Implement StringPool for binary kv1 used by Steam

[xPaw]

@yaakov-h how do we implement this sanely? They invented this and used by appinfo.vdf in Steam.

KV3 does the same thing, there's a string array for the keys. The only difference is that for kv1 they put the string pool separate from the KV1 data, so the parser can't parse it on its own.

Ref: SteamDatabase/SteamAppInfo@56b1fec#diff-97374b6129341b7a97d4a8056e32c8865a2553ad49aa9a70c841058fbccdfb2f

[yaakov-h]

What happened here?

Looking over the code, it sounds like:

• They added a string table which gets shipped out-of-band (i.e. not in the actual KV1 binary structure)
• When parsing KV1 binary you need the same string table used to serialize
• KV1-with-string-table uses the string table for keys, but not for values

?

[xPaw]

That's correct. The method I saw being used is CKeyValuesSystem::AddStringToPool.

For ref, same thing in binary kv3: https://github.com/ValveResourceFormat/ValveResourceFormat/blob/25ac2246fed63e0321eaecef0e419e3fc0456aed/ValveResourceFormat/Resource/ResourceTypes/BinaryKV3.cs#L643-L647

[terrymacdonald]

Hi,

I'm developer of DisplayMagician (https://github.com/terrymacdonald/DisplayMagician) and some users asked me to investigate why DisplayMagician can't detect games within the latest Steam Families Beta client appinfo.vdf. It looks like you are both all over the changes (thank you so, so much), but I was wondering how much work is left before this update could be supported in ValveKeyValue?

Will it be months, or is it fairly imminent? I can tell my users to stay on the current version until this is all ready.

Also, I just wanted to thank you both for your awesome work on this. I am amazed at how well you can keep this in step with Valves file format. Its very inspiring.

Thanks
Terry

[yaakov-h]

I've had a look and gone with a slightly different approach in #100. This passes the string table around, avoiding changes to other internal interfaces.

I kinda suspect we may eventually need to pass the whole Options object around, but for now I'm passing around just the string table.