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facebook/zstd zstd-0.4.2
Zstandard - Fast real-time compression algorithm
⭐️ 22,405
🕓 2 years ago
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.package(url: "https://github.com/facebook/zstd.git", from: "zstd-0.4.2")

Zstandard

Zstandard, or zstd as short version, is a fast lossless compression algorithm, targeting real-time compression scenarios at zlib-level and better compression ratios. It's backed by a very fast entropy stage, provided by Huff0 and FSE library.

Zstandard's format is stable and documented in RFC8878. Multiple independent implementations are already available. This repository represents the reference implementation, provided as an open-source dual BSD OR GPLv2 licensed C library, and a command line utility producing and decoding .zst, .gz, .xz and .lz4 files. Should your project require another programming language, a list of known ports and bindings is provided on Zstandard homepage.

Development branch status:

Build Status Build status Build status Fuzzing Status

Benchmarks

For reference, several fast compression algorithms were tested and compared on a desktop featuring a Core i7-9700K CPU @ 4.9GHz and running Ubuntu 20.04 (Linux ubu20 5.15.0-101-generic), using lzbench, an open-source in-memory benchmark by @inikep compiled with gcc 9.4.0, on the Silesia compression corpus.

Compressor name Ratio Compression Decompress.
zstd 1.5.6 -1 2.887 510 MB/s 1580 MB/s
zlib 1.2.11 -1 2.743 95 MB/s 400 MB/s
brotli 1.0.9 -0 2.702 395 MB/s 430 MB/s
zstd 1.5.6 --fast=1 2.437 545 MB/s 1890 MB/s
zstd 1.5.6 --fast=3 2.239 650 MB/s 2000 MB/s
quicklz 1.5.0 -1 2.238 525 MB/s 750 MB/s
lzo1x 2.10 -1 2.106 650 MB/s 825 MB/s
lz4 1.9.4 2.101 700 MB/s 4000 MB/s
lzf 3.6 -1 2.077 420 MB/s 830 MB/s
snappy 1.1.9 2.073 530 MB/s 1660 MB/s

The negative compression levels, specified with --fast=#, offer faster compression and decompression speed at the cost of compression ratio.

Zstd can also offer stronger compression ratios at the cost of compression speed. Speed vs Compression trade-off is configurable by small increments. Decompression speed is preserved and remains roughly the same at all settings, a property shared by most LZ compression algorithms, such as zlib or lzma.

The following tests were run on a server running Linux Debian (Linux version 4.14.0-3-amd64) with a Core i7-6700K CPU @ 4.0GHz, using lzbench, an open-source in-memory benchmark by @inikep compiled with gcc 7.3.0, on the Silesia compression corpus.

Compression Speed vs Ratio Decompression Speed
Compression Speed vs Ratio Decompression Speed

A few other algorithms can produce higher compression ratios at slower speeds, falling outside of the graph. For a larger picture including slow modes, click on this link.

The case for Small Data compression

Previous charts provide results applicable to typical file and stream scenarios (several MB). Small data comes with different perspectives.

The smaller the amount of data to compress, the more difficult it is to compress. This problem is common to all compression algorithms, and reason is, compression algorithms learn from past data how to compress future data. But at the beginning of a new data set, there is no "past" to build upon.

To solve this situation, Zstd offers a training mode, which can be used to tune the algorithm for a selected type of data. Training Zstandard is achieved by providing it with a few samples (one file per sample). The result of this training is stored in a file called "dictionary", which must be loaded before compression and decompression. Using this dictionary, the compression ratio achievable on small data improves dramatically.

The following example uses the github-users sample set, created from github public API. It consists of roughly 10K records weighing about 1KB each.

Compression Ratio Compression Speed Decompression Speed
Compression Ratio Compression Speed Decompression Speed

These compression gains are achieved while simultaneously providing faster compression and decompression speeds.

