1 /* 2 * This file is part of OpenTTD. 3 * 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. 4 * 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. 5 * 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/>. 6 */ 7 8 /** @file date_type.h Types related to the dates in OpenTTD. */ 9 10 #ifndef DATE_TYPE_H 11 #define DATE_TYPE_H 12 13 14 typedef int32 Date; ///< The type to store our dates in 15 typedef uint16 DateFract; ///< The fraction of a date we're in, i.e. the number of ticks since the last date changeover 16 typedef int32 Ticks; ///< The type to store ticks in 17 18 typedef int32 Year; ///< Type for the year, note: 0 based, i.e. starts at the year 0. 19 typedef uint8 Month; ///< Type for the month, note: 0 based, i.e. 0 = January, 11 = December. 20 typedef uint8 Day; ///< Type for the day of the month, note: 1 based, first day of a month is 1. 21 22 /** 23 * 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. On 24 * an overflow the new day begun and 65535 / 885 = 74. 25 * 1 tick is approximately 30 ms. 26 * 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normally 27 */ 28 static const int DAY_TICKS = 74; ///< ticks per day 29 static const int DAYS_IN_YEAR = 365; ///< days per year 30 static const int DAYS_IN_LEAP_YEAR = 366; ///< sometimes, you need one day more... 31 static const int MONTHS_IN_YEAR = 12; ///< months per year 32 33 static const int STATION_RATING_TICKS = 185; ///< cycle duration for updating station rating 34 static const int STATION_ACCEPTANCE_TICKS = 250; ///< cycle duration for updating station acceptance 35 static const int STATION_LINKGRAPH_TICKS = 504; ///< cycle duration for cleaning dead links 36 static const int CARGO_AGING_TICKS = 185; ///< cycle duration for aging cargo 37 static const int INDUSTRY_PRODUCE_TICKS = 256; ///< cycle duration for industry production 38 static const int TOWN_GROWTH_TICKS = 70; ///< cycle duration for towns trying to grow. (this originates from the size of the town array in TTD 39 static const int INDUSTRY_CUT_TREE_TICKS = INDUSTRY_PRODUCE_TICKS * 2; ///< cycle duration for lumber mill's extra action 40 41 42 /* 43 * ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are 44 * primarily used for loading newgrf and savegame data and returning some 45 * newgrf (callback) functions that were in the original (TTD) inherited 46 * format, where '_date == 0' meant that it was 1920-01-01. 47 */ 48 49 /** The minimum starting year/base year of the original TTD */ 50 static const Year ORIGINAL_BASE_YEAR = 1920; 51 /** The original ending year */ 52 static const Year ORIGINAL_END_YEAR = 2051; 53 /** The maximum year of the original TTD */ 54 static const Year ORIGINAL_MAX_YEAR = 2090; 55 56 /** 57 * Calculate the number of leap years till a given year. 58 * 59 * Each passed leap year adds one day to the 'day count'. 60 * 61 * A special case for the year 0 as no year has been passed, 62 * but '(year - 1) / 4' does not yield '-1' to counteract the 63 * '+1' at the end of the formula as divisions round to zero. 64 * 65 * @param year the year to get the leap years till. 66 * @return the number of leap years. 67 */ 68 #define LEAP_YEARS_TILL(year) ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1) 69 70 /** 71 * Calculate the date of the first day of a given year. 72 * @param year the year to get the first day of. 73 * @return the date. 74 */ 75 #define DAYS_TILL(year) (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year)) 76 77 /** 78 * The offset in days from the '_date == 0' till 79 * 'ConvertYMDToDate(ORIGINAL_BASE_YEAR, 0, 1)' 80 */ 81 #define DAYS_TILL_ORIGINAL_BASE_YEAR DAYS_TILL(ORIGINAL_BASE_YEAR) 82 83 /** The absolute minimum & maximum years in OTTD */ 84 static const Year MIN_YEAR = 0; 85 86 /** The default starting year */ 87 static const Year DEF_START_YEAR = 1950; 88 /** The default scoring end year */ 89 static const Year DEF_END_YEAR = ORIGINAL_END_YEAR - 1; 90 91 /** 92 * MAX_YEAR, nicely rounded value of the number of years that can 93 * be encoded in a single 32 bits date, about 2^31 / 366 years. 94 */ 95 static const Year MAX_YEAR = 5000000; 96 97 /** The number of days till the last day */ 98 #define MAX_DAY (DAYS_TILL(MAX_YEAR + 1) - 1) 99 100 /** 101 * Data structure to convert between Date and triplet (year, month, and day). 102 * @see ConvertDateToYMD(), ConvertYMDToDate() 103 */ 104 struct YearMonthDay { 105 Year year; ///< Year (0...) 106 Month month; ///< Month (0..11) 107 Day day; ///< Day (1..31) 108 }; 109 110 static const Year INVALID_YEAR = -1; ///< Representation of an invalid year 111 static const Date INVALID_DATE = -1; ///< Representation of an invalid date 112 static const Ticks INVALID_TICKS = -1; ///< Representation of an invalid number of ticks 113 114 #endif /* DATE_TYPE_H */ 115