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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 io.trino.operator.aggregation.histogram.TypedHistogram;
import io.trino.spi.block.Block;
import io.trino.spi.block.MapBlock;
import io.trino.spi.block.MapBlockBuilder;
import io.trino.spi.block.SqlMap;
import io.trino.spi.block.ValueBlock;
import io.trino.spi.function.Convention;
import io.trino.spi.function.Description;
import io.trino.spi.function.OperatorDependency;
import io.trino.spi.function.OperatorType;
import io.trino.spi.function.ScalarFunction;
import io.trino.spi.function.SqlType;
import io.trino.spi.function.TypeParameter;
import io.trino.spi.type.MapType;
import io.trino.spi.type.Type;
import java.lang.invoke.MethodHandle;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.FLAT;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.VALUE_BLOCK_POSITION_NOT_NULL;
import static io.trino.spi.function.InvocationConvention.InvocationReturnConvention.BLOCK_BUILDER;
import static io.trino.spi.function.InvocationConvention.InvocationReturnConvention.FAIL_ON_NULL;
import static io.trino.spi.function.InvocationConvention.InvocationReturnConvention.FLAT_RETURN;
@Description("Return a map containing the counts of the elements in the array")
@ScalarFunction(value = "array_histogram")
public final class ArrayHistogramFunction
{
private ArrayHistogramFunction() {}
@TypeParameter("T")
@SqlType("map(T, bigint)")
public static SqlMap arrayHistogram(
@TypeParameter("T") Type elementType,
@OperatorDependency(
operator = OperatorType.READ_VALUE,
argumentTypes = "T",
convention = @Convention(arguments = FLAT, result = BLOCK_BUILDER)) MethodHandle readFlat,
@OperatorDependency(
operator = OperatorType.READ_VALUE,
argumentTypes = "T",
convention = @Convention(arguments = VALUE_BLOCK_POSITION_NOT_NULL, result = FLAT_RETURN)) MethodHandle writeFlat,
@OperatorDependency(
operator = OperatorType.HASH_CODE,
argumentTypes = "T",
convention = @Convention(arguments = FLAT, result = FAIL_ON_NULL)) MethodHandle hashFlat,
@OperatorDependency(
operator = OperatorType.IS_DISTINCT_FROM,
argumentTypes = {"T", "T"},
convention = @Convention(arguments = {FLAT, VALUE_BLOCK_POSITION_NOT_NULL}, result = FAIL_ON_NULL)) MethodHandle distinctFlatBlock,
@OperatorDependency(
operator = OperatorType.HASH_CODE,
argumentTypes = "T",
convention = @Convention(arguments = VALUE_BLOCK_POSITION_NOT_NULL, result = FAIL_ON_NULL)) MethodHandle hashBlock,
@TypeParameter("map(T, bigint)") MapType mapType,
@SqlType("array(T)") Block arrayBlock)
{
TypedHistogram histogram = new TypedHistogram(elementType, readFlat, writeFlat, hashFlat, distinctFlatBlock, hashBlock, false);
ValueBlock valueBlock = arrayBlock.getUnderlyingValueBlock();
for (int i = 0; i < arrayBlock.getPositionCount(); i++) {
int position = arrayBlock.getUnderlyingValuePosition(i);
if (!arrayBlock.isNull(position)) {
histogram.add(0, valueBlock, position, 1L);
}
}
MapBlockBuilder blockBuilder = mapType.createBlockBuilder(null, histogram.size());
histogram.serialize(0, blockBuilder);
MapBlock mapBlock = (MapBlock) blockBuilder.build();
return mapType.getObject(mapBlock, 0);
}
}
