lz4/lib/README.md

LZ4 - Library Files
================================

All source material within __lib__ directory are BSD 2-Clause licensed.
See [LICENSE](LICENSE) for details.
The license is also repeated at the top of each source file.

The directory contains many files, but depending on project's objectives,
not all of them are necessary.

The minimum required is **`lz4.c`** and **`lz4.h`**,
which will provide the fast compression and decompression algorithm.

For more compression at the cost of compression speed,
the High Compression variant **lz4hc** is available.
It's necessary to add **`lz4hc.c`** and **`lz4hc.h`**.
The variant still depends on regular `lz4` source files.
In particular, the decompression is still provided by `lz4.c`.

In order to produce files or streams compatible with `lz4` command line utility,
it's necessary to encode lz4-compressed blocks using the [official interoperable frame format].
This format is generated and decoded automatically by the **lz4frame** library.
In order to work properly, lz4frame needs lz4 and lz4hc, and also **xxhash**,
which provides error detection.
(_Advanced stuff_ : It's possible to hide xxhash symbols into a local namespace.
This is what `liblz4` does, to avoid symbol duplication
in case a user program would link to several libraries containing xxhash symbols.)

A more complex `lz4frame_static.h` is also provided.
It contains definitions which are not guaranteed to remain stable within future versions.
It must be used with static linking ***only***.

Other files present in the directory are not source code. There are :

 - LICENSE : contains the BSD license text
 - Makefile : script to compile or install lz4 library (static or dynamic)
 - liblz4.pc.in : for pkg-config (make install)
 - README.md : this file

[official interoperable frame format]: ../doc/lz4_Frame_format.md