date_type.h

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/* $Id: date_type.h 14823 2009-01-04 11:32:26Z rubidium $ */

#ifndef DATE_TYPE_H
#define DATE_TYPE_H

#define DAY_TICKS 74

/*
 * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
 * primarily used for loading newgrf and savegame data and returning some
 * newgrf (callback) functions that were in the original (TTD) inherited
 * format, where '_date == 0' meant that it was 1920-01-01.
 */

#define ORIGINAL_BASE_YEAR 1920

#define ORIGINAL_END_YEAR 2051

#define ORIGINAL_MAX_YEAR 2090

#define DAYS_TILL_ORIGINAL_BASE_YEAR (365 * ORIGINAL_BASE_YEAR + ORIGINAL_BASE_YEAR / 4 - ORIGINAL_BASE_YEAR / 100 + ORIGINAL_BASE_YEAR / 400)

/* The absolute minimum & maximum years in OTTD */
#define MIN_YEAR 0
/* MAX_YEAR, nicely rounded value of the number of years that can
 * be encoded in a single 32 bits date, about 2^31 / 366 years. */
#define MAX_YEAR 5000000

typedef int32  Date;
typedef uint16 DateFract;

typedef int32  Year;
typedef uint8  Month;
typedef uint8  Day;

struct YearMonthDay {
  Year  year;   
  Month month;  
  Day   day;    
};

static const Year INVALID_YEAR = -1;
static const Date INVALID_DATE = -1;

#endif /* DATE_TYPE_H */