date_type.h

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00001 /* $Id: date_type.h 19812 2010-05-13 09:44:44Z rubidium $ */
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 
00015 
00016 typedef int32  Date;      
00017 typedef uint16 DateFract; 
00018 typedef int32  Ticks;     
00019 
00020 typedef int32  Year;  
00021 typedef uint8  Month; 
00022 typedef uint8  Day;   
00023 
00030 static const int DAY_TICKS         =  74; 
00031 static const int DAYS_IN_YEAR      = 365; 
00032 static const int DAYS_IN_LEAP_YEAR = 366; 
00033 
00034 /*
00035  * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
00036  * primarily used for loading newgrf and savegame data and returning some
00037  * newgrf (callback) functions that were in the original (TTD) inherited
00038  * format, where '_date == 0' meant that it was 1920-01-01.
00039  */
00040 
00042 static const Year ORIGINAL_BASE_YEAR = 1920;
00044 static const Year ORIGINAL_END_YEAR  = 2051;
00046 static const Year ORIGINAL_MAX_YEAR  = 2090;
00047 
00060 #define LEAP_YEARS_TILL(year) ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1)
00061 
00067 #define DAYS_TILL(year) (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year))
00068 
00073 #define DAYS_TILL_ORIGINAL_BASE_YEAR DAYS_TILL(ORIGINAL_BASE_YEAR)
00074 
00076 static const Year MIN_YEAR = 0;
00077 
00079 static const Year DEF_START_YEAR = 1950;
00080 
00085 static const Year MAX_YEAR  = 5000000;
00086 
00088 #define MAX_DAY (DAYS_TILL(MAX_YEAR + 1) - 1)
00089 
00094 struct YearMonthDay {
00095   Year  year;   
00096   Month month;  
00097   Day   day;    
00098 };
00099 
00100 static const Year  INVALID_YEAR  = -1; 
00101 static const Date  INVALID_DATE  = -1; 
00102 static const Ticks INVALID_TICKS = -1; 
00103 
00104 #endif /* DATE_TYPE_H */

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