/*
* linux/fs/msdos/misc.c
*
* Written 1992,1993 by Werner Almesberger
*/
/* Linear day numbers of the respective 1sts in non-leap years. */
static int day_n[] = { 0,31,59,90,120,151,181,212,243,273,304,334,0,0,0,0 };
/* JanFebMarApr May Jun Jul Aug Sep Oct Nov Dec */
/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
int date_dos2unix(unsigned short time,unsigned short date)
{
int month, year, secs;
month = ((date >> 5) & 15)-1;
year = date >> 9;
secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400*
((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
month < 2 ? 1 : 0)+3653);
/* days since 1.1.70 plus 80's leap day */
return secs;
}
/* Convert linear UNIX date to a MS-DOS time/date pair. */
void date_unix2dos(int unix_date,unsigned short *time,
unsigned short *date)
{
int day, year, nl_day, month;
*time = (unix_date % 60)/2+(((unix_date/60) % 60) << 5)+
(((unix_date/3600) % 24) << 11);
day = unix_date/86400-3652;
year = day/365;
if ((year+3)/4+365*year > day) year--;
day -= (year+3)/4+365*year;
if (day == 59 && !(year & 3)) {
nl_day = day;
month = 2;
} else {
nl_day = (year & 3) || day <= 59 ? day : day-1;
for (month = 0; month < 12; month++)
if (day_n[month] > nl_day) break;
}
*date = nl_day-day_n[month-1]+1+(month << 5)+(year << 9);
}
/* Convert yapp format 8 hex characters into Unix time */
int yapp2unix(char * ytime)
{
int i;
unsigned short time, date;
if (strlen(ytime) != 8) return 0;
for(i = 0; i < 8; i++) if (! isxdigit(ytime[i])) return 0;
time = strtoul(ytime+4, (char **)NULL, 16);
ytime[4]=0;
date = strtoul(ytime, (char **)NULL, 16);
return(date_dos2unix(time, date));
}
/* Convert unix time to 8 character yapp hex format */
void unix2yapp(int unix_date, char * buffer)
{
unsigned short time, date;
date_unix2dos(unix_date, &time, &date);
sprintf(buffer, "%04X%04X", date, time);
}
