| /* |
| * 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.file.metadata.enums.TSEncoding; |
| |
| import java.io.ByteArrayOutputStream; |
| |
| /** |
| * Gorilla encoding. For more information about how it works, please see |
| * http://www.vldb.org/pvldb/vol8/p1816-teller.pdf |
| */ |
| public abstract class GorillaEncoderV1 extends Encoder { |
| |
| // flag to indicate whether the first value is saved |
| protected boolean flag; |
| protected int leadingZeroNum; |
| protected int tailingZeroNum; |
| // 8-bit buffer of bits to write out |
| protected byte buffer; |
| // number of bits remaining in buffer |
| protected int numberLeftInBuffer; |
| |
| protected GorillaEncoderV1() { |
| super(TSEncoding.GORILLA_V1); |
| this.flag = false; |
| } |
| |
| protected void writeBit(boolean b, ByteArrayOutputStream out) { |
| // add bit to buffer |
| buffer <<= 1; |
| if (b) { |
| buffer |= 1; |
| } |
| |
| // if buffer is full (8 bits), write out as a single byte |
| numberLeftInBuffer++; |
| if (numberLeftInBuffer == 8) { |
| clearBuffer(out); |
| } |
| } |
| |
| protected void writeBit(int i, ByteArrayOutputStream out) { |
| writeBit(i != 0, out); |
| } |
| |
| protected void writeBit(long i, ByteArrayOutputStream out) { |
| writeBit(i != 0, out); |
| } |
| |
| protected void clearBuffer(ByteArrayOutputStream out) { |
| if (numberLeftInBuffer == 0) { |
| return; |
| } |
| if (numberLeftInBuffer > 0) { |
| buffer <<= (8 - numberLeftInBuffer); |
| } |
| out.write(buffer); |
| numberLeftInBuffer = 0; |
| buffer = 0; |
| } |
| |
| protected void reset() { |
| this.flag = false; |
| this.numberLeftInBuffer = 0; |
| this.buffer = 0; |
| } |
| } |