---
title: "Single compressed files and .tar.* archives"
url: https://recursiveai.org/onearchive/docs/single-streams/
description: "A .gz, .bz2, .zst, .lz4, .xz or .lz file that holds no container is an archive of one file (ArchiveFormat.SingleStream). Brotli (.br) has no magic number…"
version: "1.0.0"
source: https://github.com/recursive-ai-oss/onearchive-csharp/blob/38be9d7d05d1001649666d9a7200353750bd4a16/docs/single-streams.md
---

# Single compressed files and .tar.* archives

A `.gz`, `.bz2`, `.zst`, `.lz4`, `.xz` or `.lz` file that holds no container is an archive of one file (`ArchiveFormat.SingleStream`).
Brotli (`.br`) has no magic number, so it is recognised by its file name only. A tar inside any of these is one archive. The
normative rules (detection order, the entry name, writing) are in `archive.md` ("Detection", "Single compressed files").

| | |
|---|---|
| Types | `SingleStreamReader`, `SingleStreamWriter`, `ArchiveCompression` |
| Detection | magic bytes first, then the first 512 bytes of the decompressed stream, then the file name |
| Entry name | the gzip header's file name, else the archive name without its compression extension, else `data` |
| Writing | exactly one regular file; levels through `ArchiveCreateOptions.CompressionLevel` |
| Limits | the whole decompressed stream is metered against `MaxTotalSize` and `MaxExpansionRatio`; the window (Zstandard) or dictionary (xz, lzip) a stream may declare is limited by `MaxWindowSize`, 8 MiB by default |