xref: /netbsd-src/usr.bin/cal/cal.c (revision ae9172d6cd9432a6a1a56760d86b32c57a66c39c)
1 /*
2  * Copyright (c) 1989 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kim Letkeman.
7  *
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. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifndef lint
38 char copyright[] =
39 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
40  All rights reserved.\n";
41 #endif /* not lint */
42 
43 #ifndef lint
44 /*static char sccsid[] = "from: @(#)cal.c	5.2 (Berkeley) 4/19/91";*/
45 static char rcsid[] = "$Id: cal.c,v 1.3 1994/01/25 00:49:35 cgd Exp $";
46 #endif /* not lint */
47 
48 #include <sys/types.h>
49 #include <sys/time.h>
50 #include <stdio.h>
51 #include <ctype.h>
52 
53 #define	THURSDAY		4		/* for reformation */
54 #define	SATURDAY 		6		/* 1 Jan 1 was a Saturday */
55 
56 #define	FIRST_MISSING_DAY 	639787		/* 3 Sep 1752 */
57 #define	NUMBER_MISSING_DAYS 	11		/* 11 day correction */
58 
59 #define	MAXDAYS			42		/* max slots in a month array */
60 #define	SPACE			-1		/* used in day array */
61 
62 static int days_in_month[2][13] = {
63 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
64 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
65 };
66 
67 int sep1752[MAXDAYS] = {
68 	SPACE,	SPACE,	1,	2,	14,	15,	16,
69 	17,	18,	19,	20,	21,	22,	23,
70 	24,	25,	26,	27,	28,	29,	30,
71 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
72 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
73 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
74 }, j_sep1752[MAXDAYS] = {
75 	SPACE,	SPACE,	245,	246,	258,	259,	260,
76 	261,	262,	263,	264,	265,	266,	267,
77 	268,	269,	270,	271,	272,	273,	274,
78 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
79 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
80 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
81 }, empty[MAXDAYS] = {
82 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
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 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
87 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
88 };
89 
90 char *month_names[12] = {
91 	"January", "February", "March", "April", "May", "June",
92 	"July", "August", "September", "October", "November", "December",
93 };
94 
95 char *day_headings = " S  M Tu  W Th  F  S";
96 char *j_day_headings = "  S   M  Tu   W  Th   F   S";
97 
98 /* leap year -- account for gregorian reformation in 1752 */
99 #define	leap_year(yr) \
100 	((yr) <= 1752 ? !((yr) % 4) : \
101 	!((yr) % 4) && ((yr) % 100) || !((yr) % 400))
102 
103 /* number of centuries since 1700, not inclusive */
104 #define	centuries_since_1700(yr) \
105 	((yr) > 1700 ? (yr) / 100 - 17 : 0)
106 
107 /* number of centuries since 1700 whose modulo of 400 is 0 */
108 #define	quad_centuries_since_1700(yr) \
109 	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
110 
111 /* number of leap years between year 1 and this year, not inclusive */
112 #define	leap_years_since_year_1(yr) \
113 	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
114 
115 int julian;
116 
117 main(argc, argv)
118 	int argc;
119 	char **argv;
120 {
121 	extern char *optarg;
122 	extern int optind;
123 	struct tm *local_time;
124 	time_t now, time();
125 	int ch, month, year, yflag;
126 
127 	yflag = 0;
128 	while ((ch = getopt(argc, argv, "jy")) != EOF)
129 		switch(ch) {
130 		case 'j':
131 			julian = 1;
132 			break;
133 		case 'y':
134 			yflag = 1;
135 			break;
136 		case '?':
137 		default:
138 			usage();
139 		}
140 	argc -= optind;
141 	argv += optind;
142 
143 	month = 0;
144 	switch(argc) {
145 	case 2:
146 		if ((month = atoi(*argv++)) <= 0 || month > 12) {
147 			(void)fprintf(stderr,
148 			    "cal: illegal month value: use 0-12\n");
149 			exit(1);
150 		}
151 		/* FALLTHROUGH */
152 	case 1:
153 		if ((year = atoi(*argv)) <= 0 || year > 9999) {
154 			(void)fprintf(stderr,
155 			    "cal: illegal year value: use 0-9999\n");
156 			exit(1);
157 		}
158 		break;
159 	case 0:
160 		(void)time(&now);
