/*
* 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.scalar;
import com.facebook.presto.spi.PageBuilder;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.function.Description;
import com.facebook.presto.spi.function.OperatorDependency;
import com.facebook.presto.spi.function.ScalarFunction;
import com.facebook.presto.spi.function.SqlType;
import com.facebook.presto.spi.function.TypeParameter;
import com.facebook.presto.spi.type.StandardTypes;
import com.facebook.presto.spi.type.Type;
import com.google.common.collect.ImmutableList;
import it.unimi.dsi.fastutil.ints.AbstractIntComparator;
import it.unimi.dsi.fastutil.ints.IntArrays;
import it.unimi.dsi.fastutil.ints.IntComparator;
import java.lang.invoke.MethodHandle;
import static com.facebook.presto.spi.function.OperatorType.LESS_THAN;
@ScalarFunction("array_intersect")
@Description("Intersects elements of the two given arrays")
public final class ArrayIntersectFunction
{
private static final int INITIAL_SIZE = 128;
private int[] leftPositions = new int[INITIAL_SIZE];
private int[] rightPositions = new int[INITIAL_SIZE];
private final PageBuilder pageBuilder;
@TypeParameter("E")
public ArrayIntersectFunction(@TypeParameter("E") Type elementType)
{
pageBuilder = new PageBuilder(ImmutableList.of(elementType));
}
private static IntComparator intBlockCompare(Type type, Block block)
{
return new AbstractIntComparator()
{
@Override
public int compare(int left, int right)
{
if (block.isNull(left) && block.isNull(right)) {
return 0;
}
if (block.isNull(left)) {
return -1;
}
if (block.isNull(right)) {
return 1;
}
return type.compareTo(block, left, block, right);
}
};
}
@TypeParameter("E")
@SqlType("array(E)")
public Block intersect(
@OperatorDependency(operator = LESS_THAN, returnType = StandardTypes.BOOLEAN, argumentTypes = {"E", "E"}) MethodHandle lessThanFunction,
@TypeParameter("E") Type type,
@SqlType("array(E)") Block leftArray,
@SqlType("array(E)") Block rightArray)
{
int leftPositionCount = leftArray.getPositionCount();
int rightPositionCount = rightArray.getPositionCount();
if (leftPositionCount == 0) {
return leftArray;
}
if (rightPositionCount == 0) {
return rightArray;
}
if (leftPositions.length < leftPositionCount) {
leftPositions = new int[leftPositionCount];
}
if (rightPositions.length < rightPositionCount) {
rightPositions = new int[rightPositionCount];
}
if (pageBuilder.isFull()) {
pageBuilder.reset();
}
for (int i = 0; i < leftPositionCount; i++) {
leftPositions[i] = i;
}
for (int i = 0; i < rightPositionCount; i++) {
rightPositions[i] = i;
}
IntArrays.quickSort(leftPositions, 0, leftPositionCount, intBlockCompare(type, leftArray));
IntArrays.quickSort(rightPositions, 0, rightPositionCount, intBlockCompare(type, rightArray));
BlockBuilder resultBlockBuilder = pageBuilder.getBlockBuilder(0);
int leftCurrentPosition = 0;
int rightCurrentPosition = 0;
int leftBasePosition;
int rightBasePosition;
int totalCount = 0;
while (leftCurrentPosition < leftPositionCount && rightCurrentPosition < rightPositionCount) {
leftBasePosition = leftCurrentPosition;
rightBasePosition = rightCurrentPosition;
int compareValue = type.compareTo(leftArray, leftPositions[leftCurrentPosition], rightArray, rightPositions[rightCurrentPosition]);
if (compareValue > 0) {
rightCurrentPosition++;
}
else if (compareValue < 0) {
leftCurrentPosition++;
}
else {
type.appendTo(leftArray, leftPositions[leftCurrentPosition], resultBlockBuilder);
leftCurrentPosition++;
rightCurrentPosition++;
totalCount++;
while (leftCurrentPosition < leftPositionCount && type.equalTo(leftArray, leftPositions[leftBasePosition], leftArray, leftPositions[leftCurrentPosition])) {
leftCurrentPosition++;
}
while (rightCurrentPosition < rightPositionCount && type.equalTo(rightArray, rightPositions[rightBasePosition], rightArray, rightPositions[rightCurrentPosition])) {
rightCurrentPosition++;
}
}
}
pageBuilder.declarePositions(totalCount);
return resultBlockBuilder.getRegion(resultBlockBuilder.getPositionCount() - totalCount, totalCount);
}
}