Range error in TClipperOffset.BuildNormals (Delphi)

[rinntech-ak]

During using shrinking of paths I got range error in procedure BuildNormals.
If pathlength is zero (len=0) fNorms[len-1] accesses element -1

procedure TClipperOffset.BuildNormals;
var
i, len: integer;
begin
len := Length(fInPath);
SetLength(fNorms, len);
for i := 0 to len-2 do
fNorms[i] := GetUnitNormal(fInPath[i], fInPath[i+1]);
fNorms[len -1] := GetUnitNormal(fInPath[len -1], fInPath[0]);
end;

My suggest for fix (works fine in my project):
if len>0 then fNorms[len -1] := GetUnitNormal(fInPath[len -1], fInPath[0]);

Best regards
Andreas

[rakkie]

I am seeing the same exception when offsetting in C#.

Here is some minimal code that reproduces the issue.

using Clipper2Lib;

var path = new Path64 { new Point64(100,  100) };
var paths = new Paths64() { path };

var clipperOffset = new ClipperOffset();
clipperOffset.AddPaths(paths, JoinType.Miter, EndType.Polygon);

var solution = new Paths64();
clipperOffset.Execute(-10, solution);

Expected Result: Empty solution (as in previous Clipper versions)
Actual Result: Out of range exception.

regards,
Richard