xref: /original-bsd/usr.bin/cal/cal.c (revision 93ab02a6)
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  * %sccs.include.redist.c%
9  */
10 
11 #ifndef lint
12 char copyright[] =
13 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
14  All rights reserved.\n";
15 #endif /* not lint */
16 
17 #ifndef lint
18 static char sccsid[] = "@(#)cal.c	5.2 (Berkeley) 04/19/91";
19 #endif /* not lint */
20 
21 #include <sys/types.h>
22 #include <sys/time.h>
23 #include <stdio.h>
24 #include <ctype.h>
25 
26 #define	THURSDAY		4		/* for reformation */
27 #define	SATURDAY 		6		/* 1 Jan 1 was a Saturday */
28 
29 #define	FIRST_MISSING_DAY 	639787		/* 3 Sep 1752 */
30 #define	NUMBER_MISSING_DAYS 	11		/* 11 day correction */
31 
32 #define	MAXDAYS			42		/* max slots in a month array */
33 #define	SPACE			-1		/* used in day array */
34 
35 static int days_in_month[2][13] = {
36 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
37 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
38 };
39 
40 int sep1752[MAXDAYS] = {
41 	SPACE,	SPACE,	1,	2,	14,	15,	16,
42 	17,	18,	19,	20,	21,	22,	23,
43 	24,	25,	26,	27,	28,	29,	30,
44 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
45 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
46 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
47 }, j_sep1752[MAXDAYS] = {
48 	SPACE,	SPACE,	245,	246,	258,	259,	260,
49 	261,	262,	263,	264,	265,	266,	267,
50 	268,	269,	270,	271,	272,	273,	274,
51 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
52 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
53 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
54 }, empty[MAXDAYS] = {
55 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
56 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
57 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
58 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
59 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
60 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
61 };
62 
63 char *month_names[12] = {
64 	"January", "February", "March", "April", "May", "June",
65 	"July", "August", "September", "October", "November", "December",
66 };
67 
68 char *day_headings = " S  M Tu  W Th  F  S";
69 char *j_day_headings = "  S   M  Tu   W  Th   F   S";
70 
71 /* leap year -- account for gregorian reformation in 1752 */
72 #define	leap_year(yr) \
73 	((yr) <= 1752 ? !((yr) % 4) : \
74 	!((yr) % 4) && ((yr) % 100) || !((yr) % 400))
75 
76 /* number of centuries since 1700, not inclusive */
77 #define	centuries_since_1700(yr) \
78 	((yr) > 1700 ? (yr) / 100 - 17 : 0)
79 
80 /* number of centuries since 1700 whose modulo of 400 is 0 */
81 #define	quad_centuries_since_1700(yr) \
82 	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
83 
84 /* number of leap years between year 1 and this year, not inclusive */
85 #define	leap_years_since_year_1(yr) \
86 	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
87 
88 int julian;
89 
90 main(argc, argv)
91 	int argc;
92 	char **argv;
93 {
94 	extern char *optarg;
95 	extern int optind;
96 	struct tm *local_time;
97 	time_t now, time();
98 	int ch, month, year, yflag;
99 
100 	yflag = 0;
101 	while ((ch = getopt(argc, argv, "jy")) != EOF)
102 		switch(ch) {
103 		case 'j':
104 			julian = 1;
105 			break;
106 		case 'y':
107 			yflag = 1;
108 			break;
109 		case '?':
110 		default:
111 			usage();
112 		}
113 	argc -= optind;
114 	argv += optind;
115 
116 	month = 0;
117 	switch(argc) {
118 	case 2:
119 		if ((month = atoi(*argv++)) <= 0 || month > 12) {
120 			(void)fprintf(stderr,
121 			    "cal: illegal month value: use 0-12\n");
122 			exit(1);
123 		}
124 		/* FALLTHROUGH */
125 	case 1:
126 		if ((year = atoi(*argv)) <= 0 || year > 9999) {
127 			(void)fprintf(stderr,
128 			    "cal: illegal year value: use 0-9999\n");
129 			exit(1);
130 		}
131 		break;
132 	case 0:
133 		(void)time(&now);
134 		local_time = localtime(&now);
