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/*
* 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 io.trino.operator.scalar;
import com.google.common.collect.ImmutableList;
import com.google.common.primitives.Primitives;
import io.trino.metadata.SqlScalarFunction;
import io.trino.spi.block.Block;
import io.trino.spi.function.BoundSignature;
import io.trino.spi.function.FunctionMetadata;
import io.trino.spi.function.Signature;
import io.trino.spi.type.ArrayType;
import io.trino.spi.type.Type;
import io.trino.spi.type.TypeSignature;
import io.trino.sql.gen.lambda.BinaryFunctionInterface;
import io.trino.sql.gen.lambda.UnaryFunctionInterface;
import java.lang.invoke.MethodHandle;
import java.util.Optional;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.BOXED_NULLABLE;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.FUNCTION;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.NEVER_NULL;
import static io.trino.spi.function.InvocationConvention.InvocationReturnConvention.NULLABLE_RETURN;
import static io.trino.spi.type.TypeSignature.arrayType;
import static io.trino.spi.type.TypeSignature.functionType;
import static io.trino.spi.type.TypeUtils.readNativeValue;
import static io.trino.util.Reflection.methodHandle;
public final class ArrayReduceFunction
extends SqlScalarFunction
{
public static final ArrayReduceFunction ARRAY_REDUCE_FUNCTION = new ArrayReduceFunction();
private static final MethodHandle METHOD_HANDLE = methodHandle(ArrayReduceFunction.class, "reduce", Type.class, Block.class, Object.class, BinaryFunctionInterface.class, UnaryFunctionInterface.class);
private ArrayReduceFunction()
{
super(FunctionMetadata.scalarBuilder("reduce")
.signature(Signature.builder()
.typeVariable("T")
.typeVariable("S")
.typeVariable("R")
.returnType(new TypeSignature("R"))
.argumentType(arrayType(new TypeSignature("T")))
.argumentType(new TypeSignature("S"))
.argumentType(functionType(new TypeSignature("S"), new TypeSignature("T"), new TypeSignature("S")))
.argumentType(functionType(new TypeSignature("S"), new TypeSignature("R")))
.build())
.nullable()
.argumentNullability(false, true, false, false)
.nondeterministic()
.description("Reduce elements of the array into a single value")
.build());
}
@Override
protected SpecializedSqlScalarFunction specialize(BoundSignature boundSignature)
{
ArrayType arrayType = (ArrayType) boundSignature.getArgumentTypes().get(0);
Type inputType = arrayType.getElementType();
Type intermediateType = boundSignature.getArgumentTypes().get(1);
Type outputType = boundSignature.getReturnType();
MethodHandle methodHandle = METHOD_HANDLE.bindTo(inputType);
return new ChoicesSpecializedSqlScalarFunction(
boundSignature,
NULLABLE_RETURN,
ImmutableList.of(NEVER_NULL, BOXED_NULLABLE, FUNCTION, FUNCTION),
ImmutableList.of(BinaryFunctionInterface.class, UnaryFunctionInterface.class),
methodHandle.asType(
methodHandle.type()
.changeParameterType(1, Primitives.wrap(intermediateType.getJavaType()))
.changeReturnType(Primitives.wrap(outputType.getJavaType()))),
Optional.empty());
}
public static Object reduce(
Type inputType,
Block block,
Object initialIntermediateValue,
BinaryFunctionInterface inputFunction,
UnaryFunctionInterface outputFunction)
{
int positionCount = block.getPositionCount();
Object intermediateValue = initialIntermediateValue;
for (int position = 0; position < positionCount; position++) {
Object input = readNativeValue(inputType, block, position);
intermediateValue = inputFunction.apply(intermediateValue, input);
}
return outputFunction.apply(intermediateValue);
}
}
