/*
* 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;
import com.facebook.presto.spi.Page;
import com.facebook.presto.spi.PageBuilder;
import javax.annotation.Nullable;
import java.util.Optional;
import static java.lang.Math.toIntExact;
import static java.util.Objects.requireNonNull;
// This implementation assumes arrays used in the hash are always a power of 2
public final class JoinHash
implements LookupSource
{
private final PagesHash pagesHash;
// we unwrap Optional<JoinFilterFunction> to actual verifier or null in constructor for performance reasons
// we do quick check for `filterFunction == null` in `isJoinPositionEligible` to avoid calls to applyFilterFunction
@Nullable
private final JoinFilterFunction filterFunction;
private final PositionLinks positionLinks;
public JoinHash(PagesHash pagesHash, Optional<JoinFilterFunction> filterFunction, PositionLinks positionLinks)
{
this.pagesHash = requireNonNull(pagesHash, "pagesHash is null");
this.filterFunction = requireNonNull(filterFunction, "filterFunction can not be null").orElse(null);
this.positionLinks = requireNonNull(positionLinks, "positionLinks is null");
}
@Override
public final int getChannelCount()
{
return pagesHash.getChannelCount();
}
@Override
public int getJoinPositionCount()
{
return pagesHash.getPositionCount();
}
@Override
public long getInMemorySizeInBytes()
{
return pagesHash.getInMemorySizeInBytes() + positionLinks.getSizeInBytes();
}
@Override
public long getJoinPosition(int position, Page hashChannelsPage, Page allChannelsPage)
{
int addressIndex = pagesHash.getAddressIndex(position, hashChannelsPage, allChannelsPage);
return startJoinPosition(addressIndex, position, allChannelsPage);
}
@Override
public long getJoinPosition(int position, Page hashChannelsPage, Page allChannelsPage, long rawHash)
{
int addressIndex = pagesHash.getAddressIndex(position, hashChannelsPage, allChannelsPage, rawHash);
return startJoinPosition(addressIndex, position, allChannelsPage);
}
private long startJoinPosition(int currentJoinPosition, int probePosition, Page allProbeChannelsPage)
{
if (currentJoinPosition == -1) {
return -1;
}
return positionLinks.start(currentJoinPosition, probePosition, allProbeChannelsPage);
}
@Override
public final long getNextJoinPosition(long currentJoinPosition, int probePosition, Page allProbeChannelsPage)
{
return positionLinks.next(toIntExact(currentJoinPosition), probePosition, allProbeChannelsPage);
}
@Override
public boolean isJoinPositionEligible(long currentJoinPosition, int probePosition, Page allProbeChannelsPage)
{
return filterFunction == null || filterFunction.filter(toIntExact(currentJoinPosition), probePosition, allProbeChannelsPage);
}
@Override
public void appendTo(long position, PageBuilder pageBuilder, int outputChannelOffset)
{
pagesHash.appendTo(toIntExact(position), pageBuilder, outputChannelOffset);
}
@Override
public void close()
{
}
}