135 		year = local_time->tm_year + 1900;
136 		if (!yflag)
137 			month = local_time->tm_mon + 1;
138 		break;
139 	default:
140 		usage();
141 	}
142 
143 	if (month)
144 		monthly(month, year);
145 	else if (julian)
146 		j_yearly(year);
147 	else
148 		yearly(year);
149 	exit(0);
150 }
151 
152 #define	DAY_LEN		3		/* 3 spaces per day */
153 #define	J_DAY_LEN	4		/* 4 spaces per day */
154 #define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
155 #define	J_WEEK_LEN	27		/* 7 * 4 - one space at the end */
156 #define	HEAD_SEP	2		/* spaces between day headings */
157 #define	J_HEAD_SEP	2
158 
159 monthly(month, year)
160 	int month, year;
161 {
162 	register int col, row;
163 	register char *p;
164 	int len, days[MAXDAYS];
165 	char lineout[30];
166 
167 	day_array(month, year, days);
168 	len = sprintf(lineout, "%s %d", month_names[month - 1], year);
169 	(void)printf("%*s%s\n%s\n",
170 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
171 	    lineout, julian ? j_day_headings : day_headings);
172 	for (row = 0; row < 6; row++) {
173 		for (col = 0, p = lineout; col < 7; col++,
174 		    p += julian ? J_DAY_LEN : DAY_LEN)
175 			ascii_day(p, days[row * 7 + col]);
176 		trim_trailing_spaces(lineout);
177 		(void)printf("%s\n", lineout);
178 	}
179 }
180 
181 j_yearly(year)
182 	int year;
183 {
184 	register int col, *dp, i, month, row, which_cal;
185 	register char *p;
186 	int days[12][MAXDAYS];
187 	char lineout[80];
188 
189 	(void)sprintf(lineout, "%d", year);
190 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
191 	(void)printf("\n\n");
192 	for (i = 0; i < 12; i++)
193 		day_array(i + 1, year, days[i]);
194 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
195 	lineout[sizeof(lineout) - 1] = '\0';
196 	for (month = 0; month < 12; month += 2) {
197 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
198 		center(month_names[month + 1], J_WEEK_LEN, 0);
199 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
200 		    j_day_headings);
201 		for (row = 0; row < 6; row++) {
202 			for (which_cal = 0; which_cal < 2; which_cal++) {
203 				p = lineout + which_cal * (J_WEEK_LEN + 2);
204 				dp = &days[month + which_cal][row * 7];
205 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
206 					ascii_day(p, *dp++);
207 			}
208 			trim_trailing_spaces(lineout);
209 			(void)printf("%s\n", lineout);
210 		}
211 	}
212 	(void)printf("\n");
213 }
214 
215 yearly(year)
216 	int year;
217 {
218 	register int col, *dp, i, month, row, which_cal;
219 	register char *p;
220 	int days[12][MAXDAYS];
221 	char lineout[80];
222 
223 	(void)sprintf(lineout, "%d", year);
224 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
225 	(void)printf("\n\n");
226 	for (i = 0; i < 12; i++)
227 		day_array(i + 1, year, days[i]);
228 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
229 	lineout[sizeof(lineout) - 1] = '\0';
230 	for (month = 0; month < 12; month += 3) {
231 		center(month_names[month], WEEK_LEN, HEAD_SEP);
232 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
233 		center(month_names[month + 2], WEEK_LEN, 0);
234 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
235 		    "", day_headings, HEAD_SEP, "", day_headings);
236 		for (row = 0; row < 6; row++) {
237 			for (which_cal = 0; which_cal < 3; which_cal++) {
238 				p = lineout + which_cal * (WEEK_LEN + 2);
239 				dp = &days[month + which_cal][row * 7];
240 				for (col = 0; col < 7; col++, p += DAY_LEN)
241 					ascii_day(p, *dp++);
242 			}
243 			trim_trailing_spaces(lineout);
244 			(void)printf("%s\n", lineout);
245 		}
246 	}
247 	(void)printf("\n");
248 }
249 
250 /*
251  * day_array --
252  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
253  *	that you took the (maximum) 6 rows in a calendar and stretched them
254  *	out end to end.  You would have 42 numbers or spaces.  This routine
255  *	builds that array for any month from Jan. 1 through Dec. 9999.
