xref: /freebsd/usr.bin/ncal/ncal.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
1 /*-
2  * Copyright (c) 1997 Wolfgang Helbig
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #ifndef lint
28 static const char rcsid[] =
29   "$FreeBSD$";
30 #endif /* not lint */
31 
32 #include <calendar.h>
33 #include <ctype.h>
34 #include <err.h>
35 #include <langinfo.h>
36 #include <locale.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <sysexits.h>
41 #include <time.h>
42 #include <unistd.h>
43 
44 /* Width of one month with backward compatibility */
45 #define MONTH_WIDTH_B_J 27
46 #define MONTH_WIDTH_B 20
47 
48 #define MONTH_WIDTH_J 24
49 #define MONTH_WIDTH 18
50 
51 #define MAX_WIDTH 28
52 
53 typedef struct date date;
54 
55 struct monthlines {
56 	char name[MAX_WIDTH + 1];
57 	char lines[7][MAX_WIDTH + 1];
58 	char weeks[MAX_WIDTH + 1];
59 };
60 
61 struct weekdays {
62 	char names[7][4];
63 };
64 
65 /* The switches from Julian to Gregorian in some countries */
66 static struct djswitch {
67 	char *cc;	/* Country code according to ISO 3166 */
68 	char *nm;	/* Name of country */
69 	date dt;	/* Last day of Julian calendar */
70 } switches[] = {
71 	{"AL", "Albania",       {1912, 11, 30}},
72 	{"AT", "Austria",       {1583, 10,  5}},
73 	{"AU", "Australia",     {1752,  9,  2}},
74 	{"BE", "Belgium",       {1582, 12, 14}},
75 	{"BG", "Bulgaria",      {1916,  3, 18}},
76 	{"CA", "Canada",        {1752,  9,  2}},
77 	{"CH", "Switzerland",   {1655,  2, 28}},
78 	{"CN", "China",         {1911, 12, 18}},
79 	{"CZ", "Czech Republic",{1584,  1,  6}},
80 	{"DE", "Germany",       {1700,  2, 18}},
81 	{"DK", "Denmark",       {1700,  2, 18}},
82 	{"ES", "Spain",         {1582, 10,  4}},
83 	{"FI", "Finland",       {1753,  2, 17}},
84 	{"FR", "France",        {1582, 12,  9}},
85 	{"GB", "United Kingdom",{1752,  9,  2}},
86 	{"GR", "Greece",        {1924,  3,  9}},
87 	{"HU", "Hungary",       {1587, 10, 21}},
88 	{"IS", "Iceland",       {1700, 11, 16}},
89 	{"IT", "Italy",         {1582, 10,  4}},
90 	{"JP", "Japan",         {1918, 12, 18}},
91 	{"LI", "Lithuania",     {1918,  2,  1}},
92 	{"LN", "Latin",         {9999, 05, 31}},
93 	{"LU", "Luxembourg",    {1582, 12, 14}},
94 	{"LV", "Latvia",        {1918,  2,  1}},
95 	{"NL", "Netherlands",   {1582, 12, 14}},
96 	{"NO", "Norway",        {1700,  2, 18}},
97 	{"PL", "Poland",        {1582, 10,  4}},
98 	{"PT", "Portugal",      {1582, 10,  4}},
99 	{"RO", "Romania",       {1919,  3, 31}},
100 	{"RU", "Russia",        {1918,  1, 31}},
101 	{"SI", "Slovenia",      {1919,  3,  4}},
102 	{"SW", "Sweden",        {1753,  2, 17}},
103 	{"TR", "Turkey",        {1926, 12, 18}},
104 	{"US", "United States", {1752,  9,  2}},
105 	{"YU", "Yugoslavia",    {1919,  3,  4}}
106 };
107 
108 struct djswitch *dftswitch =
109     switches + sizeof(switches) / sizeof(struct djswitch) - 2;
110     /* default switch (should be "US") */
111 
112 /* Table used to print day of month and week numbers */
113 char daystr[] = "     1  2  3  4  5  6  7  8  9 10 11 12 13 14 15"
114 		" 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31"
115 		" 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47"
116 		" 48 49 50 51 52 53";
117 
118 /* Table used to print day of year and week numbers */
119 char jdaystr[] = "       1   2   3   4   5   6   7   8   9"
120 		 "  10  11  12  13  14  15  16  17  18  19"
121 		 "  20  21  22  23  24  25  26  27  28  29"
122 		 "  30  31  32  33  34  35  36  37  38  39"
123 		 "  40  41  42  43  44  45  46  47  48  49"
124 		 "  50  51  52  53  54  55  56  57  58  59"