Training works if there is some correlation in a family of small data samples. The more data-specific a dictionary is, the more efficient it is (there is no universal dictionary). Hence, deploying one dictionary per type of data will provide the greatest benefits. Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm will gradually use previously decoded content to better compress the rest of the file.

Dictionary compression How To:

  1. Create the dictionary

    zstd --train FullPathToTrainingSet/* -o dictionaryName

  2. Compress with dictionary

    zstd -D dictionaryName FILE

  3. Decompress with dictionary

    zstd -D dictionaryName --decompress FILE.zst

Build instructions

make is the officially maintained build system of this project. All other build systems are "compatible" and 3rd-party maintained, they may feature small differences in advanced options. When your system allows it, prefer using make to build zstd and libzstd.

Makefile

If your system is compatible with standard make (or gmake), invoking make in root directory will generate zstd cli in root directory. It will also create libzstd into lib/.

Other available options include:

  • make install : create and install zstd cli, library and man pages
  • make check : create and run zstd, test its behavior on local platform

The Makefile follows the GNU Standard Makefile conventions, allowing staged install, standard flags, directory variables and command variables.

For advanced use cases, specialized compilation flags which control binary generation are documented in lib/README.md for the libzstd library and in programs/README.md for the zstd CLI.

cmake

A cmake project generator is provided within build/cmake. It can generate Makefiles or other build scripts to create zstd binary, and libzstd dynamic and static libraries.

By default, CMAKE_BUILD_TYPE is set to Release.

Support for Fat (Universal2) Output

zstd can be built and installed with support for both Apple Silicon (M1/M2) as well as Intel by using CMake's Universal2 support. To perform a Fat/Universal2 build and install use the following commands:

cmake -B build-cmake-debug -S build/cmake -G Ninja -DCMAKE_OSX_ARCHITECTURES="x86_64;x86_64h;arm64"
cd build-cmake-debug
ninja
sudo ninja install

Meson

A Meson project is provided within build/meson. Follow build instructions in that directory.

You can also take a look at .travis.yml file for an example about how Meson is used to build this project.

Note that default build type is release.

VCPKG

You can build and install zstd vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install zstd

The zstd port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Visual Studio (Windows)

Going into build directory, you will find additional possibilities:

  • Projects for Visual Studio 2005, 2008 and 2010.
    • VS2010 project is compatible with VS2012, VS2013, VS2015 and VS2017.
  • Automated build scripts for Visual compiler by @KrzysFR, in build/VS_scripts, which will build zstd cli and libzstd library without any need to open Visual Studio solution.

Buck

You can build the zstd binary via buck by executing: buck build programs:zstd from the root of the repo. The output binary will be in buck-out/gen/programs/.

Bazel

You easily can integrate zstd into your Bazel project by using the module hosted on the Bazel Central Repository.

Testing

You can run quick local smoke tests by running make check. If you can't use make, execute the playTest.sh script from the src/tests directory. Two env variables $ZSTD_BIN and $DATAGEN_BIN are needed for the test script to locate the zstd and datagen binary. For information on CI testing, please refer to TESTING.md.

Status

Zstandard is currently deployed within Facebook and many other large cloud infrastructures. It is run continuously to compress large amounts of data in multiple formats and use cases. Zstandard is considered safe for production environments.

License

Zstandard is dual-licensed under BSD OR GPLv2.

Contributing

The dev branch is the one where all contributions are merged before reaching release. If you plan to propose a patch, please commit into the dev branch, or its own feature branch. Direct commit to release are not permitted. For more information, please read CONTRIBUTING.

GitHub

link
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Last commit: 1 hour ago
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Release Notes

Zstandard v1.5.6 - Chrome Edition
3 weeks ago

This release highlights the deployment of Google Chrome 123, introducing zstd-encoding for Web traffic, introduced as a preferable option for compression of dynamic contents. With limited web server support for zstd-encoding due to its novelty, we are launching an updated Zstandard version to facilitate broader adoption.

