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import com.googlecode.javaewah.EWAHCompressedBitmap;

import java.io.*;

import java.nio.ByteBuffer;

/**

* Simple illustrative example.

*

* @author Daniel Lemire

*

*/

public class example

{

/**

* @param args

* arguments from the command line

* @throws IOException

* if an IO error occurs

*/

public static void main(final String[] args) throws Exception {

EWAHCompressedBitmap ewahBitmap1 = EWAHCompressedBitmap.bitmapOf(0, 2, 55,

64, 1 << 30);

EWAHCompressedBitmap ewahBitmap2 = EWAHCompressedBitmap.bitmapOf(1, 3, 64,

1 << 30);

System.out.println("bitmap 1: " + ewahBitmap1);

System.out.println("bitmap 2: " + ewahBitmap2);

// or

EWAHCompressedBitmap orbitmap = ewahBitmap1.or(ewahBitmap2);

System.out.println("bitmap 1 OR bitmap 2: " + orbitmap);

System.out.println("memory usage: " + orbitmap.sizeInBytes() + " bytes");

// and

EWAHCompressedBitmap andbitmap = ewahBitmap1.and(ewahBitmap2);

System.out.println("bitmap 1 AND bitmap 2: " + andbitmap);

System.out.println("memory usage: " + andbitmap.sizeInBytes() + " bytes");

// xor

EWAHCompressedBitmap xorbitmap = ewahBitmap1.xor(ewahBitmap2);

System.out.println("bitmap 1 XOR bitmap 2:" + xorbitmap);

System.out.println("memory usage: " + xorbitmap.sizeInBytes() + " bytes");

// fast aggregation over many bitmaps

EWAHCompressedBitmap ewahBitmap3 = EWAHCompressedBitmap.bitmapOf(5, 55,

1 << 30);

EWAHCompressedBitmap ewahBitmap4 = EWAHCompressedBitmap.bitmapOf(4, 66,

1 << 30);

System.out.println("bitmap 3: " + ewahBitmap3);

System.out.println("bitmap 4: " + ewahBitmap4);

andbitmap = EWAHCompressedBitmap.and(ewahBitmap1, ewahBitmap2, ewahBitmap3,

ewahBitmap4);

System.out.println("b1 AND b2 AND b3 AND b4: " + andbitmap);

// serialization

ByteArrayOutputStream bos = new ByteArrayOutputStream();

// Note: you could use a file output steam instead of ByteArrayOutputStream

ewahBitmap1.serialize(new DataOutputStream(bos));

EWAHCompressedBitmap ewahBitmap1new = new EWAHCompressedBitmap();

byte[] bout = bos.toByteArray();

ewahBitmap1new.deserialize(new DataInputStream(new ByteArrayInputStream(

bout)));

System.out.println("bitmap 1 (recovered) : " + ewahBitmap1new);

if (!ewahBitmap1.equals(ewahBitmap1new))

throw new RuntimeException("Will not happen");

//

// we can use a ByteBuffer as backend for a bitmap

// which allows memory-mapped bitmaps

//

ByteBuffer bb = ByteBuffer.wrap(bout);

EWAHCompressedBitmap rmap = new EWAHCompressedBitmap(bb);

System.out.println("bitmap 1 (mapped) : " + rmap);

if (!rmap.equals(ewahBitmap1))

throw new RuntimeException("Will not happen");

//

// support for threshold function (new as of version 0.8.0):

// mark as true a bit that occurs at least T times in the source

// bitmaps

//

EWAHCompressedBitmap threshold2 = EWAHCompressedBitmap.threshold(2,

ewahBitmap1, ewahBitmap2, ewahBitmap3, ewahBitmap4);

System.out.println("threshold 2 : " + threshold2);

}

}