xxhash-cffi 1.3.0

安装

$ pip install xxhash-cffi

$ apt-get install libcffi-dev python-dev gcc

$ yum install libcffi-devel python-devel gcc redhat-rpm-config

用法

可以使用模块属性VERSION和XXHASH_VERSION分别检索模块版本及其后端xxHash库版本。

>>> import xxhash_cffi as xxhash
>>> xxhash.VERSION
'1.0.1'
>>> xxhash.XXHASH_VERSION
'0.6.2'

此模块符合hashlib规范，这意味着您可以使用与hashlib.md5相同的方式使用它。

update() – 使用附加字符串更新当前摘要

digest() – 返回当前摘要值

hexdigest() – 返回当前摘要的十六进制数字字符串

intdigest() – 返回当前摘要的整数

copy() – 返回当前xxhash对象的副本

reset() – 重置状态

md5摘要返回字节，但原始xxh32和xxh64 C API返回整数。虽然此模块已符合hashlib规范，但仍然提供了intdigest()以获取整数摘要。

此模块提供的哈希算法构造函数是xxh32()和xxh64()。

例如，为了获取字节字符串b'Nobody inspects the spammish repetition'的摘要

>>> import xxhash_cffi as 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

更简洁的

>>> xxhash.xxh32(b'Nobody inspects the spammish repetition').hexdigest()
'e2293b2f'
>>> xxhash.xxh32(b'Nobody inspects the spammish repetition').digest() == x.digest()
True

可以使用一个可选的种子（默认为0）来有预测性地改变结果

>>> import xxhash_cffi as 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

请注意，xxh32函数接受无符号32位整数作为种子，而xxh64函数接受无符号64位整数。虽然无符号整数溢出是定义良好的行为，但最好避免这种情况发生。

>>> 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() 返回整数摘要的大端表示形式的字节。

>>> import xxhash_cffi as 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

除了上述xxh32/xxh64函数之外，还提供了oneshot函数。通过使用oneshot函数，我们可以避免在堆上分配XXH32/64_state。

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)

>>> import xxhash_cffi as 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'

注意事项

版权和许可

版权（c）2014-2018 杜越 - https://github.com/ifduyue

在BSD 2-Clause License许可下发布