// subjInKeyspace appends an increasing number to the prefix until it finds a
// string that will hash into the given keyspace.
func subjInKeyspace(keyspace *protocol.Keyspace, prefix string) string {
subj := prefix
i := 1
for !keyspace.Includes(murmur3.Sum64([]byte(subj))) {
subj = prefix + strconv.Itoa(i)
i++
}
return subj
}
// Bloom returns a ScalableBloomFilter containing all the triples the current node has in the optional keyspace.
func (ts *TripleStore) Bloom(keyspace *protocol.Keyspace) (*boom.ScalableBloomFilter, error) {
filter := boom.NewDefaultScalableBloomFilter(BloomFalsePositiveRate)
results, errs := ts.EachTripleBatch(DefaultTripleBatchSize)
for triples := range results {
for _, triple := range triples {
if keyspace != nil {
hash := murmur3.Sum64([]byte(triple.Subj))
if !keyspace.Includes(hash) {
continue
}
}
data, err := triple.Marshal()
if err != nil {
return nil, err
}
filter.Add(data)
}
}
for err := range errs {
return nil, err
}
return filter, nil
}