sbase/cal.c

148 lines
2.9 KiB
C

/* See LICENSE file for copyright and license details. */
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "util.h"
#define MONTHMAX 100
static void drawcal(int, int, int, int, int);
static int dayofweek(int, int, int);
static bool isleap(int);
static void usage(void);
static void
drawcal(int year, int month, int day, int ncols, int nmons)
{
char str[21];
int count[MONTHMAX];
int d, i, r;
int moff, yoff, cur, last, ndays, day1;
char *smon[]= {
" January", " February", " March",
" April", " May", " June",
" July", " August", " September",
" October", " November", " December" };
int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
int row = 0;
while (nmons > 0) {
last = MIN(nmons, ncols);
for (i = 0; i < last; i++) {
moff = month + ncols * row + i - 1;
cur = moff % 12;
yoff = year + moff / 12;
sprintf(str, "%s %d", smon[cur], yoff);
printf("%-20s ", str);
count[i] = 1;
}
printf("\n");
for (i = 0; i < last; i++)
printf("Su M Tu W Th F Sa ");
printf("\n");
for (r = 0; r < 6; r++) {
for (i = 0; i < last; i++) {
moff = month + ncols * row + i - 1;
cur = moff % 12;
yoff = year + moff / 12;
ndays = mdays[cur] + ((cur == 1) & isleap(yoff));
day1 = dayofweek(year, cur, 1);
for (d = 0; d < 7; d++)
if ((r || d >= day1) && count[i] <= ndays)
printf("%2d ", count[i]++);
else
printf(" ");
printf(" ");
}
printf("\n");
}
nmons -= ncols;
row++;
}
}
static void
defaults(int *year, int *month, int *day, int *ncols, int *nmons)
{
time_t now;
struct tm *ltime;
now = time(NULL);
ltime = localtime(&now);
*year = ltime->tm_year + 1900;
*month = ltime->tm_mon + 1;
*day = ltime->tm_mday;
*ncols = 3;
*nmons = 1;
}
static int
dayofweek(int year, int month, int day)
{
int a, y, m;
month++;
a = (14 - month) / 12;
y = year + 4800 - a;
m = month + 12 * a -3;
return (day + (153 * m + 2) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 32045 + 1) % 7;
}
static bool
isleap(int year)
{
bool leap = false;
if (year % 4 == 0) leap = true;
if (year % 100 == 0) leap = false;
if (year % 400 == 0) leap = true;
return leap;
}
static void
usage(void)
{
eprintf("usage: %s [-c columns] [-m month] [-n number] [-y year]\n", argv0);
exit(1);
}
int
main(int argc, char *argv[])
{
int year, month, day, ncols, nmons;
defaults(&year, &month, &day, &ncols, &nmons);
ARGBEGIN {
case 'c':
ncols = (int) estrtol(EARGF(usage()), 0);
break;
case 'm':
month = (int) estrtol(EARGF(usage()), 0);
break;
case 'n':
nmons = (int) estrtol(EARGF(usage()), 0);
break;
case 'y':
year = (int) estrtol(EARGF(usage()), 0);
break;
default:
usage();
} ARGEND;
if (ncols < 0 || ncols > MONTHMAX || month < 1 || month > 12 || nmons < 1 || year > 9999)
usage();
drawcal(year, month, day, ncols, nmons);
exit(0);
}