nuclear@36: #include <stdio.h>
nuclear@36: #include "time.h"
nuclear@36: 
nuclear@36: #define MINSEC		60
nuclear@36: #define HOURSEC		(60 * MINSEC)
nuclear@36: #define DAYSEC		(24 * HOURSEC)
nuclear@36: 
nuclear@36: static int is_leap_year(int yr);
nuclear@36: 
nuclear@36: 
nuclear@36: static char *wday[] = {
nuclear@36: 	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
nuclear@36: };
nuclear@36: static char *mon[] = {
nuclear@36: 	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
nuclear@36: 	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
nuclear@36: };
nuclear@36: 
nuclear@36: 
nuclear@36: char *asctime(struct tm *tm)
nuclear@36: {
nuclear@36: 	static char buf[64];
nuclear@36: 
nuclear@36: 	sprintf(buf, "%s %s %d %02d:%02d:%02d %d\n", wday[tm->tm_wday],
nuclear@36: 			mon[tm->tm_mon], tm->tm_mday, tm->tm_hour, tm->tm_min,
nuclear@36: 			tm->tm_sec, tm->tm_year + 1900);
nuclear@36: 	return buf;
nuclear@36: }
nuclear@36: 
nuclear@36: time_t mktime(struct tm *tm)
nuclear@36: {
nuclear@36: 	int i, num_years = tm->tm_year - 70;
nuclear@36: 	int year = 1970;
nuclear@36: 	int days = day_of_year(tm->tm_year + 1900, tm->tm_mon, tm->tm_mday - 1);
nuclear@36: 
nuclear@36: 	for(i=0; i<num_years; i++) {
nuclear@36: 		days += is_leap_year(year++) ? 366 : 365;
nuclear@36: 	}
nuclear@36: 
nuclear@36: 	return (time_t)days * DAYSEC + tm->tm_hour * HOURSEC +
nuclear@36: 		tm->tm_min * MINSEC + tm->tm_sec;
nuclear@36: }
nuclear@36: 
nuclear@36: int day_of_year(int year, int mon, int day)
nuclear@36: {
nuclear@36: 	static int commdays[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
nuclear@36: 	static int leapdays[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
nuclear@36: 	int *mdays, i, yday;
nuclear@36: 
nuclear@36: 	mdays = is_leap_year(year) ? leapdays : commdays;
nuclear@36: 
nuclear@36: 	yday = day;
nuclear@36: 	for(i=0; i<mon; i++) {
nuclear@36: 		yday += mdays[i];
nuclear@36: 	}
nuclear@36: 	return yday;
nuclear@36: }
nuclear@36: 
nuclear@36: static int is_leap_year(int yr)
nuclear@36: {
nuclear@36: 	/* exceptions first */
nuclear@36: 	if(yr % 400 == 0) {
nuclear@36: 		return 1;
nuclear@36: 	}
nuclear@36: 	if(yr % 100 == 0) {
nuclear@36: 		return 0;
nuclear@36: 	}
nuclear@36: 	/* standard case */
nuclear@36: 	return yr % 4 == 0;
nuclear@36: }