ncal.c revision 74612
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
28static const char rcsid[] =
29  "$FreeBSD: head/usr.bin/ncal/ncal.c 74612 2001-03-22 00:25:26Z ache $";
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
53typedef struct date date;
54
55struct monthlines {
56	char name[MAX_WIDTH + 1];
57	char lines[7][MAX_WIDTH + 1];
58	char weeks[MAX_WIDTH + 1];
59};
60
61struct weekdays {
62	char names[7][4];
63};
64
65/* The switches from Julian to Gregorian in some countries */
66static 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	{"SU", "USSR",          {1920,  3,  4}},
103	{"SW", "Sweden",        {1753,  2, 17}},
104	{"TR", "Turkey",        {1926, 12, 18}},
105	{"US", "United States", {1752,  9,  2}},
106	{"YU", "Yugoslavia",    {1919,  3,  4}}
107};
108
109struct djswitch *dftswitch =
110    switches + sizeof(switches) / sizeof(struct djswitch) - 2;
111    /* default switch (should be "US") */
112
113/* Table used to print day of month and week numbers */
114char daystr[] = "     1  2  3  4  5  6  7  8  9 10 11 12 13 14 15"
115		" 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31"
116		" 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47"
117		" 48 49 50 51 52 53";
118
119/* Table used to print day of year and week numbers */
120char jdaystr[] = "       1   2   3   4   5   6   7   8   9"
121		 "  10  11  12  13  14  15  16  17  18  19"
122		 "  20  21  22  23  24  25  26  27  28  29"
123		 "  30  31  32  33  34  35  36  37  38  39"
124		 "  40  41  42  43  44  45  46  47  48  49"
125		 "  50  51  52  53  54  55  56  57  58  59"
126		 "  60  61  62  63  64  65  66  67  68  69"
127		 "  70  71  72  73  74  75  76  77  78  79"
128		 "  80  81  82  83  84  85  86  87  88  89"
129		 "  90  91  92  93  94  95  96  97  98  99"
130		 " 100 101 102 103 104 105 106 107 108 109"
131		 " 110 111 112 113 114 115 116 117 118 119"
132		 " 120 121 122 123 124 125 126 127 128 129"
133		 " 130 131 132 133 134 135 136 137 138 139"
134		 " 140 141 142 143 144 145 146 147 148 149"
135		 " 150 151 152 153 154 155 156 157 158 159"
136		 " 160 161 162 163 164 165 166 167 168 169"
137		 " 170 171 172 173 174 175 176 177 178 179"
138		 " 180 181 182 183 184 185 186 187 188 189"
139		 " 190 191 192 193 194 195 196 197 198 199"
140		 " 200 201 202 203 204 205 206 207 208 209"
141		 " 210 211 212 213 214 215 216 217 218 219"
142		 " 220 221 222 223 224 225 226 227 228 229"
143		 " 230 231 232 233 234 235 236 237 238 239"
144		 " 240 241 242 243 244 245 246 247 248 249"
145		 " 250 251 252 253 254 255 256 257 258 259"
146		 " 260 261 262 263 264 265 266 267 268 269"
147		 " 270 271 272 273 274 275 276 277 278 279"
148		 " 280 281 282 283 284 285 286 287 288 289"
149		 " 290 291 292 293 294 295 296 297 298 299"
150		 " 300 301 302 303 304 305 306 307 308 309"
151		 " 310 311 312 313 314 315 316 317 318 319"
152		 " 320 321 322 323 324 325 326 327 328 329"
153		 " 330 331 332 333 334 335 336 337 338 339"
154		 " 340 341 342 343 344 345 346 347 348 349"
155		 " 350 351 352 353 354 355 356 357 358 359"
156		 " 360 361 362 363 364 365 366";
157
158int     flag_weeks;		/* user wants number of week */
159int     nswitch;		/* user defined switch date */
160int	nswitchb;		/* switch date for backward compatibility */
161
162char   *center(char *s, char *t, int w);
163void	mkmonth(int year, int month, int jd_flag, struct monthlines * monthl);
164void    mkmonthb(int year, int month, int jd_flag, struct monthlines * monthl);
