Jenkins哈希的Python实现？

Question

是否存在Jenkins hash算法的本地Python实现？

我需要一个采用任意字符串并将其转换为32位整数的散列算法。对于给定的字符串，它必须保证跨平台返回相同的整数。

我看过ELF哈希算法，其中我找到了一个Python实现。鉴于上述标准，这可能是一个合适的替代品吗？ （http://www.partow.net/programming/hashfunctions/#ELFHashFunction）

Answer 1

PyPi上已经有"jenkins" package。但它不是“土”为核心的实现是C.

Answer 2

你可以只使用了截至实现它在我自己的的md5sum

>>> from hashlib import md5 
>>> from struct import unpack 
>>> unpack("<IIII",md5("thestring").digest())[0] 
1515985217 

Answer 3

的前32位。根据原始版权声明发布（见下文）。使用您自己的风险，并有乐趣:-)

'''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) 

Answer 4

这种原生的Python代码应该给你相同的哈希与原始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. 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)