161 		local_time = localtime(&now);
162 		year = local_time->tm_year + 1900;
163 		if (!yflag)
164 			month = local_time->tm_mon + 1;
165 		break;
166 	default:
167 		usage();
168 	}
169 
170 	if (month)
171 		monthly(month, year);
172 	else if (julian)
173 		j_yearly(year);
174 	else
175 		yearly(year);
176 	exit(0);
177 }
178 
179 #define	DAY_LEN		3		/* 3 spaces per day */
180 #define	J_DAY_LEN	4		/* 4 spaces per day */
181 #define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
182 #define	J_WEEK_LEN	27		/* 7 * 4 - one space at the end */
183 #define	HEAD_SEP	2		/* spaces between day headings */
184 #define	J_HEAD_SEP	2
185 
186 monthly(month, year)
187 	int month, year;
188 {
189 	register int col, row;
190 	register char *p;
191 	int len, days[MAXDAYS];
192 	char lineout[30];
193 
194 	day_array(month, year, days);
195 	len = sprintf(lineout, "%s %d", month_names[month - 1], year);
196 	(void)printf("%*s%s\n%s\n",
197 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
198 	    lineout, julian ? j_day_headings : day_headings);
199 	for (row = 0; row < 6; row++) {
200 		for (col = 0, p = lineout; col < 7; col++,
201 		    p += julian ? J_DAY_LEN : DAY_LEN)
202 			ascii_day(p, days[row * 7 + col]);
203 		*p = '\0';
204 		trim_trailing_spaces(lineout);
205 		(void)printf("%s\n", lineout);
206 	}
207 }
208 
209 j_yearly(year)
210 	int year;
211 {
212 	register int col, *dp, i, month, row, which_cal;
213 	register char *p;
214 	int days[12][MAXDAYS];
215 	char lineout[80];
216 
217 	(void)sprintf(lineout, "%d", year);
218 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
219 	(void)printf("\n\n");
220 	for (i = 0; i < 12; i++)
221 		day_array(i + 1, year, days[i]);
222 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
223 	lineout[sizeof(lineout) - 1] = '\0';
224 	for (month = 0; month < 12; month += 2) {
225 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
226 		center(month_names[month + 1], J_WEEK_LEN, 0);
227 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
228 		    j_day_headings);
229 		for (row = 0; row < 6; row++) {
230 			for (which_cal = 0; which_cal < 2; which_cal++) {
231 				p = lineout + which_cal * (J_WEEK_LEN + 2);
232 				dp = &days[month + which_cal][row * 7];
233 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
234 					ascii_day(p, *dp++);
235 			}
236 			*p = '\0';
237 			trim_trailing_spaces(lineout);
238 			(void)printf("%s\n", lineout);
239 		}
240 	}
241 	(void)printf("\n");
242 }
243 
244 yearly(year)
245 	int year;
246 {
247 	register int col, *dp, i, month, row, which_cal;
248 	register char *p;
249 	int days[12][MAXDAYS];
250 	char lineout[80];
251 
252 	(void)sprintf(lineout, "%d", year);
253 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
254 	(void)printf("\n\n");
255 	for (i = 0; i < 12; i++)
256 		day_array(i + 1, year, days[i]);
257 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
258 	lineout[sizeof(lineout) - 1] = '\0';
259 	for (month = 0; month < 12; month += 3) {
260 		center(month_names[month], WEEK_LEN, HEAD_SEP);
261 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
262 		center(month_names[month + 2], WEEK_LEN, 0);
263 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
264 		    "", day_headings, HEAD_SEP, "", day_headings);
265 		for (row = 0; row < 6; row++) {
266 			for (which_cal = 0; which_cal < 3; which_cal++) {
267 				p = lineout + which_cal * (WEEK_LEN + 2);
268 				dp = &days[month + which_cal][row * 7];
269 				for (col = 0; col < 7; col++, p += DAY_LEN)
270 					ascii_day(p, *dp++);
271 			}
272 			*p = '\0';
273 			trim_trailing_spaces(lineout);
274 			(void)printf("%s\n", lineout);
275 		}
276 	}
277 	(void)printf("\n");
278 }
279 
280 /*
281  * day_array --
282  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
283  *	that you took the (maximum) 6 rows in a calendar and stretched them
284  *	out end to end.  You would have 42 numbers or spaces.  This routine
285  *	builds that array for any month from Jan. 1 through Dec. 9999.
