/*
* Licensed 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 com.facebook.presto.operator;
import com.facebook.presto.Session;
import com.facebook.presto.spi.Page;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.block.BlockBuilderStatus;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.sql.gen.JoinCompiler;
import java.util.List;
import java.util.Optional;
import static com.facebook.presto.operator.GroupByHash.createGroupByHash;
import static com.facebook.presto.spi.type.BooleanType.BOOLEAN;
public class MarkDistinctHash
{
private final GroupByHash groupByHash;
private long nextDistinctId;
public MarkDistinctHash(Session session, List<Type> types, int[] channels, Optional<Integer> hashChannel, JoinCompiler joinCompiler)
{
this(session, types, channels, hashChannel, 10_000, joinCompiler);
}
public MarkDistinctHash(Session session, List<Type> types, int[] channels, Optional<Integer> hashChannel, int expectedDistinctValues, JoinCompiler joinCompiler)
{
this.groupByHash = createGroupByHash(session, types, channels, hashChannel, expectedDistinctValues, joinCompiler);
}
public long getEstimatedSize()
{
return groupByHash.getEstimatedSize();
}
public Block markDistinctRows(Page page)
{
GroupByIdBlock ids = groupByHash.getGroupIds(page);
BlockBuilder blockBuilder = BOOLEAN.createBlockBuilder(new BlockBuilderStatus(), ids.getPositionCount());
for (int i = 0; i < ids.getPositionCount(); i++) {
if (ids.getGroupId(i) == nextDistinctId) {
BOOLEAN.writeBoolean(blockBuilder, true);
nextDistinctId++;
}
else {
BOOLEAN.writeBoolean(blockBuilder, false);
}
}
return blockBuilder.build();
}
}