1/* vi: set sw=4 ts=4: */
2/*
3 * Calendar implementation for busybox
4 *
5 * See original copyright at the end of this file
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10/* BB_AUDIT SUSv3 compliant with -j and -y extensions (from util-linux). */
11/* BB_AUDIT BUG: The output of 'cal -j 1752' is incorrect.  The upstream
12 * BB_AUDIT BUG: version in util-linux seems to be broken as well. */
13/* http://www.opengroup.org/onlinepubs/007904975/utilities/cal.html */
14
15/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
16 *
17 * Major size reduction... over 50% (>1.5k) on i386.
18 */
19#include "libbb.h"
20#include "unicode.h"
21
22/* We often use "unsigned" intead of "int", it's easier to div on most CPUs */
23
24#define	THURSDAY		4		/* for reformation */
25#define	SATURDAY		6		/* 1 Jan 1 was a Saturday */
26
27#define	FIRST_MISSING_DAY	639787		/* 3 Sep 1752 */
28#define	NUMBER_MISSING_DAYS	11		/* 11 day correction */
29
30#define	MAXDAYS			42		/* max slots in a month array */
31#define	SPACE			-1		/* used in day array */
32
33static const unsigned char days_in_month[] ALIGN1 = {
34	0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
35};
36
37static const unsigned char sep1752[] ALIGN1 = {
38		 1,	2,	14,	15,	16,
39	17,	18,	19,	20,	21,	22,	23,
40	24,	25,	26,	27,	28,	29,	30
41};
42
43/* Set to 0 or 1 in main */
44#define julian ((unsigned)option_mask32)
45
46/* leap year -- account for Gregorian reformation in 1752 */
47static int leap_year(unsigned yr)
48{
49	if (yr <= 1752)
50		return !(yr % 4);
51	return (!(yr % 4) && (yr % 100)) || !(yr % 400);
52}
53
54/* number of centuries since 1700, not inclusive */
55#define	centuries_since_1700(yr) \
56	((yr) > 1700 ? (yr) / 100 - 17 : 0)
57
58/* number of centuries since 1700 whose modulo of 400 is 0 */
59#define	quad_centuries_since_1700(yr) \
60	((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
61
62/* number of leap years between year 1 and this year, not inclusive */
63#define	leap_years_since_year_1(yr) \
64	((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
65
66static void center(char *, unsigned, unsigned);
67static void day_array(unsigned, unsigned, unsigned *);
68static void trim_trailing_spaces_and_print(char *);
69
70static void blank_string(char *buf, size_t buflen);
71static char *build_row(char *p, unsigned *dp);
72
73#define	DAY_LEN		3		/* 3 spaces per day */
74#define	J_DAY_LEN	(DAY_LEN + 1)
75#define	WEEK_LEN	20		/* 7 * 3 - one space at the end */
76#define	J_WEEK_LEN	(WEEK_LEN + 7)
77#define	HEAD_SEP	2		/* spaces between day headings */
78
79int cal_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
80int cal_main(int argc UNUSED_PARAM, char **argv)
81{
82	struct tm zero_tm;
83	time_t now;
84	unsigned month, year, flags, i;
85	char *month_names[12];
86	/* normal heading: */
87	/* "Su Mo Tu We Th Fr Sa" */
88	/* -j heading: */
89	/* " Su  Mo  Tu  We  Th  Fr  Sa" */
90	char day_headings[ENABLE_UNICODE_SUPPORT ? 28 * 6 : 28];
91	IF_UNICODE_SUPPORT(char *hp = day_headings;)
92	char buf[40];
93
94	init_unicode();
95
96	flags = getopt32(argv, "jy");
97	/* This sets julian = flags & 1: */
98	option_mask32 &= 1;
99	month = 0;
100	argv += optind;
101
102	if (!argv[0]) {
103		struct tm *ptm;
104
105		time(&now);
106		ptm = localtime(&now);
107		year = ptm->tm_year + 1900;
