https://github.com/ifduyue/python-xxhash
Python Binding for xxHash
https://github.com/ifduyue/python-xxhash
cpython hash python xxhash
Last synced: 9 months ago
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Python Binding for xxHash
- Host: GitHub
- URL: https://github.com/ifduyue/python-xxhash
- Owner: ifduyue
- License: bsd-2-clause
- Created: 2014-07-30T15:38:47.000Z (over 11 years ago)
- Default Branch: master
- Last Pushed: 2025-04-28T01:10:38.000Z (9 months ago)
- Last Synced: 2025-05-03T02:09:25.359Z (9 months ago)
- Topics: cpython, hash, python, xxhash
- Language: C
- Homepage: https://pypi.org/project/xxhash/
- Size: 245 KB
- Stars: 397
- Watchers: 15
- Forks: 34
- Open Issues: 5
-
Metadata Files:
- Readme: README.rst
- Changelog: CHANGELOG.rst
- License: LICENSE
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README
python-xxhash
=============
.. image:: https://github.com/ifduyue/python-xxhash/actions/workflows/test.yml/badge.svg
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:alt: Github Actions Status
.. image:: https://img.shields.io/pypi/v/xxhash.svg
:target: https://pypi.org/project/xxhash/
:alt: Latest Version
.. image:: https://img.shields.io/pypi/pyversions/xxhash.svg
:target: https://pypi.org/project/xxhash/
:alt: Supported Python versions
.. image:: https://img.shields.io/pypi/l/xxhash.svg
:target: https://pypi.org/project/xxhash/
:alt: License
.. _HMAC: http://en.wikipedia.org/wiki/Hash-based_message_authentication_code
.. _xxHash: https://github.com/Cyan4973/xxHash
.. _Cyan4973: https://github.com/Cyan4973
xxhash is a Python binding for the xxHash_ library by `Yann Collet`__.
__ Cyan4973_
Installation
------------
.. code-block:: bash
$ pip install xxhash
You can also install using conda:
.. code-block:: bash
$ conda install -c conda-forge python-xxhash
Installing From Source
~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: bash
$ pip install --no-binary xxhash xxhash
Prerequisites
++++++++++++++
On Debian/Ubuntu:
.. code-block:: bash
$ apt-get install python-dev gcc
On CentOS/Fedora:
.. code-block:: bash
$ yum install python-devel gcc redhat-rpm-config
Linking to libxxhash.so
~~~~~~~~~~~~~~~~~~~~~~~~
By default python-xxhash will use bundled xxHash,
we can change this by specifying ENV var ``XXHASH_LINK_SO``:
.. code-block:: bash
$ XXHASH_LINK_SO=1 pip install --no-binary xxhash xxhash
Usage
--------
Module version and its backend xxHash library version can be retrieved using
the module properties ``VERSION`` AND ``XXHASH_VERSION`` respectively.
.. code-block:: python
>>> import xxhash
>>> xxhash.VERSION
'2.0.0'
>>> xxhash.XXHASH_VERSION
'0.8.0'
This module is hashlib-compliant, which means you can use it in the same way as ``hashlib.md5``.
| update() -- update the current digest with an additional string
| digest() -- return the current digest value
| hexdigest() -- return the current digest as a string of hexadecimal digits
| intdigest() -- return the current digest as an integer
| copy() -- return a copy of the current xxhash object
| reset() -- reset state
md5 digest returns bytes, but the original xxh32 and xxh64 C APIs return integers.
While this module is made hashlib-compliant, ``intdigest()`` is also provided to
get the integer digest.
Constructors for hash algorithms provided by this module are ``xxh32()`` and ``xxh64()``.
