bit7z

A C++ static library offering a clean and simple interface to the 7-zip DLLs

Supported Features • Getting Started • Download • Requirements • Building • Donations • License

Introduction

bit7z is a C++ static library which allows to compress and extract many file archive formats, all through a clean, simple and entirely object-oriented interface to the dynamic libraries from the 7-zip project (https://www.7-zip.org/).
It supports compression and extraction to and from the filesystem or the memory, reading of archives metadata, multi-volume archives, operation progress callbacks and many other functionalities.

Supported Features

Compression of files and directories in the following archive formats: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM.
Extraction of the following archive formats: 7z, AR, ARJ, BZIP2, CAB, CHM, CPIO, CramFS, DEB, DMG, EXT, FAT, GPT, GZIP, HFS, HXS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RAR5, RPM, SquashFS, TAR, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR, XZ, Z and ZIP.
Reading metadata of archives and of their content (from v3.x)
Testing archives for errors (from v3.x)
Compression and extraction to and from memory (from v2.x — compression to memory is supported only for BZIP2, GZIP, XZ and TAR formats).
Compression using a custom directory system in the output archives (from v3.x)
Selective extraction of only specified files/folders contained in archives (from v3.x)
Creation of encrypted archives (strong AES-256 encryption — only for 7z and ZIP formats).
Archive header encryption (only for 7z format).
Choice of the compression level (from none to ultra, not all supported by every output archive format).
Solid archives (only for 7z).
Multi-volume archives (from v2.1.x).
Operation callbacks, through which it is possible to obtain real time information about the ongoing extraction or compression operation (from v2.1.x).

Please note that the presence or not of some of the above features depends on the particular .dll used along with bit7z. For example, the 7z.dll should support all these features, while 7za.dll should support only the 7z file format and the 7zxa.dll can only extract 7z files. For more information about the 7z SDK DLLs, please see this wiki page.

Getting Started (Library Usage)

Below are a few examples that show how to use some of the main features of bit7z:

Extracting files from an archive

Bit7zLibrary lib( L"7za.dll" );
BitExtractor extractor( lib, BitFormat::SevenZip );

//extracts a simple archive
extractor.extract( L"path/to/archive.7z", L"output/dir/" );

//extracts a specific file from the archive
extractor.extractMatching( L"path/to/archive.7z", L"file.pdf", L"output/dir/" );

//extracts the first file of an archive to a buffer
vector<byte_t> buffer;
extractor.extract( L"path/to/archive.7z", buffer );

//extracts an encrypted archive
extractor.setPassword( L"password" );
extractor.extract( L"path/to/another/archive.7z", L"output/dir/" );

Compressing files into an archive

Bit7zLibrary lib( L"7z.dll" );
BitCompressor compressor( lib, BitFormat::Zip );

std::vector<std::wstring> files = { L"path/to/file1.jpg", L"path/to/file2.pdf" };
//creates a simple zip archive of two files
compressor.compress( files, L"output_archive.zip" );

std::map<std::wstring, std::wstring> files_map = { { L"path/to/file1.jpg",L"alias/path/file1.jpg" },
 { L"path/to/file2.pdf", L"alias/path/file2.pdf" } };
//creates a zip archive with a custom directory structure
compressor.compress( files_map, L"output_archive2.zip" );

//compresses a directory
compressor.compressDirectory( L"dir/path/", L"dir_archive.zip" );

//creates an encrypted zip archive of two files
compressor.setPassword( L"password" );
compressor.compressFiles( files, L"protected_archive.zip" );

//compresses a single file into a buffer
vector<byte_t> buffer;
BitCompressor compressor2( lib, BitFormat::BZip2 );
compressor2.compressFile( files[0], buffer );

Reading archive metadata

Bit7zLibrary lib( L"7za.dll" );
BitArchiveInfo info( lib, L"archive.7z", BitFormat::SevenZip );

//printing archive metadata
wcout << L"Archive properties" << endl;
wcout << L" Items count: "   << info.itemsCount() << endl;
wcout << L" Folders count: " << info.foldersCount() << endl;
wcout << L" Files count: "   << info.filesCount() << endl;
wcout << L" Size: "          << info.size() << endl;
wcout << L" Packed size: "   << info.packSize() << endl;
wcout << endl;

//printing archive items metadata
wcout << L"Archive items";
auto arc_items = info.items();
for ( auto& item : arc_items ) {
    wcout << endl;
    wcout << L" Item index: "   << item.index() << endl;
    wcout << L"  Name: "        << item.name() << endl;
    wcout << L"  Extension: "   << item.extension() << endl;
    wcout << L"  Path: "        << item.path() << endl;
    wcout << L"  IsDir: "       << item.isDir() << endl;
    wcout << L"  Size: "        << item.size() << endl;
    wcout << L"  Packed size: " << item.packSize() << endl;
}

A complete API reference is available in the wiki section.

Download

The released packages contain a precompiled version of the library (both in debug and release mode) and the public API headers that are needed to use it in your program; they are available for both x86 and x64 architectures.

Obviously, you can also clone/download this repository and build the library by yourself (please, see the wiki).

Requirements

Target OS: Windows (both x86 and x64).
Compiler: MSVC 2012 or greater (MSVC 2010 supported until v2.x).
DLLs: 7-zip DLLs (v18.05).

The 7-zip dlls are not shipped with bit7z but they are available at 7-zip.org

Note: in order to use this library you should link your program not only with bit7z but also with oleaut32 and user32 (e.g. -lbit7z -loleaut32 -luser32)

Note 2: even if compiled with the latest version of 7-zip, bit7z should work also with the dlls of previous versions, such as v16.04. However, it is strongly suggested to use dlls with the same version.

Note 3: the code has been tested with MSVC 2012, 2015 and 2017.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Sqdwr/bit7z