108		if (!(flags & 2)) { /* no -y */
109			month = ptm->tm_mon + 1;
110		}
111	} else {
112		if (argv[1]) {
113			if (argv[2]) {
114				bb_show_usage();
115			}
116			if (!(flags & 2)) { /* no -y */
117				month = xatou_range(*argv, 1, 12);
118			}
119			argv++;
120		}
121		year = xatou_range(*argv, 1, 9999);
122	}
123
124	blank_string(day_headings, sizeof(day_headings) - 7 + 7*julian);
125
126	i = 0;
127	do {
128		zero_tm.tm_mon = i;
129		/* full month name according to locale */
130		strftime(buf, sizeof(buf), "%B", &zero_tm);
131		month_names[i] = xstrdup(buf);
132
133		if (i < 7) {
134			zero_tm.tm_wday = i;
135			/* abbreviated weekday name according to locale */
136			strftime(buf, sizeof(buf), "%a", &zero_tm);
137#if ENABLE_UNICODE_SUPPORT
138			if (julian)
139				*hp++ = ' ';
140			{
141				char *two_wchars = unicode_conv_to_printable_fixedwidth(/*NULL,*/ buf, 2);
142				strcpy(hp, two_wchars);
143				free(two_wchars);
144			}
145			hp += strlen(hp);
146			*hp++ = ' ';
147#else
148			strncpy(day_headings + i * (3+julian) + julian, buf, 2);
149#endif
150		}
151	} while (++i < 12);
152	IF_UNICODE_SUPPORT(hp[-1] = '\0';)
153
154	if (month) {
155		unsigned row, len, days[MAXDAYS];
156		unsigned *dp = days;
157		char lineout[30];
158
159		day_array(month, year, dp);
160		len = sprintf(lineout, "%s %d", month_names[month - 1], year);
161		printf("%*s%s\n%s\n",
162			   ((7*julian + WEEK_LEN) - len) / 2, "",
163			   lineout, day_headings);
164		for (row = 0; row < 6; row++) {
165			build_row(lineout, dp)[0] = '\0';
166			dp += 7;
167			trim_trailing_spaces_and_print(lineout);
168		}
169	} else {
170		unsigned row, which_cal, week_len, days[12][MAXDAYS];
171		unsigned *dp;
172		char lineout[80];
173
174		sprintf(lineout, "%u", year);
175		center(lineout,
176			   (WEEK_LEN * 3 + HEAD_SEP * 2)
177			   + julian * (J_WEEK_LEN * 2 + HEAD_SEP
178						   - (WEEK_LEN * 3 + HEAD_SEP * 2)),
179			   0);
180		puts("\n");		/* two \n's */
181		for (i = 0; i < 12; i++) {
182			day_array(i + 1, year, days[i]);
183		}
184		blank_string(lineout, sizeof(lineout));
185		week_len = WEEK_LEN + julian * (J_WEEK_LEN - WEEK_LEN);
186		for (month = 0; month < 12; month += 3-julian) {
187			center(month_names[month], week_len, HEAD_SEP);
188			if (!julian) {
189				center(month_names[month + 1], week_len, HEAD_SEP);
190			}
191			center(month_names[month + 2 - julian], week_len, 0);
192			printf("\n%s%*s%s", day_headings, HEAD_SEP, "", day_headings);
193			if (!julian) {
194				printf("%*s%s", HEAD_SEP, "", day_headings);
195			}
196			bb_putchar('\n');
197			for (row = 0; row < (6*7); row += 7) {
198				for (which_cal = 0; which_cal < 3-julian; which_cal++) {
199					dp = days[month + which_cal] + row;
200					build_row(lineout + which_cal * (week_len + 2), dp);
201				}
202				/* blank_string took care of nul termination. */
203				trim_trailing_spaces_and_print(lineout);
204			}
205		}
206	}
207
208	fflush_stdout_and_exit(EXIT_SUCCESS);
209}
210
211/*
212 * day_array --
213 *	Fill in an array of 42 integers with a calendar.  Assume for a moment
214 *	that you took the (maximum) 6 rows in a calendar and stretched them
215 *	out end to end.  You would have 42 numbers or spaces.  This routine
216 *	builds that array for any month from Jan. 1 through Dec. 9999.
