int getLastActiveFactoryIndex(BigInteger index, FieldFactory[] factories) {
		for (int i = factories.length - 1; i >= 0; i--) {
			if (factories[i].isActive(index)) {
				return i;
			}
		}
		return -1;
	}
Returns the index of the last factory that is active for a given index
@param index the line index
@param factories the list of factories that generate values on a line
@return the index of the last active factory on that line. This will be factories.length
except for the last line of a block which may end part way in the line.
Ghidra/Features/ByteViewer/src/main/java/ghidra/app/plugin/core/byteviewer/IndexMap.java