Improving binary data handling functions

[coyo-t]

As someone that works a lot with binary formats, I find Godot's File.* (or FileAccess.* in GD 4?) functions incredibly lacking and janky (especially coming from Gamemaker, where the buffer_* functions are very nearly perfect to me, though are lacking in some text-oriented functions).

Originally I had a large list of points about FileAccess's methods and how bizzare and disjointed they are compared to buffer_*'s, but then I took a look at PackedByteArray's methods and hey! It's fairly synonymous with GM's buffer_* functions! Except it lacks the cursor capabilities of buffer and FileAccess. And both FileAccess and PackedByteArray lack the cursor handling modes and alignment abilities buffer has to offer (IE buffer_fixed/grow/wrap).

So I want to look into what can be done about this. Ideally, I'd just have GM's buffer ported over near-verbatim into GD, with the added feat that it's general purpose (IE can work with PackedByteArray or file streams, of which buffer can only do the GM equivalent of the former). However that's probably an undertaking and a half, so it'd probably just be easier to make the two (FA and PBA) on-par with each other and eventually that could be condensed into one generic Buffer system.
Or maybe just port buffer over verbatim but have it not be a generic takeover of FA and PBA's encoding/decoding abilities, and just have it be its own thing that can be dumped to a PBA. I think that one's the easiest of the 3, but I'd like to know from someone more familiar with GD's internals than I am.

[Zireael07]

Drive by comment:

1. I wanted to use binary serialization but without using File (just for in-memory storage). The fact you can't do this is NOT called out in the Binary serialization docs page...
2. Buffers or strings of bytes or whatever you call them should have a function to convert them to int (for what is called "packing" stuff in integers)