256  */
257 day_array(month, year, days)
258 	register int *days;
259 	int month, year;
260 {
261 	register int i, day, dw, dm;
262 
263 	if (month == 9 && year == 1752) {
264 		bcopy(julian ? j_sep1752 : sep1752,
265 		    days, MAXDAYS * sizeof(int));
266 		return;
267 	}
268 	bcopy(empty, days, MAXDAYS * sizeof(int));
269 	dm = days_in_month[leap_year(year)][month];
270 	dw = day_in_week(1, month, year);
271 	day = julian ? day_in_year(1, month, year) : 1;
272 	while (dm--)
273 		days[dw++] = day++;
274 }
275 
276 /*
277  * day_in_year --
278  *	return the 1 based day number within the year
279  */
280 day_in_year(day, month, year)
281 	register int day, month;
282 	int year;
283 {
284 	register int i, leap;
285 
286 	leap = leap_year(year);
287 	for (i = 1; i < month; i++)
288 		day += days_in_month[leap][i];
289 	return(day);
290 }
291 
292 /*
293  * day_in_week
294  *	return the 0 based day number for any date from 1 Jan. 1 to
295  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
296  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
297  *	missing days.
298  */
299 day_in_week(day, month, year)
300 	int day, month, year;
301 {
302 	long temp;
303 
304 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
305 	    + day_in_year(day, month, year);
306 	if (temp < FIRST_MISSING_DAY)
307 		return((temp - 1 + SATURDAY) % 7);
308 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
309 		return(((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
310 	return(THURSDAY);
311 }
312 
313 ascii_day(p, day)
314 	register char *p;
315 	register int day;
316 {
317 	register int display, val;
318 	static char *aday[] = {
319 		"",
320 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
321 		" 8", " 9", "10", "11", "12", "13", "14",
322 		"15", "16", "17", "18", "19", "20", "21",
323 		"22", "23", "24", "25", "26", "27", "28",
324 		"29", "30", "31",
325 	};
326 
327 	if (day == SPACE) {
328 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
329 		return;
330 	}
331 	if (julian) {
332 		if (val = day / 100) {
333 			day %= 100;
334 			*p++ = val + '0';
335 			display = 1;
336 		} else {
337 			*p++ = ' ';
338 			display = 0;
339 		}
340 		val = day / 10;
341 		if (val || display)
342 			*p++ = val + '0';
343 		else
344 			*p++ = ' ';
345 		*p++ = day % 10 + '0';
346 	} else {
347 		*p++ = aday[day][0];
348 		*p++ = aday[day][1];
349 	}
350 	*p = ' ';
351 }
352 
353 trim_trailing_spaces(s)
354 	register char *s;
355 {
356 	register char *p;
357 
358 	for (p = s; *p; ++p);
359 	while (p > s && isspace(*--p));
360 	if (p > s)
361 		++p;
362 	*p = '\0';
363 }
364 
365 center(str, len, separate)
366 	char *str;
367 	register int len;
368 	int separate;
369 {
370 	len -= strlen(str);
371 	(void)printf("%*s%s%*s", len / 2, "", str, len / 2 + len % 2, "");
372 	if (separate)
373 		(void)printf("%*s", separate, "");
374 }
375 
376 usage()
377 {
378 	(void)fprintf(stderr, "usage: cal [-jy] [[month] year]\n");
379 	exit(1);
380 }
381