static void weekofyear(int year,int month,int day,
int *rtn_year,int *rtn_week,int *rtn_day)
{
int firstday=dayofweek(year,0,0);
int doy=dayofyear(year,month,day);
if(firstday>=5)
{
firstday-=7;
if(firstday+doy<0)
{
weekofyear(year-1,12-1,31-1,
rtn_year,rtn_week,rtn_day);
*rtn_day+=doy+1;
return;
}
}
if(firstday!=4 && (firstday+doy)/7>=52)
{
*rtn_year=year+1;
*rtn_week=0;
*rtn_day=(firstday+doy)-52*7;
}
else
{
*rtn_year = year;
*rtn_week = (firstday+doy)/7;
*rtn_day = (firstday+doy)%7;
}
}
int weekofyear(struct tm localtime)
{
int wDayOnFirst;
int wKYear;
wDayOnFirst = localtime.tm_wday - (localtime.tm_yday%7);
if(wDayOnFirst<0) wDayOnFirst += 7;
wKYear = 1 + localtime.tm_yday / 7;
if(wDayOnFirst>3) wKYear++;
if(localtime.tm_wday==0) wKYear--;
if(wKYear==0)
{
struct tm last = localtime;
last.tm_year--;
last.tm_wday--;
if(last.tm_wday<0) last.tm_wday += 7;
if((last.tm_year%4)==0) last.tm_yday = 365;
else last.tm_yday = 364;
wKYear = weekofyear(last);
}
return wKYear;
}
void printweek(char *buf,const char *date)
{
int year;
int month;
int day;
int yr;
int wkn;
int dny;
buf[0]=0; if(!date[0]) return;
numericdate(date,&year,&month,&day);
weekofyear(year,month,day,&yr,&wkn,&dny);
sprintf(buf,"%d",wkn+1);
}
void printdate1w(char *buf,const char *date)
{
int year;
int month;
int day;
int dow;
int yr;
int wkn;
int dny;
buf[0]=0; if(!date[0]) return;
numericdate(date,&year,&month,&day);
dow=dayofweek(year,month,day);
weekofyear(year,month,day,&yr,&wkn,&dny);
sprintf(buf,"%s %s %d wk%d",days[dow],months[month],day+1,wkn+1);
}
