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bit7z is a cross-platform C++ static library that allows the compression/extraction of archive files through a clean and simple wrapper interface to the dynamic libraries from the 7-zip project.
It supports compression and extraction to and from the filesystem or the memory, reading archives metadata, updating existing ones, creating multi-volume archives, operation progress callbacks, and many other functionalities.
- Compression using the following archive formats: 7z, XZ, BZIP2, GZIP, TAR, ZIP, and WIM.
- Extraction of many 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 their content.
- Testing archives for errors.
- Updating existing file archives with new files.
- Renaming, updating, or deleting old items in existing file archives.
- Compression and extraction to and from memory and C++ standard streams.
- Compression using custom path aliases for the items in the output archives.
- Selective extraction of only specified files/folders using wildcards and regular expressions.
- Creation of encrypted archives (strong AES-256 encryption; only for 7z and ZIP formats).
- Archive header encryption (only for 7z format).
- Possibility to choose the compression level (if supported by the archive format), the compression method (supported methods), the dictionary size, and the word size.
- Automatic input archive format detection.
- Solid archives (only for 7z).
- Multi-volume archives.
- Operation callbacks for obtaining real-time information about ongoing operations.
- Canceling or pausing the current operation.
The presence or not of some of the above features depends on the particular shared library used along with bit7z.
For example, 7z.dll should support all these features, 7za.dll should work only with the 7z file format, and 7zxa.dll can only extract 7z files. For more information about the 7-zip DLLs, please check this wiki page.
In the end, some other features (e.g., automatic format detection and selective extraction using regular expressions) are disabled by default, and macro definitions must be used during compilation to have them available (wiki).
Below are a few examples that show how to use some of the main features of bit7z.
#include <bit7z/bitfileextractor.hpp>
try { // bit7z classes can throw BitException objects
using namespace bit7z;
Bit7zLibrary lib{ "7za.dll" };
BitFileExtractor extractor{ lib, BitFormat::SevenZip };
// Extracting a simple archive
extractor.extract( "path/to/archive.7z", "out/dir/" );
// Extracting a specific file inside an archive
extractor.extractMatching( "path/to/archive.7z", "file.pdf", "out/dir/" );
// Extracting the first file of an archive to a buffer
std::vector< byte_t > buffer;
extractor.extract( "path/to/archive.7z", buffer );
// Extracting an encrypted archive
extractor.setPassword( "password" );
extractor.extract( "path/to/another/archive.7z", "out/dir/" );
} catch ( const bit7z::BitException& ex ) { /* Do something with ex.what()...*/ }Alternatively, if you only need to work on a single archive:
#include <bit7z/bitarchivereader.hpp>
try { // bit7z classes can throw BitException objects
using namespace bit7z;
Bit7zLibrary lib{ "7z.dll" };
// Opening the archive
BitArchiveReader archive{ lib, "path/to/archive.gz", BitFormat::GZip };
// Testing the archive
archive.test();
// Extracting the archive
archive.extractTo( "out/dir/" );
} catch ( const bit7z::BitException& ex ) { /* Do something with ex.what()...*/ }#include <bit7z/bitfilecompressor.hpp>
try { // bit7z classes can throw BitException objects
using namespace bit7z;
Bit7zLibrary lib{ "7z.dll" };
BitFileCompressor compressor{ lib, BitFormat::Zip };
std::vector< std::string > files = { "path/to/file1.jpg", "path/to/file2.pdf" };
// Creating a simple zip archive
compressor.compress( files, "output_archive.zip" );
// Creating a zip archive with a custom directory structure
std::map< std::string, std::string > files_map = {
{ "path/to/file1.jpg", "alias/path/file1.jpg" },
{ "path/to/file2.pdf", "alias/path/file2.pdf" }
};
compressor.compress( files_map, "output_archive2.zip" );
// Compressing a directory
compressor.compressDirectory( "dir/path/", "dir_archive.zip" );
// Creating an encrypted zip archive of two files
compressor.setPassword( "password" );
compressor.compressFiles( files, "protected_archive.zip" );
// Updating an existing zip archive
compressor.setUpdateMode( UpdateMode::Append );
compressor.compressFiles( files, "existing_archive.zip" );
// Compressing a single file into a buffer
std::vector< bit7z::byte_t > buffer;
BitFileCompressor compressor2{ lib, BitFormat::BZip2 };
compressor2.compressFile( files[0], buffer );
} catch ( const bit7z::BitException& ex ) { /* Do something with ex.what()...*/ }Alternatively, if you only need to work on a single archive:
#include <bit7z/bitarchivewriter.hpp>
try { // bit7z classes can throw BitException objects
using namespace bit7z;
Bit7zLibrary lib{ "7z.dll" };
BitArchiveWriter archive{ lib, BitFormat::SevenZip };
// Adding the items to be compressed (no compression is performed here)
archive.addFile( "path/to/file.txt" );
archive.addDirectory( "path/to/dir/" );
// Compressing the added items to the output archive
archive.compressTo( "output.7z" );
} catch ( const bit7z::BitException& ex ) { /* Do something with ex.what()...*/ }#include <bit7z/bitarchivereader.hpp>
try { // bit7z classes can throw BitException objects
using namespace bit7z;
Bit7zLibrary lib{ "7za.dll" };
BitArchiveReader arc{ lib, "archive.7z", BitFormat::SevenZip };
// Printing archive metadata
std::cout << "Archive properties\n";
std::cout << " Items count: " << arc.itemsCount() << '\n';
std::cout << " Folders count: " << arc.foldersCount() << '\n';
std::cout << " Files count: " << arc.filesCount() << '\n';
std::cout << " Size: " << arc.size() <<'\n';
std::cout << " Packed size: " << arc.packSize() << "\n\n";
// Printing the metadata of the archived items
std::cout << "Archived items";
for ( const auto& item : arc ) {
std::cout << '\n';
std::cout << " Item index: " << item.index() << '\n';
std::cout << " Name: " << item.name() << '\n';
std::cout << " Extension: " << item.extension() << '\n';
std::cout << " Path: " << item.path() << '\n';
std::cout << " IsDir: " << item.isDir() << '\n';
std::cout << " Size: " << item.size() << '\n';
std::cout << " Packed size: " << item.packSize() << '\n';
std::cout << " CRC: " << std::hex << item.crc() << std::dec << '\n';
}
std::cout.flush();
} catch ( const bit7z::BitException& ex ) { /* Do something with ex.what()...*/ }A complete API reference is available in the wiki section.
