rubidium@4261: /* $Id$ */
rubidium@4261: 
peter1138@4666: #ifndef DATE_H
peter1138@4666: #define DATE_H
peter1138@4666: 
rubidium@4261: /**
rubidium@4261:  * 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. On
rubidium@4261:  *                    an overflow the new day begun and 65535 / 885 = 74.
rubidium@4261:  * 1 tick is approximately 30 ms.
rubidium@4261:  * 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normally
rubidium@4261:  */
rubidium@4261: #define DAY_TICKS 74
rubidium@4261: 
rubidium@4322: /*
rubidium@4322:  * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
rubidium@4322:  * primarily used for loading newgrf and savegame data and returning some
rubidium@4322:  * newgrf (callback) functions that were in the original (TTD) inherited
rubidium@4322:  * format, where '_date == 0' meant that it was 1920-01-01.
rubidium@4322:  */
rubidium@4322: 
rubidium@4322: /** The minimum starting year/base year of the original TTD */
rubidium@4322: #define ORIGINAL_BASE_YEAR 1920
rubidium@4322: /** The maximum year of the original TTD */
rubidium@4322: #define ORIGINAL_MAX_YEAR 2090
rubidium@4322: 
rubidium@4322: /**
rubidium@4322:  * The offset in days from the '_date == 0' till
rubidium@4322:  * 'ConvertYMDToDate(ORIGINAL_BASE_YEAR, 0, 1)'
rubidium@4322:  */
rubidium@4326: #define DAYS_TILL_ORIGINAL_BASE_YEAR (365 * ORIGINAL_BASE_YEAR + ORIGINAL_BASE_YEAR / 4 - ORIGINAL_BASE_YEAR / 100 + ORIGINAL_BASE_YEAR / 400)
rubidium@4322: 
rubidium@4322: /* The absolute minimum & maximum years in OTTD */
rubidium@4326: #define MIN_YEAR 0
rubidium@4326: /* MAX_YEAR, nicely rounded value of the number of years that can
rubidium@4326:  * be encoded in a single 32 bits date, about 2^31 / 366 years. */
rubidium@4326: #define MAX_YEAR 5000000
rubidium@4261: 
rubidium@4261: /* Year and Date are defined elsewhere */
rubidium@4261: typedef uint8  Month;
rubidium@4261: typedef uint8  Day;
rubidium@4261: typedef uint16 DateFract;
rubidium@4261: 
rubidium@4261: typedef struct YearMonthDay {
rubidium@4261: 	Year  year;
rubidium@4261: 	Month month;
rubidium@4261: 	Day   day;
rubidium@4261: } YearMonthDay;
rubidium@4261: 
rubidium@4261: extern Year      _cur_year;
rubidium@4261: extern Month     _cur_month;
rubidium@4261: extern Date      _date;
rubidium@4261: extern DateFract _date_fract;
rubidium@4261: 
rubidium@4261: 
rubidium@4261: void SetDate(Date date);
rubidium@4288: void ConvertDateToYMD(Date date, YearMonthDay *ymd);
rubidium@4288: Date ConvertYMDToDate(Year year, Month month, Day day);
peter1138@4666: 
peter1138@4666: #endif /* DATE_H */