165void    mkweekdays(struct weekdays * wds);
166void    printcc(void);
167void    printeaster(int year, int julian, int orthodox);
168void    printmonth(int year, int month, int jd_flag);
169void    printmonthb(int year, int month, int jd_flag);
170void    printyear(int year, int jd_flag);
171void    printyearb(int year, int jd_flag);
172int	firstday(int y, int m);
173date   *sdate(int ndays, struct date * d);
174date   *sdateb(int ndays, struct date * d);
175int     sndays(struct date * d);
176int     sndaysb(struct date * d);
177static void usage(void);
178int     weekdayb(int nd);
179
180int
181main(int argc, char *argv[])
182{
183	struct  djswitch *p, *q;	/* to search user defined switch date */
184	date	never = {10000, 1, 1};	/* outside valid range of dates */
185	date	ukswitch = {1752, 9, 2};/* switch date for Great Britain */
186	int     ch;			/* holds the option character */
187	int     m = 0;			/* month */
188	int	y = 0;			/* year */
189	int     flag_backward = 0;	/* user called cal--backward compat. */
190	int     flag_hole_year = 0;	/* user wants the whole year */
191	int	flag_julian_cal = 0;	/* user wants Julian Calendar */
192	int     flag_julian_day = 0;	/* user wants the Julian day
193					 * numbers */
194	int	flag_orthodox = 0;	/* use wants Orthodox easter */
195	int	flag_easter = 0;	/* use wants easter date */
196	char	*cp;			/* character pointer */
197	char    *locale;		/* locale to get country code */
198
199	/*
200	 * Use locale to determine the country code,
201	 * and use the country code to determine the default
202	 * switchdate and date format from the switches table.
203	 */
204	if (setlocale(LC_ALL, "") == NULL)
205		warn("setlocale");
206	locale = setlocale(LC_TIME, NULL);
207	if (locale == NULL || locale == "C")
208		locale = "_US";
209	q = switches + sizeof(switches) / sizeof(struct djswitch);
210	for (p = switches; p != q; p++)
211		if ((cp = strstr(locale, p->cc)) != NULL && *(cp - 1) == '_')
212			break;
213	if (p == q) {
214		nswitch = ndaysj(&dftswitch->dt);
215	} else {
216		nswitch = ndaysj(&p->dt);
217		dftswitch = p;
218	}
219
220
221	/*
222	 * Get the filename portion of argv[0] and set flag_backward if
223	 * this program is called "cal".
224	 */
225	for (cp = argv[0]; *cp; cp++)
226		;
227	while (cp >= argv[0] && *cp != '/')
228		cp--;
229	if (strcmp("cal", ++cp) == 0)
230		flag_backward = 1;
231
232	/* Set the switch date to United Kingdom if backwards compatible */
233	if (flag_backward)
234		nswitchb = ndaysj(&ukswitch);
235
236	while ((ch = getopt(argc, argv, "Jejops:wy")) != -1)
237		switch (ch) {
238		case 'J':
239			if (flag_backward)
240				usage();
241			nswitch = ndaysj(&never);
242			flag_julian_cal = 1;
243			break;
244		case 'e':
245			if (flag_backward)
246				usage();
247			flag_easter = 1;
248			break;
249		case 'j':
250			flag_julian_day = 1;
251			break;
252		case 'o':
253			if (flag_backward)
254				usage();
255			flag_orthodox = 1;
256			flag_easter = 1;
257			break;
258		case 'p':
259			if (flag_backward)
260				usage();
261			printcc();
262			return (0);
263			break;
264		case 's':
265			if (flag_backward)
266				usage();
267			q = switches +
268			    sizeof(switches) / sizeof(struct djswitch);
269			for (p = switches;
270			     p != q && strcmp(p->cc, optarg) != 0; p++)
271				;
272			if (p == q)
273				errx(EX_USAGE,
274				    "%s: invalid country code", optarg);
275			nswitch = ndaysj(&(p->dt));
276			break;
277		case 'w':
278			if (flag_backward)
279				usage();
