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The .nx Archive Format (Rust Edition)



High Performance File Format
For Loading and Sharing Mods.

GitHub Workflow Status

About

The Nexus (.nx) format is a semi-SOLID archive format, using modern compression technologies such as ZStandard and LZ4 under the hood.

flowchart TD
    subgraph Block 2
        BigFile1.bin
    end

    subgraph Block 1
        BigFile0.bin
    end

    subgraph Block 0
        ModConfig.json -.-> Updates.json
        Updates.json -.-> more["... more .json files"]
    end

Between size optimized SOLID archives like .7z w/ LZMA and non-SOLID archives like .zip w/ Deflate, the .nx format bridges the gap; reaping most of the benefits from both worlds.

Nx aims to be a simple format, appropriate for both local storage of mods and for downloading from the web.

Motivations

Why does Nx exist?

  • For Fast Random Access

Nx uses small SOLID blocks, for grouping small files where SOLID compression matters the most.
Large files can be split up into multiple blocks, with parallel decompression.

Combine with single core LZ4 and ZStandard algorithms for decent random access speeds.

  • For Reducing Storage Sizes

For longer term archival; Nx is designed to bring top of the line compression to filesystems that don't support it.
Wouldn't it be cool to store your mods compressed? I think so.

  • For File Downloads

This format allows us to do partial downloads of mods. If only a few files in a mod were updated; why should you need to download the entire thing again?

In the Nexus Mods App

Nx was originally designed by me for the Nexus Mods App; to allow recompressing of legacy uploaded mods for faster deployment and re-deployment.

And of course, for the community ❤️ 😺.

Why Rust?

I originally designed and created Nx for the Nexus Mods App

The transition to Rust here is mainly for technical reasons involving my own required use cases.

  • .NET cannot be safely used for hooking Operating System APIs.

    • This is due to GC Transitions.
    • I need this for building Nx Accelerated Virtual File Systems.

  • The Reloaded3 Project requires more portability than what .NET targets.

    • R3 aims to support esoteric platforms like embedded devices and consoles wherever possible.
    • .NET (C#) is not available on these platforms, but LLVM (and thus Rust) often are.
    • Using NativeAOT would massively bloat the binary size.
    • The rest of the R3 ecosystem is in Rust, which leads to binary savings thanks to code reuse.

Technical Questions

If you have technical questions, direct them to library & docs author @Sewer56 via one of these methods:

Happy Hacking ❤️