counting days for absence

Hi,

is there some function module / bapi / or anything what could calculate amount of days for given absence (type, begin, end) ? I need to get number of days of deduction quota for planning absence. It should count it according to all customizing settings in 554 556 tables.

I can code it myself if there is nothing for this as a standard, but connections between those customizing tables / settings are not clear to me.

Could you please help me?

Thanks

Martin