9753ac4c91
Pattern analysis (currently limited to long ranges of identical bytes) is actually detrimental to performance when `nbSearches` is low. Reason is : `nbSearches` provides a built-in protection for these cases. The problem with patterns is that they dramatically increase the number of candidates to visit. But with a low nbSearches, the match finder just aborts early. In such cases, pattern analysis adds some complexity without reducing total nb of candidates. It actually increases compression ratio a little bit, by filtering only "good" candidates, but at a measurable speed cost, so it's not a good trade-off. This patch makes pattern analysis optional. It's enabled for levels 8+ only. |
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|---|---|---|
| .. | ||
| dll | ||
| .gitignore | ||
| liblz4.pc.in | ||
| LICENSE | ||
| lz4.c | ||
| lz4.h | ||
| lz4frame_static.h | ||
| lz4frame.c | ||
| lz4frame.h | ||
| lz4hc.c | ||
| lz4hc.h | ||
| lz4opt.h | ||
| Makefile | ||
| README.md | ||
| xxhash.c | ||
| xxhash.h | ||
LZ4 - Library Files
The /lib directory contains many files, but depending on project's objectives,
not all of them are necessary.
Minimal LZ4 build
The minimum required is lz4.c and lz4.h,
which provides the fast compression and decompression algorithm.
They generate and decode data using LZ4 block format.
High Compression variant
For more compression ratio at the cost of compression speed,
the High Compression variant called lz4hc is available.
Add files lz4hc.c, lz4hc.h and lz4opt.h.
The variant still depends on regular lib/lz4.* source files.
Frame variant, for interoperability
In order to produce compressed data 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.
Its public API is described in lib/lz4frame.h.
In order to work properly, lz4frame needs all other modules present in /lib,
including, lz4 and lz4hc, and also xxhash.
So it's necessary to include all *.c and *.h files present in /lib.
Advanced / Experimental API
A complex API defined in lz4frame_static.h contains definitions
which are not guaranteed to remain stable in future versions.
As a consequence, it must be used with static linking only.
Windows : using MinGW+MSYS to create DLL
DLL can be created using MinGW+MSYS with the make liblz4 command.
This command creates dll\liblz4.dll and the import library dll\liblz4.lib.
The import library is only required with Visual C++.
The header files lz4.h, lz4hc.h, lz4frame.h and the dynamic library
dll\liblz4.dll are required to compile a project using gcc/MinGW.
The dynamic library has to be added to linking options.
It means that if a project that uses LZ4 consists of a single test-dll.c
file it should be linked with dll\liblz4.dll. For example:
gcc $(CFLAGS) -Iinclude/ test-dll.c -o test-dll dll\liblz4.dll
The compiled executable will require LZ4 DLL which is available at dll\liblz4.dll.
Miscellaneous
Other files present in the directory are not source code. There are :
LICENSE: contains the BSD license textMakefile:makescript to compile and install lz4 library (static and dynamic)liblz4.pc.in: forpkg-config(used inmake install)README.md: this file
License
All source material within lib directory are BSD 2-Clause licensed. See LICENSE for details. The license is also reminded at the top of each source file.