SteamKit VPK

This crate is a simple library to help parse and read files based on the VPK file format.

To-do

• [ ] Remove the CS:GO & Portal 2 dir assets (even though they mostly only describe the rest of the pack).
• [ ] Add some generated/custom packs for testing reading and value checking.
• [ ] Add a test for reading data from preload.
• [ ] Add a test for reading from data section.
• [ ] Add a test for reading from a separate archive-part.
• [x] Optimize the tree parser (with capacity hints).