/*
* 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.serde;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockEncoding;
import com.facebook.presto.block.BlockIterable;
import com.facebook.presto.spi.type.Type;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.AbstractIterator;
import io.airlift.slice.Slice;
import io.airlift.slice.SliceInput;
import io.airlift.units.DataSize;
import io.airlift.units.DataSize.Unit;
import java.util.Iterator;
public class EncodedBlockIterable
implements BlockIterable
{
private final BlockEncoding blockEncoding;
private final Slice blocksSlice;
private final int positionCount;
public EncodedBlockIterable(BlockEncoding blockEncoding, Slice blocksSlice, int positionCount)
{
this.positionCount = positionCount;
Preconditions.checkNotNull(blockEncoding, "blockEncoding is null");
Preconditions.checkNotNull(blocksSlice, "blocksSlice is null");
this.blockEncoding = blockEncoding;
this.blocksSlice = blocksSlice;
}
@Override
public Type getType()
{
return blockEncoding.getType();
}
@Override
public Optional<DataSize> getDataSize()
{
return Optional.of(new DataSize(blocksSlice.length(), Unit.BYTE));
}
@Override
public Optional<Integer> getPositionCount()
{
return Optional.of(positionCount);
}
@Override
public Iterator<Block> iterator()
{
return new EncodedBlockIterator(blockEncoding, blocksSlice.getInput());
}
private static class EncodedBlockIterator
extends AbstractIterator<Block>
{
private final BlockEncoding blockEncoding;
private final SliceInput sliceInput;
private EncodedBlockIterator(BlockEncoding blockEncoding, SliceInput sliceInput)
{
this.blockEncoding = blockEncoding;
this.sliceInput = sliceInput;
}
protected Block computeNext()
{
if (!sliceInput.isReadable()) {
return endOfData();
}
Block block = blockEncoding.readBlock(sliceInput);
return block;
}
}
}