125 		 "  60  61  62  63  64  65  66  67  68  69"
126 		 "  70  71  72  73  74  75  76  77  78  79"
127 		 "  80  81  82  83  84  85  86  87  88  89"
128 		 "  90  91  92  93  94  95  96  97  98  99"
129 		 " 100 101 102 103 104 105 106 107 108 109"
130 		 " 110 111 112 113 114 115 116 117 118 119"
131 		 " 120 121 122 123 124 125 126 127 128 129"
132 		 " 130 131 132 133 134 135 136 137 138 139"
133 		 " 140 141 142 143 144 145 146 147 148 149"
134 		 " 150 151 152 153 154 155 156 157 158 159"
135 		 " 160 161 162 163 164 165 166 167 168 169"
136 		 " 170 171 172 173 174 175 176 177 178 179"
137 		 " 180 181 182 183 184 185 186 187 188 189"
138 		 " 190 191 192 193 194 195 196 197 198 199"
139 		 " 200 201 202 203 204 205 206 207 208 209"
140 		 " 210 211 212 213 214 215 216 217 218 219"
141 		 " 220 221 222 223 224 225 226 227 228 229"
142 		 " 230 231 232 233 234 235 236 237 238 239"
143 		 " 240 241 242 243 244 245 246 247 248 249"
144 		 " 250 251 252 253 254 255 256 257 258 259"
145 		 " 260 261 262 263 264 265 266 267 268 269"
146 		 " 270 271 272 273 274 275 276 277 278 279"
147 		 " 280 281 282 283 284 285 286 287 288 289"
148 		 " 290 291 292 293 294 295 296 297 298 299"
149 		 " 300 301 302 303 304 305 306 307 308 309"
150 		 " 310 311 312 313 314 315 316 317 318 319"
151 		 " 320 321 322 323 324 325 326 327 328 329"
152 		 " 330 331 332 333 334 335 336 337 338 339"
153 		 " 340 341 342 343 344 345 346 347 348 349"
154 		 " 350 351 352 353 354 355 356 357 358 359"
155 		 " 360 361 362 363 364 365 366";
156 
157 int     flag_weeks;		/* user wants number of week */
158 int     nswitch;		/* user defined switch date */
159 int	nswitchb;		/* switch date for backward compatibility */
160 
161 char   *center(char *s, char *t, int w);
162 void	mkmonth(int year, int month, int jd_flag, struct monthlines * monthl);
163 void    mkmonthb(int year, int month, int jd_flag, struct monthlines * monthl);
164 void    mkweekdays(struct weekdays * wds);
165 void    printcc(void);
166 void    printeaster(int year, int julian, int orthodox);
167 void    printmonth(int year, int month, int jd_flag);
168 void    printmonthb(int year, int month, int jd_flag);
169 void    printyear(int year, int jd_flag);
170 void    printyearb(int year, int jd_flag);
171 int	firstday(int y, int m);
172 date   *sdate(int ndays, struct date * d);
173 date   *sdateb(int ndays, struct date * d);
174 int     sndays(struct date * d);
175 int     sndaysb(struct date * d);
176 static void usage(void);
177 int     weekdayb(int nd);
178 
179 int
180 main(int argc, char *argv[])
181 {
182 	struct  djswitch *p, *q;	/* to search user defined switch date */
183 	date	never = {10000, 1, 1};	/* outside valid range of dates */
184 	date	ukswitch = {1752, 9, 2};/* switch date for Great Britain */
185 	int     ch;			/* holds the option character */
186 	int     m = 0;			/* month */
187 	int	y = 0;			/* year */
188 	int     flag_backward = 0;	/* user called cal--backward compat. */
189 	int     flag_hole_year = 0;	/* user wants the whole year */
190 	int	flag_julian_cal = 0;	/* user wants Julian Calendar */
191 	int     flag_julian_day = 0;	/* user wants the Julian day
192 					 * numbers */
193 	int	flag_orthodox = 0;	/* use wants Orthodox easter */
194 	int	flag_easter = 0;	/* use wants easter date */
195 	char	*cp;			/* character pointer */
196 	char    *locale;		/* locale to get country code */
197 
198 	/*
199 	 * Use locale to determine the country code,
200 	 * and use the country code to determine the default
201 	 * switchdate and date format from the switches table.
