hush/coreutils/cal.c
2007-07-26 11:12:51 +00:00

348 lines
9.1 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Calendar implementation for busybox
*
* See original copyright at the end of this file
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/* BB_AUDIT SUSv3 compliant with -j and -y extensions (from util-linux). */
/* BB_AUDIT BUG: The output of 'cal -j 1752' is incorrect. The upstream
* BB_AUDIT BUG: version in util-linux seems to be broken as well. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/cal.html */
/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Major size reduction... over 50% (>1.5k) on i386.
*/
#include "libbb.h"
/* We often use "unsigned" intead of "int", it's easier to div on most CPUs */
#define THURSDAY 4 /* for reformation */
#define SATURDAY 6 /* 1 Jan 1 was a Saturday */
#define FIRST_MISSING_DAY 639787 /* 3 Sep 1752 */
#define NUMBER_MISSING_DAYS 11 /* 11 day correction */
#define MAXDAYS 42 /* max slots in a month array */
#define SPACE -1 /* used in day array */
static const unsigned char days_in_month[] = {
0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static const unsigned char sep1752[] = {
1, 2, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30
};
static unsigned julian;
/* leap year -- account for Gregorian reformation in 1752 */
static int leap_year(unsigned yr)
{
if (yr <= 1752)
return !(yr % 4);
return (!(yr % 4) && (yr % 100)) || !(yr % 400);
}
/* number of centuries since 1700, not inclusive */
#define centuries_since_1700(yr) \
((yr) > 1700 ? (yr) / 100 - 17 : 0)
/* number of centuries since 1700 whose modulo of 400 is 0 */
#define quad_centuries_since_1700(yr) \
((yr) > 1600 ? ((yr) - 1600) / 400 : 0)
/* number of leap years between year 1 and this year, not inclusive */
#define leap_years_since_year_1(yr) \
((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))
static void center(char *, unsigned, unsigned);
static void day_array(unsigned, unsigned, unsigned *);
static void trim_trailing_spaces_and_print(char *);
static void blank_string(char *buf, size_t buflen);
static char *build_row(char *p, unsigned *dp);
#define DAY_LEN 3 /* 3 spaces per day */
#define J_DAY_LEN (DAY_LEN + 1)
#define WEEK_LEN 20 /* 7 * 3 - one space at the end */
#define J_WEEK_LEN (WEEK_LEN + 7)
#define HEAD_SEP 2 /* spaces between day headings */
int cal_main(int argc, char **argv);
int cal_main(int argc, char **argv)
{
struct tm *local_time;
struct tm zero_tm;
time_t now;
unsigned month, year, flags, i;
char *month_names[12];
char day_headings[28]; /* 28 for julian, 21 for nonjulian */
char buf[40];
flags = getopt32(argc, argv, "jy");
julian = flags & 1;
month = 0;
argv += optind;
argc -= optind;
if (argc > 2) {
bb_show_usage();
}
if (!argc) {
time(&now);
local_time = localtime(&now);
year = local_time->tm_year + 1900;
if (!(flags & 2)) {
month = local_time->tm_mon + 1;
}
} else {
if (argc == 2) {
month = xatou_range(*argv++, 1, 12);
}
year = xatou_range(*argv, 1, 9999);
}
blank_string(day_headings, sizeof(day_headings) - 7 + 7*julian);
i = 0;
do {
zero_tm.tm_mon = i;
strftime(buf, sizeof(buf), "%B", &zero_tm);
month_names[i] = xstrdup(buf);
if (i < 7) {
zero_tm.tm_wday = i;
strftime(buf, sizeof(buf), "%a", &zero_tm);
strncpy(day_headings + i * (3+julian) + julian, buf, 2);
}
} while (++i < 12);
if (month) {
unsigned row, len, days[MAXDAYS];
unsigned *dp = days;
char lineout[30];
day_array(month, year, dp);
len = sprintf(lineout, "%s %d", month_names[month - 1], year);
printf("%*s%s\n%s\n",
((7*julian + WEEK_LEN) - len) / 2, "",
lineout, day_headings);
for (row = 0; row < 6; row++) {
build_row(lineout, dp)[0] = '\0';
dp += 7;
