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Various cal(1) improvements 

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
View File

@ -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;
}