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.io.sstable.format.bti;
  
  import java.io.IOException;
  import java.io.PrintStream;
  
  import org.apache.cassandra.io.sstable.format.Version;
  import org.apache.cassandra.io.sstable.format.bti.RowIndexReader.IndexInfo;
  import org.apache.cassandra.io.tries.ReverseValueIterator;
  import org.apache.cassandra.io.util.FileHandle;
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  
  /**
   * Reverse iterator over the row index. Needed to get previous index blocks for reverse iteration.
   */
  class RowIndexReverseIterator extends ReverseValueIterator<RowIndexReverseIterator>
  {
      private long currentNode = -1;
      private final Version version;
  
      public RowIndexReverseIterator(FileHandle file, long root, ByteComparable start, ByteComparable end, Version version)
      {
          super(file.instantiateRebufferer(null), root, start, end, true);
          this.version = version;
      }
  
      public RowIndexReverseIterator(FileHandle file, TrieIndexEntry entry, ByteComparable end, Version version)
      {
          this(file, entry.indexTrieRoot, ByteComparable.EMPTY, end, version);
      }
  
      public IndexInfo nextIndexInfo() throws IOException
      {
          if (currentNode == -1)
          {
              currentNode = nextPayloadedNode();
              if (currentNode == -1)
                  return null;
          }
  
          go(currentNode);
          IndexInfo info = RowIndexReader.readPayload(buf, payloadPosition(), payloadFlags(), version);
  
          currentNode = -1;
          return info;
      }
  
      // debug/test code
      @SuppressWarnings("unused")
      public void dumpTrie(PrintStream out) throws IOException
      {
          dumpTrie(out, RowIndexReader::dumpRowIndexEntry, version);
      }
  }
  