MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper

DavidCoombes — Sun, 12 Dec 2021 16:36:23 GMT

I have been chasing a problem in that I can't retrieve curves from the GDB when using the .NET wrapper.

Using Reflector, I finally tracked it down to the Curves Get property not applying the calculated offset during the memcpy:

public byte[] Curves
{
    get
    {
        int numParts = this.NumParts;
        int numPoints = this.NumPoints;
        Enum modopt(ShapeType) modopt(IsBoxed) shapeType = base.shapeType;
        int offset = (((numPoints * 4) + numParts) * 4) + 44;
        if (ShapeBuffer.HasZs(shapeType))
        {
            offset = ((numPoints * 8) + offset) + 16;
        }
        if (ShapeBuffer.HasMs(shapeType))
        {
            offset = ((numPoints * 8) + offset) + 16;
        }
        int allocatedLength = ((int) base.inUseLength) + (-4 - offset);
        byte[] result = new byte[allocatedLength];
        ref byte modopt(IsExplicitlyDereferenced) pinned pinResult = (ref byte modopt(IsExplicitlyDereferenced)) &(result[0]);
        memcpy(pinResult, *(((int*) (base.NativeShapeBuffer + 4))), allocatedLength);
        return result;
    }
    set
    {
        int numParts = this.NumParts;
        int numPoints = this.NumPoints;
        Enum modopt(ShapeType) modopt(IsBoxed) shapeType = base.shapeType;
        int offset = (((numPoints * 4) + numParts) * 4) + 44;
        if (ShapeBuffer.HasZs(shapeType))
        {
            offset = ((numPoints * 8) + offset) + 16;
        }
        if (ShapeBuffer.HasMs(shapeType))
        {
            offset = ((numPoints * 8) + offset) + 16;
        }
        offset += 4;
        int allocatedLength = ((int) base.inUseLength) - offset;
        ref byte modopt(IsExplicitlyDereferenced) pinned pinBytes = (ref byte modopt(IsExplicitlyDereferenced)) &(value[0]);
        memcpy((*(((int*) (base.NativeShapeBuffer + 4))) + offset), pinBytes, allocatedLength);
    }
}

I am using the following work around:

ShapeBuffer shapeBuffer = row.GetGeometry();
byte[] shapeBufferBytes = shapeBuffer.shapeBuffer;
MultiPartShapeBuffer geometry = shapeBuffer;
byte[] curveBuffer = geometry.Curves;
int bytes = curveBuffer.Length;
int offset = ( ( geometry.NumPoints * 4 ) + geometry.NumParts ) * 4 + 44;
if ( ShapeBuffer.HasZs( geometry.shapeType ) )
{
    offset += geometry.NumPoints * 8 + 16;
}
if ( ShapeBuffer.HasMs( geometry.shapeType ) )
{
    offset += geometry.NumPoints * 8 + 16;
}
for ( int i = 0; i < bytes; i++ )
{
    curveBuffer[ i ] = shapeBufferBytes[ i + offset + 4 ];
}
//Messy code copying the byte buffer to an array of structures...

Re: MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper

LanceShipman — Wed, 20 Feb 2013 16:57:11 GMT

What version of the API are you using?

Re: MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper

DavidCoombes — Thu, 21 Feb 2013 05:06:45 GMT

I am using API v1.3.

topic MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper in File Geodatabase API Questions

MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper

Re: MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper

Re: MultiPartShapeBuffer.Curves is returning the wrong data via the .NET wrapper