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/**
* 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();
}
}
}