358 
359 void
360 ascii_day(p, day)
361 	char *p;
362 	int day;
363 {
364 	int display, val;
365 	static char *aday[] = {
366 		"",
367 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
368 		" 8", " 9", "10", "11", "12", "13", "14",
369 		"15", "16", "17", "18", "19", "20", "21",
370 		"22", "23", "24", "25", "26", "27", "28",
371 		"29", "30", "31",
372 	};
373 
374 	if (day == SPACE) {
375 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
376 		return;
377 	}
378 	if (julian) {
379 		if ((val = day / 100) != 0) {
380 			day %= 100;
381 			*p++ = val + '0';
382 			display = 1;
383 		} else {
384 			*p++ = ' ';
385 			display = 0;
386 		}
387 		val = day / 10;
388 		if (val || display)
389 			*p++ = val + '0';
390 		else
391 			*p++ = ' ';
392 		*p++ = day % 10 + '0';
393 	} else {
394 		*p++ = aday[day][0];
395 		*p++ = aday[day][1];
396 	}
397 	*p = ' ';
398 }
399 
400 void
401 trim_trailing_spaces(s)
402 	char *s;
403 {
404 	char *p;
405 
406 	for (p = s; *p; ++p)
407 		continue;
408 	while (p > s && isspace(*--p))
409 		continue;
410 	if (p > s)
411 		++p;
412 	*p = '\0';
413 }
414 
415 void
416 center(str, len, separate)
417 	char *str;
418 	int len;
419 	int separate;
420 {
421 
422 	len -= strlen(str);
423 	(void)printf("%*s%s%*s", len / 2, "", str, len / 2 + len % 2, "");
424 	if (separate)
425 		(void)printf("%*s", separate, "");
426 }
427 
428 void
429 usage()
430 {
431 
432 	(void)fprintf(stderr, "usage: cal [-jy] [[month] year]\n");
433 	exit(1);
434 }
435