是否存在Python原生实现的Jenkins哈希算法？
我需要一个哈希算法，能将任意字符串转换成32位整数。对于给定的字符串，它必须保证跨平台返回相同的整数。
我已经查看了ELF哈希算法的Python实现。鉴于上述条件，这是否可以作为一种合适的替代品？(http://www.partow.net/programming/hashfunctions/#ELFHashFunction)
6个回答
14
这段原生的Python代码应该会给你与原始的lookup3.c相同的哈希值
# Need to constrain U32 to only 32 bits using the & 0xffffffff
# since Python has no native notion of integers limited to 32 bit
# http://docs.python.org/library/stdtypes.html#numeric-types-int-float-long-complex
'''Original copyright notice:
By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
code any way you wish, private, educational, or commercial. Its free.
'''
def rot(x,k):
return (((x)<<(k)) | ((x)>>(32-(k))))
def mix(a, b, c):
a &= 0xffffffff; b &= 0xffffffff; c &= 0xffffffff
a -= c; a &= 0xffffffff; a ^= rot(c,4); a &= 0xffffffff; c += b; c &= 0xffffffff
b -= a; b &= 0xffffffff; b ^= rot(a,6); b &= 0xffffffff; a += c; a &= 0xffffffff
c -= b; c &= 0xffffffff; c ^= rot(b,8); c &= 0xffffffff; b += a; b &= 0xffffffff
a -= c; a &= 0xffffffff; a ^= rot(c,16); a &= 0xffffffff; c += b; c &= 0xffffffff
b -= a; b &= 0xffffffff; b ^= rot(a,19); b &= 0xffffffff; a += c; a &= 0xffffffff
c -= b; c &= 0xffffffff; c ^= rot(b,4); c &= 0xffffffff; b += a; b &= 0xffffffff
return a, b, c
def final(a, b, c):
a &= 0xffffffff; b &= 0xffffffff; c &= 0xffffffff
c ^= b; c &= 0xffffffff; c -= rot(b,14); c &= 0xffffffff
a ^= c; a &= 0xffffffff; a -= rot(c,11); a &= 0xffffffff
b ^= a; b &= 0xffffffff; b -= rot(a,25); b &= 0xffffffff
c ^= b; c &= 0xffffffff; c -= rot(b,16); c &= 0xffffffff
a ^= c; a &= 0xffffffff; a -= rot(c,4); a &= 0xffffffff
b ^= a; b &= 0xffffffff; b -= rot(a,14); b &= 0xffffffff
c ^= b; c &= 0xffffffff; c -= rot(b,24); c &= 0xffffffff
return a, b, c
def hashlittle2(data, initval = 0, initval2 = 0):
length = lenpos = len(data)
a = b = c = (0xdeadbeef + (length) + initval)
c += initval2; c &= 0xffffffff
p = 0 # string offset
while lenpos > 12:
a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24)); a &= 0xffffffff
b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); b &= 0xffffffff
c += (ord(data[p+8]) + (ord(data[p+9])<<8) + (ord(data[p+10])<<16) + (ord(data[p+11])<<24)); c &= 0xffffffff
a, b, c = mix(a, b, c)
p += 12
lenpos -= 12
if lenpos == 12: c += (ord(data[p+8]) + (ord(data[p+9])<<8) + (ord(data[p+10])<<16) + (ord(data[p+11])<<24)); b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 11: c += (ord(data[p+8]) + (ord(data[p+9])<<8) + (ord(data[p+10])<<16)); b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 10: c += (ord(data[p+8]) + (ord(data[p+9])<<8)); b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 9: c += (ord(data[p+8])); b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 8: b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 7: b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16)); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 6: b += ((ord(data[p+5])<<8) + ord(data[p+4])); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24))
if lenpos == 5: b += (ord(data[p+4])); a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24));
if lenpos == 4: a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24))
if lenpos == 3: a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16))
