CODEWITHSUNDEEP
visual-studiomfc
Brian Lacy
Brian Lacy

Reputation: 19098

MFC CDocument: How to read contents of database files created by defunct app?

I have almost zero experience coding in Visual Studio, MFC, etc. But I've got several data files that were created in a now-defunct MFC application, which I need to migrate to another format.

Unfortunately there's really no good way, within the application itself, to extract the data (short of copy-pasting hundreds or even thousands of records individually). And viewing the files themselves, i.e. in a Hex Editor, has proven fruitless; even though the raw data stored by the app is text-based, the database files are encoded in some cryptic binary format.

So far I've been able to determine that the app was written using MFC and that it uses the CDocument class (or a simple derivative thereof) to store the files. I understand that CDocument-based data files have something to do with serializing the data, but I'm not sure how to make sense of the encoding.

  1. Does anyone know enough about MFC to explain to me how CDocument actually works?

  2. Does anyone have any ideas on how I might be able to decode these files to extract the text?

Upvotes: 0

Views: 418

Answers (1)

Owen Wengerd
Owen Wengerd

Reputation: 1628

I once faced an almost identical scenario. I eventually worked out the code to deserialize the data, but it wasn't easy.

Write a small MFC application to do the work, that way you can leverage the same serialization code that the original app used. The topic of reverse engineering a data format is way too complex to answer here. It's probably not encrypted; more likely compressed.

If you're an experienced programmer you should be able to read the MFC source code, then apply that knowledge to the raw data. Not everything can be heuristically determined just by observing the raw data, but if you have an independent way of determining the actual content, it's certainly possible with sufficient work.

Upvotes: 1

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