56 lines
1.2 KiB
Python
56 lines
1.2 KiB
Python
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import random
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try: #
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shathree = __import__('sha3').sha3_256
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except:
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shathree = __import__('python_sha3').sha3_256
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params = {
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"size": 256,
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"pecks": 32
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}
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def decode_int(x):
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o = 0
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for a in x:
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o = o * 256 + ord(a)
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return o
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def sha3(x):
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return shathree(x).digest()
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def bloom_insert(params, bloom, val):
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k = decode_int(sha3(val)) * (3**160 + 112)
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for i in range(params["pecks"]):
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bloom |= 1 << (k % params["size"])
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k //= params["size"]
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return bloom
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def bloom_query(params, bloom, val):
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o = bloom_insert(params, 0, val)
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return (bloom & o) == o
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def test_params(size, pecks, objcount):
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params = {"size": size, "pecks": pecks}
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count = 0
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for i in range(100):
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objs = [str(random.randrange(2**40)) for i in range(objcount)]
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bloom = 0
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for o in objs:
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bloom = bloom_insert(params, bloom, o)
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for o in objs:
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assert bloom_query(params, bloom, o)
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for i in range(100):
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if bloom_query(params, bloom, str(random.randrange(2**40))):
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count += 1
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print 'False positive rate: %f' % (count / 10000.)
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