xref: /netbsd-src/usr.bin/cal/cal.c (revision 76dfffe33547c37f8bdd446e3e4ab0f3c16cea4b)
1 /*	$NetBSD: cal.c,v 1.6 1995/03/26 03:10:24 glass 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 #ifndef lint
40 static char copyright[] =
41 "@(#) 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 static char rcsid[] = "$NetBSD: cal.c,v 1.6 1995/03/26 03:10:24 glass 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 void	trim_trailing_spaces __P((char *));
135 void	usage __P((void));
136 void	yearly __P((int));
137 
138 int
139 main(argc, argv)
140 	int argc;
141 	char **argv;
142 {
143 	struct tm *local_time;
144 	time_t now;
145 	int ch, month, year, yflag;
146 
147 	yflag = 0;
148 	while ((ch = getopt(argc, argv, "jy")) != EOF)
149 		switch(ch) {
150 		case 'j':
151 			julian = 1;
152 			break;
153 		case 'y':
154 			yflag = 1;
155 			break;
156 		case '?':
157 		default:
158 			usage();
159 		}
160 	argc -= optind;
161 	argv += optind;
162 
163 	month = 0;
164 	switch(argc) {
165 	case 2:
166 		if ((month = atoi(*argv++)) < 1 || month > 12)
167 			errx(1, "illegal month value: use 1-12");
168 		/* FALLTHROUGH */
169 	case 1:
170 		if ((year = atoi(*argv)) < 1 || year > 9999)
171 			errx(1, "illegal year value: use 1-9999");
172 		break;
173 	case 0:
174 		(void)time(&now);
175 		local_time = localtime(&now);
176 		year = local_time->tm_year + 1900;
177 		if (!yflag)
178 			month = local_time->tm_mon + 1;
179 		break;
180 	default:
181 		usage();
182 	}
183 
184 	if (month)
185 		monthly(month, year);
186 	else if (julian)
187 		j_yearly(year);
188 	else
189 		yearly(year);
190 	exit(0);
191 }
192 
193 #define	DAY_LEN		3		/* 3 spaces per day */
194 #define	J_DAY_LEN	4		/* 4 spaces per day */
195 #define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
196 #define	J_WEEK_LEN	27		/* 7 * 4 - one space at the end */
197 #define	HEAD_SEP	2		/* spaces between day headings */
198 #define	J_HEAD_SEP	2
199 
200 void
201 monthly(month, year)
202 	int month, year;
203 {
204 	int col, row, len, days[MAXDAYS];
205 	char *p, lineout[30];
206 
207 	day_array(month, year, days);
208 	len = sprintf(lineout, "%s %d", month_names[month - 1], year);
209 	(void)printf("%*s%s\n%s\n",
210 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
211 	    lineout, julian ? j_day_headings : day_headings);
212 	for (row = 0; row < 6; row++) {
213 		for (col = 0, p = lineout; col < 7; col++,
214 		    p += julian ? J_DAY_LEN : DAY_LEN)
215 			ascii_day(p, days[row * 7 + col]);
216 		*p = '\0';
217 		trim_trailing_spaces(lineout);
218 		(void)printf("%s\n", lineout);
219 	}
220 }
221 
222 void
223 j_yearly(year)
224 	int year;
225 {
226 	int col, *dp, i, month, row, which_cal;
227 	int days[12][MAXDAYS];
228 	char *p, lineout[80];
229 
230 	(void)sprintf(lineout, "%d", year);
231 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
232 	(void)printf("\n\n");
233 	for (i = 0; i < 12; i++)
234 		day_array(i + 1, year, days[i]);
235 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
236 	lineout[sizeof(lineout) - 1] = '\0';
237 	for (month = 0; month < 12; month += 2) {
238 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
239 		center(month_names[month + 1], J_WEEK_LEN, 0);
240 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
241 		    j_day_headings);
242 		for (row = 0; row < 6; row++) {
243 			for (which_cal = 0; which_cal < 2; which_cal++) {
244 				p = lineout + which_cal * (J_WEEK_LEN + 2);
245 				dp = &days[month + which_cal][row * 7];
246 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
247 					ascii_day(p, *dp++);
248 			}
249 			*p = '\0';
250 			trim_trailing_spaces(lineout);
251 			(void)printf("%s\n", lineout);
252 		}
253 	}
254 	(void)printf("\n");
255 }
256 
257 void
258 yearly(year)
259 	int year;
260 {
261 	int col, *dp, i, month, row, which_cal;
262 	int days[12][MAXDAYS];
263 	char *p, lineout[80];
264 
265 	(void)sprintf(lineout, "%d", year);
266 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
267 	(void)printf("\n\n");
268 	for (i = 0; i < 12; i++)
269 		day_array(i + 1, year, days[i]);
270 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
271 	lineout[sizeof(lineout) - 1] = '\0';
272 	for (month = 0; month < 12; month += 3) {
273 		center(month_names[month], WEEK_LEN, HEAD_SEP);
274 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
275 		center(month_names[month + 2], WEEK_LEN, 0);
276 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
277 		    "", day_headings, HEAD_SEP, "", day_headings);
278 		for (row = 0; row < 6; row++) {
279 			for (which_cal = 0; which_cal < 3; which_cal++) {
280 				p = lineout + which_cal * (WEEK_LEN + 2);
281 				dp = &days[month + which_cal][row * 7];
282 				for (col = 0; col < 7; col++, p += DAY_LEN)
283 					ascii_day(p, *dp++);
284 			}
285 			*p = '\0';
286 			trim_trailing_spaces(lineout);
287 			(void)printf("%s\n", lineout);
288 		}
289 	}
290 	(void)printf("\n");
291 }
292 
293 /*
294  * day_array --
295  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
296  *	that you took the (maximum) 6 rows in a calendar and stretched them
297  *	out end to end.  You would have 42 numbers or spaces.  This routine
298  *	builds that array for any month from Jan. 1 through Dec. 9999.