280			flag_weeks = 1;
281			break;
282		case 'y':
283			flag_hole_year = 1;
284			break;
285		default:
286			usage();
287		}
288
289	argc -= optind;
290	argv += optind;
291
292	if (argc == 0) {
293		time_t t;
294		struct tm *tm;
295
296		t = time(NULL);
297		tm = localtime(&t);
298		y = tm->tm_year + 1900;
299		m = tm->tm_mon + 1;
300	}
301
302	switch (argc) {
303	case 2:
304		if (flag_easter)
305			usage();
306		m = atoi(*argv++);
307		if (m < 1 || m > 12)
308			errx(EX_USAGE, "month %d not in range 1..12", m);
309		/* FALLTHROUGH */
310	case 1:
311		y = atoi(*argv++);
312		if (y < 1 || y > 9999)
313			errx(EX_USAGE, "year %d not in range 1..9999", y);
314		break;
315	case 0:
316		break;
317	default:
318		usage();
319	}
320
321	if (flag_easter)
322		printeaster(y, flag_julian_cal, flag_orthodox);
323	else if (argc == 1 || flag_hole_year)
324		if (flag_backward)
325			printyearb(y, flag_julian_day);
326		else
327			printyear(y, flag_julian_day);
328	else
329		if (flag_backward)
330			printmonthb(y, m, flag_julian_day);
331		else
332			printmonth(y, m, flag_julian_day);
333
334	return (0);
335}
336
337static void
338usage(void)
339{
340
341	fprintf(stderr, "%s\n%s\n%s\n",
342	    "usage: cal [-jy] [[month] year]",
343	    "       ncal [-Jjpwy] [-s country_code] [[month] year]",
344	    "       ncal [-Jeo] [year]");
345	exit(EX_USAGE);
346}
347
348/* print the assumed switches for all countries */
349void
350printcc(void)
351{
352	struct djswitch *p;
353	int n;	/* number of lines to print */
354	int m;	/* offset from left to right table entry on the same line */
355
356#define FSTR "%c%s %-15s%4d-%02d-%02d"
357#define DFLT(p) ((p) == dftswitch ? '*' : ' ')
358#define FSTRARG(p) DFLT(p), (p)->cc, (p)->nm, (p)->dt.y, (p)->dt.m, (p)->dt.d
359
360	n = sizeof(switches) / sizeof(struct djswitch);
361	m = (n + 1) / 2;
362	n /= 2;
363	for (p = switches; p != switches + n; p++)
364		printf(FSTR"     "FSTR"\n", FSTRARG(p), FSTRARG(p+m));
365	if (m != n)
366		printf(FSTR"\n", FSTRARG(p));
367}
368
369/* print the date of easter sunday */
370void
371printeaster(int y, int julian, int orthodox)
372{
373	date    dt;
374	struct tm tm;
375	char    buf[80];
376	static int d_first = -1;
377
378	if (d_first < 0)
379		d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
380	/* force orthodox easter for years before 1583 */
381	if (y < 1583)
382		orthodox = 1;
383
384	if (orthodox)
385		if (julian)
386			easteroj(y, &dt);
387		else
388			easterog(y, &dt);
389	else
390		easterg(y, &dt);
391
392	memset(&tm, 0, sizeof(tm));
393	tm.tm_year = dt.y - 1900;
394	tm.tm_mon  = dt.m - 1;
395	tm.tm_mday = dt.d;
396	strftime(buf, sizeof(buf), d_first ? "%e %B %Y" : "%B %e %Y",  &tm);
397	printf("%s\n", buf);
398}
399
400void
401printmonth(int y, int m, int jd_flag)
402{
403	struct monthlines month;
404	struct weekdays wds;
405	int i;
406
407	mkmonth(y, m - 1, jd_flag, &month);
408	mkweekdays(&wds);
409	printf("    %s %d\n", month.name, y);
410	for (i = 0; i != 7; i++)
411		printf("%.2s%s\n", wds.names[i], month.lines[i]);
412	if (flag_weeks)
413		printf("  %s\n", month.weeks);
414}
415
416void
417printmonthb(int y, int m, int jd_flag)
418{
419	struct monthlines month;
420	struct weekdays wds;
421	char s[MAX_WIDTH], t[MAX_WIDTH];
422	int i;
423	int mw;
424
425	mkmonthb(y, m - 1, jd_flag, &month);
426	mkweekdays(&wds);
427
428	mw = jd_flag ? MONTH_WIDTH_B_J : MONTH_WIDTH_B;
429
430	sprintf(s, "%s %d", month.name, y);
431	printf("%s\n", center(t, s, mw));
432