trim_trailing_spaces_and_print(lineout);
}
} else {
unsigned row, which_cal, week_len, days[12][MAXDAYS];
unsigned *dp;
char lineout[80];
sprintf(lineout, "%d", year);
center(lineout,
(WEEK_LEN * 3 + HEAD_SEP * 2)
+ julian * (J_WEEK_LEN * 2 + HEAD_SEP
- (WEEK_LEN * 3 + HEAD_SEP * 2)),
0);
puts("\n"); /* two \n's */
for (i = 0; i < 12; i++) {
day_array(i + 1, year, days[i]);
}
blank_string(lineout, sizeof(lineout));
week_len = WEEK_LEN + julian * (J_WEEK_LEN - WEEK_LEN);
for (month = 0; month < 12; month += 3-julian) {
center(month_names[month], week_len, HEAD_SEP);
if (!julian) {
center(month_names[month + 1], week_len, HEAD_SEP);
}
center(month_names[month + 2 - julian], week_len, 0);
printf("\n%s%*s%s", day_headings, HEAD_SEP, "", day_headings);
if (!julian) {
printf("%*s%s", HEAD_SEP, "", day_headings);
}
putchar('\n');
for (row = 0; row < (6*7); row += 7) {
for (which_cal = 0; which_cal < 3-julian; which_cal++) {
dp = days[month + which_cal] + row;
build_row(lineout + which_cal * (week_len + 2), dp);
}
/* blank_string took care of nul termination. */
trim_trailing_spaces_and_print(lineout);
}
}
}
fflush_stdout_and_exit(0);
}
/*
* day_array --
* Fill in an array of 42 integers with a calendar. Assume for a moment
* that you took the (maximum) 6 rows in a calendar and stretched them
* out end to end. You would have 42 numbers or spaces. This routine
* builds that array for any month from Jan. 1 through Dec. 9999.
*/
static void day_array(unsigned month, unsigned year, unsigned *days)
{
unsigned long temp;
unsigned i;
unsigned day, dw, dm;
memset(days, SPACE, MAXDAYS * sizeof(int));
if ((month == 9) && (year == 1752)) {
/* Assumes the Gregorian reformation eliminates
* 3 Sep. 1752 through 13 Sep. 1752.
*/
unsigned j_offset = julian * 244;
size_t oday = 0;
do {
days[oday+2] = sep1752[oday] + j_offset;
} while (++oday < sizeof(sep1752));
return;
}
/* day_in_year
* return the 1 based day number within the year
*/
day = 1;
if ((month > 2) && leap_year(year)) {
++day;
}
i = month;
while (i) {
day += days_in_month[--i];
}
/* day_in_week
* return the 0 based day number for any date from 1 Jan. 1 to
* 31 Dec. 9999. Assumes the Gregorian reformation eliminates
* 3 Sep. 1752 through 13 Sep. 1752. Returns Thursday for all
* missing days.
*/
temp = (long)(year - 1) * 365 + leap_years_since_year_1(year - 1) + day;
if (temp < FIRST_MISSING_DAY) {
dw = ((temp - 1 + SATURDAY) % 7);
} else {
dw = (((temp - 1 + SATURDAY) - NUMBER_MISSING_DAYS) % 7);
}
if (!julian) {
day = 1;
}
dm = days_in_month[month];
if ((month == 2) && leap_year(year)) {
++dm;
}
do {
days[dw++] = day++;
} while (--dm);
}
static void trim_trailing_spaces_and_print(char *s)
{
char *p = s;
while (*p) {
++p;
}
while (p != s) {
--p;
if (!(isspace)(*p)) { /* We want the function... not the inline. */
p[1] = '\0';
break;
}
}
puts(s);
}
static void center(char *str, unsigned len, unsigned separate)
{
unsigned n = strlen(str);
len -= n;
printf("%*s%*s", (len/2) + n, str, (len/2) + (len % 2) + separate, "");
}
static void blank_string(char *buf, size_t buflen)
{
memset(buf, ' ', buflen);
buf[buflen-1] = '\0';
}
static char *build_row(char *p, unsigned *dp)
{
unsigned col, val, day;
memset(p, ' ', (julian + DAY_LEN) * 7);
col = 0;
do {
day = *dp++;
if (day != SPACE) {
if (julian) {
++p;
if (day >= 100) {
*p = '0';
p[-1] = (day / 100) + '0';
day %= 100;
}
}
val = day / 10;
if (val > 0) {
*p = val + '0';
}
*++p = day % 10 + '0';
p += 2;
} else {
p += DAY_LEN + julian;
}
} while (++col < 7);
return p;
}
/*
* Copyright (c) 1989, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kim Letkeman.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/