299  */
300 void
301 day_array(month, year, days)
302 	int month, year;
303 	int *days;
304 {
305 	int day, dw, dm;
306 
307 	if (month == 9 && year == 1752) {
308 		memmove(days,
309 			julian ? j_sep1752 : sep1752, MAXDAYS * sizeof(int));
310 		return;
311 	}
312 	memmove(days, empty, MAXDAYS * sizeof(int));
313 	dm = days_in_month[leap_year(year)][month];
314 	dw = day_in_week(1, month, year);
315 	day = julian ? day_in_year(1, month, year) : 1;
316 	while (dm--)
317 		days[dw++] = day++;
318 }
319 
320 /*
321  * day_in_year --
322  *	return the 1 based day number within the year
323  */
324 int
325 day_in_year(day, month, year)
326 	int day, month, year;
327 {
328 	int i, leap;
329 
330 	leap = leap_year(year);
331 	for (i = 1; i < month; i++)
332 		day += days_in_month[leap][i];
333 	return (day);
334 }
335 
336 /*
337  * day_in_week
338  *	return the 0 based day number for any date from 1 Jan. 1 to
339  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
340  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
341  *	missing days.
342  */
343 int
344 day_in_week(day, month, year)
345 	int day, month, year;
346 {
347 	long temp;
348 
349 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
350 	    + day_in_year(day, month, year);
351 	if (temp < FIRST_MISSING_DAY)
352 		return ((temp - 1 + SATURDAY) % 7);
353 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
354 		return (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
355 	return (THURSDAY);
356 }
357 
358 void
359 ascii_day(p, day)
360 	char *p;
361 	int day;
362 {
363 	int display, val;
364 	static char *aday[] = {
365 		"",
366 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
367 		" 8", " 9", "10", "11", "12", "13", "14",
368 		"15", "16", "17", "18", "19", "20", "21",
369 		"22", "23", "24", "25", "26", "27", "28",
370 		"29", "30", "31",
371 	};
372 
373 	if (day == SPACE) {
374 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
375 		return;
376 	}
377 	if (julian) {
378 		if (val = day / 100) {
379 			day %= 100;
380 			*p++ = val + '0';
381 			display = 1;
382 		} else {
383 			*p++ = ' ';
384 			display = 0;
385 		}
386 		val = day / 10;
387 		if (val || display)
388 			*p++ = val + '0';
389 		else
390 			*p++ = ' ';
391 		*p++ = day % 10 + '0';
392 	} else {
393 		*p++ = aday[day][0];
394 		*p++ = aday[day][1];
395 	}
396 	*p = ' ';
397 }
398 
399 void
400 trim_trailing_spaces(s)
401 	char *s;
402 {
403 	char *p;
404 
405 	for (p = s; *p; ++p)
406 		continue;
407 	while (p > s && isspace(*--p))
408 		continue;
409 	if (p > s)
410 		++p;
411 	*p = '\0';
412 }
413 
414 void
415 center(str, len, separate)
416 	char *str;
417 	int len;
418 	int separate;
419 {
420 
421 	len -= strlen(str);
422 	(void)printf("%*s%s%*s", len / 2, "", str, len / 2 + len % 2, "");
423 	if (separate)
424 		(void)printf("%*s", separate, "");
425 }
426 
427 void
428 usage()
429 {
430 
431 	(void)fprintf(stderr, "usage: cal [-jy] [[month] year]\n");
432 	exit(1);
433 }
434