433	if (jd_flag)
434		printf(" %s %s %s %s %s %s %.2s\n", wds.names[6], wds.names[0],
435			wds.names[1], wds.names[2], wds.names[3],
436			wds.names[4], wds.names[5]);
437	else
438		printf("%s%s%s%s%s%s%.2s\n", wds.names[6], wds.names[0],
439			wds.names[1], wds.names[2], wds.names[3],
440			wds.names[4], wds.names[5]);
441
442	for (i = 0; i != 6; i++)
443		printf("%s\n", month.lines[i]+1);
444}
445
446void
447printyear(int y, int jd_flag)
448{
449	struct monthlines year[12];
450	struct weekdays wds;
451	char    s[80], t[80];
452	int     i, j;
453	int     mpl;
454	int     mw;
455
456	for (i = 0; i != 12; i++)
457		mkmonth(y, i, jd_flag, year + i);
458	mkweekdays(&wds);
459	mpl = jd_flag ? 3 : 4;
460	mw = jd_flag ? MONTH_WIDTH_J : MONTH_WIDTH;
461
462	sprintf(s, "%d", y);
463	printf("%s\n", center(t, s, mpl * mw));
464
465	for (j = 0; j != 12; j += mpl) {
466		printf("    %-*s%-*s",
467		    mw, year[j].name,
468		    mw, year[j + 1].name);
469		if (mpl == 3)
470			printf("%s\n", year[j + 2].name);
471		else
472			printf("%-*s%s\n",
473		    	    mw, year[j + 2].name,
474		    	    year[j + 3].name);
475		for (i = 0; i != 7; i++) {
476			printf("%.2s%-*s%-*s",
477			    wds.names[i],
478			    mw, year[j].lines[i],
479			    mw, year[j + 1].lines[i]);
480			if (mpl == 3)
481				printf("%s\n", year[j + 2].lines[i]);
482			else
483				printf("%-*s%s\n",
484			    	    mw, year[j + 2].lines[i],
485			    	    year[j + 3].lines[i]);
486		}
487		if (flag_weeks) {
488			if (mpl == 3)
489				printf("  %-*s%-*s%-s\n",
490				    mw, year[j].weeks,
491				    mw, year[j + 1].weeks,
492				    year[j + 2].weeks);
493			else
494				printf("  %-*s%-*s%-*s%-s\n",
495				    mw, year[j].weeks,
496				    mw, year[j + 1].weeks,
497				    mw, year[j + 2].weeks,
498				    year[j + 3].weeks);
499		}
500	}
501}
502
503void
504printyearb(int y, int jd_flag)
505{
506	struct monthlines year[12];
507	struct weekdays wds;
508	char	s[80], t[80];
509	int     i, j;
510	int     mpl;
511	int     mw;
512
513	for (i = 0; i != 12; i++)
514		mkmonthb(y, i, jd_flag, year + i);
515	mkweekdays(&wds);
516	mpl = jd_flag ? 2 : 3;
517	mw = jd_flag ? MONTH_WIDTH_B_J : MONTH_WIDTH_B;
518
519	sprintf(s, "%d", y);
520	printf("%s\n\n", center(t, s, mw * mpl + mpl));
521
522	for (j = 0; j != 12; j += mpl) {
523		printf("%-*s  ", mw, center(s, year[j].name, mw));
524		if (mpl == 2)
525			printf("%s\n", center(s, year[j + 1].name, mw));
526		else
527			printf("%-*s  %s\n", mw,
528			    center(s, year[j + 1].name, mw),
529			    center(t, year[j + 2].name, mw));
530
531		if (mpl == 2)
532			printf(" %s %s %s %s %s %s %s "
533			       " %s %s %s %s %s %s %.2s\n",
534				wds.names[6], wds.names[0], wds.names[1],
535				wds.names[2], wds.names[3], wds.names[4],
536				wds.names[5],
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		else
541			printf("%s%s%s%s%s%s%s "
542				"%s%s%s%s%s%s%s "
543				"%s%s%s%s%s%s%.2s\n",
544				wds.names[6], wds.names[0], wds.names[1],
545				wds.names[2], wds.names[3], wds.names[4],
546				wds.names[5],
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		for (i = 0; i != 6; i++) {
554			if (mpl == 2)
555				printf("%-*s  %s\n",
556			    mw, year[j].lines[i]+1,
557			    year[j + 1].lines[i]+1);
558			else
559				printf("%-*s  %-*s  %s\n",
560			    mw, year[j].lines[i]+1,
561			    mw, year[j + 1].lines[i]+1,
562			    year[j + 2].lines[i]+1);
563
564		}
565	}
566}
567
568void
569mkmonth(int y, int m, int jd_flag, struct monthlines *mlines)