202 	 */
203 	if (setlocale(LC_ALL, "") == NULL)
204 		warn("setlocale");
205 	locale = setlocale(LC_TIME, NULL);
206 	if (locale == NULL ||
207 	    strcmp(locale, "C") == 0 ||
208 	    strcmp(locale, "POSIX") == 0 ||
209 	    strcmp(locale, "ASCII") == 0 ||
210 	    strcmp(locale, "US-ASCII") == 0)
211 		locale = "_US";
212 	q = switches + sizeof(switches) / sizeof(struct djswitch);
213 	for (p = switches; p != q; p++)
214 		if ((cp = strstr(locale, p->cc)) != NULL && *(cp - 1) == '_')
215 			break;
216 	if (p == q) {
217 		nswitch = ndaysj(&dftswitch->dt);
218 	} else {
219 		nswitch = ndaysj(&p->dt);
220 		dftswitch = p;
221 	}
222 
223 
224 	/*
225 	 * Get the filename portion of argv[0] and set flag_backward if
226 	 * this program is called "cal".
227 	 */
228 	for (cp = argv[0]; *cp; cp++)
229 		;
230 	while (cp >= argv[0] && *cp != '/')
231 		cp--;
232 	if (strcmp("cal", ++cp) == 0)
233 		flag_backward = 1;
234 
235 	/* Set the switch date to United Kingdom if backwards compatible */
236 	if (flag_backward)
237 		nswitchb = ndaysj(&ukswitch);
238 
239 	while ((ch = getopt(argc, argv, "Jejops:wy")) != -1)
240 		switch (ch) {
241 		case 'J':
242 			if (flag_backward)
243 				usage();
244 			nswitch = ndaysj(&never);
245 			flag_julian_cal = 1;
246 			break;
247 		case 'e':
248 			if (flag_backward)
249 				usage();
250 			flag_easter = 1;
251 			break;
252 		case 'j':
253 			flag_julian_day = 1;
254 			break;
255 		case 'o':
256 			if (flag_backward)
257 				usage();
258 			flag_orthodox = 1;
259 			flag_easter = 1;
260 			break;
261 		case 'p':
262 			if (flag_backward)
263 				usage();
264 			printcc();
265 			return (0);
266 			break;
267 		case 's':
268 			if (flag_backward)
269 				usage();
270 			q = switches +
271 			    sizeof(switches) / sizeof(struct djswitch);
272 			for (p = switches;
273 			     p != q && strcmp(p->cc, optarg) != 0; p++)
274 				;
275 			if (p == q)
276 				errx(EX_USAGE,
277 				    "%s: invalid country code", optarg);
278 			nswitch = ndaysj(&(p->dt));
279 			break;
280 		case 'w':
281 			if (flag_backward)
282 				usage();
283 			flag_weeks = 1;
284 			break;
285 		case 'y':
286 			flag_hole_year = 1;
287 			break;
288 		default:
289 			usage();
290 		}
291 
292 	argc -= optind;
293 	argv += optind;
294 
295 	if (argc == 0) {
296 		time_t t;
297 		struct tm *tm;
298 
299 		t = time(NULL);
300 		tm = localtime(&t);
301 		y = tm->tm_year + 1900;
302 		m = tm->tm_mon + 1;
303 	}
304 
305 	switch (argc) {
306 	case 2:
307 		if (flag_easter)
308 			usage();
309 		m = atoi(*argv++);
310 		if (m < 1 || m > 12)
311 			errx(EX_USAGE, "month %d not in range 1..12", m);
