/*
* 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.bytecode.DynamicClassLoader;
import com.facebook.presto.metadata.BoundVariables;
import com.facebook.presto.metadata.FunctionRegistry;
import com.facebook.presto.metadata.SqlAggregationFunction;
import com.facebook.presto.operator.aggregation.state.NullableLongState;
import com.facebook.presto.operator.aggregation.state.StateCompiler;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.type.StandardTypes;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import java.lang.invoke.MethodHandle;
import java.util.List;
import static com.facebook.presto.metadata.Signature.comparableTypeParameter;
import static com.facebook.presto.operator.aggregation.AggregationMetadata.ParameterMetadata;
import static com.facebook.presto.operator.aggregation.AggregationMetadata.ParameterMetadata.ParameterType.BLOCK_INDEX;
import static com.facebook.presto.operator.aggregation.AggregationMetadata.ParameterMetadata.ParameterType.NULLABLE_BLOCK_INPUT_CHANNEL;
import static com.facebook.presto.operator.aggregation.AggregationMetadata.ParameterMetadata.ParameterType.STATE;
import static com.facebook.presto.operator.aggregation.AggregationUtils.generateAggregationName;
import static com.facebook.presto.spi.type.BigintType.BIGINT;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.spi.type.VarbinaryType.VARBINARY;
import static com.facebook.presto.util.Reflection.methodHandle;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static io.airlift.slice.Slices.wrappedLongArray;
public class ChecksumAggregationFunction
extends SqlAggregationFunction
{
public static final ChecksumAggregationFunction CHECKSUM_AGGREGATION = new ChecksumAggregationFunction();
@VisibleForTesting
public static final long PRIME64 = 0x9E3779B185EBCA87L;
private static final String NAME = "checksum";
private static final MethodHandle OUTPUT_FUNCTION = methodHandle(ChecksumAggregationFunction.class, "output", NullableLongState.class, BlockBuilder.class);
private static final MethodHandle INPUT_FUNCTION = methodHandle(ChecksumAggregationFunction.class, "input", Type.class, NullableLongState.class, Block.class, int.class);
private static final MethodHandle COMBINE_FUNCTION = methodHandle(ChecksumAggregationFunction.class, "combine", NullableLongState.class, NullableLongState.class);
public ChecksumAggregationFunction()
{
super(NAME,
ImmutableList.of(comparableTypeParameter("T")),
ImmutableList.of(),
parseTypeSignature(StandardTypes.VARBINARY),
ImmutableList.of(parseTypeSignature("T")));
}
@Override
public String getDescription()
{
return "Checksum of the given values";
}
@Override
public InternalAggregationFunction specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type valueType = boundVariables.getTypeVariable("T");
return generateAggregation(valueType);
}
private static InternalAggregationFunction generateAggregation(Type type)
{
DynamicClassLoader classLoader = new DynamicClassLoader(ChecksumAggregationFunction.class.getClassLoader());
List<Type> inputTypes = ImmutableList.of(type);
AggregationMetadata metadata = new AggregationMetadata(
generateAggregationName(NAME, type.getTypeSignature(), inputTypes.stream().map(Type::getTypeSignature).collect(toImmutableList())),
createInputParameterMetadata(type),
INPUT_FUNCTION.bindTo(type),
COMBINE_FUNCTION,
OUTPUT_FUNCTION,
NullableLongState.class,
StateCompiler.generateStateSerializer(NullableLongState.class, classLoader),
StateCompiler.generateStateFactory(NullableLongState.class, classLoader),
VARBINARY);
GenericAccumulatorFactoryBinder factory = AccumulatorCompiler.generateAccumulatorFactoryBinder(metadata, classLoader);
return new InternalAggregationFunction(NAME, inputTypes, BIGINT, VARBINARY, true, factory);
}
private static List<ParameterMetadata> createInputParameterMetadata(Type type)
{
return ImmutableList.of(new ParameterMetadata(STATE), new ParameterMetadata(NULLABLE_BLOCK_INPUT_CHANNEL, type), new ParameterMetadata(BLOCK_INDEX));
}
public static void input(Type type, NullableLongState state, Block block, int position)
{
state.setNull(false);
if (block.isNull(position)) {
state.setLong(state.getLong() + PRIME64);
}
else {
state.setLong(state.getLong() + type.hash(block, position) * PRIME64);
}
}
public static void combine(NullableLongState state, NullableLongState otherState)
{
state.setNull(state.isNull() && otherState.isNull());
state.setLong(state.getLong() + otherState.getLong());
}
public static void output(NullableLongState state, BlockBuilder out)
{
if (state.isNull()) {
out.appendNull();
}
else {
VARBINARY.writeSlice(out, wrappedLongArray(state.getLong()));
}
}
}