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.db;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.Objects;
  
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.io.util.DataInputPlus;
  import org.apache.cassandra.io.util.DataOutputPlus;
  import org.apache.cassandra.utils.Comparables;
  
  /**
   * A slice represents the selection of a range of rows.
   * <p>
   * A slice has a start and an end bound that are both (potentially full) clustering prefixes.
   * A slice selects every row whose clustering is included within its start and end bounds.
   * Both start and end can be either inclusive or exclusive.
   */
  public class Slice
  {
      public static final Serializer serializer = new Serializer();
  
      /**
       * The slice selecting all rows (of a given partition)
       */
      public static final Slice ALL = new Slice(BufferClusteringBound.BOTTOM, BufferClusteringBound.TOP)
      {
          @Override
          public boolean includes(ClusteringComparator comparator, ClusteringPrefix<?> clustering)
          {
              return true;
          }
  
          @Override
          public boolean intersects(ClusteringComparator comparator, Slice other)
          {
              return !other.isEmpty(comparator);
          }
  
          @Override
          public String toString(ClusteringComparator comparator)
          {
              return "ALL";
          }
      };
  
      private final ClusteringBound<?> start;
      private final ClusteringBound<?> end;
  
      private Slice(ClusteringBound<?> start, ClusteringBound<?> end)
      {
          assert start.isStart() && end.isEnd();
          this.start = start;
          this.end = end;
      }
  
      public static Slice make(ClusteringBound<?> start, ClusteringBound<?> end)
      {
          assert start != null && end != null;
  
          if (start.isBottom() && end.isTop())
              return ALL;
  
          return new Slice(start, end);
      }
  
      public static Slice make(ClusteringComparator comparator, Object... values)
      {
          CBuilder builder = CBuilder.create(comparator);
          for (Object val : values)
          {
              if (val instanceof ByteBuffer)
                  builder.add((ByteBuffer) val);
              else
                  builder.add(val);
          }
          return new Slice(builder.buildBound(true, true), builder.buildBound(false, true));
      }
  
      /**
       * Makes a slice covering a single clustering
       */
      public static Slice make(Clustering<?> clustering)
      {
          // This doesn't give us what we want with the clustering prefix
          assert clustering != Clustering.STATIC_CLUSTERING;
          return new Slice(ClusteringBound.inclusiveStartOf(clustering), ClusteringBound.inclusiveEndOf(clustering));
      }
  
      /**
       * Makes a slice covering a range from start to end clusterings, with both start and end included
       */
      public static Slice make(Clustering<?> start, Clustering<?> end)
      {
          // This doesn't give us what we want with the clustering prefix
          assert start != Clustering.STATIC_CLUSTERING && end != Clustering.STATIC_CLUSTERING;
          return new Slice(ClusteringBound.inclusiveStartOf(start), ClusteringBound.inclusiveEndOf(end));
      }
  
      /**
       * Makes a slice for the given bounds
       */
      public static Slice make(ClusteringBoundOrBoundary<?> start, ClusteringBoundOrBoundary<?> end)
      {
          // This doesn't give us what we want with the clustering prefix
          return make(start.asStartBound(), end.asEndBound());
      }
  
      public ClusteringBound<?> start()
      {
          return start;
      }
  
      public ClusteringBound<?> end()
      {
          return end;
      }
  
      public ClusteringBound<?> open(boolean reversed)
      {
          return reversed ? end : start;
      }
  
      public ClusteringBound<?> close(boolean reversed)
      {
          return reversed ? start : end;
      }
  
      /**
       * Return whether the slice is empty.
       *
       * @param comparator the comparator to compare the bounds.
       * @return whether the slice formed is empty or not.
       */
      public boolean isEmpty(ClusteringComparator comparator)
      {
          return isEmpty(comparator, start(), end());
      }
  
      /**
       * Return whether the slice formed by the two provided bound is empty or not.
       *
       * @param comparator the comparator to compare the bounds.
       * @param start      the start for the slice to consider. This must be a start bound.
       * @param end        the end for the slice to consider. This must be an end bound.
       * @return whether the slice formed by {@code start} and {@code end} is
       * empty or not.
       */
      public static boolean isEmpty(ClusteringComparator comparator, ClusteringBound<?> start, ClusteringBound<?> end)
      {
          assert start.isStart() && end.isEnd();
          // Note: the comparator orders inclusive starts and exclusive ends as equal, and inclusive ends as being greater than starts.
          return comparator.compare(start, end) >= 0;
      }
  
      /**
       * Returns whether a given clustering or bound is included in this slice.
       *
       * @param comparator the comparator for the table this is a slice of.
       * @param bound      the bound to test inclusion of.
       * @return whether {@code bound} is within the bounds of this slice.
       */
      public boolean includes(ClusteringComparator comparator, ClusteringPrefix<?> bound)
      {
          return comparator.compare(start, bound) <= 0 && comparator.compare(bound, end) <= 0;
      }
  
