[jira] [Created] (COLLECTIONS-823) BloomFilter: Optimize ArrayCountingBloomFilter.ForEachBitMap

["Claude Warren (Jira)" <ji...@apache.org>]

Claude Warren created COLLECTIONS-823:
-----------------------------------------

             Summary: BloomFilter: Optimize ArrayCountingBloomFilter.ForEachBitMap
                 Key: COLLECTIONS-823
                 URL: https://issues.apache.org/jira/browse/COLLECTIONS-823
             Project: Commons Collections
          Issue Type: Improvement
          Components: Collection
    Affects Versions: 4.5
            Reporter: Claude Warren


 
 
 Member 
h3. !https://avatars.githubusercontent.com/u/886334?s=48&v=4|width=24,height=24!  *[aherbert|https://github.com/aherbert]*  [on 27 Feb|https://github.com/apache/commons-collections/pull/258#discussion_r812499923]
This converts all the non zero indices to a bitmap long[] array. But to do so requires using the {{forEachIndex}} method with a conditional boolean check on each loop iteration. I wonder if this should be brought inline for efficiency:

     @Override
    public boolean forEachBitMap(LongPredicate consumer) {
        Objects.requireNonNull(consumer, "consumer");
        long[] result = new long[BitMap.numberOfBitMaps(shape.getNumberOfBits())];
        for (int i = 0; i < counts.length; i++) {
            if (counts[i] != 0) {
                // Avoids a second check on the predicate result in forEachIndex
                BitMap.set(result, i);
            }
        }
        return BitMapProducer.fromBitMapArray(result).forEachBitMap(consumer);
    }


Or better yet, avoid the {{long[]}} array:

        int blocksm1 = BitMap.numberOfBitMaps(shape.getNumberOfBits()) - 1;
        int i = 0;
        long value;
        for (int j = 0; j < blocksm1; j++) {
            value = 0;
            for (int k = 0; k < Long.SIZE; k++) {
                if (counts[i++] != 0) {
                    value |= BitMap.getLongBit(k);
                }
            }
            if (!consumer.test(value)) {
                return false;
            }
        }
        // Final block
        value = 0;
        for (int k = 0; i < counts.length; k++) {
            if (counts[i++] != 0) {
                value |= BitMap.getLongBit(k);
            }
        }
        return consumer.test(value);



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