/**
* Fetch the next record information.
*
* @param offset
* @throws IOException
* @return The record instance associated with this reader.
*/
public Geometry geomAt(int offset) throws IOException {
// need to update position
buffer.position(offset);
// record header
buffer.skip(8);
// shape record is all little endian
buffer.order(ByteOrder.LITTLE_ENDIAN);
// read the type, handlers don't need it
ShapeType recordType = ShapeType.forID(buffer.getInt());
// this usually happens if the handler logic is bunk,
// but bad files could exist as well...
if (recordType != ShapeType.NULL && recordType != fileShapeType) {
throw new IllegalStateException(
"ShapeType changed illegally from " + fileShapeType + " to " + recordType);
}
return handler.read(buffer, recordType);
}
public Geometry read(ReadBufferManager buffer, ShapeType type) throws IOException {
if (type == ShapeType.NULL) {
return null;
}
int dimensions = (shapeType == ShapeType.ARCZ) ? 3 : 2;
// read bounding box (not needed)
buffer.skip(4 * 8);
int numParts = buffer.getInt();
int numPoints = buffer.getInt(); // total number of points
int[] partOffsets = new int[numParts];
// points = new Coordinate[numPoints];
for (int i = 0; i < numParts; i++) {
partOffsets[i] = buffer.getInt();
}
// read the first two coordinates and start building the coordinate
// sequences
PackedCoordinateSequence[] lines = new PackedCoordinateSequence[numParts];
int finish, start = 0;
int length = 0;
boolean clonePoint = false;
for (int part = 0; part < numParts; part++) {
start = partOffsets[part];
if (part == (numParts - 1)) {
finish = numPoints;
} else {
finish = partOffsets[part + 1];
}
length = finish - start;
if (length == 1) {
length = 2;
clonePoint = true;
} else {
clonePoint = false;
}
// TODO With next version of JTS uncomment this line
// PackedCoordinateSequence builder = new
// PackedCoordinateSequence.Double(
// length, dimension);
PackedCoordinateSequence builder = new PackedCoordinateSequence.Double(length, 3);
for (int i = 0; i < length; i++) {
builder.setOrdinate(i, 0, buffer.getDouble());
builder.setOrdinate(i, 1, buffer.getDouble());
// TODO With next version of JTS remove this line
builder.setOrdinate(i, 2, Double.NaN);
}
if (clonePoint) {
builder.setOrdinate(1, 0, builder.getOrdinate(0, 0));
builder.setOrdinate(1, 1, builder.getOrdinate(1, 0));
// TODO With next version of JTS remove this line
builder.setOrdinate(1, 2, Double.NaN);
}
lines[part] = builder;
}
// if we have another coordinate, read and add to the coordinate
// sequences
if (dimensions == 3) {
// z min, max
buffer.skip(2 * 8);
for (int part = 0; part < numParts; part++) {
start = partOffsets[part];
if (part == (numParts - 1)) {
finish = numPoints;
} else {
finish = partOffsets[part + 1];
}
length = finish - start;
if (length == 1) {
length = 2;
clonePoint = true;
} else {
clonePoint = false;
}
for (int i = 0; i < length; i++) {
lines[part].setOrdinate(i, 2, buffer.getDouble());
}
}
}
// Prepare line strings and return the multilinestring
LineString[] lineStrings = new LineString[numParts];
for (int part = 0; part < numParts; part++) {
lineStrings[part] = geometryFactory.createLineString(lines[part]);
}
return geometryFactory.createMultiLineString(lineStrings);
}