570{
571
572	struct tm tm;		/* for strftime printing local names of
573				 * months */
574	date    dt;		/* handy date */
575	int     dw;		/* width of numbers */
576	int     first;		/* first day of month */
577	int     firstm;		/* first day of first week of month */
578	int     i, j, k;	/* just indices */
579	int     last;		/* the first day of next month */
580	int     jan1 = 0;	/* the first day of this year */
581	char   *ds;		/* pointer to day strings (daystr or
582				 * jdaystr) */
583
584	/* Set name of month. */
585	memset(&tm, 0, sizeof(tm));
586	tm.tm_mon = m;
587	strftime(mlines->name, sizeof(mlines->name), "%OB", &tm);
588	mlines->name[0] = toupper((unsigned char)mlines->name[0]);
589
590	/*
591	 * Set first and last to the day number of the first day of this
592	 * month and the first day of next month respectively. Set jan1 to
593	 * the day number of the first day of this year.
594	 */
595	first = firstday(y, m + 1);
596	if (m == 11)
597		last = firstday(y + 1, 1);
598	else
599		last = firstday(y, m + 2);
600
601	if (jd_flag)
602		jan1 = firstday(y, 1);
603
604	/*
605	 * Set firstm to the day number of monday of the first week of
606	 * this month. (This might be in the last month)
607	 */
608	firstm = first - weekday(first);
609
610	/* Set ds (daystring) and dw (daywidth) according to the jd_flag */
611	if (jd_flag) {
612		ds = jdaystr;
613		dw = 4;
614	} else {
615		ds = daystr;
616		dw = 3;
617	}
618
619	/*
620	 * Fill the lines with day of month or day of year (julian day)
621	 * line index: i, each line is one weekday. column index: j, each
622	 * column is one day number. print column index: k.
623	 */
624	for (i = 0; i != 7; i++) {
625		for (j = firstm + i, k = 0; j < last; j += 7, k += dw)
626			if (j >= first) {
627				if (jd_flag)
628					dt.d = j - jan1 + 1;
629				else
630					sdate(j, &dt);
631				memcpy(mlines->lines[i] + k,
632				       ds + dt.d * dw, dw);
633			} else
634				memcpy(mlines->lines[i] + k, "    ", dw);
635		mlines->lines[i][k] = '\0';
636
637	}
638
639	/* fill the weeknumbers */
640	if (flag_weeks) {
641		for (j = firstm, k = 0; j < last;  k += dw, j += 7)
642			if (j <= nswitch)
643				memset(mlines->weeks + k, ' ', dw);
644			else
645				memcpy(mlines->weeks + k,
646				    ds + week(j, &i)*dw, dw);
647		mlines->weeks[k] = '\0';
648	}
649}
650
651void
652mkmonthb(int y, int m, int jd_flag, struct monthlines *mlines)
653{
654
655	struct tm tm;		/* for strftime printing local names of
656				 * months */
657	date    dt;		/* handy date */
658	int     dw;		/* width of numbers */
659	int     first;		/* first day of month */
660	int     firsts;		/* sunday of first week of month */
661	int     i, j, k;	/* just indices */
662	int     jan1 = 0;	/* the first day of this year */
663	int     last;		/* the first day of next month */
664	char   *ds;		/* pointer to day strings (daystr or
665				 * jdaystr) */
666
667	/* Set ds (daystring) and dw (daywidth) according to the jd_flag */
668	if (jd_flag) {
669		ds = jdaystr;
670		dw = 4;
671	} else {
672		ds = daystr;
673		dw = 3;
674	}
675
676	/* Set name of month centered */
677	memset(&tm, 0, sizeof(tm));
678	tm.tm_mon = m;
679	strftime(mlines->name, sizeof(mlines->name), "%OB", &tm);
680	mlines->name[0] = toupper((unsigned char)mlines->name[0]);
681
682	/*
683	 * Set first and last to the day number of the first day of this
684	 * month and the first day of next month respectively. Set jan1 to
685	 * the day number of Jan 1st of this year.
