Contributing to 7-Zip

Overview

7-Zip is a file archiver developed and maintained by Igor Pavlov. The project is open source and distributed under the GNU LGPL license (with some exceptions for specific components). 7-Zip Copyright (C) 1999-2026 Igor Pavlov.

Source Code Repository

The 7-Zip source code is organized into several main directories:

DOC - Documentation files
Asm - Optimized assembler code for CRC, SHA, AES, and LZMA decoding
C - Source code in C
CPP - Source code in C++
- Common - Common files for C++ projects
- Windows - Windows-specific code
- 7zip - Core 7-Zip modules

Compilation Instructions

Compiling on Windows

To compile 7-Zip on Windows, you need Visual Studio or Windows SDK.

Windows Compilation Options

Supported Platforms:

x86 (Visual C++ 6.0 with Platform SDK or VS 2017/2019/2022)
x64 (Windows Server 2003 R2 Platform SDK or VS 2017/2019/2022)
arm64 (VS 2017/2019/2022)
arm (VS 2017/2019/2022)
ia64 (Windows Server 2003 R2 Platform SDK)

Required Tools:

Microsoft Macro Assembler (ml.exe for x86, ml64.exe for x64)

Compile Options:

Via makefile (recommended for production):

cd SRC\CPP\7zip
%comspec% /k "C:\Program Files\VS2022\VC\Auxiliary\Build\vcvars64.bat"
nmake

Via DSP file in Visual Studio (for development/debugging)

Makefile Macros:

PLATFORM - x64, x86, arm64, arm, ia64
OLD_COMPILER - for old VC compilers like MSVC 6.0
MY_DYNAMIC_LINK - for dynamic linking to msvcrt.dll

Compiling on Linux/macOS

7-Zip can be compiled on Unix-like systems using GCC or Clang.

Linux/macOS Compilation Options

Assembler Support:For optimal performance, you can compile with assembler code:

x86/x86-64: Requires MASM syntax assembler (Asmc or UASM)
- Asmc: https://github.com/nidud/asmc
- UASM: https://github.com/Terraspace/UASM
arm64: Uses GNU assembler (supported by GCC/Clang)

Basic Compilation:

cd CPP/7zip/Bundles/Alone2
make -j -f makefile.gcc

Optimized Compilation:

# GCC without assembler
make -j -f ../../cmpl_gcc.mak

# Clang without assembler
make -j -f ../../cmpl_clang.mak

# GCC x86-64 with assembler
make -j -f ../../cmpl_gcc_x64.mak

# GCC arm64 with assembler
make -j -f ../../cmpl_gcc_arm64.mak

# macOS arm64
make -j -f ../../cmpl_mac_arm64.mak

Makefile Variables:

USE_JWASM=1 - Use JWasm instead of Asmc (note: JWasm doesn’t support AES instructions)
DISABLE_RAR=1 - Remove all RAR-related code
DISABLE_RAR_COMPRESS=1 - Remove RAR decompression codecs (keeps archive listing/stored file extraction)

Using UASM:

UASM="$PWD/GccUnixR/uasm"
cd "7zip-src/CPP/7zip/Bundles/Alone2"
make -f makefile.gcc -j IS_X64=1 USE_ASM=1 MY_ASM="$UASM"

Build Targets

The 7-Zip source can be compiled into various binaries:

Target	Description
7za.exe	Standalone console version (7z/xz/cab/zip/gzip/bzip2/tar)
7zz.exe	Standalone console version (all formats)
7zr.exe	Standalone console version (7z only, reduced)
7z.exe	Console version
7zFM.exe	7-Zip File Manager
7zG.exe	7-Zip GUI version
7z.dll	DLL supporting all formats
7za.dll	DLL for .7z support
7-zip.dll	7-Zip Shell extension
lzma.exe	LZMA compression/decompression

Development Guidelines

Code Organization

7-Zip uses a modular COM-based architecture (though it doesn’t use standard COM interfaces):

7zip/Common - Common modules
7zip/Archive - Archive format handlers
7zip/Compress - Compression/decompression algorithms
7zip/Crypto - Encryption/decryption
7zip/UI - User interface components
7zip/Bundle - Standalone module bundles

Using 7-Zip DLLs

See the 7zip/UI/Client7z folder for examples of using 7-Zip DLL files.

Some DLL files may depend on other 7-Zip DLLs. For standalone DLLs without dependencies, use bundle versions like 7zip/Bundles/Format7z.

RAR Support Compilation Options

RAR decompression codecs have additional license restrictions that may not be fully compatible with free-software licenses.

When compiling, you can control RAR support:

Full RAR support (default) - Includes all RAR decompression capabilities
DISABLE_RAR_COMPRESS=1 - Removes “not fully free” RAR decompression codecs. 7-Zip can still:
- Open RAR archives
- List files
- Extract stored (uncompressed) files
DISABLE_RAR=1 - Completely removes RAR support

LZMA SDK

The 7-Zip source package includes files from LZMA SDK, which is written and placed in the public domain by Igor Pavlov. LZMA SDK is available separately at: http://www.7-zip.org/sdk.html

7-Zip vs p7zip

There are two different ports of 7-Zip for Linux/macOS:

p7zip - Independent port (latest version 16.02, now outdated)
- http://sourceforge.net/projects/p7zip/
7-Zip for Linux/macOS - Official port with all changes from latest Windows version
- Recommended for new projects

These ports are not identical. Some Linux-specific features may be better implemented in p7zip.

Additional Resources

7zC.txt - 7z ANSI-C Decoder description
7zFormat.txt - 7z format specification
Methods.txt - Compression method IDs
lzma.txt - LZMA compression description
src-history.txt - Source code change history

Contact

Igor Pavlov
http://www.7-zip.org

Building from Source

SDK & Integration

Contributing

Contributing to 7-Zip

Overview

Source Code Repository

Compilation Instructions

Compiling on Windows

Compiling on Linux/macOS

Build Targets

Development Guidelines

Code Organization

Using 7-Zip DLLs

RAR Support Compilation Options

LZMA SDK

7-Zip vs p7zip

Additional Resources

Contact

​Overview

​Source Code Repository

​Compilation Instructions

​Compiling on Windows

​Compiling on Linux/macOS

​Build Targets

​Development Guidelines

​Code Organization

​Using 7-Zip DLLs

​RAR Support Compilation Options

​LZMA SDK

​Related Projects

​7-Zip vs p7zip

​Additional Resources

​Contact

Overview

Source Code Repository

Compilation Instructions

Compiling on Windows

Compiling on Linux/macOS

Build Targets

Development Guidelines

Code Organization

Using 7-Zip DLLs

RAR Support Compilation Options

LZMA SDK

Related Projects

7-Zip vs p7zip

Additional Resources

Contact