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Various cal(1) improvements

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1) No limit on number of months (removed MONTHMAX)
2) Strings printed to stdout rather than copied to an internal buffer
3) Rewritten date calculation algorithms
This commit is contained in:
Greg Reagle 2015-01-02 13:12:59 +00:00 committed by sin
parent 6faeb36e14
commit c6f1e8aa20
2 changed files with 87 additions and 84 deletions
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1
LICENSE
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@ -54,3 +54,4 @@ Authors/contributors include:
© 2014 Ari Malinen <ari.malinen@gmail.com>
© 2014 Brandon Mulcahy <brandon@jangler.info>
© 2014 Adria Garriga <rhaps0dy@installgentoo.com>
© 2014 Greg Reagle <greg.reagle@umbc.edu>

170
cal.c
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@ -5,87 +5,6 @@
#include "util.h"
#define MONTHMAX 100
static void drawcal(int, int, int, int, int, int);
static int dayofweek(int, int, int, int);
static int isleap(int);
static void usage(void);
static void
drawcal(int year, int month, int day, int ncols, int nmons, int fday)
{
char str[21];
int count[MONTHMAX];
int d, i, r, j;
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;
char *days[] = { "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa", };
if (!ncols)
ncols = nmons;
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;
snprintf(str, sizeof(str), "%s %d", smon[cur], yoff);
printf("%-20s ", str);
count[i] = 1;
}
printf("\n");
for (i = 0; i < last; i++) {
for (j = fday; j < LEN(days); j++)
printf("%s ", days[j]);
for (j = 0; j < fday; j++)
printf("%s ", days[j]);
printf(" ");
}
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(yoff, cur, 1, fday);
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 int
dayofweek(int year, int month, int day, int fday)
{
static int t[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
day += 7 - fday;
year -= month < 2;
return (year + year / 4 - year / 100 + year / 400 + t[month] + day) % 7;
}
static int
isleap(int year)
{
@ -96,6 +15,90 @@ isleap(int year)
return (year % 4 == 0);
}
static int
monthlength(int year, int month)
{
int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
return (month==1 && isleap(year)) ? 29 : mdays[month];
}
/* From http://www.tondering.dk/claus/cal/chrweek.php#calcdow */
static int
dayofweek(int year, int month, int dom)
{
int m, y, a;
month += 1; /* in this formula, 1 <= month <= 12 */
a = (14 - month) / 12;
y = year - a;
m = month + 12*a - 2;
return (dom + y + y/4 - y/100 + y/400 +((31*m)/12)) % 7;
}
static void
printgrid(int year, int month, int fday, int line)
{
int dom, offset, d=0;
offset = dayofweek(year, month, 1) - fday;
if (offset < 0)
offset += 7;
if (line==1) {
for ( ; d < offset; ++d)
printf(" ");
dom = 1;
} else {
dom = 8-offset + (line-2)*7;
}
for ( ; d < 7 && dom <= monthlength(year, month); ++d, ++dom)
printf("%2d ", dom);
for ( ; d < 7; ++d)
printf(" ");
}
static void
drawcal(int year, int month, int day, int ncols, int nmons, int fday)
{
char *smon[] = {" January", " February", " March", " April",
" May", " June", " July", " August",
"September", " October", " November", " December" };
char *days[] = { "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa", };
int m, n, col, cur_year, cur_month, line, dow;
for (m = 0; m < nmons; ) {
n = m;
for (col = 0; m < nmons && col < ncols; ++col, ++m) {
cur_year = year + m/12;
cur_month = month + m%12;
if (cur_month > 11) {
cur_month -= 12;
cur_year += 1;
}
printf(" %s %d ", smon[cur_month], cur_year);
printf(" ");
}
printf("\n");
for (col = 0, m = n; m < nmons && col < ncols; ++col, ++m) {
for (dow = fday; dow < (fday+7); ++dow)
printf("%s ", days[dow%7]);
printf(" ");
}
printf("\n");
for (line=1; line<=6; ++line) {
for (col=0, m=n; m<nmons && col<ncols; ++col, ++m) {
cur_year = year + m/12;
cur_month = month + m%12;
if (cur_month > 11) {
cur_month -= 12;
cur_year += 1;
}
printgrid(cur_year, cur_month, fday, line);
printf(" ");
}
printf("\n");
}
}
}
static void
usage(void)
{
@ -172,12 +175,11 @@ main(int argc, char *argv[])
usage();
}
if (ncols < 0 || month < 1 || month > 12 || nmons < 1 \
|| nmons > MONTHMAX || fday < 0 || fday > 6) {
if (ncols < 0 || month < 1 || month > 12 || nmons < 1 || fday < 0 || fday > 6) {
usage();
}
drawcal(year, month, day, ncols, nmons, fday);
drawcal(year, month-1, day, ncols, nmons, fday);
return 0;
}