The newest bit7z v4 introduced some significant breaking changes to the library's API.
Expand for more details!
- By default, the project now follows the UTF-8 Everywhere Manifesto:
- The default string type is
std::string(instead ofstd::wstring), so users can use the library in cross-platform projects more easily (v4 introduced Linux/macOS support too). - Input
std::strings will be considered as UTF-8 encoded. - You can still achieve the old behavior on Windows using the
-DBIT7Z_USE_NATIVE_STRINGCMake option.
- The default string type is
- The old
BitExtractorclass is now calledBitFileExtractor.- Now
BitExtractoris just the name of a template class for all the extraction classes.
- Now
- The old
BitCompressorclass is now calledBitFileCompressor.- Now
BitCompressoris just the name of a template class for all the compression classes.
- Now
- The
ProgressCallbacknow must return aboolvalue indicating whether the current operation can continue (true) or not (false). - The project structure changed:
- Public API headers moved from
include/to theinclude/bit7z/folder, so#includedirectives now need to prependbit7z/to the included header name (e.g.,#include <bit7z/bitfileextractor.hpp>).- Even though it is a bit verbose, it is a typical structure for C and C++ libraries, and it makes explicit which third-party library a header file belongs to.
- By default, the output folder of bit7z is now
lib/<architecture>/; if the CMake generator is multi-config (e.g., Visual Studio generators), the default output folder islib/<architecture>/<build type>/.- Optionally, you can force using the "Visual Studio style" output path by enabling the
BIT7Z_VS_LIBNAME_OUTDIR_STYLECMake option.
- Optionally, you can force using the "Visual Studio style" output path by enabling the
- Third-party dependencies are no longer handled using git submodules but are automatically downloaded using CPM.cmake when configuring/using the library via CMake.
- Public API headers moved from
Each released package contains:
- A pre-compiled version of bit7z (both in debug and release mode);
- The public API headers needed to use the library in your program;
Packages are available for both x86 and x64 architectures.
You can also clone/download this repository and build the library yourself (please, read the wiki).
- Operating System: Windows, Linux, macOS, Android1.
- Architecture: x86, x86_64, arm, arm64.
- Language Standard: C++11 (for using the library), C++14 (for building the library).
- Compiler: MSVC 2015 or later2, MinGW v6.4 or later, GCC v4.9 or later, Clang 3.6 or later.
- Shared Library: a 7-zip
.dlllibrary on Windows, a 7-zip/p7zip.solibrary on Unix3.
For building the library:
cd <bit7z folder>
mkdir build && cd build
cmake ../ -DCMAKE_BUILD_TYPE=Release
cmake --build . -j --config ReleaseA more detailed guide on how to build this library is available here.
You can also directly integrate the library into your project via CMake:
- Download bit7z and copy it into a sub-directory of your project (e.g.,
third_party), or add it as a git submodule of your repository. - Then, use the command
add_subdirectory()in yourCMakeLists.txtto include bit7z. - Finally, link the
bit7zlibrary using thetarget_link_libraries()command.
For example:
add_subdirectory( ${CMAKE_SOURCE_DIR}/third_party/bit7z )
target_link_libraries( ${YOUR_TARGET} PRIVATE bit7z )The library is highly customizable: for a detailed list of the available build options, please refer to the wiki.
While configuring bit7z via CMake, it automatically downloads the latest version of 7-zip supported by the library.
Optionally, you can specify a different version of 7-zip via the CMake option BIT7Z_7ZIP_VERSION (e.g., -DBIT7Z_7ZIP_VERSION="22.01").
