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 org.apache.activemq.util;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  import java.io.Serializable;
  
  /**
   * Simple BitArray to enable setting multiple boolean values efficently Used
   * instead of BitSet because BitSet does not allow for efficent serialization.
   * Will store up to 64 boolean values
   * 
   * 
   */
  public class BitArray implements Serializable {
      
      private static final long serialVersionUID = 1L;
      
      static final int LONG_SIZE = 64;
      static final int INT_SIZE = 32;
      static final int SHORT_SIZE = 16;
      static final int BYTE_SIZE = 8;
      private static final long[] BIT_VALUES = {0x0000000000000001L, 0x0000000000000002L, 0x0000000000000004L,
                                                0x0000000000000008L, 0x0000000000000010L, 0x0000000000000020L,
                                                0x0000000000000040L, 0x0000000000000080L, 0x0000000000000100L,
                                                0x0000000000000200L, 0x0000000000000400L, 0x0000000000000800L,
                                                0x0000000000001000L, 0x0000000000002000L, 0x0000000000004000L,
                                                0x0000000000008000L, 0x0000000000010000L, 0x0000000000020000L,
                                                0x0000000000040000L, 0x0000000000080000L, 0x0000000000100000L,
                                                0x0000000000200000L, 0x0000000000400000L, 0x0000000000800000L,
                                                0x0000000001000000L, 0x0000000002000000L, 0x0000000004000000L,
                                                0x0000000008000000L, 0x0000000010000000L, 0x0000000020000000L,
                                                0x0000000040000000L, 0x0000000080000000L, 0x0000000100000000L,
                                                0x0000000200000000L, 0x0000000400000000L, 0x0000000800000000L,
                                                0x0000001000000000L, 0x0000002000000000L, 0x0000004000000000L,
                                                0x0000008000000000L, 0x0000010000000000L, 0x0000020000000000L,
                                                0x0000040000000000L, 0x0000080000000000L, 0x0000100000000000L,
                                                0x0000200000000000L, 0x0000400000000000L, 0x0000800000000000L,
                                                0x0001000000000000L, 0x0002000000000000L, 0x0004000000000000L,
                                                0x0008000000000000L, 0x0010000000000000L, 0x0020000000000000L,
                                                0x0040000000000000L, 0x0080000000000000L, 0x0100000000000000L,
                                                0x0200000000000000L, 0x0400000000000000L, 0x0800000000000000L,
                                                0x1000000000000000L, 0x2000000000000000L, 0x4000000000000000L,
                                                0x8000000000000000L};
      private long bits;
      private int length;
  
      /**
       * @return the length of bits set
       */
      public int length() {
          return length;
      }
  
      /**
       * @return the long containing the bits
       */
      public long getBits() {
          return bits;
      }
  
      /**
       * set the boolean value at the index
       * 
       * @param index
       * @param flag
       * @return the old value held at this index
       */
      public boolean set(int index, boolean flag) {
          length = Math.max(length, index + 1);
          boolean oldValue = (bits & BIT_VALUES[index]) != 0;
          if (flag) {
              bits |= BIT_VALUES[index];
          } else if (oldValue) {
              bits &= ~(BIT_VALUES[index]);
          }
          return oldValue;
      }
  
      /**
       * @param index
       * @return the boolean value at this index
       */
      public boolean get(int index) {
          return (bits & BIT_VALUES[index]) != 0;
      }
  
      /**
       * reset all the bit values to false
       */
      public void reset() {
          bits = 0;
      }
  
      /**
       * reset all the bits to the value supplied
       * 
       * @param bits
       */
      public void reset(long bits) {
          this.bits = bits;
      }
  
      private void writeObject(java.io.ObjectOutputStream out) throws IOException {
          writeToStream(out);
      }
      
      private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
          readFromStream(in);
      }
      
      /**
       * write the bits to an output stream
       * 
       * @param dataOut
       * @throws IOException
       */
      public void writeToStream(DataOutput dataOut) throws IOException {
          dataOut.writeByte(length);
          if (length <= BYTE_SIZE) {
              dataOut.writeByte((byte)bits);
          } else if (length <= SHORT_SIZE) {
              dataOut.writeShort((short)bits);
          } else if (length <= INT_SIZE) {
              dataOut.writeInt((int)bits);
          } else {
              dataOut.writeLong(bits);
          }
      }
  
      /**
       * read the bits from an input stream
       * 
       * @param dataIn
       * @throws IOException
       */
      public void readFromStream(DataInput dataIn) throws IOException {
          length = dataIn.readByte();
          if (length <= BYTE_SIZE) {
              bits = dataIn.readByte();
          } else if (length <= SHORT_SIZE) {
              bits = dataIn.readShort();
          } else if (length <= INT_SIZE) {
              bits = dataIn.readInt();
          } else {
              bits = dataIn.readLong();
          }
      }
  }
  