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cal.c revision 1.10
      1 /*	$NetBSD: cal.c,v 1.10 1998/07/28 19:26:09 mycroft 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 1.10 1998/07/28 19:26:09 mycroft 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 <tzfile.h>
     62 #include <unistd.h>
     63 
     64 #define	THURSDAY		4		/* for reformation */
     65 #define	SATURDAY 		6		/* 1 Jan 1 was a Saturday */
     66 
     67 #define	FIRST_MISSING_DAY 	639799		/* 3 Sep 1752 */
     68 #define	NUMBER_MISSING_DAYS 	11		/* 11 day correction */
     69 
     70 #define	MAXDAYS			42		/* max slots in a month array */
     71 #define	SPACE			-1		/* used in day array */
     72 
     73 static int days_in_month[2][13] = {
     74 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
     75 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
     76 };
     77 
     78 int sep1752[MAXDAYS] = {
     79 	SPACE,	SPACE,	1,	2,	14,	15,	16,
     80 	17,	18,	19,	20,	21,	22,	23,
     81 	24,	25,	26,	27,	28,	29,	30,
     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 }, j_sep1752[MAXDAYS] = {
     86 	SPACE,	SPACE,	245,	246,	258,	259,	260,
     87 	261,	262,	263,	264,	265,	266,	267,
     88 	268,	269,	270,	271,	272,	273,	274,
     89 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
     90 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
     91 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
     92 }, empty[MAXDAYS] = {
     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 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,
     99 };
    100 
    101 char *month_names[12] = {
    102 	"January", "February", "March", "April", "May", "June",
    103 	"July", "August", "September", "October", "November", "December",
    104 };
    105 
    106 char *day_headings = " S  M Tu  W Th  F  S";
    107 char *j_day_headings = "  S   M  Tu   W  Th   F   S";
    108 
    109 /* leap year -- account for gregorian reformation in 1752 */
    110 #define	leap_year(yr) \
    111 	((yr) <= 1752 ? !((yr) % 4) : \
    112 	(!((yr) % 4) && ((yr) % 100)) || !((yr) % 400))
    113 
    114 /* number of centuries since 1700, not inclusive */
    115 #define	centuries_since_1700(yr) \
    116 	((yr) > 1700 ? (yr) / 100 - 17 : 0)
    117 
    118 /* number of centuries since 1700 whose modulo of 400 is 0 */
    119 #define	quad_centuries_since_1700(yr) \
    120 	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
    121 
    122 /* number of leap years between year 1 and this year, not inclusive */
    123 #define	leap_years_since_year_1(yr) \
    124 	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
    125 
    126 int julian;
    127 
    128 void	ascii_day __P((char *, int));
    129 void	center __P((char *, int, int));
    130 void	day_array __P((int, int, int *));
    131 int	day_in_week __P((int, int, int));
    132 int	day_in_year __P((int, int, int));
    133 void	j_yearly __P((int));
    134 void	monthly __P((int, int));
    135 int	main __P((int, char **));
    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 = snprintf(lineout, sizeof(lineout), "%s %d",
    211 	    month_names[month - 1], year);
    212 	(void)printf("%*s%s\n%s\n",
    213 	    ((julian ? J_WEEK_LEN : WEEK_LEN) - len) / 2, "",
    214 	    lineout, julian ? j_day_headings : day_headings);
    215 	for (row = 0; row < 6; row++) {
    216 		for (col = 0, p = lineout; col < 7; col++,
    217 		    p += julian ? J_DAY_LEN : DAY_LEN)
    218 			ascii_day(p, days[row * 7 + col]);
    219 		*p = '\0';
    220 		trim_trailing_spaces(lineout);
    221 		(void)printf("%s\n", lineout);
    222 	}
    223 }
    224 
    225 void
    226 j_yearly(year)
    227 	int year;
    228 {
    229 	int col, *dp, i, month, row, which_cal;
    230 	int days[12][MAXDAYS];
    231 	char *p, lineout[80];
    232 
    233 	(void)snprintf(lineout, sizeof(lineout), "%d", year);
    234 	center(lineout, J_WEEK_LEN * 2 + J_HEAD_SEP, 0);
    235 	(void)printf("\n\n");
    236 	for (i = 0; i < 12; i++)
    237 		day_array(i + 1, year, days[i]);
    238 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
    239 	lineout[sizeof(lineout) - 1] = '\0';
    240 	for (month = 0; month < 12; month += 2) {
    241 		center(month_names[month], J_WEEK_LEN, J_HEAD_SEP);
    242 		center(month_names[month + 1], J_WEEK_LEN, 0);
    243 		(void)printf("\n%s%*s%s\n", j_day_headings, J_HEAD_SEP, "",
    244 		    j_day_headings);
    245 		for (row = 0; row < 6; row++) {