Alternatively, you can specify a custom path containing the 7-zip source code via the option BIT7Z_CUSTOM_7ZIP_PATH.
Please note that, in general, it is best to use the same version of 7-zip of the shared libraries that you will use at runtime.
By default, bit7z is compatible with the 7z.so from 7-zip v23.01 and later.
If you plan to use the 7z.so from p7zip or 7-zip v22.01 and earlier instead, you have two ways to make bit7z compatible:
- Configure bit7z with the CMake option
-DBIT7Z_USE_LEGACY_IUNKNOWN=ON; or - Configure bit7z for 7-zip v22.01 (i.e.,
-DBIT7Z_7ZIP_VERSION="22.01").
Expand for more details
On Linux and macOS, 7-zip v23.01 introduced breaking changes to the IUnknown interface. As a result, if you build bit7z for such a version of 7-zip (the default), it will not support using the shared libraries from previous versions of 7-zip (or from p7zip). Conversely, bit7z made for earlier versions of 7-zip or for p7zip is incompatible with the shared libraries from 7-zip v23.01 and later.
You can build the shared libraries of 7-zip v23.01 in a backward-compatible mode by defining the macro Z7_USE_VIRTUAL_DESTRUCTOR_IN_IUNKNOWN.
If this is your case, you'll need to enable the BIT7Z_USE_LEGACY_IUNKNOWN to make bit7z work (in this case, bit7z will be compatible also with previous versions of 7-zip/p7zip).
By default, bit7z follows the UTF-8 Everywhere Manifesto to simplify the use of the library within cross-platform projects. In short, this means that:
- The default path string type is
std::string. - Input
std::strings are considered as UTF-8 encoded; outputstd::strings are UTF-8 encoded.
Expand for more details and for other string encoding options!
On POSIX systems, std::strings are usually already UTF-8 encoded, and no configuration is needed.
The situation is a bit more complex on Windows since, by default, Windows treats std::strings as encoded using the system code page, which may not necessarily be UTF-8, like, for example, Windows-1252.
If your program deals exclusively with ASCII-only strings, you should be fine with the default bit7z settings (as ASCII characters are also UTF-8).
However, if you need to handle non-ASCII/Unicode characters, as it is likely, you have the following options:
-
Enforcing using the UTF-8 code page for your whole application, as explained by Microsoft here:
- Recommended, but supported only since Windows 10 1903 and later.
-
Manually ensuring the encoding of the
std::strings passed to bit7z:- You can use some string encoding library or C++11's UTF-8 string literals for input strings.
- User-input strings (e.g., the password of an archive) can be handled as explained here; in short: read the input as an UTF-16 wide string (e.g., via
ReadConsoleW), and convert it to UTF-8 (bit7z provides a utility function for this,bit7z::to_tstring). - You can correctly print the UTF-8 output strings from bit7z (e.g., the path/name metadata of a file in an archive) to the console by calling
SetConsoleOutputCP(CP_UTF8)before.
-
Configuring bit7z to use UTF-16 encoded wide strings (i.e.,
std::wstring) by enabling theBIT7Z_USE_NATIVE_STRINGoption via CMake.-
If your program is Windows-only, or you already use wide strings on Windows, this might be the best choice since it will avoid any internal string conversions (7-zip always uses wide strings).
-
This option makes developing cross-platform applications slightly inconvenient since you'll still have to use
std::stringon POSIX systems. -
The library provides a type alias
bit7z::tstringand a macro functionBIT7Z_STRINGfor defining wide string variables and literals on Windows and narrow ones on other platforms. -
You must programmatically set the standard input and output encoding to UTF-16 to correctly read and print Unicode characters:
#include <fcntl.h> //for _O_U16TEXT #include <io.h> //for _setmode _setmode(_fileno(stdout), _O_U16TEXT); // setting the stdout encoding to UTF16 _setmode(_fileno(stdin), _O_U16TEXT); // setting the stdin encoding to UTF16
-
-
Configuring bit7z to use the system code page encoding for
std::stringby enabling theBIT7Z_USE_SYSTEM_CODEPAGEoption via CMake.- Not recommended: using this option, your program will be limited in the set of characters it can pass to and read from bit7z.
If you have found this project helpful, please consider supporting me with a small donation so that I can keep improving it! Thank you! 🙏
This project is licensed under the terms of the Mozilla Public License v2.0.
For more details, please check:
- The LICENSE file.
- Mozilla's MPL-2.0 FAQ
Older versions (v3.x and earlier) of bit7z were released under the GNU General Public License v2.
Footnotes
-
On Windows, you should link your program also with oleaut32 (e.g.,
-lbit7z -loleaut32).
On Linux and macOS, you should link your program also with dl (e.g.,-lbit7z -ldl).
If you are using the library via CMake, these dependencies will be linked automatically to your project. ↩ -
MSVC 2010 was supported until v2.x, MSVC 2012/2013 until v3.x. ↩
-
bit7z doesn't ship with the 7-zip shared libraries. You can build them from the source code available at 7-zip.org. ↩