312 		/* FALLTHROUGH */
313 	case 1:
314 		y = atoi(*argv++);
315 		if (y < 1 || y > 9999)
316 			errx(EX_USAGE, "year %d not in range 1..9999", y);
317 		break;
318 	case 0:
319 		break;
320 	default:
321 		usage();
322 	}
323 
324 	if (flag_easter)
325 		printeaster(y, flag_julian_cal, flag_orthodox);
326 	else if (argc == 1 || flag_hole_year)
327 		if (flag_backward)
328 			printyearb(y, flag_julian_day);
329 		else
330 			printyear(y, flag_julian_day);
331 	else
332 		if (flag_backward)
333 			printmonthb(y, m, flag_julian_day);
334 		else
335 			printmonth(y, m, flag_julian_day);
336 
337 	return (0);
338 }
339 
340 static void
341 usage(void)
342 {
343 
344 	fprintf(stderr, "%s\n%s\n%s\n",
345 	    "usage: cal [-jy] [[month] year]",
346 	    "       ncal [-Jjpwy] [-s country_code] [[month] year]",
347 	    "       ncal [-Jeo] [year]");
348 	exit(EX_USAGE);
349 }
350 
351 /* print the assumed switches for all countries */
352 void
353 printcc(void)
354 {
355 	struct djswitch *p;
356 	int n;	/* number of lines to print */
357 	int m;	/* offset from left to right table entry on the same line */
358 
359 #define FSTR "%c%s %-15s%4d-%02d-%02d"
360 #define DFLT(p) ((p) == dftswitch ? '*' : ' ')
361 #define FSTRARG(p) DFLT(p), (p)->cc, (p)->nm, (p)->dt.y, (p)->dt.m, (p)->dt.d
362 
363 	n = sizeof(switches) / sizeof(struct djswitch);
364 	m = (n + 1) / 2;
365 	n /= 2;
366 	for (p = switches; p != switches + n; p++)
367 		printf(FSTR"     "FSTR"\n", FSTRARG(p), FSTRARG(p+m));
368 	if (m != n)
369 		printf(FSTR"\n", FSTRARG(p));
370 }
371 
372 /* print the date of easter sunday */
373 void
374 printeaster(int y, int julian, int orthodox)
375 {
376 	date    dt;
377 	struct tm tm;
378 	char    buf[80];
379 	static int d_first = -1;
380 
381 	if (d_first < 0)
382 		d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
383 	/* force orthodox easter for years before 1583 */
384 	if (y < 1583)
385 		orthodox = 1;
386 
387 	if (orthodox)
388 		if (julian)
389 			easteroj(y, &dt);
390 		else
391 			easterog(y, &dt);
392 	else
393 		easterg(y, &dt);
394 
395 	memset(&tm, 0, sizeof(tm));
396 	tm.tm_year = dt.y - 1900;
397 	tm.tm_mon  = dt.m - 1;
398 	tm.tm_mday = dt.d;
399 	strftime(buf, sizeof(buf), d_first ? "%e %B %Y" : "%B %e %Y",  &tm);
400 	printf("%s\n", buf);
401 }
402 
403 void
404 printmonth(int y, int m, int jd_flag)
405 {
406 	struct monthlines month;
407 	struct weekdays wds;
408 	int i;
409 
410 	mkmonth(y, m - 1, jd_flag, &month);
411 	mkweekdays(&wds);
412 	printf("    %s %d\n", month.name, y);
413 	for (i = 0; i != 7; i++)
414 		printf("%.2s%s\n", wds.names[i], month.lines[i]);
