Signature/pattern scanning

[Loomeh]

Working on a pattern scanning feature for LibreSplit but I'm having some trouble and could use some input. I currently don't think this is too far developed to warrant a PR so I'm putting it here.

I've added a new function called sig_scan that allows the auto splitter developer to do a signature scan for an IDA byte array.

featuretest = sig_scan("89 5C 24 ?? 89 44 24 ?? 74 ?? 48 8D 15")

They can also provide an offset.

featuretest = sig_scan("89 5C 24 ?? 89 44 24 ?? 74 ?? 48 8D 15", "0x4")

However, things just don't seem to be adding up properly.

I'm currently trying to replicate this instruction from the SPRAWL autosplitter

var fNamePoolTrg = new SigScanTarget(13, "89 5C 24 ?? 89 44 24 ?? 74 ?? 48 8D 15") { OnFound = (p, s, ptr) => ptr + 0x4 + game.ReadValue<int>(ptr) };

From what I understand, this code performs a signature scan on this byte array, adds an offset of 0x4 to the found address and then proceeds to read its value. However, when I try this in LibreSplit, I can never find an address. I can find the base address from the sig scan, but that's not the address I need. Trying to add on the offset results in a bunch of memory access violations.

I don't think my parsing is correct but I'm not sure in what way.