/*
* 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.hive.parquet.dictionary;
import parquet.bytes.BytesUtils;
import parquet.column.values.ValuesReader;
import parquet.column.values.rle.RunLengthBitPackingHybridDecoder;
import parquet.io.ParquetDecodingException;
import parquet.io.api.Binary;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import static com.google.common.base.Preconditions.checkArgument;
public class ParquetDictionaryReader
extends ValuesReader
{
private final ParquetDictionary dictionary;
private RunLengthBitPackingHybridDecoder decoder;
public ParquetDictionaryReader(ParquetDictionary dictionary)
{
this.dictionary = dictionary;
}
@Override
public void initFromPage(int valueCount, byte[] page, int offset)
throws IOException
{
checkArgument(page.length > offset, "Attempt to read offset not in the Parquet page");
ByteArrayInputStream in = new ByteArrayInputStream(page, offset, page.length - offset);
int bitWidth = BytesUtils.readIntLittleEndianOnOneByte(in);
decoder = new RunLengthBitPackingHybridDecoder(bitWidth, in);
}
@Override
public int readValueDictionaryId()
{
return readInt();
}
@Override
public Binary readBytes()
{
return dictionary.decodeToBinary(readInt());
}
@Override
public float readFloat()
{
return dictionary.decodeToFloat(readInt());
}
@Override
public double readDouble()
{
return dictionary.decodeToDouble(readInt());
}
@Override
public int readInteger()
{
return dictionary.decodeToInt(readInt());
}
@Override
public long readLong()
{
return dictionary.decodeToLong(readInt());
}
@Override
public void skip()
{
readInt();
}
private int readInt()
{
try {
return decoder.readInt();
}
catch (IOException e) {
throw new ParquetDecodingException(e);
}
}
}