protected void setLength() {

		if (hasVfunctions == null) {
			isValid = false;
			return;
		}
		if (!hasVfunctions) {
			length = (int) (typeinfoRefAddress.getOffset() + defaultPointerSize -
				vtableAddress.getOffset());
			return;
		}

		if (numVfunctions == null || vfunctionTop == null) {
			isValid = false;
			return;
		}

		Address endAddr = vfunctionTop.add(numVfunctions * defaultPointerSize);
		length = (int) (endAddr.getOffset() - vtableAddress.getOffset());

	}
Method to determine if there are enough zeros to make a null poihnter and no
references into or out of the middle

@param address the given address
@return true if the given address could be a valid null pointer, false if not
Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/Vtable.java