WinSquish

A Windows file-manager for SQUISH archives — browse a .sqsh archive like a folder, drill into its tree, and extract files without inflating the rest. Built as a WPF (.NET 10) desktop app over the native libsquish (squish.dll) through a thin P/Invoke layer.

What it does

• Open & browse any SQUISH archive — an Explorer-style layout with a folder tree, a details list (name · type · size · packed size · % saved), a breadcrumb, and a status bar. Folder rows show aggregated sizes and ratios.
• Extract the whole archive, a selected subtree, or a single file — each member seeks straight to its own blocks, so you never inflate the rest.
• Preview a file: double-click to extract it to a temp folder and open it in its default app. Save As writes one file wherever you choose.
• Create a new archive by compressing a folder (uses all cores).
• Multi-select with Ctrl/Shift click, Ctrl+A select-all, a right-click context menu (Open · Extract · Save As · Select All · Extract All), and drag files straight out to Explorer.
• Drag & drop an archive onto the window to open it.

Every extraction is checksum-verified by libsquish (each coded block carries a 32-bit checksum of its original bytes).

Windows shell integration

WinSquish registers itself as the handler for .sqsh / .sq and adds Explorer right-click menus. The app is the single source of truth — it writes the keys itself, so the installer just calls it:

WinSquish.exe --register [--allusers] [--quiet]     # HKLM with --allusers, else HKCU
WinSquish.exe --unregister [--allusers] [--quiet]

That adds:

• On a .sqsh / .sq file: Open with WinSquish, Extract Here, Extract to folder\ — each is a one-shot GUI action with a progress window.
• On any folder: Compress to SQUISH archive → <folder>.sqsh.

The same one-shot actions are available on the command line:

WinSquish.exe archive.sqsh            # open & browse
WinSquish.exe --extract-here a.sqsh   # extract into the archive's own folder
WinSquish.exe --extract-to   a.sqsh   # extract into a subfolder named after it
WinSquish.exe --compress     path     # compress a file or folder to path.sqsh

You can also click “Make WinSquish the default for .sqsh files” on the welcome screen to register for your account (no admin needed).

Installer

An Inno Setup installer builds a single winsquish-setup.exe that installs a self-contained build (no .NET runtime prerequisite), offers per-user or all-users scope, wires up the file associations and context menus via --register, and cleanly unregisters on uninstall.

REM needs Inno Setup 6.3+ on PATH or in Program Files
installer\build-installer.bat
REM -> build\winsquish-setup.exe

Code signing

The build signs everything with Azure Trusted Signing: the app binaries (WinSquish.exe, WinSquish.dll, squish.dll) and the installer plus its embedded uninstaller, SHA-256 and RFC-3161 timestamped.

Signing is driven by installer\sign.bat — a wrapper around the sign dotnet tool — and turns on automatically whenever installer\signer.json is present. That file holds the Trusted Signing account details; they are identifiers only, no secrets, so it is committed:

{
  "endpoint": "https://eus.codesigning.azure.net/",
  "account": "SullivanTechnology",
  "certificateProfile": "Personal",
  "timestampUrl": "http://timestamp.acs.microsoft.com/"
}

Authentication uses your Azure credentials through the tool's DefaultAzureCredential chain — no key material ever touches the repo:

• Locally — run az login once.
• CI — set AZURE_TENANT_ID / AZURE_CLIENT_ID / AZURE_CLIENT_SECRET, or use a managed / workload identity.

Install the signing tool once, then just build:

dotnet tool install --global sign --prerelease   # one-time prerequisite

installer\build-installer.bat   # everything comes out signed + timestamped

Any SIGN_ENDPOINT, SIGN_ACCOUNT, SIGN_CERTIFICATE_PROFILE, or SIGN_TIMESTAMP_URL environment variable overrides the matching signer.json field (handy in CI). To build without signing — e.g. a contributor without access to the signing account — remove or rename installer\signer.json and the build skips signing entirely. See installer\sign.bat for the full contract.

Requirements

• Windows 10 / 11, x64.
• .NET 10 SDK to build (or the .NET Desktop Runtime 10 to run a published build).
• squish.dll (x64). By default the build looks for it at ..\squish\squish.dll — the sibling SQUISH checkout. The DLL is self-contained (statically linked; it only needs KERNEL32), so nothing else is required.

Build & run

# from the repo root
dotnet build -c Release

# run it (squish.dll is copied next to the exe automatically)
dotnet run --project src -c Release
# ... or open an archive straight away:
dotnet run --project src -c Release -- path\to\archive.sqsh

If your squish.dll lives elsewhere, point the build at it:

dotnet build -c Release -p:SquishDll=C:\path\to\squish.dll

Architecture

src/
  Interop/          P/Invoke over squish.dll
    SquishNative.cs   raw extern declarations (1:1 with squish.h)
    SquishArchive.cs  resource-safe managed wrapper (open/list/extract/create)
    SquishException.cs status-code -> exception
  Models/
    ArchiveNode.cs    flat '/'-separated entry list -> browsable folder tree
  Mvvm/               ObservableObject + RelayCommand
  Shell/
    ShellIntegration.cs  register/unregister file types + Explorer verbs
  StartupOptions.cs   parses the command line into one startup action
  ViewModels/
    MainViewModel.cs  owns the archive, drives navigation & async operations
  Views/
    MainWindow.xaml   toolbar · breadcrumb · tree · details · status · overlay
    Converters.cs     byte/ratio/glyph formatting
  Themes/Styles.xaml  the light "fluent" theme (buttons, tree, list, progress)
  assets/winsquish.ico  app + window icon
installer/
  winsquish.iss       Inno Setup script (per-user / all-users)
  build-installer.bat publish + compile the installer
  sign.bat            Azure Trusted Signing wrapper (the 'sign' tool)
  signer.json         Trusted Signing account details (identifiers, no secrets)

All libsquish calls funnel through SquishArchive, which serializes them on the handle; long operations (open, extract, create) run on a background thread and report progress to a busy overlay. The archive handle is opened once and its entry index read eagerly, so browsing is instant and only extraction touches the compressed data.

Notes

• SQUISH trades CPU for ratio (~0.5–0.7 MB/s, symmetric). Extracting or creating a large archive takes real time; the progress overlay shows bytes and throughput.
• Directory members, empty directories, and Unix permission bits are preserved by the format and surfaced in the list.
• Extraction refuses absolute paths and .., so an archive can never write outside the folder you pick (enforced by libsquish).

License

GPL-3.0-or-later, matching SQUISH. © 2026 Paige Julianne Sullivan.