}
@Override
public void writeBytes(byte[] abyte0, int offset, int len) throws IOException {
assureLength(filePointer+len);
NSMutableRange range = new NSMutableRange((int)filePointer, len);
byte[] bytes = data().bytesNoCopy(range);
System.arraycopy(abyte0, offset, bytes, (int)filePointer, len);
filePointer += len;
dirty = true;
}