# date_type.h

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    00001 /* $Id: date_type.h 15077 2009-01-13 22:58:03Z smatz $ */
    00002
    00005 #ifndef DATE_TYPE_H
    00006 #define DATE_TYPE_H
    00007
    00014 enum {
    00015   DAY_TICKS = 74,
    00016   DAYS_IN_YEAR = 365,
    00017   DAYS_IN_LEAP_YEAR = 366,
    00018 };
    00019
    00020 /*
    00021  * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
    00022  * primarily used for loading newgrf and savegame data and returning some
    00023  * newgrf (callback) functions that were in the original (TTD) inherited
    00024  * format, where '_date == 0' meant that it was 1920-01-01.
    00025  */
    00026
    00028 #define ORIGINAL_BASE_YEAR 1920
    00029
    00030 #define ORIGINAL_END_YEAR 2051
    00031
    00032 #define ORIGINAL_MAX_YEAR 2090
    00033
    00038 #define DAYS_TILL_ORIGINAL_BASE_YEAR (DAYS_IN_YEAR * ORIGINAL_BASE_YEAR + ORIGINAL_BASE_YEAR / 4 - ORIGINAL_BASE_YEAR / 100 + ORIGINAL_BASE_YEAR / 400)
    00039
    00040 /* The absolute minimum & maximum years in OTTD */
    00041 #define MIN_YEAR 0
    00042 /* MAX_YEAR, nicely rounded value of the number of years that can
    00043  * be encoded in a single 32 bits date, about 2^31 / 366 years. */
    00044 #define MAX_YEAR 5000000
    00045
    00046 typedef int32  Date;
    00047 typedef uint16 DateFract;
    00048
    00049 typedef int32  Year;
    00050 typedef uint8  Month;
    00051 typedef uint8  Day;
    00052
    00057 struct YearMonthDay {
    00058   Year  year;
    00059   Month month;
    00060   Day   day;
    00061 };
    00062
    00063 static const Year INVALID_YEAR = -1;
    00064 static const Date INVALID_DATE = -1;
    00065
    00066 #endif /* DATE_TYPE_H */