# Format support

## Version 0.1.0 support matrix

| Input or feature                   | Status                 | Tested evidence and boundary                                                                      |
| ---------------------------------- | ---------------------- | ------------------------------------------------------------------------------------------------- |
| Desktop revision-store `.one`      | Supported subset       | Real 34,904-byte Joplin golden; three pages                                                       |
| FSSHTTP-packaged `.one`            | Unsupported            | Header is detected and rejected with a controlled diagnostic                                      |
| Unknown/legacy `.one` variants     | Unsupported            | File type and format GUIDs are validated before traversal                                         |
| `.onepkg`, single CAB, LZX         | Supported subset       | Real Joplin package: LZX `0x1203`, three CFDATA blocks, seven entries, five sections, seven pages |
| CAB LZX `0x1303`                   | Supported extraction   | Byte-for-byte rust-cab MIT unit fixture, two text entries                                         |
| CAB without compression            | Supported extraction   | Byte-for-byte rust-cab MIT unit fixture                                                           |
| CAB MSZIP                          | Supported extraction   | rust-cab single-block fixture plus a generated two-block dictionary-chain fixture                 |
| CAB Quantum                        | Unsupported            | Metadata is recognized; extraction fails with `cab-compression-unsupported`                       |
| Multi-cabinet CAB / spanning files | Unsupported            | Header flags and spanning folder indexes are rejected                                             |
| `.onetoc2` package entries         | Listed only            | Files are identified, but notebook hierarchy and section order are not interpreted                |
| Standalone `.onetoc2`              | Unsupported in the app | The picker accepts only `.one` and `.onepkg`                                                      |

“Supported subset” is intentionally narrower than “all files with this
extension.” A successful open requires the tested desktop OneStore structures
and content graph nodes. Malformed offsets, counts, references, CAB checksums,
paths, compressed data, and unsupported variants produce bounded diagnostics or
a controlled failure.

The default LZX limit accepts CAB window sizes through 8 MiB, but compatibility
claims are fixture-backed only for window bits 18 (`0x1203`) and 19 (`0x1303`).
MSZIP validates the `CK` prefix, limits each compressed block to 32 KiB + 12,
decodes into a fixed-size output buffer, requires the declared output length,
and carries at most 32 KiB of history between blocks in one folder. The MSZIP
tests establish CAB extraction behavior; no redistributable MSZIP-compressed
OneNote export is currently present, so they do not establish producer-specific
`.onepkg` compatibility.
Trailing CAB data is ignored with a warning. Reserved CAB areas are bounded and
skipped. CAB names are decoded as strict UTF-8; unmarked valid UTF-8 receives a
warning, while invalid non-ASCII legacy-code-page names are rejected rather
than guessed.

## Extracted OneNote data

The desktop section path currently returns:

- section display name;
- page ID, title, created/updated timestamp when available, and page level;
- visible Unicode/extended-ASCII rich text as plain text and a text preview;
- diagnostics tied to an offset, structure, or page where available.

It does not preserve visual position, rich-text formatting, list formatting,
tables, images, ink, equations, embedded files, audio/video, active links,
page versions/conflicts, or exports. Unsupported content objects remain visible
as diagnostics instead of being silently presented as parsed.

Within a supported `.onepkg`, each `.one` entry is parsed independently.
Malformed or unsupported sections are marked failed/unsupported while other
sections remain available. Package navigation is temporary normalized-path
order until `.onetoc2` interpretation is implemented.

## Test fixtures

The exact hashes, source revisions, licences, expected page names, and CAB
structures are recorded in
[`tests/fixtures/README.md`](../tests/fixtures/README.md). Tests use no private
notebooks and do not treat a synthetic archive as proof of Microsoft OneNote
export compatibility.