rubidium@8140: /* $Id$ */
rubidium@8140: 
rubidium@8140: /** @file date_type.h Types related to the dates in OpenTTD. */
rubidium@8140: 
rubidium@8140: #ifndef DATE_TYPE_H
rubidium@8140: #define DATE_TYPE_H
rubidium@8140: 
rubidium@8140: /**
rubidium@8140:  * 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. On
rubidium@8140:  *                    an overflow the new day begun and 65535 / 885 = 74.
rubidium@8140:  * 1 tick is approximately 30 ms.
rubidium@8140:  * 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normally
rubidium@8140:  */
rubidium@8140: #define DAY_TICKS 74
rubidium@8140: 
rubidium@8140: /*
rubidium@8140:  * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
rubidium@8140:  * primarily used for loading newgrf and savegame data and returning some
rubidium@8140:  * newgrf (callback) functions that were in the original (TTD) inherited
rubidium@8140:  * format, where '_date == 0' meant that it was 1920-01-01.
rubidium@8140:  */
rubidium@8140: 
rubidium@8140: /** The minimum starting year/base year of the original TTD */
rubidium@8140: #define ORIGINAL_BASE_YEAR 1920
rubidium@8140: /** The maximum year of the original TTD */
rubidium@8140: #define ORIGINAL_MAX_YEAR 2090
rubidium@8140: 
rubidium@8140: /**
rubidium@8140:  * The offset in days from the '_date == 0' till
rubidium@8140:  * 'ConvertYMDToDate(ORIGINAL_BASE_YEAR, 0, 1)'
rubidium@8140:  */
rubidium@8140: #define DAYS_TILL_ORIGINAL_BASE_YEAR (365 * ORIGINAL_BASE_YEAR + ORIGINAL_BASE_YEAR / 4 - ORIGINAL_BASE_YEAR / 100 + ORIGINAL_BASE_YEAR / 400)
rubidium@8140: 
rubidium@8140: /* The absolute minimum & maximum years in OTTD */
rubidium@8140: #define MIN_YEAR 0
rubidium@8140: /* MAX_YEAR, nicely rounded value of the number of years that can
rubidium@8140:  * be encoded in a single 32 bits date, about 2^31 / 366 years. */
rubidium@8140: #define MAX_YEAR 5000000
rubidium@8140: 
rubidium@8140: typedef int32  Date;
rubidium@8140: typedef uint16 DateFract;
rubidium@8140: 
rubidium@8140: typedef int32  Year;
rubidium@8140: typedef uint8  Month;
rubidium@8140: typedef uint8  Day;
rubidium@8140: 
rubidium@8140: struct YearMonthDay {
rubidium@8140: 	Year  year;
frosch@9570: 	Month month; ///< 0 - 11
frosch@9570: 	Day   day;   ///< 1 - 31
rubidium@8140: };
rubidium@8140: 
rubidium@8140: static const Year INVALID_YEAR = -1;
rubidium@8140: static const Date INVALID_DATE = -1;
rubidium@8140: 
rubidium@8140: #endif /* DATE_TYPE_H */