if lenpos == 2: a += (ord(data[p+0]) + (ord(data[p+1])<<8))
if lenpos == 1: a += ord(data[p+0])
a &= 0xffffffff; b &= 0xffffffff; c &= 0xffffffff
if lenpos == 0: return c, b
a, b, c = final(a, b, c)
return c, b
def hashlittle(data, initval=0):
c, b = hashlittle2(data, initval, 0)
return c
if __name__ == "__main__":
import sys
hashstr = 'Four score and seven years ago'
hash, hash2 = hashlittle2(hashstr, 0xdeadbeef, 0xdeadbeef)
print '"%s": %x %x' % (hashstr, hash, hash2)
hash = hashlittle(hashstr, 0)
print '"%s": %x' % (hashstr, hash)
- Valentin
1
太棒了！完美运行，我已经测试过与本地C实现的相同哈希值，非常感谢！你为我节省了大量的工作 :) - Gearoid Murphy
6
您只需使用md5sum的前32位即可。
>>> from hashlib import md5
>>> from struct import unpack
>>> unpack("<IIII",md5("thestring").digest())[0]
1515985217
- John La Rooy
1
2通常情况下，为了速度原因，除非您真的需要加密哈希，否则应避免使用MD5。但是，当然，C库实现的MD5将很可能比上述算法的纯Python实现快得多！ - Joe Koberg
4
最终我自己实现了它。根据原始版权声明发布（见下文）。使用时请自行承担风险，祝玩得愉快 :-)
'''Implements a straight Jenkins lookup hash - http://burtleburtle.net/bob/hash/doobs.html
Usage:
from jhash import jhash
print jhash('My hovercraft is full of eels')
Returns: unsigned 32 bit integer value
Prereqs: None
Tested with Python 2.6.
Version 1.00 - der@dod.no - 23.08.2010
Partly based on the Perl module Digest::JHash
http://search.cpan.org/~shlomif/Digest-JHash-0.06/lib/Digest/JHash.pm
Original copyright notice:
By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
code any way you wish, private, educational, or commercial. It's free.
See http://burtleburtle.net/bob/hash/evahash.html
Use for hash table lookup, or anything where one collision in 2^^32 is
acceptable. Do NOT use for cryptographic purposes.
'''
def mix(a, b, c):
'''mix() -- mix 3 32-bit values reversibly.
For every delta with one or two bits set, and the deltas of all three
high bits or all three low bits, whether the original value of a,b,c
is almost all zero or is uniformly distributed,
* If mix() is run forward or backward, at least 32 bits in a,b,c
have at least 1/4 probability of changing.
* If mix() is run forward, every bit of c will change between 1/3 and
2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.)'''
# Need to constrain U32 to only 32 bits using the & 0xffffffff
# since Python has no native notion of integers limited to 32 bit
# http://docs.python.org/library/stdtypes.html#numeric-types-int-float-long-complex
a &= 0xffffffff; b &= 0xffffffff; c &= 0xffffffff
a -= b; a -= c; a ^= (c>>13); a &= 0xffffffff
b -= c; b -= a; b ^= (a<<8); b &= 0xffffffff
c -= a; c -= b; c ^= (b>>13); c &= 0xffffffff
a -= b; a -= c; a ^= (c>>12); a &= 0xffffffff
b -= c; b -= a; b ^= (a<<16); b &= 0xffffffff
c -= a; c -= b; c ^= (b>>5); c &= 0xffffffff
a -= b; a -= c; a ^= (c>>3); a &= 0xffffffff
b -= c; b -= a; b ^= (a<<10); b &= 0xffffffff
c -= a; c -= b; c ^= (b>>15); c &= 0xffffffff
return a, b, c
def jhash(data, initval = 0):
'''hash() -- hash a variable-length key into a 32-bit value
data : the key (the unaligned variable-length array of bytes)
initval : can be any 4-byte value, defaults to 0
Returns a 32-bit value. Every bit of the key affects every bit of
the return value. Every 1-bit and 2-bit delta achieves avalanche.'''
