73773c6b6a
for some reason, these tests started failing recently on CircleCI |
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.. | ||
common | ||
compress | ||
decompress | ||
deprecated | ||
dictBuilder | ||
dll | ||
legacy | ||
.gitignore | ||
BUCK | ||
libzstd.pc.in | ||
Makefile | ||
README.md | ||
zstd.h |
Zstandard library files
The lib directory is split into several sub-directories, in order to make it easier to select or exclude features.
Building
Makefile
script is provided, supporting all standard Makefile conventions,
including commands variables, staged install, directory variables and standard targets.
make
: generates both static and dynamic librariesmake install
: install libraries in default system directories
libzstd
default scope includes compression, decompression, dictionary building,
and decoding support for legacy formats >= v0.5.0.
API
Zstandard's stable API is exposed within lib/zstd.h.
Advanced API
Optional advanced features are exposed via :
lib/common/zstd_errors.h
: translatessize_t
function results into anZSTD_ErrorCode
, for accurate error handling.ZSTD_STATIC_LINKING_ONLY
: if this macro is defined before includingzstd.h
, it unlocks access to advanced experimental API, exposed in second part ofzstd.h
. These APIs are not "stable", their definition may change in the future. As a consequence, it shall never be used with dynamic library ! Only static linking is allowed.
Modular build
It's possible to compile only a limited set of features.
- Directory
lib/common
is always required, for all variants. - Compression source code lies in
lib/compress
- Decompression source code lies in
lib/decompress
- It's possible to include only
compress
or onlydecompress
, they don't depend on each other. lib/dictBuilder
: makes it possible to generate dictionaries from a set of samples. The API is exposed inlib/dictBuilder/zdict.h
. This module depends on bothlib/common
andlib/compress
.lib/legacy
: source code to decompress legacy zstd formats, starting fromv0.1.0
. This module depends onlib/common
andlib/decompress
. To enable this feature, defineZSTD_LEGACY_SUPPORT
during compilation. Specifying a number limits versions supported to that version onward. For example,ZSTD_LEGACY_SUPPORT=2
means : "support legacy formats >= v0.2.0".ZSTD_LEGACY_SUPPORT=3
means : "support legacy formats >= v0.3.0", and so on. Currently, the default library setting isZST_LEGACY_SUPPORT=5
. It can be changed at build by any other value. Note that any number >= 8 translates into "do not support legacy formats", since all versions ofzstd
>= v0.8 are compatible with v1+ specification.ZSTD_LEGACY_SUPPORT=0
also means "do not support legacy formats". Once enabled, this capability is transparently triggered within decompression functions. It's also possible to invoke directly legacy API, as exposed inlib/legacy/zstd_legacy.h
. Each version also provides an additional dedicated set of advanced API. For example, advanced API for versionv0.4
is exposed inlib/legacy/zstd_v04.h
. Note :lib/legacy
only supports decoding legacy formats.- Similarly, you can define
ZSTD_LIB_COMPRESSION, ZSTD_LIB_DECOMPRESSION
,ZSTD_LIB_DICTBUILDER
, andZSTD_LIB_DEPRECATED
as 0 to forgo compilation of the corresponding features. This will also disable compilation of all dependencies (eg.ZSTD_LIB_COMPRESSION=0
will also disable dictBuilder).
Multithreading support
Multithreading is disabled by default when building with make
.
Enabling multithreading requires 2 conditions :
- set macro
ZSTD_MULTITHREAD
- on POSIX systems : compile with pthread (
-pthread
compilation flag forgcc
)
Both conditions are automatically triggered by invoking make lib-mt
target.
Note that, when linking a POSIX program with a multithreaded version of libzstd
,
it's necessary to trigger -pthread
flag during link stage.
Multithreading capabilities are exposed
via advanced API ZSTD_compress_generic()
defined in lib/zstd.h
.
This API is still considered experimental,
but is expected to become "stable" at some point in the future.
Windows : using MinGW+MSYS to create DLL
DLL can be created using MinGW+MSYS with the make libzstd
command.
This command creates dll\libzstd.dll
and the import library dll\libzstd.lib
.
The import library is only required with Visual C++.
The header file zstd.h
and the dynamic library dll\libzstd.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 ZSTD consists of a single test-dll.c
file it should be linked with dll\libzstd.dll
. For example:
gcc $(CFLAGS) -Iinclude/ test-dll.c -o test-dll dll\libzstd.dll
The compiled executable will require ZSTD DLL which is available at dll\libzstd.dll
.
Deprecated API
Obsolete API on their way out are stored in directory lib/deprecated
.
At this stage, it contains older streaming prototypes, in lib/deprecated/zbuff.h
.
These prototypes will be removed in some future version.
Consider migrating code towards supported streaming API exposed in zstd.h
.
Miscellaneous
The other files are not source code. There are :
LICENSE
: contains the BSD license textMakefile
:make
script to build and install zstd library (static and dynamic)BUCK
: support forbuck
build system (https://buckbuild.com/)libzstd.pc.in
: forpkg-config
(used inmake install
)README.md
: this file