For example, to obtain the digest of the byte string ``b'Nobody inspects the spammish repetition'``:
.. code-block:: python
>>> import xxhash
>>> x = xxhash.xxh32()
>>> x.update(b'Nobody inspects')
>>> x.update(b' the spammish repetition')
>>> x.digest()
b'\xe2);/'
>>> x.digest_size
4
>>> x.block_size
16
More condensed:
.. code-block:: python
>>> xxhash.xxh32(b'Nobody inspects the spammish repetition').hexdigest()
'e2293b2f'
>>> xxhash.xxh32(b'Nobody inspects the spammish repetition').digest() == x.digest()
True
An optional seed (default is 0) can be used to alter the result predictably:
.. code-block:: python
>>> import xxhash
>>> xxhash.xxh64('xxhash').hexdigest()
'32dd38952c4bc720'
>>> xxhash.xxh64('xxhash', seed=20141025).hexdigest()
'b559b98d844e0635'
>>> x = xxhash.xxh64(seed=20141025)
>>> x.update('xxhash')
>>> x.hexdigest()
'b559b98d844e0635'
>>> x.intdigest()
13067679811253438005
Be careful that xxh32 takes an unsigned 32-bit integer as seed, while xxh64
takes an unsigned 64-bit integer. Although unsigned integer overflow is
defined behavior, it's better not to make it happen:
.. code-block:: python
>>> xxhash.xxh32('I want an unsigned 32-bit seed!', seed=0).hexdigest()
'f7a35af8'
>>> xxhash.xxh32('I want an unsigned 32-bit seed!', seed=2**32).hexdigest()
'f7a35af8'
>>> xxhash.xxh32('I want an unsigned 32-bit seed!', seed=1).hexdigest()
'd8d4b4ba'
>>> xxhash.xxh32('I want an unsigned 32-bit seed!', seed=2**32+1).hexdigest()
'd8d4b4ba'
>>>
>>> xxhash.xxh64('I want an unsigned 64-bit seed!', seed=0).hexdigest()
'd4cb0a70a2b8c7c1'
>>> xxhash.xxh64('I want an unsigned 64-bit seed!', seed=2**64).hexdigest()
'd4cb0a70a2b8c7c1'
>>> xxhash.xxh64('I want an unsigned 64-bit seed!', seed=1).hexdigest()
'ce5087f12470d961'
>>> xxhash.xxh64('I want an unsigned 64-bit seed!', seed=2**64+1).hexdigest()
'ce5087f12470d961'
``digest()`` returns bytes of the **big-endian** representation of the integer
digest:
.. code-block:: python
>>> import xxhash
>>> h = xxhash.xxh64()
>>> h.digest()
b'\xefF\xdb7Q\xd8\xe9\x99'
>>> h.intdigest().to_bytes(8, 'big')
b'\xefF\xdb7Q\xd8\xe9\x99'
>>> h.hexdigest()
'ef46db3751d8e999'
>>> format(h.intdigest(), '016x')
'ef46db3751d8e999'
>>> h.intdigest()
17241709254077376921
>>> int(h.hexdigest(), 16)
17241709254077376921
Besides xxh32/xxh64 mentioned above, oneshot functions are also provided,
so we can avoid allocating XXH32/64 state on heap:
| xxh32_digest(bytes, seed=0)
| xxh32_intdigest(bytes, seed=0)
| xxh32_hexdigest(bytes, seed=0)
| xxh64_digest(bytes, seed=0)
| xxh64_intdigest(bytes, seed=0)
| xxh64_hexdigest(bytes, seed=0)
.. code-block:: python
>>> import xxhash
>>> xxhash.xxh64('a').digest() == xxhash.xxh64_digest('a')
True
>>> xxhash.xxh64('a').intdigest() == xxhash.xxh64_intdigest('a')
True
>>> xxhash.xxh64('a').hexdigest() == xxhash.xxh64_hexdigest('a')
True
>>> xxhash.xxh64_hexdigest('xxhash', seed=20141025)
'b559b98d844e0635'
>>> xxhash.xxh64_intdigest('xxhash', seed=20141025)
13067679811253438005L
>>> xxhash.xxh64_digest('xxhash', seed=20141025)
'\xb5Y\xb9\x8d\x84N\x065'
.. code-block:: python
In [1]: import xxhash
In [2]: %timeit xxhash.xxh64_hexdigest('xxhash')
268 ns ± 24.1 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
In [3]: %timeit xxhash.xxh64('xxhash').hexdigest()
416 ns ± 17.3 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
XXH3 hashes are available since v2.0.0 (xxHash v0.8.0), they are:
Streaming classes:
| xxh3_64
| xxh3_128
Oneshot functions:
| xxh3_64_digest(bytes, seed=0)
| xxh3_64_intdigest(bytes, seed=0)
| xxh3_64_hexdigest(bytes, seed=0)
| xxh3_128_digest(bytes, seed=0)
| xxh3_128_intdigest(bytes, seed=0)
| xxh3_128_hexdigest(bytes, seed=0)
And aliases:
| xxh128 = xxh3_128
| xxh128_digest = xxh3_128_digest
| xxh128_intdigest = xxh3_128_intdigest
| xxh128_hexdigest = xxh3_128_hexdigest
Caveats
-------
SEED OVERFLOW
~~~~~~~~~~~~~~
xxh32 takes an unsigned 32-bit integer as seed, and xxh64 takes
an unsigned 64-bit integer as seed. Make sure that the seed is greater than
or equal to ``0``.
ENDIANNESS
~~~~~~~~~~~
As of python-xxhash 0.3.0, ``digest()`` returns bytes of the
**big-endian** representation of the integer digest. It used
to be little-endian.
DONT USE XXHASH IN HMAC
~~~~~~~~~~~~~~~~~~~~~~~
Though you can use xxhash as an HMAC_ hash function, but it's
highly recommended not to.
xxhash is **NOT** a cryptographic hash function, it is a
non-cryptographic hash algorithm aimed at speed and quality.
Do not put xxhash in any position where cryptographic hash
functions are required.
Copyright and License
---------------------
Copyright (c) 2014-2024 Yue Du - https://github.com/ifduyue
Licensed under `BSD 2-Clause License `_