415 	if (flag_weeks)
416 		printf("  %s\n", month.weeks);
417 }
418 
419 void
420 printmonthb(int y, int m, int jd_flag)
421 {
422 	struct monthlines month;
423 	struct weekdays wds;
424 	char s[MAX_WIDTH], t[MAX_WIDTH];
425 	int i;
426 	int mw;
427 
428 	mkmonthb(y, m - 1, jd_flag, &month);
429 	mkweekdays(&wds);
430 
431 	mw = jd_flag ? MONTH_WIDTH_B_J : MONTH_WIDTH_B;
432 
433 	sprintf(s, "%s %d", month.name, y);
434 	printf("%s\n", center(t, s, mw));
435 
436 	if (jd_flag)
437 		printf(" %s %s %s %s %s %s %.2s\n", wds.names[6], wds.names[0],
438 			wds.names[1], wds.names[2], wds.names[3],
439 			wds.names[4], wds.names[5]);
440 	else
441 		printf("%s%s%s%s%s%s%.2s\n", wds.names[6], wds.names[0],
442 			wds.names[1], wds.names[2], wds.names[3],
443 			wds.names[4], wds.names[5]);
444 
445 	for (i = 0; i != 6; i++)
446 		printf("%s\n", month.lines[i]+1);
447 }
448 
449 void
450 printyear(int y, int jd_flag)
451 {
452 	struct monthlines year[12];
453 	struct weekdays wds;
454 	char    s[80], t[80];
455 	int     i, j;
456 	int     mpl;
457 	int     mw;
458 
459 	for (i = 0; i != 12; i++)
460 		mkmonth(y, i, jd_flag, year + i);
461 	mkweekdays(&wds);
462 	mpl = jd_flag ? 3 : 4;
463 	mw = jd_flag ? MONTH_WIDTH_J : MONTH_WIDTH;
464 
465 	sprintf(s, "%d", y);
466 	printf("%s\n", center(t, s, mpl * mw));
467 
468 	for (j = 0; j != 12; j += mpl) {
469 		printf("    %-*s%-*s",
470 		    mw, year[j].name,
471 		    mw, year[j + 1].name);
472 		if (mpl == 3)
473 			printf("%s\n", year[j + 2].name);
474 		else
475 			printf("%-*s%s\n",
476 		    	    mw, year[j + 2].name,
477 		    	    year[j + 3].name);
478 		for (i = 0; i != 7; i++) {
479 			printf("%.2s%-*s%-*s",
480 			    wds.names[i],
481 			    mw, year[j].lines[i],
482 			    mw, year[j + 1].lines[i]);
483 			if (mpl == 3)
484 				printf("%s\n", year[j + 2].lines[i]);
485 			else
486 				printf("%-*s%s\n",
487 			    	    mw, year[j + 2].lines[i],
488 			    	    year[j + 3].lines[i]);
489 		}
490 		if (flag_weeks) {
491 			if (mpl == 3)
492 				printf("  %-*s%-*s%-s\n",
493 				    mw, year[j].weeks,
494 				    mw, year[j + 1].weeks,
495 				    year[j + 2].weeks);
496 			else
497 				printf("  %-*s%-*s%-*s%-s\n",
498 				    mw, year[j].weeks,
499 				    mw, year[j + 1].weeks,
500 				    mw, year[j + 2].weeks,
501 				    year[j + 3].weeks);
502 		}
503 	}
504 }
505 
506 void
507 printyearb(int y, int jd_flag)
508 {
509 	struct monthlines year[12];
510 	struct weekdays wds;
511 	char	s[80], t[80];
512 	int     i, j;
513 	int     mpl;
514 	int     mw;
515 
516 	for (i = 0; i != 12; i++)
517 		mkmonthb(y, i, jd_flag, year + i);
518 	mkweekdays(&wds);
