#ifndef __date_h__
#define __date_h__

#define THURSDAY                4               /* for reformation */
#define SATURDAY                6               /* 1 Jan 1 was a Saturday */

#define FIRST_MISSING_DAY       639799          /* 3 Sep 1752 */
#define NUMBER_MISSING_DAYS     11              /* 11 day correction */

/* leap year -- account for gregorian reformation in 1752 */ 
#define leap_year(yr) \
        ((yr) <= 1752 ? !((yr) % 4) : \
        (!((yr) % 4) && ((yr) % 100)) || !((yr) % 400))

/* number of centuries since 1700, not inclusive */
#define centuries_since_1700(yr) \
        ((yr) > 1700 ? (yr) / 100 - 17 : 0)

/* number of centuries since 1700 whose modulo of 400 is 0 */ 
#define quad_centuries_since_1700(yr) \
        ((yr) > 1600 ? ((yr) - 1600) / 400 : 0)

/* number of leap years between year 1 and this year, not inclusive */ 
#define leap_years_since_year_1(yr) \
        ((yr) / 4 - centuries_since_1700(yr) + quad_centuries_since_1700(yr))

extern int day_in_year(int day, int month, int year);
extern int day_in_week(int day, int month, int year);

#endif