content: /**
   * 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 com.aliyun.odps.io;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  
  public class BitMapWritable implements Writable {
    
    private byte[] bits;
    private int size;
    
    public BitMapWritable(int size) {
      if (size < 0) {
        throw new IllegalArgumentException();
      }
      int arraySize = size / 8;
      if (size % 8 != 0) {
        arraySize ++;
      }
      bits = new byte[arraySize];
      this.size = arraySize;
    }
  
    @Override
    public void write(DataOutput out) throws IOException {
      out.write(bits);
    }
  
    @Override
    public void readFields(DataInput in) throws IOException {
      in.readFully(bits);
    }
    
    public boolean get(int index) {
      int i = index / 8;
      int j = index % 8;
      byte flag = bits[i];
      int ret = (flag >>> j) & 0x01;
      return ret != 0;
    }
    
    public void set(int index, boolean flag) {
      int i = index / 8;
      int j = index % 8;
      int mask = flag ? 0x01 : 0;
      mask = mask << j;
      bits[i] = (byte) (bits[i] | mask);
    }
    
    public int getDataSize() {
      return size;
    }
  
  }