519 	mpl = jd_flag ? 2 : 3;
520 	mw = jd_flag ? MONTH_WIDTH_B_J : MONTH_WIDTH_B;
521 
522 	sprintf(s, "%d", y);
523 	printf("%s\n\n", center(t, s, mw * mpl + mpl));
524 
525 	for (j = 0; j != 12; j += mpl) {
526 		printf("%-*s  ", mw, center(s, year[j].name, mw));
527 		if (mpl == 2)
528 			printf("%s\n", center(s, year[j + 1].name, mw));
529 		else
530 			printf("%-*s  %s\n", mw,
531 			    center(s, year[j + 1].name, mw),
532 			    center(t, year[j + 2].name, mw));
533 
534 		if (mpl == 2)
535 			printf(" %s %s %s %s %s %s %s "
536 			       " %s %s %s %s %s %s %.2s\n",
537 				wds.names[6], wds.names[0], wds.names[1],
538 				wds.names[2], wds.names[3], wds.names[4],
539 				wds.names[5],
540 				wds.names[6], wds.names[0], wds.names[1],
541 				wds.names[2], wds.names[3], wds.names[4],
542 				wds.names[5]);
543 		else
544 			printf("%s%s%s%s%s%s%s "
545 				"%s%s%s%s%s%s%s "
546 				"%s%s%s%s%s%s%.2s\n",
547 				wds.names[6], wds.names[0], wds.names[1],
548 				wds.names[2], wds.names[3], wds.names[4],
549 				wds.names[5],
550 				wds.names[6], wds.names[0], wds.names[1],
551 				wds.names[2], wds.names[3], wds.names[4],
552 				wds.names[5],
553 				wds.names[6], wds.names[0], wds.names[1],
554 				wds.names[2], wds.names[3], wds.names[4],
555 				wds.names[5]);
556 		for (i = 0; i != 6; i++) {
557 			if (mpl == 2)
558 				printf("%-*s  %s\n",
559 			    mw, year[j].lines[i]+1,
560 			    year[j + 1].lines[i]+1);
561 			else
562 				printf("%-*s  %-*s  %s\n",
563 			    mw, year[j].lines[i]+1,
564 			    mw, year[j + 1].lines[i]+1,
565 			    year[j + 2].lines[i]+1);
566 
567 		}
568 	}
569 }
570 
571 void
572 mkmonth(int y, int m, int jd_flag, struct monthlines *mlines)
573 {
574 
575 	struct tm tm;		/* for strftime printing local names of
576 				 * months */
577 	date    dt;		/* handy date */
578 	int     dw;		/* width of numbers */
579 	int     first;		/* first day of month */
580 	int     firstm;		/* first day of first week of month */
581 	int     i, j, k;	/* just indices */
582 	int     last;		/* the first day of next month */
583 	int     jan1 = 0;	/* the first day of this year */
584 	char   *ds;		/* pointer to day strings (daystr or
585 				 * jdaystr) */
586 
587 	/* Set name of month. */
588 	memset(&tm, 0, sizeof(tm));
589 	tm.tm_mon = m;
590 	strftime(mlines->name, sizeof(mlines->name), "%OB", &tm);
591 	mlines->name[0] = toupper((unsigned char)mlines->name[0]);
592 
593 	/*
594 	 * Set first and last to the day number of the first day of this
595 	 * month and the first day of next month respectively. Set jan1 to
596 	 * the day number of the first day of this year.
