/*
* 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.aggregation;
import com.facebook.presto.block.Block;
import com.facebook.presto.block.BlockBuilder;
import com.facebook.presto.block.BlockCursor;
import com.facebook.presto.operator.GroupByIdBlock;
import com.facebook.presto.util.array.BooleanBigArray;
import com.facebook.presto.util.array.LongBigArray;
import com.google.common.base.Optional;
import static com.facebook.presto.tuple.TupleInfo.SINGLE_LONG;
import static com.facebook.presto.tuple.TupleInfo.Type.FIXED_INT_64;
import static com.google.common.base.Preconditions.checkState;
public class LongMaxAggregation
extends SimpleAggregationFunction
{
public static final LongMaxAggregation LONG_MAX = new LongMaxAggregation();
public LongMaxAggregation()
{
super(SINGLE_LONG, SINGLE_LONG, FIXED_INT_64);
}
@Override
protected GroupedAccumulator createGroupedAccumulator(Optional<Integer> maskChannel, int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
return new LongMaxGroupedAccumulator(valueChannel);
}
public static class LongMaxGroupedAccumulator
extends SimpleGroupedAccumulator
{
private final BooleanBigArray notNull;
private final LongBigArray maxValues;
public LongMaxGroupedAccumulator(int valueChannel)
{
super(valueChannel, SINGLE_LONG, SINGLE_LONG, Optional.<Integer>absent());
this.notNull = new BooleanBigArray();
this.maxValues = new LongBigArray(Long.MIN_VALUE);
}
@Override
public long getEstimatedSize()
{
return notNull.sizeOf() + maxValues.sizeOf();
}
@Override
protected void processInput(GroupByIdBlock groupIdsBlock, Block valuesBlock, Optional<Block> maskBlock)
{
notNull.ensureCapacity(groupIdsBlock.getGroupCount());
maxValues.ensureCapacity(groupIdsBlock.getGroupCount(), Long.MIN_VALUE);
BlockCursor values = valuesBlock.cursor();
for (int position = 0; position < groupIdsBlock.getPositionCount(); position++) {
checkState(values.advanceNextPosition());
long groupId = groupIdsBlock.getGroupId(position);
if (!values.isNull()) {
notNull.set(groupId, true);
long value = values.getLong();
value = Math.max(value, maxValues.get(groupId));
maxValues.set(groupId, value);
}
}
checkState(!values.advanceNextPosition());
}
@Override
public void evaluateFinal(int groupId, BlockBuilder output)
{
if (notNull.get((long) groupId)) {
long value = maxValues.get((long) groupId);
output.append(value);
}
else {
output.appendNull();
}
}
}
@Override
protected Accumulator createAccumulator(Optional<Integer> maskChannel, int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
return new LongMaxAccumulator(valueChannel);
}
public static class LongMaxAccumulator
extends SimpleAccumulator
{
private boolean notNull;
private long max = Long.MIN_VALUE;
public LongMaxAccumulator(int valueChannel)
{
super(valueChannel, SINGLE_LONG, SINGLE_LONG, Optional.<Integer>absent());
}
@Override
protected void processInput(Block block, Optional<Block> maskBlock)
{
BlockCursor values = block.cursor();
for (int position = 0; position < block.getPositionCount(); position++) {
checkState(values.advanceNextPosition());
if (!values.isNull()) {
notNull = true;
max = Math.max(max, values.getLong());
}
}
}
@Override
public void evaluateFinal(BlockBuilder out)
{
if (notNull) {
out.append(max);
}
else {
out.appendNull();
}
}
}
}