/**
* Copyright 2012 Twitter, Inc.
*
* 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 parquet.column.values.deltalengthbytearray;
import static parquet.Log.DEBUG;
import java.io.IOException;
import parquet.Log;
import parquet.column.values.ValuesReader;
import parquet.column.values.delta.DeltaBinaryPackingValuesReader;
import parquet.io.api.Binary;
/**
* Reads binary data written by {@link DeltaLengthByteArrayValueWriter}
*
* @author Aniket Mokashi
*
*/
public class DeltaLengthByteArrayValuesReader extends ValuesReader {
private static final Log LOG = Log.getLog(DeltaLengthByteArrayValuesReader.class);
private ValuesReader lengthReader;
private byte[] in;
private int offset;
public DeltaLengthByteArrayValuesReader() {
this.lengthReader = new DeltaBinaryPackingValuesReader();
}
@Override
public void initFromPage(int valueCount, byte[] in, int offset)
throws IOException {
if (DEBUG) LOG.debug("init from page at offset "+ offset + " for length " + (in.length - offset));
lengthReader.initFromPage(valueCount, in, offset);
offset = lengthReader.getNextOffset();
this.in = in;
this.offset = offset;
}
@Override
public Binary readBytes() {
int length = lengthReader.readInteger();
int start = offset;
offset = start + length;
return Binary.fromByteArray(in, start, length);
}
@Override
public void skip() {
int length = lengthReader.readInteger();
offset = offset + length;
}
}