@Override
	public BigInteger map(BigInteger value) {
		Address address = from.getAddress(value);
		if (address == null) {
			return BigInteger.ZERO;
		}
		BigInteger mapped = to.getIndex(address);
		return mapped != null ? mapped : BigInteger.ZERO;
	}
Implementation of IndexMapper that uses an old and new AddressIndexMap to map indexes 
 when the AddressIndexMap changes.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/util/AddressBasedIndexMapper.java