poka.sh

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ZST

Generated by scripts/gen-format-pages.py from docs/data/format-metadata/, FILE_FORMATS.csv and docs/formats-master.csv. Do not edit by hand: change the source, then run the script.

Zstandard Preview.

At a glance
Purpose A Zstandard-compressed file: one or more frames of zstd data, possibly with skippable frames.
Extensions .zst
Poka parser poka-zst
Viewer poka-metadata-card-viewer
Depth tier Metadata card (see Depth tiers)
Breadth tier B4 Summary (see Breadth tiers)

How much Poka reads

B4 Summary. The container and metadata are read and summarised (counts, properties, structure), but the main content is not rendered.

Confidence: medium (the reviewer read the code). Basis: Reviewed 2026-10-26: read parsers/poka-zst/src/main.rs (508 lines) and plugin.json. The five unit tests cover the frame walk and the truncation findings; corpus_zsts_have_no_integrity_findings runs the corpus testZSTD.zst through the integrity check. Covers .zst and .zstd. The card walks every frame: standard and skippable frame counts, skippable bytes, the implied total content size and, for the first frame, content size, window size, dictionary ID, checksum flag and single-segment flag; a file that ends inside a frame is flagged. Judgement: B4: the stream's structure is walked and summarised, but nothing is decompressed.

What Poka does not read

  • The data is not decompressed, so the content is not shown
  • Frame details are shown for the first frame only
  • XXH64 checksums are not verified
  • Files over 16 GiB are cut (flagged)

Libraries

Libraries Poka uses or has assessed for this format, with the status, licence and language the registry records.

  • ruzstd (candidate; MIT; Rust; https://github.com/KillingSpark/zstd-rs) — Pure-Rust Zstandard decoder (complete) and encoder; no_std with alloc; README says actively maintained.
  • zstd (zstd-rs) (candidate; BSD-3-Clause; Rust (wraps C); https://github.com/gyscos/zstd-rs) — Rust binding to the C zstd library; bundled C library is dual BSD/GPLv2; C build needed for wasm.
  • zstd (reference implementation) (candidate; BSD-3-Clause OR GPL-2.0; C; https://github.com/facebook/zstd) — Reference library and CLI; README states dual BSD OR GPLv2.
  • zzz-arc (candidate; MIT; Rust; https://github.com/redthing1/zzz) — A fast compression multitool supporting zst, tgz, txz, zip, and 7z formats with optional encryption; v0.4.3, updated 2026-03-15; matched on lib.rs, not tested
  • ndjson_zst (candidate; MIT; Rust; https://crates.io/crates/ndjson_zst) — simple nsjson zst reader/writer; v0.2.0, updated 2024-05-16; matched on lib.rs, not tested

Sources

  • parsers/poka-zst/src/main.rs
  • parsers/poka-zst/plugin.json