| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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 org.apache.iotdb.tsfile.encoding.decoder; |
| |
| import org.apache.iotdb.tsfile.common.conf.TSFileConfig; |
| import org.apache.iotdb.tsfile.encoding.bitpacking.LongPacker; |
| import org.apache.iotdb.tsfile.exception.encoding.TsFileDecodingException; |
| import org.apache.iotdb.tsfile.utils.ReadWriteForEncodingUtils; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| /** Decoder for long value using rle or bit-packing. */ |
| public class LongRleDecoder extends RleDecoder { |
| |
| private static final Logger logger = LoggerFactory.getLogger(LongRleDecoder.class); |
| |
| /** current value for rle repeated value. */ |
| private long currentValue; |
| |
| /** buffer to save all values in group using bit-packing. */ |
| private long[] currentBuffer; |
| |
| /** packer for unpacking long value. */ |
| private LongPacker packer; |
| |
| public LongRleDecoder() { |
| super(); |
| currentValue = 0; |
| } |
| |
| /** |
| * read a long value from InputStream. |
| * |
| * @param buffer - InputStream |
| * @return value - current valid value |
| */ |
| @Override |
| public long readLong(ByteBuffer buffer) { |
| if (!isLengthAndBitWidthReaded) { |
| // start to read a new rle+bit-packing pattern |
| readLengthAndBitWidth(buffer); |
| } |
| |
| if (currentCount == 0) { |
| try { |
| readNext(); |
| } catch (IOException e) { |
| logger.error( |
| "tsfile-encoding IntRleDecoder: error occurs when reading all encoding number, length " |
| + "is {}, bit width is {}", |
| length, |
| bitWidth, |
| e); |
| } |
| } |
| --currentCount; |
| long result; |
| switch (mode) { |
| case RLE: |
| result = currentValue; |
| break; |
| case BIT_PACKED: |
| result = currentBuffer[bitPackingNum - currentCount - 1]; |
| break; |
| default: |
| throw new TsFileDecodingException( |
| String.format("tsfile-encoding LongRleDecoder: not a valid mode %s", mode)); |
| } |
| |
| if (!hasNextPackage()) { |
| isLengthAndBitWidthReaded = false; |
| } |
| return result; |
| } |
| |
| @Override |
| protected void initPacker() { |
| packer = new LongPacker(bitWidth); |
| } |
| |
| @Override |
| protected void readNumberInRle() throws IOException { |
| currentValue = |
| ReadWriteForEncodingUtils.readLongLittleEndianPaddedOnBitWidth(byteCache, bitWidth); |
| } |
| |
| @Override |
| protected void readBitPackingBuffer(int bitPackedGroupCount, int lastBitPackedNum) { |
| currentBuffer = new long[bitPackedGroupCount * TSFileConfig.RLE_MIN_REPEATED_NUM]; |
| byte[] bytes = new byte[bitPackedGroupCount * bitWidth]; |
| int bytesToRead = bitPackedGroupCount * bitWidth; |
| bytesToRead = Math.min(bytesToRead, byteCache.remaining()); |
| byteCache.get(bytes, 0, bytesToRead); |
| |
| // save all long values in currentBuffer |
| packer.unpackAllValues(bytes, bytesToRead, currentBuffer); |
| } |
| } |