public void
jump(int index) {
	if (index >= byteBuffer.capacity()) {
		throw new IllegalArgumentException("cannot jump past " +
						   "end of input");
	}
	byteBuffer.position(index);
	byteBuffer.limit(byteBuffer.capacity());
}
Resets the current position of the input stream to the specified index,
and clears the active region.
@param index The position to continue parsing at.
@throws IllegalArgumentException The index is not within the input.
src/main/java/core/org/xbill/DNS/DNSInput.java