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.kafka.streams.state.internals;
  
  import org.apache.kafka.common.utils.Bytes;
  import org.apache.kafka.streams.KeyValue;
  
  import org.rocksdb.RocksIterator;
  
  import java.util.Comparator;
  
  class RocksDBRangeIterator extends RocksDbIterator {
      // RocksDB's JNI interface does not expose getters/setters that allow the
      // comparator to be pluggable, and the default is lexicographic, so it's
      // safe to just force lexicographic comparator here for now.
      private final Comparator<byte[]> comparator = Bytes.BYTES_LEXICO_COMPARATOR;
      private final byte[] rawLastKey;
      private final boolean forward;
      private final boolean toInclusive;
  
      RocksDBRangeIterator(final String storeName,
                           final RocksIterator iter,
                           final Bytes from,
                           final Bytes to,
                           final boolean forward,
                           final boolean toInclusive) {
          super(storeName, iter, forward);
          this.forward = forward;
          this.toInclusive = toInclusive;
          if (forward) {
              if (from == null) {
                  iter.seekToFirst();
              } else {
                  iter.seek(from.get());
              }
              rawLastKey = to == null ? null : to.get();
          } else {
              if (to == null) {
                  iter.seekToLast();
              } else {
                  iter.seekForPrev(to.get());
              }
              rawLastKey = from == null ? null : from.get();
          }
      }
  
      @Override
      protected KeyValue<Bytes, byte[]> makeNext() {
          final KeyValue<Bytes, byte[]> next = super.makeNext();
          if (next == null) {
              return allDone();
          } else if (rawLastKey == null) {
              //null means range endpoint is open
              return next;
  
          } else {
              if (forward) {
                  if (comparator.compare(next.key.get(), rawLastKey) < 0) {
                      return next;
                  } else if (comparator.compare(next.key.get(), rawLastKey) == 0) {
                      return toInclusive ? next : allDone();
                  } else {
                      return allDone();
                  }
              } else {
                  if (comparator.compare(next.key.get(), rawLastKey) >= 0) {
                      return next;
                  } else {
                      return allDone();
                  }
              }
          }
      }
  }
  