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
________________________________________________________
Be one who knows what they don't know,
Instead of being one who knows not what they don't know,
Thinking they know everything about all things.
http://www.partow.net
--
http://mail.python.org/mailman/listinfo/python-list
