content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.cassandra.index.sai.disk.v1.vector;
  
  import java.util.Set;
  
  import org.cliffc.high_scale_lib.NonBlockingHashMapLong;
  
  import io.github.jbellis.jvector.util.Bits;
  
  public class BitsUtil
  {
      public static Bits bitsIgnoringDeleted(Bits toAccept, Set<Integer> deletedOrdinals)
      {
          return deletedOrdinals.isEmpty()
                 ? toAccept
                 : toAccept == null ? new NoDeletedBits(deletedOrdinals) : new NoDeletedIntersectingBits(toAccept, deletedOrdinals);
      }
  
      public static <T> Bits bitsIgnoringDeleted(Bits toAccept, NonBlockingHashMapLong<VectorPostings<T>> postings)
      {
          return toAccept == null ? new NoDeletedPostings<>(postings) : new NoDeletedIntersectingPostings<>(toAccept, postings);
      }
  
      private static abstract class BitsWithoutLength implements Bits, org.apache.lucene.util.Bits
      {
          @Override
          public int length()
          {
              // length() is not called on search path
              throw new UnsupportedOperationException();
          }
      }
  
      private static class NoDeletedBits extends BitsWithoutLength
      {
          private final Set<Integer> deletedOrdinals;
  
          private NoDeletedBits(Set<Integer> deletedOrdinals)
          {
              this.deletedOrdinals = deletedOrdinals;
          }
  
          @Override
          public boolean get(int i)
          {
              return !deletedOrdinals.contains(i);
          }
      }
  
      private static class NoDeletedIntersectingBits extends BitsWithoutLength
      {
          private final Bits toAccept;
          private final Set<Integer> deletedOrdinals;
  
          private NoDeletedIntersectingBits(Bits toAccept, Set<Integer> deletedOrdinals)
          {
              this.toAccept = toAccept;
              this.deletedOrdinals = deletedOrdinals;
          }
  
          @Override
          public boolean get(int i)
          {
              return !deletedOrdinals.contains(i) && toAccept.get(i);
          }
      }
  
      private static class NoDeletedPostings<T> extends BitsWithoutLength
      {
          private final NonBlockingHashMapLong<VectorPostings<T>> postings;
  
          public NoDeletedPostings(NonBlockingHashMapLong<VectorPostings<T>> postings)
          {
              this.postings = postings;
          }
  
          @Override
          public boolean get(int i)
          {
              VectorPostings<T> p = postings.get(i);
              assert p != null : "No postings for ordinal " + i;
              return !p.isEmpty();
          }
      }
  
      private static class NoDeletedIntersectingPostings<T> extends BitsWithoutLength
      {
          private final Bits toAccept;
          private final NonBlockingHashMapLong<VectorPostings<T>> postings;
  
          public NoDeletedIntersectingPostings(Bits toAccept, NonBlockingHashMapLong<VectorPostings<T>> postings)
          {
              this.toAccept = toAccept;
              this.postings = postings;
          }
  
          @Override
          public boolean get(int i)
          {
              VectorPostings<T> p = postings.get(i);
              assert p != null : "No postings for ordinal " + i;
              return !p.isEmpty() && toAccept.get(i);
          }
      }
  }
  