length = lenpos = len(data)
# empty string returns 0
if length == 0:
return 0
# Set up the internal state
a = b = 0x9e3779b9 # the golden ratio; an arbitrary value
c = initval # the previous hash value
p = 0 # string offset
# ------------------------- handle most of the key in 12 byte chunks
while lenpos >= 12:
a += (ord(data[p+0]) + (ord(data[p+1])<<8) + (ord(data[p+2])<<16) + (ord(data[p+3])<<24))
b += (ord(data[p+4]) + (ord(data[p+5])<<8) + (ord(data[p+6])<<16) + (ord(data[p+7])<<24))
c += (ord(data[p+8]) + (ord(data[p+9])<<8) + (ord(data[p+10])<<16) + (ord(data[p+11])<<24))
a, b, c = mix(a, b, c)
p += 12
lenpos -= 12
# ------------------------- handle the last 11 bytes
c += length
if lenpos >= 11: c += ord(data[p+10])<<24
if lenpos >= 10: c += ord(data[p+9])<<16
if lenpos >= 9: c += ord(data[p+8])<<8
# the first byte of c is reserved for the length
if lenpos >= 8: b += ord(data[p+7])<<24
if lenpos >= 7: b += ord(data[p+6])<<16
if lenpos >= 6: b += ord(data[p+5])<<8
if lenpos >= 5: b += ord(data[p+4])
if lenpos >= 4: a += ord(data[p+3])<<24
if lenpos >= 3: a += ord(data[p+2])<<16
if lenpos >= 2: a += ord(data[p+1])<<8
if lenpos >= 1: a += ord(data[p+0])
a, b, c = mix(a, b, c)
# ------------------------- report the result
return c
if __name__ == "__main__":
hashstr = 'My hovercraft is full of eels'
myhash = jhash(hashstr)
print 'jhash("%s"): %d' % (hashstr, myhash)
- MrPilt
1
1这实现了Jenkins哈希查找2，供参考，以便人们不会感到困惑。 - Zenul_Abidin
2
这是一个简单的实现，来自于维基百科中给出的一次一个哈希算法。请注意，此算法具有雪崩效应。
def getJenkinHash(ba : bytearray):
hash : int = 0
for i in range(len(ba)):
hash += ba[i]
hash &= 0xFFFFFFFF
hash += hash << 10
hash &= 0xFFFFFFFF
hash ^= hash >> 6
hash &= 0xFFFFFFFF
hash += hash << 3
hash &= 0xFFFFFFFF
hash ^= hash >> 11
hash &= 0xFFFFFFFF
hash += hash << 15
hash &= 0xFFFFFFFF
return hash
- Stefan Jaritz
0
这里是一个最小化的实现：
def hash(x):
""" Jenkins Hash 32bits."""
x = (x + int('7ed55d16', 16)) + (x << 12)
x = (x ^ int('c761c23c', 16)) ^ (x >> 19)
x = (x + int('165667b1', 16)) + (x << 5)
x = (x + int('d3a2646c', 16)) ^ (x << 9)
x = (x + int('fd7046c5', 16)) + (x << 3)
x = (x ^ int('b55a4f09', 16)) ^ (x >> 16)
return x
- nowox
0
在 PyPi 上已经有一个 "jenkins" package。但它不是“本地”的，因为核心实现是用 C 编写的。
- kennytm
2
是的，我找到了它，但当我尝试在Windows上安装它时，会收到有关一些缺少.bat文件的错误消息。 我正在寻找一种具有最少先决条件的解决方案。 - DavidR
Jenkins 1.0.2 PyPi软件包在Linux上构建时也出现了错误，错误信息为"OSError: /usr/lib/python2.6/dist-packages/lookup3.so: cannot open shared object file: No such file or directory"。 - Paul Whipp
网页内容由stack overflow 提供, 点击上面的可以查看英文原文，
原文链接
原文链接