217 */
218static void day_array(unsigned month, unsigned year, unsigned *days)
219{
220	unsigned long temp;
221	unsigned i;
222	unsigned day, dw, dm;
223
224	memset(days, SPACE, MAXDAYS * sizeof(int));
225
226	if ((month == 9) && (year == 1752)) {
227		/* Assumes the Gregorian reformation eliminates
228		 * 3 Sep. 1752 through 13 Sep. 1752.
229		 */
230		unsigned j_offset = julian * 244;
231		size_t oday = 0;
232
233		do {
234			days[oday+2] = sep1752[oday] + j_offset;
235		} while (++oday < sizeof(sep1752));
236
237		return;
238	}
239
240	/* day_in_year
241	 * return the 1 based day number within the year
242	 */
243	day = 1;
244	if ((month > 2) && leap_year(year)) {
245		++day;
246	}
247
248	i = month;
249	while (i) {
250		day += days_in_month[--i];
251	}
252
253	/* day_in_week
254	 * return the 0 based day number for any date from 1 Jan. 1 to
255	 * 31 Dec. 9999.  Assumes the Gregorian reformation eliminates
256	 * 3 Sep. 1752 through 13 Sep. 1752.  Returns Thursday for all
257	 * missing days.
258	 */
259	temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1) + day;
260	if (temp < FIRST_MISSING_DAY) {
261		dw = ((temp - 1 + SATURDAY) % 7);
262	} else {
263		dw = (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
264	}
265
266	if (!julian) {
267		day = 1;
268	}
269
270	dm = days_in_month[month];
271	if ((month == 2) && leap_year(year)) {
272		++dm;
273	}
274
275	do {
276		days[dw++] = day++;
277	} while (--dm);
278}
279
280static void trim_trailing_spaces_and_print(char *s)
281{
282	char *p = s;
283
284	while (*p) {
285		++p;
286	}
287	while (p != s) {
288		--p;
289		if (!isspace(*p)) {
290			p[1] = '\0';
291			break;
292		}
293	}
294
295	puts(s);
296}
297
298static void center(char *str, unsigned len, unsigned separate)
299{
300	unsigned n = strlen(str);
301	len -= n;
302	printf("%*s%*s", (len/2) + n, str, (len/2) + (len % 2) + separate, "");
303}
304
305static void blank_string(char *buf, size_t buflen)
306{
307	memset(buf, ' ', buflen);
308	buf[buflen-1] = '\0';
309}
310
311static char *build_row(char *p, unsigned *dp)
312{
313	unsigned col, val, day;
314
315	memset(p, ' ', (julian + DAY_LEN) * 7);
316
317	col = 0;
318	do {
319		day = *dp++;
320		if (day != SPACE) {
321			if (julian) {
322				++p;
323				if (day >= 100) {
324					*p = '0';
325					p[-1] = (day / 100) + '0';
326					day %= 100;
327				}
328			}
329			val = day / 10;
330			if (val > 0) {
331				*p = val + '0';
332			}
333			*++p = day % 10 + '0';
334			p += 2;
335		} else {
336			p += DAY_LEN + julian;
337		}
338	} while (++col < 7);
339
340	return p;
341}
342
343/*
344 * Copyright (c) 1989, 1993, 1994
345 *	The Regents of the University of California.  All rights reserved.
346 *
347 * This code is derived from software contributed to Berkeley by
348 * Kim Letkeman.
349 *
350 * Redistribution and use in source and binary forms, with or without
351 * modification, are permitted provided that the following conditions
352 * are met:
353 * 1. Redistributions of source code must retain the above copyright
354 *    notice, this list of conditions and the following disclaimer.
355 * 2. Redistributions in binary form must reproduce the above copyright
356 *    notice, this list of conditions and the following disclaimer in the
357 *    documentation and/or other materials provided with the distribution.
358 * 3. Neither the name of the University nor the names of its contributors
359 *    may be used to endorse or promote products derived from this software
360 *    without specific prior written permission.
361 *
362 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
363 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
364 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
365 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
366 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
367 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
368 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
369 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
370 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
371 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
372 * SUCH DAMAGE.
373 */
374