Identifying cocoa (NSData, NSArray, etc) objects in a file format [duplicate]

This question already exists: Reverse engineering NSDocument file Closed 9 years ago.

In order to reverse engineer a file format, How can I identify cocoa objects in a file format?

I've got a document format based with NSDocument, the program which created it can't export in a sane format and the vendor can't help export the data - they've gone out of business.

I've tried debugging the application and get back to -[docFile initWithContentsOfFile:ofType:] but beyond that isn't much help.

I'm assuming they're writing pure cocoa objects to disk - like NSA开发者_C百科rray, NSObject, NSDate, etc. So how do I recognize this structures on disk?

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class-dump will dump all the internal classes/structs from a binary into a header file. It's the same as tool -ov, but it dumps into an .h file.

It's not perfect, but it'll get you a long way there right off the bat.