2019-12-09 11:08:42 +00:00
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import stint, nimcrypto/[keccak, hash]
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2019-02-05 14:22:21 +00:00
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type UInt2048 = StUint[2048]
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iterator chunksForBloom(h: MDigest[256]): array[2, uint8] =
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yield [h.data[0], h.data[1]]
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yield [h.data[2], h.data[3]]
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yield [h.data[4], h.data[5]]
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proc chunkToBloomBits(chunk: array[2, uint8]): UInt2048 =
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let h = chunk[0].int
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let l = chunk[1].int
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one(UInt2048) shl ((l + (h shl 8)) and 2047)
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iterator bloomBits(h: MDigest[256]): UInt2048 =
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for chunk in chunksForBloom(h):
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yield chunkToBloomBits(chunk)
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type BloomFilter* = object
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value*: UInt2048
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proc incl(f: var BloomFilter, h: MDigest[256]) = # Should this be public?
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for bits in bloomBits(h):
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f.value = f.value or bits
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# TODO: The following 2 procs should be one genric, but it doesn't compile. Nim bug?
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proc incl*(f: var BloomFilter, v: string) = f.incl(keccak256.digest(v))
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proc incl*(f: var BloomFilter, v: openarray[byte]) = f.incl(keccak256.digest(v))
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proc contains(f: BloomFilter, h: MDigest[256]): bool = # Should this be public?
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for bits in bloomBits(h):
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if (f.value and bits).isZero: return false
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return true
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template contains*[T](f: BloomFilter, v: openarray[T]): bool =
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f.contains(keccak256.digest(v))
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