| /* |
| * 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.encoder; |
| |
| import org.apache.iotdb.tsfile.encoding.bitpacking.LongPacker; |
| import org.apache.iotdb.tsfile.encoding.fire.LongFire; |
| import org.apache.iotdb.tsfile.exception.encoding.TsFileEncodingException; |
| import org.apache.iotdb.tsfile.utils.ReadWriteForEncodingUtils; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.util.Vector; |
| |
| public class DoubleSprintzEncoder extends SprintzEncoder { |
| |
| // bit packer |
| LongPacker packer; |
| |
| // Long Fire Predictor |
| LongFire firePred; |
| |
| // we save all value in a list and calculate its bitWidth |
| protected Vector<Double> values; |
| |
| // convert to Long Buffer |
| long[] convertBuffer; |
| |
| public DoubleSprintzEncoder() { |
| super(); |
| values = new Vector<>(); |
| firePred = new LongFire(3); |
| convertBuffer = new long[Block_size]; |
| } |
| |
| @Override |
| protected void reset() { |
| super.reset(); |
| values.clear(); |
| } |
| |
| @Override |
| public int getOneItemMaxSize() { |
| return 1 + (1 + Block_size) * Double.BYTES; |
| } |
| |
| @Override |
| public long getMaxByteSize() { |
| return 1 + (long) (values.size() + 1) * Double.BYTES; |
| } |
| |
| protected long predict(Double value, Double preVlaue) throws TsFileEncodingException { |
| long pred; |
| if (predictMethod.equals("delta")) { |
| pred = delta(value, preVlaue); |
| } else if (predictMethod.equals("fire")) { |
| pred = fire(value, preVlaue); |
| } else { |
| throw new TsFileEncodingException( |
| "Config: Predict Method {} of SprintzEncoder is not supported."); |
| } |
| if (pred <= 0) { |
| pred = -2 * pred; |
| } else { |
| pred = 2 * pred - 1; // TODO:overflow |
| } |
| return pred; |
| } |
| |
| @Override |
| protected void bitPack() throws IOException { |
| final double preValue = values.get(0); |
| values.remove(0); |
| Vector<Long> convertBufferList = new Vector<>(); |
| for (long itemBuffer : convertBuffer) { |
| convertBufferList.add(itemBuffer); |
| } |
| this.bitWidth = ReadWriteForEncodingUtils.getLongMaxBitWidth(convertBufferList); |
| packer = new LongPacker(this.bitWidth); |
| byte[] bytes = new byte[bitWidth]; |
| packer.pack8Values(convertBuffer, 0, bytes); |
| ReadWriteForEncodingUtils.writeIntLittleEndianPaddedOnBitWidth(bitWidth, byteCache, 1); |
| byteCache.write(ByteBuffer.allocate(8).putDouble(preValue).array()); |
| byteCache.write(bytes, 0, bytes.length); |
| } |
| |
| protected long delta(Double value, Double preValue) { |
| return Double.doubleToLongBits(value) - Double.doubleToLongBits(preValue); |
| } |
| |
| protected long fire(Double value, Double preValue) { |
| long prev = Double.doubleToLongBits(preValue); |
| long val = Double.doubleToLongBits(value); |
| long pred = firePred.predict(prev); |
| long err = val - pred; |
| firePred.train(prev, val, err); |
| return err; |
| } |
| |
| @Override |
| public void flush(ByteArrayOutputStream out) throws IOException { |
| if (byteCache.size() > 0) { |
| byteCache.writeTo(out); |
| } |
| if (!values.isEmpty()) { |
| int size = values.size(); |
| size |= (1 << 7); |
| ReadWriteForEncodingUtils.writeIntLittleEndianPaddedOnBitWidth(size, out, 1); |
| DoublePrecisionEncoderV2 encoder = new DoublePrecisionEncoderV2(); |
| for (double val : values) { |
| encoder.encode(val, out); |
| } |
| encoder.flush(out); |
| } |
| reset(); |
| } |
| |
| @Override |
| public void encode(double value, ByteArrayOutputStream out) { |
| if (!isFirstCached) { |
| values.add(value); |
| isFirstCached = true; |
| return; |
| } else { |
| values.add(value); |
| } |
| if (values.size() == Block_size + 1) { |
| try { |
| firePred.reset(); |
| for (int i = 1; i <= Block_size; i++) { |
| convertBuffer[i - 1] = predict(values.get(i), values.get(i - 1)); |
| } |
| bitPack(); |
| isFirstCached = false; |
| values.clear(); |
| groupNum++; |
| if (groupNum == groupMax) { |
| flush(out); |
| } |
| } catch (IOException e) { |
| logger.error("Error occured when encoding INT32 Type value with with Sprintz", e); |
| } |
| } |
| } |
| } |