    246 			for (which_cal = 0; which_cal < 2; which_cal++) {
    247 				p = lineout + which_cal * (J_WEEK_LEN + 2);
    248 				dp = &days[month + which_cal][row * 7];
    249 				for (col = 0; col < 7; col++, p += J_DAY_LEN)
    250 					ascii_day(p, *dp++);
    251 			}
    252 			*p = '\0';
    253 			trim_trailing_spaces(lineout);
    254 			(void)printf("%s\n", lineout);
    255 		}
    256 	}
    257 	(void)printf("\n");
    258 }
    259 
    260 void
    261 yearly(year)
    262 	int year;
    263 {
    264 	int col, *dp, i, month, row, which_cal;
    265 	int days[12][MAXDAYS];
    266 	char *p, lineout[80];
    267 
    268 	(void)snprintf(lineout, sizeof(lineout), "%d", year);
    269 	center(lineout, WEEK_LEN * 3 + HEAD_SEP * 2, 0);
    270 	(void)printf("\n\n");
    271 	for (i = 0; i < 12; i++)
    272 		day_array(i + 1, year, days[i]);
    273 	(void)memset(lineout, ' ', sizeof(lineout) - 1);
    274 	lineout[sizeof(lineout) - 1] = '\0';
    275 	for (month = 0; month < 12; month += 3) {
    276 		center(month_names[month], WEEK_LEN, HEAD_SEP);
    277 		center(month_names[month + 1], WEEK_LEN, HEAD_SEP);
    278 		center(month_names[month + 2], WEEK_LEN, 0);
    279 		(void)printf("\n%s%*s%s%*s%s\n", day_headings, HEAD_SEP,
    280 		    "", day_headings, HEAD_SEP, "", day_headings);
    281 		for (row = 0; row < 6; row++) {
    282 			for (which_cal = 0; which_cal < 3; which_cal++) {
    283 				p = lineout + which_cal * (WEEK_LEN + 2);
    284 				dp = &days[month + which_cal][row * 7];
    285 				for (col = 0; col < 7; col++, p += DAY_LEN)
    286 					ascii_day(p, *dp++);
    287 			}
    288 			*p = '\0';
    289 			trim_trailing_spaces(lineout);
    290 			(void)printf("%s\n", lineout);
    291 		}
    292 	}
    293 	(void)printf("\n");
    294 }
    295 
    296 /*
    297  * day_array --
    298  *	Fill in an array of 42 integers with a calendar.  Assume for a moment
    299  *	that you took the (maximum) 6 rows in a calendar and stretched them
    300  *	out end to end.  You would have 42 numbers or spaces.  This routine
    301  *	builds that array for any month from Jan. 1 through Dec. 9999.
    302  */
    303 void
    304 day_array(month, year, days)
    305 	int month, year;
    306 	int *days;
    307 {
    308 	int day, dw, dm;
    309 
    310 	if (month == 9 && year == 1752) {
    311 		memmove(days,
    312 			julian ? j_sep1752 : sep1752, MAXDAYS * sizeof(int));
    313 		return;
    314 	}
    315 	memmove(days, empty, MAXDAYS * sizeof(int));
    316 	dm = days_in_month[leap_year(year)][month];
    317 	dw = day_in_week(1, month, year);
    318 	day = julian ? day_in_year(1, month, year) : 1;
    319 	while (dm--)
    320 		days[dw++] = day++;
    321 }
    322 
    323 /*
    324  * day_in_year --
    325  *	return the 1 based day number within the year
    326  */
    327 int
    328 day_in_year(day, month, year)
    329 	int day, month, year;
    330 {
    331 	int i, leap;
    332 
    333 	leap = leap_year(year);
    334 	for (i = 1; i < month; i++)
    335 		day += days_in_month[leap][i];
    336 	return (day);
    337 }
    338 
    339 /*
    340  * day_in_week
    341  *	return the 0 based day number for any date from 1 Jan. 1 to
    342  *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
    343  *	3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
    344  *	missing days.
    345  */
    346 int
    347 day_in_week(day, month, year)
    348 	int day, month, year;
    349 {
    350 	long temp;
    351 
    352 	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1)
    353 	    + day_in_year(day, month, year);
    354 	if (temp < FIRST_MISSING_DAY)
    355 		return ((temp - 1 + SATURDAY) % 7);
    356 	if (temp >= (FIRST_MISSING_DAY + NUMBER_MISSING_DAYS))
    357 		return (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
    358 	return (THURSDAY);
    359 }
    360 
    361 void
    362 ascii_day(p, day)
    363 	char *p;
    364 	int day;
    365 {
    366 	int display, val;
    367 	static char *aday[] = {
    368 		"",
    369 		" 1", " 2", " 3", " 4", " 5", " 6", " 7",
    370 		" 8", " 9", "10", "11", "12", "13", "14",
    371 		"15", "16", "17", "18", "19", "20", "21",
    372 		"22", "23", "24", "25", "26", "27", "28",
    373 		"29", "30", "31",
    374 	};
    375 
    376 	if (day == SPACE) {
    377 		memset(p, ' ', julian ? J_DAY_LEN : DAY_LEN);
    378 		return;
    379 	}
    380 	if (julian) {
    381 		if ((val = day / 100) != 0) {
    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