class BloomFilter:
def hash(self, string, prime):
h = 0
for c in string:
h = (prime * h + ord(c)) & 0xFFFFFFFF
bitset_length = (((h + 0x80000000) & 0xFFFFFFFF) - 0x80000000)
return bitset_length % self.bitset.length
def hashFunctions(self, primes):
result = list()
for p in primes:
print "lambda x: self.hash(x, ", p, ")"
result.append(lambda x: self.hash(x, p))
return result
def __init__(self, size, hashCount=0):
self.bitset = Bitset(0, size)
self.hashs = self.hashFunctions(PRIMES[0:hashCount or len(PRIMES)])
pass
def __str__(self):
return "BloomFilter[size={} value={}]".format(self.bitset.length, self.bitset.__str__())
def __contains__(self, item):
contains = True
for h in self.hashs:
contains = contains & self.bitset[h(item)]
if not contains:
break
return contains
def add(self, item):
for h in self.hashs:
self.bitset[h(item)] = True
def remove(self, item):
for h in self.hashs:
self.bitset[h(item)] = False
