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/*
* wcal - ISO weekly calendar
*
* To the extent possible under law, Leah Neukirchen <leah@vuxu.org>
* has waived all copyright and related or neighboring rights to this work.
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* -1 show current month (default)
* -3 show three months
* -y show whole year
* -c show current week only
* -i print infinite calendar
* -d YYYY-MM-DD different value for today
*/
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
int flag1, flag3, flagc, flagC, flagi, flagy;
const char monthname[13][4] = {
" ",
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
/* all args are 1-indexed */
long
ymd2jd(int year, int month, int day)
{
month--;
if (month >= 12 || month < 0) {
int adj = month / 12;
month %= 12;
if (month < 0) {
adj--;
month += 12;
}
year += adj;
}
month++;
if (month < 3) {
year--;
month += 12;
}
year += 4800;
return day + (153*(month-3)+2)/5 +
365*year + year/4 - year/100 + year/400 - 32045;
}
/* Mon = 1, Sun = 7 */
void
jd2ymdwi(long jd, int *year, int *month, int *day, int *wday, int *isoweek)
{
int _;
long e = 4*(jd+1401+(4*jd+274277)/146097*3/4-38) + 3;
long h = e%1461/4*5 + 2;
*day = h%153/5 + 1;
int m = *month = (h/153+2)%12 + 1;
int y = *year = e/1461 - 4716 + (14-m)/12;
int w = *wday = jd%7 + 1;
int yday = jd - ymd2jd(y, 1, 1) + 1;
*isoweek = (yday - w + 10) / 7;
if (*isoweek < 1)
jd2ymdwi(ymd2jd(y - 1, 12, 31), &_, &_, &_, &_, isoweek);
else if (*isoweek == 53 &&
ymd2jd(y+1, 1, 1) + (7 - (y+y/4-y/100+y/400+3)%7 - 4) <= jd)
*isoweek = 1;
}
void
parse_isodate(char *optarg, int *y, int *m, int *d)
{
*m = *d = 1;
if (isdigit(optarg[0]) &&
isdigit(optarg[1]) &&
isdigit(optarg[2]) &&
isdigit(optarg[3]) &&
(!optarg[4] || optarg[4] == '-')) {
*y = atoi(optarg);
if (!optarg[4]) {
flagy = 1;
} else if (isdigit(optarg[5]) && isdigit(optarg[6]) &&
(!optarg[7] || optarg[7] == '-')) {
*m = atoi(optarg+5);
if (isdigit(optarg[8]) && isdigit(optarg[9]) &&
(!optarg[10] || optarg[10] == '-'))
*d = atoi(optarg+8);
}
}
}
int
main(int argc, char *argv[])
{
time_t now = time(0);
struct tm *tm = localtime(&now);
int y = tm->tm_year + 1900;
int m = tm->tm_mon + 1;
int d = tm->tm_mday;
int w;
int i;
int c;
while ((c = getopt(argc, argv, "13cCid:y")) != -1)
switch (c) {
case '1': flag1 = 1; break;
case '3': flag3 = 1; break;
case 'c': flagc = 1; break;
case 'C': flagC = 1; break;
case 'y': flagy = 1; break;
case 'i': flagi = 1; break;
case 'd': parse_isodate(optarg, &y, &m, &d); break;
}
long today = ymd2jd(y, m, d);
int max_weeks = 1;
int max_months = 0;
if (flagc) {
max_weeks = 1;
} else if (flag3) {
d = 1; m--; max_weeks = 14;
} else if (flagy) {
d = 1; m = 1; max_months = 12; max_weeks = 53;
} else if (flagi) {
d = 1;
} else { /* flag1 is default */
d = 1; max_months = 1; max_weeks = 6;
}
long jd = ymd2jd(y, m, d);
jd2ymdwi(jd, &y, &m, &d, &w, &i);
jd -= (w - 1); // skip back to last monday.
jd2ymdwi(jd, &y, &m, &d, &w, &i);
int color = isatty(1) || flagC;
printf(" %sMo Tu We Th Fr Sa Su%s\n",
color ? "\e[4m" : "",
color ? "\e[0m" : "");
for (int weeks = 0, months = 0;
flagi || (max_months && months < max_months) || (weeks < max_weeks);
weeks++) {
printf("%02d ", i);
int ey, em, ed, ew, ei;
jd2ymdwi(jd + 6, &ey, &em, &ed, &ew, &ei); /* end of week */
if (ed <= 7 || weeks == 0) {
printf("%s ", monthname[em]);
months++;
} else if ((em == 1 && ed <= 14) || weeks == 1) {
printf("%04d", ey);
} else {
printf(" ");
}
do {
printf(" %s%2d%s",
color && (jd == today) ? "\e[7m" : "",
d,
color && (jd == today) ? "\e[0m" : "");
jd++;
jd2ymdwi(jd, &y, &m, &d, &w, &i);
} while (w != 1);
printf("\n");
}
}
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