New stable parameter ZSTD_c_targetCBlockSize

Using zstd compression for large documents over the Internet, data is segmented into smaller blocks of up to 128 KB, for incremental updates. This is crucial for applications like Chrome that process parts of documents as they arrive. However, on slow or congested networks, there can be some brief unresponsiveness in the middle of a block transmission, delaying update. To mitigate such scenarios, libzstd introduces the new parameter ZSTD_c_targetCBlockSize, enabling the division of blocks into even smaller segments to enhance initial byte delivery speed. Activating this feature incurs a cost, both runtime (equivalent to -2% speed at level 8) and a slight compression efficiency decrease (<0.1%), but offers some interesting latency reduction, notably beneficial in areas with less powerful network infrastructure.

Granular binary size selection

libzstd provides build customization, including options to compile only the compression or decompression modules, minimizing binary size. Enhanced in v1.5.6 (source), it now allows for even finer control by enabling selective inclusion or exclusion of specific components within these modules. This advancement aids applications needing precise binary size management.

Miscellaneous Enhancements

This release includes various minor enhancements and bug fixes to enhance user experience. Key updates include an expanded list of recognized compressed file suffixes for the --exclude-compressed flag, improving efficiency by skipping presumed incompressible content. Furthermore, compatibility has been broadened to include additional chipsets (sparc64, ARM64EC, risc-v) and operating systems (QNX, AIX, Solaris, HP-UX).

Change Log

api: Promote ZSTD_c_targetCBlockSize to Stable API by @felixhandte api: new experimental ZSTD_d_maxBlockSize parameter, to reduce streaming decompression memory, by @terrelln perf: improve performance of param ZSTD_c_targetCBlockSize, by @Cyan4973 perf: improved compression of arrays of integers at high compression, by @Cyan4973 lib: reduce binary size with selective built-time exclusion, by @felixhandte lib: improved huffman speed on small data and linux kernel, by @terrelln lib: accept dictionaries with partial literal tables, by @terrelln lib: fix CCtx size estimation with external sequence producer, by @embg lib: fix corner case decoder behaviors, by @Cyan4973 and @aimuz lib: fix zdict prototype mismatch in static_only mode, by @ldv-alt lib: fix several bugs in magicless-format decoding, by @embg cli: add common compressed file types to --exclude-compressed by @daniellerozenblit (requested by @dcog989) cli: fix mixing -c and -o commands with --rm, by @Cyan4973 cli: fix erroneous exclusion of hidden files with --output-dir-mirror by @felixhandte cli: improved time accuracy on BSD, by @felixhandte cli: better errors on argument parsing, by @KapJI tests: better compatibility with older versions of grep, by @Cyan4973 tests: lorem ipsum generator as default content generator, by @Cyan4973 build: cmake improvements by @terrelln, @sighingnow, @gjasny, @JohanMabille, @Saverio976, @gruenich, @teo-tsirpanis build: bazel support, by @jondo2010 build: fix cross-compiling for AArch64 with lld by @jcelerier build: fix Apple platform compatibility, by @nidhijaju build: fix Visual 2012 and lower compatibility, by @Cyan4973 build: improve win32 support, by @DimitriPapadopoulos build: better C90 compliance for zlibWrapper, by @emaste port: make: fat binaries on macos, by @mredig port: ARM64EC compatibility for Windows, by @dunhor port: QNX support by @klausholstjacobsen port: MSYS2 and Cygwin makefile installation and test support, by @QBos07 port: risc-v support validation in CI, by @Cyan4973 port: sparc64 support validation in CI, by @Cyan4973 port: AIX compatibility, by @likema port: HP-UX compatibility, by @likema doc: Improved specification accuracy, by @elasota bug: Fix and deprecate ZSTD_generateSequences (#3981), by @terrelln

Full change list (auto-generated)

New Contributors

Full Changelog: https://github.com/facebook/zstd/compare/v1.5.5...v1.5.6

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