io.druid.segment.data.DeltaLongEncodingReader Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets licenses this file
* to you 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.druid.segment.data;
import io.druid.java.util.common.IAE;
import java.nio.ByteBuffer;
public class DeltaLongEncodingReader implements CompressionFactory.LongEncodingReader
{
private ByteBuffer buffer;
private final long base;
private final int bitsPerValue;
private VSizeLongSerde.LongDeserializer deserializer;
public DeltaLongEncodingReader(ByteBuffer fromBuffer)
{
this.buffer = fromBuffer.asReadOnlyBuffer();
byte version = buffer.get();
if (version == CompressionFactory.DELTA_ENCODING_VERSION) {
base = buffer.getLong();
bitsPerValue = buffer.getInt();
fromBuffer.position(buffer.position());
deserializer = VSizeLongSerde.getDeserializer(bitsPerValue, buffer, buffer.position());
} else {
throw new IAE("Unknown version[%s]", version);
}
}
private DeltaLongEncodingReader(ByteBuffer buffer, long base, int bitsPerValue)
{
this.buffer = buffer;
this.base = base;
this.bitsPerValue = bitsPerValue;
deserializer = VSizeLongSerde.getDeserializer(bitsPerValue, buffer, buffer.position());
}
@Override
public void setBuffer(ByteBuffer buffer)
{
deserializer = VSizeLongSerde.getDeserializer(bitsPerValue, buffer, buffer.position());
}
@Override
public long read(int index)
{
return base + deserializer.get(index);
}
@Override
public int getNumBytes(int values)
{
return VSizeLongSerde.getSerializedSize(bitsPerValue, values);
}
@Override
public CompressionFactory.LongEncodingReader duplicate()
{
return new DeltaLongEncodingReader(buffer.duplicate(), base, bitsPerValue);
}
}