Several functions for working with the holidays:

The function

datetime LastMondayStart( datetime dt);

returns the last Sunday 22:00 before dt.

The function

datetime NextFridayEnd( datetime dt);

returns the nearest Friday 23:00 time after dt.

The function

int SundayMidnightCount( datetime start, datetime end);

returns the number of holidays between two dates.

The function

int HoursCandleCount( datetime start, datetime end);

returns the number of trading hours between two dates. In other words, it is the amount of hourly candles between 'start' and 'end'.

The function

datetime AddTradingSeconds( datetime start, int seconds);

adds trading time to the date.

Example: the position needs to be closed 5 trading hours after opening. If the position was opened on Friday at 21:00, then it should be closed on Monday at 2:00. The initial time is calculated like this:

AddTradingSeconds( OrderOpenTime(), 5*60*60 );