TestBZip2BlockDecompressor.java

package org.itadaki.bzip2;

import static org.junit.Assert.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import org.itadaki.bzip2.BZip2BlockDecompressor;
import org.itadaki.bzip2.BZip2BitInputStream;
import org.itadaki.bzip2.BZip2BitOutputStream;
import org.junit.Test;

/**
 * Tests BZip2BlockDecompressor
 */
public class TestBZip2BlockDecompressor {

    /**
     * Tests decoding an invalid BZip2 block with zero huffman tables
     * 
     * @throws Exception
     */
    @Test
    public void testErrorZeroTables() throws Exception {

	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
	BZip2BitOutputStream bitOutputStream = new BZip2BitOutputStream(outputStream);
	bitOutputStream.writeInteger(0); // block CRC
	bitOutputStream.writeBoolean(false); // randomisation
	bitOutputStream.writeBits(24, 0); // start pointer
	bitOutputStream.writeBits(16, 0); // huffman used ranges
	bitOutputStream.writeBits(3, 0); // total tables
	bitOutputStream.writeBits(15, 1); // total selectors
	bitOutputStream.flush();

	BZip2BitInputStream bitInputStream = new BZip2BitInputStream(new ByteArrayInputStream(outputStream.toByteArray()));

	try {
	    new BZip2BlockDecompressor(bitInputStream, 900000);
	    fail();
	} catch (IOException e) {
	    assertEquals("BZip2 block Huffman tables invalid", e.getMessage());
	}

    }

    /**
     * Tests decoding an invalid BZip2 block with one huffman table
     * 
     * @throws Exception
     */
    @Test
    public void testErrorOneTable() throws Exception {

	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
	BZip2BitOutputStream bitOutputStream = new BZip2BitOutputStream(outputStream);
	bitOutputStream.writeInteger(0); // block CRC
	bitOutputStream.writeBoolean(false); // randomisation
	bitOutputStream.writeBits(24, 0); // start pointer
	bitOutputStream.writeBits(16, 0); // huffman used ranges
	bitOutputStream.writeBits(3, 1); // total tables
	bitOutputStream.writeBits(15, 1); // total selectors
	bitOutputStream.flush();

	BZip2BitInputStream bitInputStream = new BZip2BitInputStream(new ByteArrayInputStream(outputStream.toByteArray()));

	try {
	    new BZip2BlockDecompressor(bitInputStream, 900000);
	    fail();
	} catch (IOException e) {
	    assertEquals("BZip2 block Huffman tables invalid", e.getMessage());
	}

    }

    /**
     * Tests decoding an invalid BZip2 block with 7 huffman tables
     * 
     * @throws Exception
     */
    @Test
    public void tesErrortSevenTables() throws Exception {

	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
	BZip2BitOutputStream bitOutputStream = new BZip2BitOutputStream(outputStream);
	bitOutputStream.writeInteger(0); // block CRC
	bitOutputStream.writeBoolean(false); // randomisation
	bitOutputStream.writeBits(24, 0); // start pointer
	bitOutputStream.writeBits(16, 0); // huffman used ranges
	bitOutputStream.writeBits(3, 7); // total tables
	bitOutputStream.writeBits(15, 1); // total selectors
	bitOutputStream.flush();

	BZip2BitInputStream bitInputStream = new BZip2BitInputStream(new ByteArrayInputStream(outputStream.toByteArray()));

	try {
	    new BZip2BlockDecompressor(bitInputStream, 900000);
	    fail();
	} catch (IOException e) {
	    assertEquals("BZip2 block Huffman tables invalid", e.getMessage());
	}

    }

    /**
     * Tests decoding an invalid BZip2 block with zero selectors
     * 
     * @throws Exception
     */
    @Test
    public void testErrorZeroSelectors() throws Exception {

	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
	BZip2BitOutputStream bitOutputStream = new BZip2BitOutputStream(outputStream);
	bitOutputStream.writeInteger(0); // block CRC
	bitOutputStream.writeBoolean(false); // randomisation
	bitOutputStream.writeBits(24, 0); // start pointer
	bitOutputStream.writeBits(16, 0); // huffman used ranges
	bitOutputStream.writeBits(3, 2); // total tables
	bitOutputStream.writeBits(15, 0); // total selectors
	bitOutputStream.flush();

	BZip2BitInputStream bitInputStream = new BZip2BitInputStream(new ByteArrayInputStream(outputStream.toByteArray()));

	try {
	    new BZip2BlockDecompressor(bitInputStream, 900000);
	    fail();
	} catch (IOException e) {
	    assertEquals("BZip2 block Huffman tables invalid", e.getMessage());
	}

    }

    /**
     * Tests decoding an invalid BZip2 block with too many
     * 
     * @throws Exception
     */
    @Test
    public void testErrorTooManySelectors() throws Exception {

	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
	BZip2BitOutputStream bitOutputStream = new BZip2BitOutputStream(outputStream);
	bitOutputStream.writeInteger(0); // block CRC
	bitOutputStream.writeBoolean(false); // randomisation
	bitOutputStream.writeBits(24, 0); // start pointer
	bitOutputStream.writeBits(16, 0); // huffman used ranges
	bitOutputStream.writeBits(3, 2); // total tables
	bitOutputStream.writeBits(15, 18002); // total selectors
	bitOutputStream.flush();

	BZip2BitInputStream bitInputStream = new BZip2BitInputStream(new ByteArrayInputStream(outputStream.toByteArray()));

	try {
	    new BZip2BlockDecompressor(bitInputStream, 900000);
	    fail();
	} catch (IOException e) {
	    assertEquals("BZip2 block Huffman tables invalid", e.getMessage());
	}

    }

}