//  calend.h
//
//  by John D. de Boer


enum { JulianCalendar,GregorianCalendar,HebrewCalendar };

typedef struct {
bool  good;     //  validity of returned contents
short calend;   //  Julian, Gregorian or Hebrew 
long  jd,       //  Julian day number + 0.5, i.e. at noon;  0 == 4713 B.C. Jan 1 (J)
      year;     //  one-based year (not astronomical)
short month,    //  zero-based month;  0 is January or Nisan;  11 to 13 are Adar, Adar I and Adar II
      date;     //  zero-based day of month;  0 == 1st of month
} Date;


int dayofweek(long JD);
int leapyear(long YEAR, bool Greg);
int jdisgreg(long JD);
int dateisgreg(Date *D);
void jdtojul(Date *D);
void jultojd(Date *D);
void jdtogreg(Date *D);
void gregtojd(Date *D);


//  Date conversion

long datetojd(int YEAR, int MONTH, int DATE);
void jdtodate(long JD, short *YEAR, short *MONTH, short *DATE);


//  the Hebrew calendar

void hebtojd(Date *D);
void jdtoheb(Date *D);


//  Proper names for days of the week and months

char *dayname(int N);
bool parsedayname(const char *S, short *D);
char *monthname(int N);
char *monthshortform(int N);
bool parsemonthname(const char *S, short *M);
char *hebmonthname(int N);
bool parsehebmonth(const char *S, short *M);


//  Test function

void testcalend(void);