python-zstd

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Release
Master

Simple python bindings to Yann Collet ZSTD compression library.

Zstd, short for Zstandard, is a new lossless compression algorithm,

which provides both good compression ratio and speed for your standard compression needs. "Standard" translates into everyday situations which neither look for highest possible ratio (which LZMA and ZPAQ cover) nor extreme speeds (which LZ4 covers).

It is provided as a BSD-license package, hosted on GitHub.

WARNING!!!

If you setup 1.0.0.99.1 version - remove it manualy to able to update. PIP matching version strings not tuple of numbers.

Result generated by versions prior to 1.0.0.99.1 is not compatible with orignial Zstd by any means. It generates custom header and can be read only by zstd python module.

As of 1.0.0.99.1 version it uses standard Zstd output, not modified.

To prevent data loss there is two functions now: `compress_old` and `decompress_old`. They are works just like in old versions prior to 1.0.0.99.1.

As of 1.1.4 version module build without them by default.

As of 1.3.4 version these functions are deprecated and will be removed in future releases.

As of 1.5.0 version these functions are removed.

DISCLAIMER

These python bindings are kept simple and blunt.

Support of dictionaries and streaming is not planned.

LINKS

• Zstandard: https://github.com/facebook/zstd
• More full-featured and compatible with Zstandard python bindings by Gregory Szorc: https://github.com/indygreg/python-zstandard

Build from source

>>> $ git clone https://github.com/sergey-dryabzhinsky/python-zstd
>>> $ git submodule update --init
>>> $ apt-get install python-dev python3-dev python-setuptools python3-setuptools
>>> $ python setup.py build_ext clean
>>> $ python3 setup.py build_ext clean

Note: Zstd legacy format support disabled by default. To build with Zstd legacy versions support - pass --legacy option to setup.py script:

>>> $ python setup.py build_ext --legacy clean

When using a PEP 517 builder you can use ZSTD_LEGACY environment variable instead:

>>> $ ZSTD_LEGACY=1 python -m build -w

Note: Python-Zstd legacy format support removed since 1.5.0. If you need to convert old data - checkout 1.4.9.1 module version. Support of it disabled by default. To build with python-zstd legacy format support (pre 1.1.2) - pass --pyzstd-legacy option to setup.py script:

>>> $ python setup.py build_ext --pyzstd-legacy clean

If you want to build with existing distribution of libzstd just add --external option. But beware! Legacy formats support state is unknown in this case. And if your version not equal with python-zstd - tests may not pass.

>>> $ python setup.py build_ext --external clean

When using a PEP 517 builder you can use ZSTD_EXTERNAL environment variable instead:

>>> $ ZSTD_EXTERNAL=1 python -m build -w

If paths to header file zstd.h and libraries is uncommon - use common build params: --libraries --include-dirs --library-dirs.

>>> $ python setup.py build_ext --external --include-dirs /opt/zstd/usr/include --libraries zstd --library-dirs /opt/zstd/lib clean

Install from pypi

>>> # for Python 2.7+
>>> $ pip install zstd
>>> # or for Python 3.4+
>>> $ pip3 install zstd

API

Error

Standard python Exception for zstd module

ZSTD_compress (data[, level, threads]): string|bytes

Function, compress input data block via mutliple threads, return compressed block, or raises Error.

Params:

• data: string|bytes - input data block, length limited by 2Gb by Python API
• level: int - compression level, ultra-fast levels from -100 (ultra) to -1 (fast) available since zstd-1.3.4, and from 1 (fast) to 22 (slowest), 0 or unset - means default (3). Default - 3.
• threads: int - how many threads to use, from 0 to 200, 0 or unset - auto-tune by cpu cores count. Default - 0. Since: 1.4.4.1

Aliases: compress(...), dumps(...)

Exception if: - level bigger than max level

Max number of threads: - 32bit system: 64 - 64bit system: 256 If provided bigger number - silemtly set maximum number (since 1.5.4.1)

Since: 0.1

ZSTD_uncompress (data): string|bytes

Function, decompress input compressed data block, return decompressed block, or raises Error.

Support compressed data with multiple/concatenated frames (blocks) (since 1.5.5.1).

Params:

• data: string|bytes - input compressed data block, length limited by 2Gb by Python API

Aliases: decompress(...), uncompress(...), loads(...)

Since: 0.1

version (): string|bytes

Returns this module doted version string.

The first three digits are folow libzstd version. Fourth digit - module release number for that version.

Since: 1.3.4.3

ZSTD_version (): string|bytes

Returns ZSTD library doted version string.

Since: 1.3.4.3

ZSTD_version_number (): int

Returns ZSTD library version in format: MAJOR*100*100 + MINOR*100 + RELEASE.

Since: 1.3.4.3

ZSTD_threads_count (): int

Returns ZSTD determined CPU cores count.

Since: 1.5.4.1

ZSTD_max_threads_count (): int

Returns ZSTD library determined maximum working threads count.

Since: 1.5.4.1

ZSTD_external (): int

Returns 0 of 1 if ZSTD library build as external.

Since: 1.5.0.2

Removed

ZSTD_compress_old (data[, level]): string|bytes

Function, compress input data block, return compressed block, or raises Error.

DEPRECATED: Returns not compatible with ZSTD block header

REMOVED: since 1.5.0

Params:

• data: string|bytes - input data block, length limited by 2Gb by Python API
• level: int - compression level, ultra-fast levels from -5 (ultra) to -1 (fast) available since zstd-1.3.4, and from 1 (fast) to 22 (slowest), 0 or unset - means default (3). Default - 3.

Since: 1.0.0.99.1

ZSTD_uncompress_old (data): string|bytes

Function, decompress input compressed data block, return decompressed block, or raises Error.

DEPRECATED: Accepts data with not compatible with ZSTD block header

REMOVED: since 1.5.0

Params:

• data: string|bytes - input compressed data block, length limited by 2Gb by Python API

Since: 1.0.0.99.1

Use

Module has simple API:

>>> import zstd
>>> dir(zstd)
['Error', 'ZSTD_compress', 'ZSTD_external', 'ZSTD_uncompress', 'ZSTD_version', 'ZSTD_version_number', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'compress', 'decompress', 'dumps', 'loads', 'uncompress', 'version']
>>> zstd.version()
'1.5.1.0'
>>> zstd.ZSTD_version()
'1.5.1'
>>> zstd.ZSTD_version_number()
10501
>>> zstd.ZSTD_external()
0

In python2

>>> data = "123456qwert"

In python3 use bytes

>>> data = b"123456qwert"

>>> cdata = zstd.compress(data, 1)
>>> data == zstd.decompress(cdata)
True
>>> cdata_mt = zstd.compress(data, 1, 4)
>>> cdata == cdata_mt
True
>>> data == zstd.decompress(cdata_mt)
True