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