597 	 */
598 	first = firstday(y, m + 1);
599 	if (m == 11)
600 		last = firstday(y + 1, 1);
601 	else
602 		last = firstday(y, m + 2);
603 
604 	if (jd_flag)
605 		jan1 = firstday(y, 1);
606 
607 	/*
608 	 * Set firstm to the day number of monday of the first week of
609 	 * this month. (This might be in the last month)
610 	 */
611 	firstm = first - weekday(first);
612 
613 	/* Set ds (daystring) and dw (daywidth) according to the jd_flag */
614 	if (jd_flag) {
615 		ds = jdaystr;
616 		dw = 4;
617 	} else {
618 		ds = daystr;
619 		dw = 3;
620 	}
621 
622 	/*
623 	 * Fill the lines with day of month or day of year (julian day)
624 	 * line index: i, each line is one weekday. column index: j, each
625 	 * column is one day number. print column index: k.
626 	 */
627 	for (i = 0; i != 7; i++) {
628 		for (j = firstm + i, k = 0; j < last; j += 7, k += dw)
629 			if (j >= first) {
630 				if (jd_flag)
631 					dt.d = j - jan1 + 1;
632 				else
633 					sdate(j, &dt);
634 				memcpy(mlines->lines[i] + k,
635 				       ds + dt.d * dw, dw);
636 			} else
637 				memcpy(mlines->lines[i] + k, "    ", dw);
638 		mlines->lines[i][k] = '\0';
639 
640 	}
641 
642 	/* fill the weeknumbers */
643 	if (flag_weeks) {
644 		for (j = firstm, k = 0; j < last;  k += dw, j += 7)
645 			if (j <= nswitch)
646 				memset(mlines->weeks + k, ' ', dw);
647 			else
648 				memcpy(mlines->weeks + k,
649 				    ds + week(j, &i)*dw, dw);
650 		mlines->weeks[k] = '\0';
651 	}
652 }
653 
654 void
655 mkmonthb(int y, int m, int jd_flag, struct monthlines *mlines)
656 {
657 
658 	struct tm tm;		/* for strftime printing local names of
659 				 * months */
660 	date    dt;		/* handy date */
661 	int     dw;		/* width of numbers */
662 	int     first;		/* first day of month */
663 	int     firsts;		/* sunday of first week of month */
664 	int     i, j, k;	/* just indices */
665 	int     jan1 = 0;	/* the first day of this year */
666 	int     last;		/* the first day of next month */
667 	char   *ds;		/* pointer to day strings (daystr or
668 				 * jdaystr) */
669 
670 	/* Set ds (daystring) and dw (daywidth) according to the jd_flag */
671 	if (jd_flag) {
672 		ds = jdaystr;
673 		dw = 4;
674 	} else {
675 		ds = daystr;
676 		dw = 3;
677 	}
678 
679 	/* Set name of month centered */
680 	memset(&tm, 0, sizeof(tm));
681 	tm.tm_mon = m;
682 	strftime(mlines->name, sizeof(mlines->name), "%OB", &tm);
683 	mlines->name[0] = toupper((unsigned char)mlines->name[0]);
684 
685 	/*
686 	 * Set first and last to the day number of the first day of this
687 	 * month and the first day of next month respectively. Set jan1 to
688 	 * the day number of Jan 1st of this year.
689 	 */
690 	dt.y = y;
691 	dt.m = m + 1;
692 	dt.d = 1;
693 	first = sndaysb(&dt);
694 	if (m == 11) {
695 		dt.y = y + 1;
696 		dt.m = 1;
697 		dt.d = 1;
698 	} else {
699 		dt.y = y;
700 		dt.m = m + 2;
701 		dt.d = 1;
702 	}
703 	last = sndaysb(&dt);
704 
705 	if (jd_flag) {
706 		dt.y = y;
707 		dt.m = 1;
708 		dt.d = 1;
709 		jan1 = sndaysb(&dt);
710 	}
711 
712 	/*
713 	 * Set firsts to the day number of sunday of the first week of
714 	 * this month. (This might be in the last month)
715 	 */
716 	firsts = first - (weekday(first)+1) % 7;
717 
718 	/*
719 	 * Fill the lines with day of month or day of year (Julian day)
720 	 * line index: i, each line is one week. column index: j, each
721 	 * column is one day number. print column index: k.
