LZ4 is a lossless compression algorithm, providing compression speed > 500 MB/s per core, scalable with multi-core CPUs. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.
Compression speed can be tuned dynamically, by selecting an "acceleration" factor which trades compression ratio for faster speed. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.
LZ4 is also compatible with dictionary compression,
both at API and CLI (-D) levels.
It can ingest any input file as dictionary, though only the final 64 KB are used.
This capability can be combined with the Zstandard Dictionary Builder,
in order to drastically improve compression performance on small files.
The LZ4 library is provided as open-source software using the BSD 2-Clause license.
The lz4 command line utility is provided under the GPL-2.0-or-later license.
The benchmark uses lzbench, from @inikep compiled with GCC v8.2.0 on Linux 64-bits (Ubuntu 4.18.0-17). The reference system uses a Core i7-9700K CPU @ 4.9GHz (w/ turbo boost). Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.
make
make install # this command may require root permissions
LZ4's Makefile supports standard Makefile conventions,
including staged installs, redirection, or command redefinition.
It is compatible with parallel builds (-j#).
Alternative build systems (CMake, Meson, Visual Studio) are provided in build/.
You can download and install LZ4 using the vcpkg dependency manager:
git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install lz4
The LZ4 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 If the version is out of date, please create an issue or pull request on the vcpkg repository.
The raw LZ4 block compression format is detailed within lz4_Block_format.
Arbitrarily long files or data streams are compressed using multiple blocks, for streaming requirements. These blocks are organized into a frame, defined in lz4_Frame_format. Interoperable versions of LZ4 must also respect the frame format.
The library API is documented in its headers: lz4.h (block API), lz4hc.h (high compression) and lz4frame.h (frame API).
Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.
Most distributions are bundled with a package manager
which allows easy installation of both the liblz4 library
and the lz4 command line interface.
- Takayuki Matsuoka, aka @t-mat, for exceptional first-class support throughout the lifetime of this project