/** Collect documents from a bitset. */
private List<Document> collectDocuments(List<Document> l, BitSet bitset) {
if (l == null) {
l = Lists.newArrayListWithCapacity((int) bitset.cardinality());
}
final BitSetIterator i = bitset.iterator();
for (int d = i.nextSetBit(); d >= 0; d = i.nextSetBit()) {
l.add(documents.get(d));
}
return l;
}
@Override
public int encodedSize() {
/*
* The number of bytes goes as follows:
*
* you need at least as many bits as the highest 1-bit in the bitSet(equivalent
* to bitSet.length()). Because each set bit will have an additional 2-bit "type delimiter"
* set afterwords, we need to have 3 bits for every set bit, but 1 for every non-set bit
*
* This is equivalent to length()+2*numSetBits().
*
* we have 4 available bits in the header, and 7 bits in each subsequent byte (we use a continuation
* bit).
*/
int numBits = (int) (bitSet.length() + 2 * bitSet.cardinality());
int numBytes = 1;
numBits -= 4;
if (numBits > 0) {
numBytes += numBits / 7;
if (numBits % 7 != 0) numBytes++;
}
return numBytes;
}
@Override
public int cardinality() {
return (int) bitSet.cardinality();
}