+################################# calcdelta #################################
+# Takes a date (year, month and day) and a time period (1d, 1w, 1m, 1y, ...)
+# and adds the latter to the former
+
+sub calcdelta {
+ my ($Year, $Month, $Day, $Period) = @_;
+ my ($NYear, $NMonth, $NDay);
+
+ if ($Period =~ /(\d+)\s*([dw])/) { # Is counted in days or weeks: Use Add_Delta_Days.
+ ($NYear, $NMonth, $NDay) = Add_Delta_Days($Year, $Month, $Day, (($2 eq "w")?$1 * 7: $1 * 1));
+ } elsif ($Period =~ /(\d+)\s*([my])/) { #Is counted in months or years: Use Add_Delta_YM
+ ($NYear, $NMonth, $NDay) = Add_Delta_YM($Year, $Month, $Day, (($2 eq "m")?(0,$1):($1,0)));
+ }
+ return ($NYear, $NMonth, $NDay);
+}
+