      /**
       * Returns a slice for continuing paging from the last returned clustering prefix.
       *
       * @param comparator   the comparator for the table this is a filter for.
       * @param lastReturned the last clustering that was returned for the query we are paging for. The
       *                     resulting slices will be such that only results coming stricly after {@code lastReturned} are returned
       *                     (where coming after means "greater than" if {@code !reversed} and "lesser than" otherwise).
       * @param inclusive    whether we want to include the {@code lastReturned} in the newly returned page of results.
       * @param reversed     whether the query we're paging for is reversed or not.
       * @return a new slice that selects results coming after {@code lastReturned}, or {@code null} if paging
       * the resulting slice selects nothing (i.e. if it originally selects nothing coming after {@code lastReturned}).
       */
      public Slice forPaging(ClusteringComparator comparator, Clustering<?> lastReturned, boolean inclusive, boolean reversed)
      {
          if (lastReturned == null)
              return this;
  
          if (reversed)
          {
              int cmp = comparator.compare(lastReturned, start);
              assert cmp != 0;
              // start is > than lastReturned; got nothing to return no more
              if (cmp < 0)
                  return null;
  
              cmp = comparator.compare(end, lastReturned);
              assert cmp != 0;
              if (cmp < 0)
                  return this;
  
              Slice slice = new Slice(start, inclusive ? ClusteringBound.inclusiveEndOf(lastReturned) : ClusteringBound.exclusiveEndOf(lastReturned));
              if (slice.isEmpty(comparator))
                  return null;
              return slice;
          }
          else
          {
              int cmp = comparator.compare(end, lastReturned);
              assert cmp != 0;
              if (cmp < 0)
                  return null;
  
              cmp = comparator.compare(lastReturned, start);
              assert cmp != 0;
              if (cmp < 0)
                  return this;
  
              Slice slice = new Slice(inclusive ? ClusteringBound.inclusiveStartOf(lastReturned) : ClusteringBound.exclusiveStartOf(lastReturned), end);
              if (slice.isEmpty(comparator))
                  return null;
              return slice;
          }
      }
  
      /**
       * Whether this slice and the provided slice intersects.
       *
       * @param comparator the comparator for the table this is a slice of.
       * @param other      the other slice to check intersection with.
       * @return whether this slice intersects {@code other}.
       */
      public boolean intersects(ClusteringComparator comparator, Slice other)
      {
          // Construct the intersection of the two slices and check if it is non-empty.
          // This also works correctly when one or more of the inputs are be empty (i.e. with end <= start).
          return comparator.compare(Comparables.max(start, other.start, comparator),
                                    Comparables.min(end, other.end, comparator)) < 0;
      }
  
      public String toString(ClusteringComparator comparator)
      {
          StringBuilder sb = new StringBuilder();
          sb.append(start.isInclusive() ? "[" : "(");
          for (int i = 0; i < start.size(); i++)
          {
              if (i > 0)
                  sb.append(':');
              sb.append(start.stringAt(i, comparator));
          }
          sb.append(", ");
          for (int i = 0; i < end.size(); i++)
          {
              if (i > 0)
                  sb.append(':');
              sb.append(end.stringAt(i, comparator));
          }
          sb.append(end.isInclusive() ? "]" : ")");
          return sb.toString();
      }
  
      @Override
      public boolean equals(Object other)
      {
          if (!(other instanceof Slice))
              return false;
  
          Slice that = (Slice) other;
          return this.start().equals(that.start())
                 && this.end().equals(that.end());
      }
  
      @Override
      public int hashCode()
      {
          return Objects.hash(start(), end());
      }
  
      public static class Serializer
      {
          public void serialize(Slice slice, DataOutputPlus out, int version, List<AbstractType<?>> types) throws IOException
          {
              ClusteringBound.serializer.serialize(slice.start, out, version, types);
              ClusteringBound.serializer.serialize(slice.end, out, version, types);
          }
  
          public long serializedSize(Slice slice, int version, List<AbstractType<?>> types)
          {
              return ClusteringBound.serializer.serializedSize(slice.start, version, types)
                     + ClusteringBound.serializer.serializedSize(slice.end, version, types);
          }
  
          public Slice deserialize(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
          {
              ClusteringBound<byte[]> start = (ClusteringBound<byte[]>) ClusteringBound.serializer.deserialize(in, version, types);
              ClusteringBound<byte[]> end = (ClusteringBound<byte[]>) ClusteringBound.serializer.deserialize(in, version, types);
              return new Slice(start, end);
          }
      }
  }