286  */
287 day_array(month, year, days)
288 	register int *days;
289 	int month, year;
290 {
291 	register int i, day, dw, dm;
292 
293 	if (month == 9 && year == 1752) {
294 		bcopy(julian ? j_sep1752 : sep1752,
295 		    days, MAXDAYS * sizeof(int));
296 		return;
297 	}
298 	bcopy(empty, days, MAXDAYS * sizeof(int));
299 	dm = days_in_month[leap_year(year)][month];
300 	dw = day_in_week(1, month, year);
301 	day = julian ? day_in_year(1, month, year) : 1;
302 	while (dm--)
303 		days[dw++] = day++;
304 }
305 
306 /*
307  * day_in_year --
308  *	return the 1 based day number within the year
309  */
310 day_in_year(day, month, year)
311 	register int day, month;
312 	int year;
313 {
314 	register int i, leap;
315 
316 	leap = leap_year(year);
317 	for (i = 1; i < month; i++)
318 		day += days_in_month[leap][i];
319 	return(day);
320 }
321 
322 /*
323  * day_in_week
324  *	return the 0 based day number for any date from 1 Jan. 1 to
325  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
326  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
327  *	missing days.
328  */
329 day_in_week(day, month, year)
330 	int day, month, year;
331 {
332 	long temp;
333 
334 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
335 	    + day_in_year(day, month, year);
336 	if (temp < FIRST_MISSING_DAY)
337 		return((temp - 1 + SATURDAY) % 7);
338 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
339 		return(((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
340 	return(THURSDAY);
341 }
342 
343 ascii_day(p, day)
344 	register char *p;
345 	register int day;
346 {
347 	register int display, val;
348 	static char *aday[] = {
349 		"",
350 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
351 		" 8", " 9", "10", "11", "12", "13", "14",
352 		"15", "16", "17", "18", "19", "20", "21",
353 		"22", "23", "24", "25", "26", "27", "28",
354 		"29", "30", "31",
355 	};
356 
357 	if (day == SPACE) {
358 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
359 		return;
360 	}
361 	if (julian) {
362 		if (val = day / 100) {
363 			day %= 100;
364 			*p++ = val + '0';
365 			display = 1;
366 		} else {
367 			*p++ = ' ';
368 			display = 0;
369 		}
370 		val = day / 10;
371 		if (val || display)
372 			*p++ = val + '0';
373 		else
374 			*p++ = ' ';
375 		*p++ = day % 10 + '0';
376 	} else {
377 		*p++ = aday[day][0];
378 		*p++ = aday[day][1];
379 	}
380 	*p = ' ';
381 }
382 
383 trim_trailing_spaces(s)
384 	register char *s;
385 {
386 	register char *p;
387 
388 	for (p = s; *p; ++p);
389 	while (p > s && isspace(*--p));
390 	if (p > s)
391 		++p;
392 	*p = '\0';
393 }
394 
395 center(str, len, separate)
396 	char *str;
397 	register int len;
398 	int separate;
399 {
400 	len -= strlen(str);
401 	(void)printf("%*s%s%*s", len / 2, "", str, len / 2 + len % 2, "");
402 	if (separate)
403 		(void)printf("%*s", separate, "");
404 }
405 
406 usage()
407 {
408 	(void)fprintf(stderr, "usage: cal [-jy] [[month] year]\n");
409 	exit(1);
410 }
411