41 lines
1 KiB
C
41 lines
1 KiB
C
/* $Header$ */
|
|
#include <time.h>
|
|
|
|
static int monthsize[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
|
|
|
|
#define SECS_DAY (24*60L*60L)
|
|
#define LEAPYEAR(year) (!((year) % 4) && (((year) % 100) || !((year) % 400)))
|
|
#define YEARSIZE(year) (LEAPYEAR(year) ? 366 : 365)
|
|
|
|
struct tm *
|
|
gmtime(clock)
|
|
long *clock;
|
|
{
|
|
long cl = *clock;
|
|
long dayclock, dayno;
|
|
static struct tm tm_buf;
|
|
register struct tm *pbuf = &tm_buf;
|
|
register int *months = monthsize;
|
|
int year = 1970;
|
|
|
|
dayclock = cl % SECS_DAY;
|
|
dayno = cl / SECS_DAY;
|
|
|
|
pbuf->tm_sec = dayclock % 60;
|
|
pbuf->tm_min = (dayclock % 3600) / 60;
|
|
pbuf->tm_hour = dayclock / 3600;
|
|
pbuf->tm_wday = (dayno + 4) % 7; /* day 0 was a thursday */
|
|
while (dayno >= YEARSIZE(year)) {
|
|
dayno -= YEARSIZE(year);
|
|
year++;
|
|
}
|
|
pbuf->tm_year = year - 1900;
|
|
pbuf->tm_yday = dayno;
|
|
pbuf->tm_isdst = 0;
|
|
if (YEARSIZE(year) == 366) monthsize[1] = 29;
|
|
while (dayno - *months >= 0) dayno -= *months++;
|
|
pbuf->tm_mday = dayno + 1;
|
|
pbuf->tm_mon = months - monthsize;
|
|
monthsize[1] = 28;
|
|
return pbuf;
|
|
}
|