General Hash Functions In Python

[Arash Partow]

Hi all,

I've ported various hash functions to python if anyone is interested:



def RSHash(key):
    a    = 378551
    b    =  63689
    hash =      0
    for i in range(len(key)):
      hash = hash * a + ord(key[i])
      a = a * b
    return (hash & 0x7FFFFFFF)


def JSHash(key):
    hash = 1315423911
    for i in range(len(key)):
      hash ^= ((hash << 5) + ord(key[i]) + (hash >> 2))
    return (hash & 0x7FFFFFFF)


def PJWHash(key):
   BitsInUnsignedInt = 4 * 8
   ThreeQuarters     = long((BitsInUnsignedInt  * 3) / 4)
   OneEighth         = long(BitsInUnsignedInt / 8)
   HighBits          = (0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth)
   hash              = 0
   test              = 0

   for i in range(len(key)):
     hash = (hash << OneEighth) + ord(key[i])
     test = hash & HighBits
     if test != 0:
       hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));
   return (hash & 0x7FFFFFFF)


def ELFHash(key):
    hash = 0
    x    = 0
    for i in range(len(key)):
      hash = (hash << 4) + ord(key[i])
      x = hash & 0xF0000000
      if x != 0:
        hash ^= (x >> 24)
        hash &= ~x
    return (hash & 0x7FFFFFFF)


def BKDRHash(key):
    seed = 131 # 31 131 1313 13131 131313 etc..
    hash = 0
    for i in range(len(key)):
      hash = (hash * seed) + ord(key[i])
    return (hash & 0x7FFFFFFF)


def SDBMHash(key):
    hash = 0
    for i in range(len(key)):
      hash = ord(key[i]) + (hash << 6) + (hash << 16) - hash;
    return (hash & 0x7FFFFFFF)


def DJBHash(key):
    hash = 5381
    for i in range(len(key)):
       hash = ((hash << 5) + hash) + ord(key[i])
    return (hash & 0x7FFFFFFF)


def DEKHash(key):
    hash = len(key);
    for i in range(len(key)):
      hash = ((hash << 5) ^ (hash >> 27)) ^ ord(key[i])
    return (hash & 0x7FFFFFFF)


def APHash(key):
    hash = 0
    for i in range(len(key)):
      if ((i & 1) == 0):
        hash ^= ((hash <<  7) ^ ord(key[i]) ^ (hash >> 3))
      else:
        hash ^= (~((hash << 11) ^ ord(key[i]) ^ (hash >> 5)))
    return (hash & 0x7FFFFFFF)


print RSHash  ('abcdefghijklmnopqrstuvwxyz1234567890')
print JSHash  ('abcdefghijklmnopqrstuvwxyz1234567890')
print PJWHash ('abcdefghijklmnopqrstuvwxyz1234567890')
print ELFHash ('abcdefghijklmnopqrstuvwxyz1234567890')
print BKDRHash('abcdefghijklmnopqrstuvwxyz1234567890')
print SDBMHash('abcdefghijklmnopqrstuvwxyz1234567890')
print DJBHash ('abcdefghijklmnopqrstuvwxyz1234567890')
print DEKHash ('abcdefghijklmnopqrstuvwxyz1234567890')
print APHash  ('abcdefghijklmnopqrstuvwxyz1234567890')





Arash Partow
________________________________________________________
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Instead of being one who knows not what they don't know,
Thinking they know everything about all things.
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