722 	 */
723 	for (i = 0; i != 6; i++) {
724 		for (j = firsts + 7 * i, k = 0; j < last && k != dw * 7;
725 		     j++, k += dw)
726 			if (j >= first) {
727 				if (jd_flag)
728 					dt.d = j - jan1 + 1;
729 				else
730 					sdateb(j, &dt);
731 				memcpy(mlines->lines[i] + k,
732 				       ds + dt.d * dw, dw);
733 			} else
734 				memcpy(mlines->lines[i] + k, "    ", dw);
735 		if (k == 0)
736 			mlines->lines[i][1] = '\0';
737 		else
738 			mlines->lines[i][k] = '\0';
739 	}
740 }
741 
742 /* Put the local names of weekdays into the wds */
743 void
744 mkweekdays(struct weekdays *wds)
745 {
746 	int i, len;
747 	struct tm tm;
748 	char buf[20];
749 
750 	memset(&tm, 0, sizeof(tm));
751 
752 	for (i = 0; i != 7; i++) {
753 		tm.tm_wday = (i+1) % 7;
754 		strftime(buf, sizeof(buf), "%a", &tm);
755 		len = strlen(buf);
756 		if (len > 2)
757 			len = 2;
758 		strcpy(wds->names[i], "   ");
759 		strncpy(wds->names[i] + 2 - len, buf, len);
760 	}
761 }
762 
763 /*
764  * Compute the day number of the first
765  * existing date after the first day in month.
766  * (the first day in month and even the month might not exist!)
767  */
768 int
769 firstday(int y, int m)
770 {
771 	date dt;
772 	int nd;
773 
774 	dt.y = y;
775 	dt.m = m;
776 	dt.d = 1;
777 	nd = sndays(&dt);
778 	for (;;) {
779 		sdate(nd, &dt);
780 		if ((dt.m >= m && dt.y == y) || dt.y > y)
781 			return (nd);
782 		else
783 			nd++;
784 	}
785 	/* NEVER REACHED */
786 }
787 
788 /*
789  * Compute the number of days from date, obey the local switch from
790  * Julian to Gregorian if specified by the user.
791  */
792 int
793 sndays(struct date *d)
794 {
795 
796 	if (nswitch != 0)
797 		if (nswitch < ndaysj(d))
798 			return (ndaysg(d));
799 		else
800 			return (ndaysj(d));
801 	else
802 		return ndaysg(d);
803 }
804 
805 /*
806  * Compute the number of days from date, obey the switch from
807  * Julian to Gregorian as used by UK and her colonies.
808  */
809 int
810 sndaysb(struct date *d)
811 {
812 
813 	if (nswitchb < ndaysj(d))
814 		return (ndaysg(d));
815 	else
816 		return (ndaysj(d));
817 }
818 
819 /* Inverse of sndays */
820 struct date *
821 sdate(int nd, struct date *d)
822 {
823 
824 	if (nswitch < nd)
825 		return (gdate(nd, d));
826 	else
827 		return (jdate(nd, d));
828 }
829 
830 /* Inverse of sndaysb */
831 struct date *
832 sdateb(int nd, struct date *d)
833 {
834 
835 	if (nswitchb < nd)
836 		return (gdate(nd, d));
837 	else
838 		return (jdate(nd, d));
839 }
840 
841 /* Center string t in string s of length w by putting enough leading blanks */
842 char *
843 center(char *s, char *t, int w)
844 {
845 	char blanks[80];
846 
847 	memset(blanks, ' ', sizeof(blanks));
848 	sprintf(s, "%.*s%s", (int)(w - strlen(t)) / 2, blanks, t);
849 	return (s);
850 }
851