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/**
* Data structure to convert between Date and triplet (year, month, and day).
* @see ConvertDateToYMD(), ConvertYMDToDate()
*/Actually that was the reason why I asked the question in the first place! That particular function has a funny way of dealing with leap years to my eyes. Playing around, I think that Date is a day counter from 0000-01-01, but then again the only advantage I can see with that is that you can use C++'s inbuilt plus/minus/times/divide rather than making new ones. (Wasted time from 0 to 1920, and we only use 1920 to 2050. 130 years, which is tiny compared to 1920 years!)Alberth wrote:... YearMonthDay ...
OpenTTD allows to start the game on 1st January 0 (or 1?) and counts years up to 5000000. Thus you can play a game for 5 million years. Quite a bit more than the assumd 130 years.LurkerL wrote:Wasted time from 0 to 1920, and we only use 1920 to 2050. 130 years, which is tiny compared to 1920 years!)
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ConvertYMDToDate(Year year, Month month, Day day)
{
int days = _accum_days_for_month[month] + day - 1;
if (!IsLeapYear(year) && days >= ACCUM_MAR) days--;
return DAYS_TILL(year) + days;
}
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ConvertYMDToDate(Year year, Month month, Day day)
{
TimeDate::Date date(year, month+1, ?);
return DAYS_TILL(year) + date.DayOfYear();
}
Yes, my badplanetmaker wrote:... OpenTTD allows to start the game on 1st January 0 (or 1?) and counts years up to 5000000. Thus you can play a game for 5 million years. Quite a bit more than the assumd 130 years.
The source code is leading. Doxygen docs have been added much later without full knowledge of the details.LurkerL wrote:Actually that was the reason why I asked the question in the first place! That particular function has a funny way of dealing with leap years to my eyes. ...Alberth wrote:... YearMonthDay ...
I think I shouldn't have been so blunt in my first post---it wasn't my intention to say bad things about the docs or the code, or to say I wasn't playing with the code to figure it out myself.Alberth wrote:The source code is leading. Doxygen docs have been added much later without full knowledge of the details.LurkerL wrote:Actually that was the reason why I asked the question in the first place! That particular function has a funny way of dealing with leap years to my eyes. ...Alberth wrote:... YearMonthDay ...
If you find new information, and supply a doxygen patch, we are happy to add it.
it used to be that way that days were counted from 1920-01-01, with a 16 bit counter, which allowed dates up to 2090-12-31. this was not enough for some people, so 32 bit date was introduced, starting in 0000-01-01 and ending in 5000000-12-31. [this is a normalised gregorian calendar with year 0]LurkerL wrote:Wasted time from 0 to 1920, and we only use 1920 to 2050. 130 years, which is tiny compared to 1920 years!