Internet Direct (Indy) Version 9.0.1 Beta
TIdDateTimeStamp.WeekOfYear
Identifies the week number for the Indy timestamp.

property WeekOfYear: Integer;
Description
WeekOFYear is a read-only Integer property that Indicates the week number for the current year of the Indy timestamp. A week is considered to begin with Sunday and may overlap a Year boundary. It is possible to have 53 weeks in a Year, with the 53rd week of a given year also being the 1st week of the following year.