src/testcases/org/apache/poi/poifs/storage/TestBlockAllocationTableWriter.java

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   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
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.poi.poifs.storage;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;

import junit.framework.TestCase;

import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.LittleEndianConsts;

/**
 * Class to test BlockAllocationTableWriter functionality
 *
 * @author Marc Johnson
 */
public final class TestBlockAllocationTableWriter extends TestCase {

    public void testAllocateSpace() {
        BlockAllocationTableWriter table         =
            new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        int[]                      blockSizes    =
        {
            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
        };
        int                        expectedIndex = 0;

        for (int j = 0; j < blockSizes.length; j++)
        {
            assertEquals(expectedIndex, table.allocateSpace(blockSizes[ j ]));
            expectedIndex += blockSizes[ j ];
        }
    }

    public void testCreateBlocks() {
        BlockAllocationTableWriter table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);

        table.allocateSpace(127);
        table.createBlocks();
        verifyBlocksCreated(table, 1);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(128);
        table.createBlocks();
        verifyBlocksCreated(table, 2);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(254);
        table.createBlocks();
        verifyBlocksCreated(table, 2);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(255);
        table.createBlocks();
        verifyBlocksCreated(table, 3);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(13843);
        table.createBlocks();
        verifyBlocksCreated(table, 109);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(13844);
        table.createBlocks();
        verifyBlocksCreated(table, 110);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(13969);
        table.createBlocks();
        verifyBlocksCreated(table, 110);
        table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
        table.allocateSpace(13970);
        table.createBlocks();
        verifyBlocksCreated(table, 111);
    }

    /**
     * Test content produced by BlockAllocationTableWriter
     */
    public void testProduct() throws IOException {
        BlockAllocationTableWriter table = new BlockAllocationTableWriter(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);

        for (int k = 1; k <= 22; k++)
        {
            table.allocateSpace(k);
        }
        table.createBlocks();
        ByteArrayOutputStream stream = new ByteArrayOutputStream();

        table.writeBlocks(stream);
        byte[] output = stream.toByteArray();

        assertEquals(1024, output.length);
        byte[] expected = new byte[ 1024 ];

        Arrays.fill(expected, ( byte ) 0xFF);
        int offset      = 0;
        int block_index = 1;

        for (int k = 1; k <= 22; k++)
        {
            int limit = k - 1;

            for (int j = 0; j < limit; j++)
            {
                LittleEndian.putInt(expected, offset, block_index++);
                offset += LittleEndianConsts.INT_SIZE;
            }
            LittleEndian.putInt(expected, offset,
                                POIFSConstants.END_OF_CHAIN);
            offset += 4;
            block_index++;
        }

        // add BAT block indices
        LittleEndian.putInt(expected, offset, block_index++);
        offset += LittleEndianConsts.INT_SIZE;
        LittleEndian.putInt(expected, offset, POIFSConstants.END_OF_CHAIN);
        for (int k = 0; k < expected.length; k++)
        {
            assertEquals("At offset " + k, expected[ k ], output[ k ]);
        }
    }

    private static void verifyBlocksCreated(BlockAllocationTableWriter table, int count){
        ByteArrayOutputStream stream = new ByteArrayOutputStream();

        try {
			table.writeBlocks(stream);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
        byte[] output = stream.toByteArray();

        assertEquals(count * 512, output.length);
    }
}