/*
* 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.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.block.BlockCursor;
import com.facebook.presto.operator.GroupByIdBlock;
import com.facebook.presto.util.array.ByteBigArray;
import com.google.common.base.Optional;
import static com.facebook.presto.spi.type.BooleanType.BOOLEAN;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
public class BooleanMinAggregation
extends SimpleAggregationFunction
{
public static final BooleanMinAggregation BOOLEAN_MIN = new BooleanMinAggregation();
public BooleanMinAggregation()
{
super(BOOLEAN, BOOLEAN, BOOLEAN);
}
@Override
protected GroupedAccumulator createGroupedAccumulator(Optional<Integer> maskChannel, Optional<Integer> sampleWeightChannel, double confidence, int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
checkArgument(confidence == 1.0, "min does not support approximate queries");
return new BooleanMinGroupedAccumulator(valueChannel);
}
public static class BooleanMinGroupedAccumulator
extends SimpleGroupedAccumulator
{
// null flag is zero so the default value in the min array is null
private static final byte NULL_VALUE = 0;
private static final byte TRUE_VALUE = 1;
private static final byte FALSE_VALUE = -1;
private final ByteBigArray minValues;
public BooleanMinGroupedAccumulator(int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
super(valueChannel, BOOLEAN, BOOLEAN, Optional.<Integer>absent(), Optional.<Integer>absent());
this.minValues = new ByteBigArray();
}
@Override
public long getEstimatedSize()
{
return minValues.sizeOf();
}
@Override
protected void processInput(GroupByIdBlock groupIdsBlock, Block valuesBlock, Optional<Block> maskBlock, Optional<Block> sampleWeightBlock)
{
minValues.ensureCapacity(groupIdsBlock.getGroupCount());
BlockCursor values = valuesBlock.cursor();
for (int position = 0; position < groupIdsBlock.getPositionCount(); position++) {
checkState(values.advanceNextPosition());
// skip null values
if (!values.isNull()) {
long groupId = groupIdsBlock.getGroupId(position);
// if value is false, update the min to false
if (!values.getBoolean()) {
minValues.set(groupId, FALSE_VALUE);
}
else {
// if the current value is null, set the min to true
if (minValues.get(groupId) == NULL_VALUE) {
minValues.set(groupId, TRUE_VALUE);
}
}
}
}
checkState(!values.advanceNextPosition());
}
@Override
public void evaluateFinal(int groupId, BlockBuilder output)
{
byte value = minValues.get((long) groupId);
if (value == NULL_VALUE) {
output.appendNull();
}
else {
output.appendBoolean(value == TRUE_VALUE);
}
}
}
@Override
protected Accumulator createAccumulator(Optional<Integer> maskChannel, Optional<Integer> sampleWeightChannel, double confidence, int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
checkArgument(confidence == 1.0, "min does not support approximate queries");
return new BooleanMinAccumulator(valueChannel);
}
public static class BooleanMinAccumulator
extends SimpleAccumulator
{
private boolean notNull;
private boolean min = true;
public BooleanMinAccumulator(int valueChannel)
{
// Min/max are not effected by distinct, so ignore it.
super(valueChannel, BOOLEAN, BOOLEAN, Optional.<Integer>absent(), Optional.<Integer>absent());
}
@Override
protected void processInput(Block block, Optional<Block> maskBlock, Optional<Block> sampleWeightBlock)
{
BlockCursor values = block.cursor();
for (int position = 0; position < block.getPositionCount(); position++) {
checkState(values.advanceNextPosition());
if (!values.isNull()) {
notNull = true;
// if value is false, update the max to false
if (!values.getBoolean()) {
min = false;
}
}
}
}
@Override
public void evaluateFinal(BlockBuilder out)
{
if (notNull) {
out.appendBoolean(min);
}
else {
out.appendNull();
}
}
}
}