protected internal ShapeMultiPoint(int recordNumber, StringDictionary metadata, IDataRecord dataRecord, byte[] shapeData)
: base(ShapeType.MultiPoint, recordNumber, metadata, dataRecord)
{
// metadata is validated by the base class
if (shapeData == null)
{
throw new ArgumentNullException("shapeData");
}
// Note, shapeData includes an 8 byte header so positions below are +8
// Position Field Value Type Number Order
// Byte 0 Shape Type 8 Integer 1 Little
// Byte 4 Box Box Double 4 Little
// Byte 36 NumPoints Num Points Integer 1 Little
// Byte 40 Points Points Point NumPoints Little
// validation step 1 - must have at least 8 + 4 + (4*8) + 4 bytes = 48
if (shapeData.Length < 48)
{
throw new InvalidOperationException("Invalid shape data");
}
// extract bounding box and points
_boundingBox = ParseBoundingBox(shapeData, 12, ProvidedOrder.Little);
int numPoints = EndianBitConverter.ToInt32(shapeData, 44, ProvidedOrder.Little);
// validation step 2 - we're expecting 16 * numPoints + 48 bytes total
if (shapeData.Length != 48 + (16 * numPoints))
{
throw new InvalidOperationException("Invalid shape data");
}
// now extract the points
_points = new PointD[numPoints];
for (int pointNum = 0; pointNum < numPoints; pointNum++)
{
_points[pointNum] = new PointD(EndianBitConverter.ToDouble(shapeData, 48 + (16 * pointNum), ProvidedOrder.Little),
EndianBitConverter.ToDouble(shapeData, 56 + (16 * pointNum), ProvidedOrder.Little));
}
}
