[Suggestion] Add Zstd (Seekable) support

[crashGG]

Zstd (Seekable) Supports random access, allowing direct jump to a specified byte.

It doesn't require consuming memory or decompress to a temporary directory. Furthermore, it leverages zstd's extremely fast decompression capabilities (even faster than copying files in certain scenarios).
Official documentation：
https://github.com/facebook/zstd/blob/dev/contrib/seekable_format/zstd_seekable_compression_format.md

Open source Rust implementation:

https://github.com/rorosen/zeekstd

https://github.com/3leaps/seekable-zstd

[drpetersonfernandes]

Thank you for the suggestion and the detailed references.

After thorough research, I've decided to decline this feature request for the following reasons:

No C# library exists

There is zero C# or .NET implementation of the Zstd Seekable format. I searched GitHub, NuGet, and the broader ecosystem. The only implementations are in C (the contrib folder in the zstd repo) and Rust (zeekstd). Implementing this would require either porting the C code to C# or shipping a native DLL with P/Invoke bindings — both are significant efforts.

No mainstream tools create this format

The Zstd Seekable format is not supported by any mainstream archive tool (7-Zip, WinRAR, PeaZip, etc.). Users would need to use a niche Rust CLI tool (zeekstd) or write custom code to create seekable .zst files. This means almost no user would have files in this format to mount.

The format is still experimental

The seekable format specification is at version 0.1.0 (since 2017) and lives in the contrib folder of the zstd repository — it is not part of the official Zstandard specification (RFC 8878).

What we support today

SimpleZipDrive currently supports ZIP, 7Z, and RAR via SharpCompress, which covers the vast majority of use cases.

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If the Zstd Seekable format matures, gains mainstream tooling support, and a C# library becomes available, I'd be happy to revisit this. For now, the development effort far outweighs the potential user benefit.

[drpetersonfernandes]

I am trying to port the library to pure c#
Give me some days