Nsis7z NSIS Plugin

NSIS plugin for extracting 7z, ZIP and NSIS archives.

---

Available Versions

Version	7-Zip	Formats	Notes
19.00	7-Zip 19.00	7z, LZMA, XZ, Split	Original updated version
25.01	7-Zip 25.01	7z, ZIP, LZMA, XZ, Split, NSIS	With NSIS archive support
26.00	7-Zip 26.00	7z, ZIP, LZMA, XZ, Split, NSIS	Recommended

Supported Architectures

Architecture	Description
x86-ansi	32-bit ANSI (legacy)
x86-unicode	32-bit Unicode
amd64-unicode	64-bit Unicode

Quick Start

!addplugindir "plugins\x86-unicode"

Section
  ; Simple extraction (7z, ZIP, NSIS)
  Nsis7z::Extract "$EXEDIR\data.7z"

  ; With progress text in label
  Nsis7z::ExtractWithDetails "$EXEDIR\data.7z" "Installing %s..."

  ; With callback to show files in listbox
  GetFunctionAddress $0 MyExtractCallback
  Nsis7z::ExtractWithFileCallback "$EXEDIR\data.7z" $0
SectionEnd

Function MyExtractCallback
  Pop $0   ; completedSize
  Pop $1   ; totalSize
  Pop $2   ; fileName
  DetailPrint "$2"
FunctionEnd

Build Scripts

The repo includes a single unified build_plugin.py script that replaces the previous per-version scripts.

Build

# Recommended: 7-Zip 26.00 with auto-detected toolset
python build_plugin.py

# Select 7-Zip version (19.00 | 25.01 | 26.00)
python build_plugin.py --7zip-version 25.01

# Specific toolset (2022|2026|auto)
python build_plugin.py --toolset 2022

# Print version and exit
python build_plugin.py --version

Repository Structure

ns7zip/
├── build_plugin.py              # Unified build script (all versions)
├── rebuild_nsis7z1900-src.ps1   # Rebuilds 19.00 sources
├── 7zip-19.00/                  # 7-Zip 19.00 modified
├── 7zip-25.01/                  # 7-Zip 25.01 modified (ZIP + NSIS handler)
└── 7zip-26.00/                  # 7-Zip 26.00 modified (ZIP + NSIS handler)

Changes from Original

NSIS Archive Handler (25.01, 26.00)

Added support for extracting .exe archives created with NSIS (not present in the original plugin):

• Archive\Nsis\NsisHandler.cpp/h
• Archive\Nsis\NsisIn.cpp/h
• Archive\Nsis\NsisDecode.cpp/h
• Archive\Nsis\NsisRegister.cpp
• Compress\BZip2Decoder.cpp/h (required by NsisDecode)
• Compress\BZip2Crc.cpp

Bug Fixes (25.01, 26.00)

• Divide-by-zero: added guard if (totalSize == 0) return 0 in GetPercentComplete
• ExtractWithFileCallback: NSIS callback triggered only on filename change (avoids crash with totalSize = UINT64_MAX on first SetTotal call)

License

• 7-Zip: LGPL 2.1 + BSD 3-clause
• NSIS Plugin: Afrow UK

Credits

• Igor Pavlov (7-Zip)
• Afrow UK (Original plugin)
• Simone (x64 support, VS2022/VS2026, ZIP, NSIS handler, ExtractWithFileCallback)

---

See README_IT.md for the Italian version.