A wrapper over lib7zip so it can be used from C without callbacks.

This project exists to enable calling 7-zip from Go via sevenzip-go. These shared libraries are packed as sidecar files with butler to facilitate extraction of archives. Butler dynamically loads these libraries at runtime for all archive extraction, as 7-zip supports a wide range of archive formats (zip, tar, gzip, rar, 7z, and many others).

lib7zip is vendored in vendor/lib7zip/, originally based on https://github.com/stonewell/lib7zip.

The library is built using CMake. A convenience Makefile wraps the CI build scripts for local development:

make build          # Build for current OS/architecture
make test           # Run test suite (after build)
make clean          # Remove build artifacts

The Makefile auto-detects your OS and architecture. To cross-compile or override:

make build OS=linux ARCH=arm64
make build OS=darwin ARCH=amd64

If all goes well, libc7zip.{dll,so,dylib} will be in the build/ folder.

The full CI build is orchestrated by release/ci-compile.js and builds for multiple platforms:

• Linux: amd64, arm64
• macOS: amd64 (Intel), arm64 (Apple Silicon)
• Windows: 32-bit (386), 64-bit (amd64), ARM64

On Linux and macOS, the build compiles from official 7-Zip source (version 25.01). The build produces:

• libc7zip.so / libc7zip.dylib - The wrapper library
• 7z.so - The 7-zip engine (built from 7-zip source)

Windows builds work differently. Instead of compiling 7-zip from source, the build downloads official pre-built 7-zip installers from https://7-zip.org/a/ (version 25.01) and extracts the 7z.dll from them. The wrapper library c7zip.dll is still compiled from source using Visual Studio.

The Windows build produces:

• c7zip.dll - The wrapper library (built from source)
• 7z.dll - The 7-zip engine (extracted from official MSI)

The built libraries are deployed to https://itchio.itch.io/libc7zip where butler can fetch them as needed.

• libc7zip itself is distributed under the MIT license (see the LICENSE file)
  • except for the utf conversion code, which is LGPL 2.1 (from 7-zip)
• lib7zip is distributed under the MPL 2.0 license (see vendor/lib7zip/COPYING)
• 7-zip is LGPL 2.1 + some other terms, depending on which build you use: http://7-zip.org/faq.html