com.facebook.presto.jdbc.internal.common.block.RunLengthBlockEncoding Maven / Gradle / Ivy
/*
* 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.jdbc.internal.common.block;
import com.facebook.presto.jdbc.internal.io.airlift.slice.SliceInput;
import com.facebook.presto.jdbc.internal.io.airlift.slice.SliceOutput;
public class RunLengthBlockEncoding
implements BlockEncoding
{
public static final String NAME = "RLE";
@Override
public String getName()
{
return NAME;
}
@Override
public void writeBlock(BlockEncodingSerde blockEncodingSerde, SliceOutput sliceOutput, Block block)
{
RunLengthEncodedBlock rleBlock = (RunLengthEncodedBlock) block;
// write the run length
sliceOutput.writeInt(rleBlock.getPositionCount());
// write the value
blockEncodingSerde.writeBlock(sliceOutput, rleBlock.getValue());
}
@Override
public RunLengthEncodedBlock readBlock(BlockEncodingSerde blockEncodingSerde, SliceInput sliceInput)
{
// read the run length
int positionCount = sliceInput.readInt();
// read the value
Block value = blockEncodingSerde.readBlock(sliceInput);
return new RunLengthEncodedBlock(value, positionCount);
}
}
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