Here are the steps I would go about merging those:
- Load the files into KeyValues handles A and B.
- (Optional) Create another KeyValues handle for the merge if you need to keep the original handles intact.
- Iterate over A keys using GotoFirstSubKey() and GotoNextKey(), grabbing the current key using GetSectionName()
- Check if A's key exists in B.
- If yes, grab B stats and store the sum in the output handle (or A's handle if no output handle).
- If no and are using an output handle, store A's data in the output handle.
- Iterate over B keys same method as A.
- If B's key does not exist in A, store B into the output handle (or A's handle if no output handle).
And there you will have them merged.