1 LZ4 - Library Files 2 ================================ 3 4 The directory contains many files, but depending on project's objectives, 5 not all of them are necessary. 6 7 #### Minimal LZ4 build 8 9 The minimum required is **`lz4.c`** and **`lz4.h`**, 10 which will provide the fast compression and decompression algorithm. 11 12 13 #### The High Compression variant of LZ4 14 15 For more compression at the cost of compression speed, 16 the High Compression variant **lz4hc** is available. 17 It's necessary to add **`lz4hc.c`** and **`lz4hc.h`**. 18 The variant still depends on regular `lz4` source files. 19 In particular, the decompression is still provided by `lz4.c`. 20 21 22 #### Compatibility issues 23 24 In order to produce files or streams compatible with `lz4` command line utility, 25 it's necessary to encode lz4-compressed blocks using the [official interoperable frame format]. 26 This format is generated and decoded automatically by the **lz4frame** library. 27 In order to work properly, lz4frame needs lz4 and lz4hc, and also **xxhash**, 28 which provides error detection. 29 (_Advanced stuff_ : It's possible to hide xxhash symbols into a local namespace. 30 This is what `liblz4` does, to avoid symbol duplication 31 in case a user program would link to several libraries containing xxhash symbols.) 32 33 34 #### Advanced API 35 36 A more complex `lz4frame_static.h` is also provided. 37 It contains definitions which are not guaranteed to remain stable within future versions. 38 It must be used with static linking ***only***. 39 40 41 #### Using MinGW+MSYS to create DLL 42 43 DLL can be created using MinGW+MSYS with the `make liblz4` command. 44 This command creates `dll\liblz4.dll` and the import library `dll\liblz4.lib`. 45 The import library is only required with Visual C++. 46 The header files `lz4.h`, `lz4hc.h`, `lz4frame.h` and the dynamic library 47 `dll\liblz4.dll` are required to compile a project using gcc/MinGW. 48 The dynamic library has to be added to linking options. 49 It means that if a project that uses LZ4 consists of a single `test-dll.c` 50 file it should be linked with `dll\liblz4.dll`. For example: 51 ``` 52 gcc $(CFLAGS) -Iinclude/ test-dll.c -o test-dll dll\liblz4.dll 53 ``` 54 The compiled executable will require LZ4 DLL which is available at `dll\liblz4.dll`. 55 56 57 #### Miscellaneous 58 59 Other files present in the directory are not source code. There are : 60 61 - LICENSE : contains the BSD license text 62 - Makefile : script to compile or install lz4 library (static or dynamic) 63 - liblz4.pc.in : for pkg-config (make install) 64 - README.md : this file 65 66 [official interoperable frame format]: ../doc/lz4_Frame_format.md 67 68 69 #### License 70 71 All source material within __lib__ directory are BSD 2-Clause licensed. 72 See [LICENSE](LICENSE) for details. 73 The license is also repeated at the top of each source file. 74