686	 */
687	dt.y = y;
688	dt.m = m + 1;
689	dt.d = 1;
690	first = sndaysb(&dt);
691	if (m == 11) {
692		dt.y = y + 1;
693		dt.m = 1;
694		dt.d = 1;
695	} else {
696		dt.y = y;
697		dt.m = m + 2;
698		dt.d = 1;
699	}
700	last = sndaysb(&dt);
701
702	if (jd_flag) {
703		dt.y = y;
704		dt.m = 1;
705		dt.d = 1;
706		jan1 = sndaysb(&dt);
707	}
708
709	/*
710	 * Set firsts to the day number of sunday of the first week of
711	 * this month. (This might be in the last month)
712	 */
713	firsts = first - (weekday(first)+1) % 7;
714
715	/*
716	 * Fill the lines with day of month or day of year (Julian day)
717	 * line index: i, each line is one week. column index: j, each
718	 * column is one day number. print column index: k.
719	 */
720	for (i = 0; i != 6; i++) {
721		for (j = firsts + 7 * i, k = 0; j < last && k != dw * 7;
722		     j++, k += dw)
723			if (j >= first) {
724				if (jd_flag)
725					dt.d = j - jan1 + 1;
726				else
727					sdateb(j, &dt);
728				memcpy(mlines->lines[i] + k,
729				       ds + dt.d * dw, dw);
730			} else
731				memcpy(mlines->lines[i] + k, "    ", dw);
732		if (k == 0)
733			mlines->lines[i][1] = '\0';
734		else
735			mlines->lines[i][k] = '\0';
736	}
737}
738
739/* Put the local names of weekdays into the wds */
740void
741mkweekdays(struct weekdays *wds)
742{
743	int i;
744	struct tm tm;
745
746	memset(&tm, 0, sizeof(tm));
747
748	for (i = 0; i != 7; i++) {
749		tm.tm_wday = (i+1) % 7;
750		strftime(wds->names[i], 4, "%a", &tm);
751		wds->names[i][2] = ' ';
752		wds->names[i][3] = '\0';
753	}
754}
755
756/*
757 * Compute the day number of the first
758 * existing date after the first day in month.
759 * (the first day in month and even the month might not exist!)
760 */
761int
762firstday(int y, int m)
763{
764	date dt;
765	int nd;
766
767	dt.y = y;
768	dt.m = m;
769	dt.d = 1;
770	nd = sndays(&dt);
771	for (;;) {
772		sdate(nd, &dt);
773		if ((dt.m >= m && dt.y == y) || dt.y > y)
774			return (nd);
775		else
776			nd++;
777	}
778	/* NEVER REACHED */
779}
780
781/*
782 * Compute the number of days from date, obey the local switch from
783 * Julian to Gregorian if specified by the user.
784 */
785int
786sndays(struct date *d)
787{
788
789	if (nswitch != 0)
790		if (nswitch < ndaysj(d))
791			return (ndaysg(d));
792		else
793			return (ndaysj(d));
794	else
795		return ndaysg(d);
796}
797
798/*
799 * Compute the number of days from date, obey the switch from
800 * Julian to Gregorian as used by UK and her colonies.
801 */
802int
803sndaysb(struct date *d)
804{
805
806	if (nswitchb < ndaysj(d))
807		return (ndaysg(d));
808	else
809		return (ndaysj(d));
810}
811
812/* Inverse of sndays */
813struct date *
814sdate(int nd, struct date *d)
815{
816
817	if (nswitch < nd)
818		return (gdate(nd, d));
819	else
820		return (jdate(nd, d));
821}
822
823/* Inverse of sndaysb */
824struct date *
825sdateb(int nd, struct date *d)
826{
827
828	if (nswitchb < nd)
829		return (gdate(nd, d));
830	else
831		return (jdate(nd, d));
832}
833
834/* Center string t in string s of length w by putting enough leading blanks */
835char *
836center(char *s, char *t, int w)
837{
838	char blanks[80];
839
840	memset(blanks, ' ', sizeof(blanks));
841	sprintf(s, "%.*s%s", (int)(w - strlen(t)) / 2, blanks, t);
842	return (s);
843}
844