Data Structures | Macros | Typedefs | Variables
date_type.h File Reference

Types related to the dates in OpenTTD. More...

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Data Structures

struct  YearMonthDay
 Data structure to convert between Date and triplet (year, month, and day). More...


#define LEAP_YEARS_TILL(year)   ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1)
 Calculate the number of leap years till a given year. More...
#define DAYS_TILL(year)   (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year))
 Calculate the date of the first day of a given year. More...
 The offset in days from the '_date == 0' till 'ConvertYMDToDate(ORIGINAL_BASE_YEAR, 0, 1)'.
#define MAX_DAY   (DAYS_TILL(MAX_YEAR + 1) - 1)
 The number of days till the last day.


typedef int32 Date
 The type to store our dates in.
typedef uint16 DateFract
 The fraction of a date we're in, i.e. the number of ticks since the last date changeover.
typedef int32 Ticks
 The type to store ticks in.
typedef int32 Year
 Type for the year, note: 0 based, i.e. starts at the year 0.
typedef uint8 Month
 Type for the month, note: 0 based, i.e. 0 = January, 11 = December.
typedef uint8 Day
 Type for the day of the month, note: 1 based, first day of a month is 1.


static const int DAY_TICKS = 74
 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. More...
static const int DAYS_IN_YEAR = 365
 days per year
static const int DAYS_IN_LEAP_YEAR = 366
 sometimes, you need one day more...
static const int STATION_RATING_TICKS = 185
 cycle duration for updating station rating
static const int STATION_ACCEPTANCE_TICKS = 250
 cycle duration for updating station acceptance
static const int STATION_LINKGRAPH_TICKS = 504
 cycle duration for cleaning dead links
static const int CARGO_AGING_TICKS = 185
 cycle duration for aging cargo
static const int INDUSTRY_PRODUCE_TICKS = 256
 cycle duration for industry production
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
 cycle duration for lumber mill's extra action
static const Year ORIGINAL_BASE_YEAR = 1920
 The minimum starting year/base year of the original TTD.
static const Year ORIGINAL_END_YEAR = 2051
 The original ending year.
static const Year ORIGINAL_MAX_YEAR = 2090
 The maximum year of the original TTD.
static const Year MIN_YEAR = 0
 The absolute minimum & maximum years in OTTD.
static const Year DEF_START_YEAR = 1950
 The default starting year.
static const Year MAX_YEAR = 5000000
 MAX_YEAR, nicely rounded value of the number of years that can be encoded in a single 32 bits date, about 2^31 / 366 years.
static const Year INVALID_YEAR = -1
 Representation of an invalid year.
static const Date INVALID_DATE = -1
 Representation of an invalid date.
static const Ticks INVALID_TICKS = -1
 Representation of an invalid number of ticks.

Detailed Description

Types related to the dates in OpenTTD.

Definition in file date_type.h.

Macro Definition Documentation


#define DAYS_TILL (   year)    (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year))

Calculate the date of the first day of a given year.

yearthe year to get the first day of.
the date.

Definition at line 76 of file date_type.h.


#define LEAP_YEARS_TILL (   year)    ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1)

Calculate the number of leap years till a given year.

Each passed leap year adds one day to the 'day count'.

A special case for the year 0 as no year has been passed, but '(year - 1) / 4' does not yield '-1' to counteract the '+1' at the end of the formula as divisions round to zero.

yearthe year to get the leap years till.
the number of leap years.

Definition at line 69 of file date_type.h.

Variable Documentation


const int DAY_TICKS = 74

1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885.

On an overflow the new day begun and 65535 / 885 = 74. 1 tick is approximately 30 ms. 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normallyticks per day

Definition at line 30 of file date_type.h.

Referenced by CmdSetTimetableStart(), HandleBankruptcyTakeover(), TimetableWindow::OnQueryTextFinished(), BuildIndustryWindow::OnTick(), ClientNetworkGameSocketHandler::Receive_SERVER_FRAME(), GUIList< const Company *>::ResetResortTimer(), BuildIndustryWindow::SetButtons(), and SetTimetableParams().