# date_type.h

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    00001 /* $Id$ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
    00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
    00008  */
    00009
    00012 #ifndef DATE_TYPE_H
    00013 #define DATE_TYPE_H
    00014
    00021 enum {
    00022   DAY_TICKS = 74,
    00023   DAYS_IN_YEAR = 365,
    00024   DAYS_IN_LEAP_YEAR = 366,
    00025 };
    00026
    00027 /*
    00028  * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
    00029  * primarily used for loading newgrf and savegame data and returning some
    00030  * newgrf (callback) functions that were in the original (TTD) inherited
    00031  * format, where '_date == 0' meant that it was 1920-01-01.
    00032  */
    00033
    00035 #define ORIGINAL_BASE_YEAR 1920
    00036
    00037 #define ORIGINAL_END_YEAR 2051
    00038
    00039 #define ORIGINAL_MAX_YEAR 2090
    00040
    00053 #define LEAP_YEARS_TILL(year) ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1)
    00054
    00060 #define DAYS_TILL(year) (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year))
    00061
    00066 #define DAYS_TILL_ORIGINAL_BASE_YEAR DAYS_TILL(ORIGINAL_BASE_YEAR)
    00067
    00069 #define MIN_YEAR 0
    00070
    00072 #define DEF_START_YEAR 1950
    00073
    00078 #define MAX_YEAR 5000000
    00079
    00081 #define MAX_DAY (DAYS_TILL(MAX_YEAR + 1) - 1)
    00082
    00083 typedef int32  Date;
    00084 typedef uint16 DateFract;
    00085 typedef int32  Ticks;
    00086
    00087 typedef int32  Year;
    00088 typedef uint8  Month;
    00089 typedef uint8  Day;
    00090
    00095 struct YearMonthDay {
    00096   Year  year;
    00097   Month month;
    00098   Day   day;
    00099 };
    00100
    00101 static const Year  INVALID_YEAR  = -1;
    00102 static const Date  INVALID_DATE  = -1;
    00103 static const Ticks INVALID_TICKS = -1;
    00104
    00105 #endif /* DATE_TYPE_H */