minix: lib/ansi/gmtime.c Source File

00001 /*
00002  * gmtime - convert the calendar time into broken down time
00003  */
00004 /* $Header: /opt/proj/minix/cvsroot/src/lib/ansi/gmtime.c,v 1.1.1.1 2005/04/21 14:56:05 beng Exp $ */
00005 
00006 #include        <time.h>
00007 #include        <limits.h>
00008 #include        "loc_time.h"
00009 
00010 struct tm *
00011 gmtime(register const time_t *timer)
00012 {
00013         static struct tm br_time;
00014         register struct tm *timep = &br_time;
00015         time_t time = *timer;
00016         register unsigned long dayclock, dayno;
00017         int year = EPOCH_YR;
00018 
00019         dayclock = (unsigned long)time % SECS_DAY;
00020         dayno = (unsigned long)time / SECS_DAY;
00021 
00022         timep->tm_sec = dayclock % 60;
00023         timep->tm_min = (dayclock % 3600) / 60;
00024         timep->tm_hour = dayclock / 3600;
00025         timep->tm_wday = (dayno + 4) % 7;       /* day 0 was a thursday */
00026         while (dayno >= YEARSIZE(year)) {
00027                 dayno -= YEARSIZE(year);
00028                 year++;
00029         }
00030         timep->tm_year = year - YEAR0;
00031         timep->tm_yday = dayno;
00032         timep->tm_mon = 0;
00033         while (dayno >= _ytab[LEAPYEAR(year)][timep->tm_mon]) {
00034                 dayno -= _ytab[LEAPYEAR(year)][timep->tm_mon];
00035                 timep->tm_mon++;
00036         }
00037         timep->tm_mday = dayno + 1;
00038         timep->tm_isdst = 0;
00039 
00040         return timep;
00041 }