jimon

https://code.google.com/p/dtl-cpp/
https://code.google.com/p/google-diff-match-patch/
https://github.com/arrbee/diff-match-patch-c
http://www.codeproject.com/Articles/3666/Diff-tool
https://github.com/ilanschnell/bsdiff4
и тд, поищи на гитхабе еще