Brutkey

mistymntncop
@blackeggs@infosec.exchange

@pervognsen@mastodon.social

RADDBG uses hierarchical string trees for storing upstream Config state (the master state where more fine-grained state is computed) and they use LCRS trees. This had me wondering how you would actually make such a data structure persistent. If you have persistency then you trivially have undo/redo I believe.

https://github.com/EpicGamesExt/raddebugger/blob/e1d6b9f3196693160dce5664e321c028b8a74aa9/src/raddbg/raddbg_core.h#L274

Per Vognsen
@pervognsen@mastodon.social

@blackeggs@infosec.exchange Persistent trees are way too much overhead compared to an undo log, though, if you can't make use of any of their other advantages.

Per Vognsen
@pervognsen@mastodon.social

@blackeggs@infosec.exchange An easy way to implement any data structure like this is to implement the memory itself semi-persistently. That is, you have a semi-persistent abstract data type which is called a memory. It implements read_uint16, write_uint32, copy_bytes, undo, redo, etc, and it keeps an undo/redo log of what it overwrites and at what offset so you can undo/redo it later.

mistymntncop
@blackeggs@infosec.exchange

@pervognsen@mastodon.social Ahh a history of diffs I think is what you mean.