001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with this
004 * work for additional information regarding copyright ownership. The ASF
005 * licenses this file to you under the Apache License, Version 2.0 (the
006 * "License"); you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
013 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
014 * License for the specific language governing permissions and limitations
015 * under the License.
016 */
017package org.apache.hadoop.hbase.io.encoding;
018
019import java.io.DataInputStream;
020import java.io.DataOutputStream;
021import java.io.IOException;
022import java.nio.ByteBuffer;
023import org.apache.hadoop.hbase.Cell;
024import org.apache.hadoop.hbase.nio.ByteBuff;
025import org.apache.hadoop.hbase.util.ByteBufferUtils;
026import org.apache.hadoop.hbase.util.Bytes;
027import org.apache.yetus.audience.InterfaceAudience;
028
029/**
030 * Just copy data, do not do any kind of compression. Use for comparison and
031 * benchmarking.
032 */
033@InterfaceAudience.Private
034public class CopyKeyDataBlockEncoder extends BufferedDataBlockEncoder {
035
036  private static class CopyKeyEncodingState extends EncodingState {
037    NoneEncoder encoder = null;
038  }
039
040  @Override
041  public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx,
042      DataOutputStream out) throws IOException {
043    if (blkEncodingCtx.getClass() != HFileBlockDefaultEncodingContext.class) {
044      throw new IOException(this.getClass().getName() + " only accepts "
045          + HFileBlockDefaultEncodingContext.class.getName() + " as the "
046          + "encoding context.");
047    }
048
049    HFileBlockDefaultEncodingContext encodingCtx =
050      (HFileBlockDefaultEncodingContext) blkEncodingCtx;
051    encodingCtx.prepareEncoding(out);
052
053    NoneEncoder encoder = new NoneEncoder(out, encodingCtx);
054    CopyKeyEncodingState state = new CopyKeyEncodingState();
055    state.encoder = encoder;
056    blkEncodingCtx.setEncodingState(state);
057  }
058
059  @Override
060  public int internalEncode(Cell cell,
061      HFileBlockDefaultEncodingContext encodingContext, DataOutputStream out)
062      throws IOException {
063    CopyKeyEncodingState state = (CopyKeyEncodingState) encodingContext
064        .getEncodingState();
065    NoneEncoder encoder = state.encoder;
066    return encoder.write(cell);
067  }
068
069  @Override
070  public Cell getFirstKeyCellInBlock(ByteBuff block) {
071    int keyLength = block.getIntAfterPosition(Bytes.SIZEOF_INT);
072    int pos = 3 * Bytes.SIZEOF_INT;
073    ByteBuffer key = block.asSubByteBuffer(pos + keyLength).duplicate();
074    return createFirstKeyCell(key, keyLength);
075  }
076
077  @Override
078  public String toString() {
079    return CopyKeyDataBlockEncoder.class.getSimpleName();
080  }
081
082  @Override
083  public EncodedSeeker createSeeker(final HFileBlockDecodingContext decodingCtx) {
084    return new SeekerStateBufferedEncodedSeeker(decodingCtx);
085  }
086
087  @Override
088  protected ByteBuffer internalDecodeKeyValues(DataInputStream source, int allocateHeaderLength,
089      int skipLastBytes, HFileBlockDefaultDecodingContext decodingCtx) throws IOException {
090    int decompressedSize = source.readInt();
091    ByteBuffer buffer = ByteBuffer.allocate(decompressedSize +
092        allocateHeaderLength);
093    buffer.position(allocateHeaderLength);
094    ByteBufferUtils.copyFromStreamToBuffer(buffer, source, decompressedSize);
095
096    return buffer;
097  }
098
099  private static class SeekerStateBufferedEncodedSeeker
100      extends BufferedEncodedSeeker<SeekerState> {
101
102    private SeekerStateBufferedEncodedSeeker(HFileBlockDecodingContext decodingCtx) {
103      super(decodingCtx);
104    }
105
106    @Override
107    protected void decodeNext() {
108      current.keyLength = currentBuffer.getInt();
109      current.valueLength = currentBuffer.getInt();
110      current.ensureSpaceForKey();
111      currentBuffer.get(current.keyBuffer, 0, current.keyLength);
112      current.valueOffset = currentBuffer.position();
113      currentBuffer.skip(current.valueLength);
114      if (includesTags()) {
115        // Read short as unsigned, high byte first
116        current.tagsLength = ((currentBuffer.get() & 0xff) << 8) ^ (currentBuffer.get() & 0xff);
117        currentBuffer.skip(current.tagsLength);
118      }
119      if (includesMvcc()) {
120        current.memstoreTS = ByteBufferUtils.readVLong(currentBuffer);
121      } else {
122        current.memstoreTS = 0;
123      }
124      current.nextKvOffset = currentBuffer.position();
125    }
126
127    @Override
128    protected void decodeFirst() {
129      currentBuffer.skip(Bytes.SIZEOF_INT);
130      current.lastCommonPrefix = 0;
131      decodeNext();
132    }
133  }
134
135}