Существует ли встроенная реализация Python алгоритма Jenkins hash?
Мне нужен алгоритм хеширования, который принимает произвольную строку и превращает ее в 32-битное целое число. Для данной строки он должен гарантировать возвращение одного и того же целого числа на разных платформах.
Я рассмотрел алгоритм хеша ELF, из которого я нашел реализацию Python. Может ли это быть подходящей заменой, учитывая вышеуказанные критерии? (http://www.partow.net/programming/hashfunctions/#ELFHashFunction)
Этот родной код python должен дать вам тот же хеш, что и исходный lookup3.c
# 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. [email protected] 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)
Вы можете просто использовать первые 32 бита md5sum
>>> from hashlib import md5
>>> from struct import unpack
>>> unpack("<IIII",md5("thestring").digest())[0]
1515985217
Закончилось внедрение этого самостоятельно. Выпускается в соответствии с оригинальным уведомлением об авторских правах (см. Ниже). Используйте на свой страх и риск: -)
'''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 - [email protected] - 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. [email protected] You may use this
code any way you wish, private, educational, or commercial. It 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)
В PyPi уже есть пакет "jenkins" . Но он не является "родным", поскольку основная реализация находится в C.
простая форма реализации хэш one_at_a_time, данный в википедии. Имейте в виду, что этот алгоритм имеет лавинное поведение.
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
Здесь минимальная реализация:
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