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More BATBlock related methods for identifying size and list offsets, plus tests 

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1051791 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nick Burch 2010-12-22 08:41:28 +00:00
parent b3f1888f6b
commit b77ffa0c7a
2 changed files with 241 additions and 3 deletions
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70
src/java/org/apache/poi/poifs/storage/BATBlock.java
View File

@ -21,6 +21,7 @@ import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
import org.apache.poi.poifs.common.POIFSBigBlockSize;
import org.apache.poi.poifs.common.POIFSConstants;
@ -194,7 +195,6 @@ public final class BATBlock extends BigBlock {
*
* @return the number of BATBlocks needed
*/
public static int calculateStorageRequirements(final POIFSBigBlockSize bigBlockSize, final int entryCount)
{
int _entries_per_block = bigBlockSize.getBATEntriesPerBlock();
@ -209,7 +209,6 @@ public final class BATBlock extends BigBlock {
*
* @return the number of XBATBlocks needed
*/
public static int calculateXBATStorageRequirements(final POIFSBigBlockSize bigBlockSize, final int entryCount)
{
int _entries_per_xbat_block = bigBlockSize.getXBATEntriesPerBlock();
@ -217,6 +216,55 @@ public final class BATBlock extends BigBlock {
/ _entries_per_xbat_block;
}
/**
* Calculates the maximum size of a file which is addressable given the
* number of FAT (BAT and XBAT) sectors specified.
* The actual file size will be between [size of fatCount-1 blocks] and
* [size of fatCount blocks].
* For 512 byte block sizes, this means we may over-estimate by up to 65kb.
* For 4096 byte block sizes, this means we may over-estimate by up to 4mb
*/
public static int calculateMaximumSize(final POIFSBigBlockSize bigBlockSize,
final int numBAT, final int numXBAT) {
int size = 1; // Header isn't FAT addressed
size += (numBAT * bigBlockSize.getBATEntriesPerBlock());
size += (numXBAT * bigBlockSize.getXBATEntriesPerBlock());
return size * bigBlockSize.getBigBlockSize();
}
public static int calculateMaximumSize(final HeaderBlock header)
{
return calculateMaximumSize(header.getBigBlockSize(), header.getBATCount(), header.getXBATCount());
}
/**
* Returns the BATBlock that handles the specified offset,
* and the relative index within it.
* The List of BATBlocks must be in sequential order
*/
public static BATBlockAndIndex getBATBlockAndIndex(final int offset,
final HeaderBlock header, final List<BATBlock> blocks) {
POIFSBigBlockSize bigBlockSize = header.getBigBlockSize();
// Are we in the BAT or XBAT range
int batRangeEndsAt = bigBlockSize.getBATEntriesPerBlock() *
header.getBATCount();
if(offset < batRangeEndsAt) {
int whichBAT = (int)Math.floor(offset / bigBlockSize.getBATEntriesPerBlock());
int index = offset % bigBlockSize.getBATEntriesPerBlock();
return new BATBlockAndIndex( index, blocks.get(whichBAT) );
}
// XBATs hold slightly less
int relOffset = offset - batRangeEndsAt;
int whichXBAT = (int)Math.floor(relOffset / bigBlockSize.getXBATEntriesPerBlock());
int index = relOffset % bigBlockSize.getXBATEntriesPerBlock();
return new BATBlockAndIndex(
index,
blocks.get(header.getBATCount() + whichXBAT)
);
}
private void setXBATChain(final POIFSBigBlockSize bigBlockSize, int chainIndex)
{
int _entries_per_xbat_block = bigBlockSize.getXBATEntriesPerBlock();
@ -277,5 +325,21 @@ public final class BATBlock extends BigBlock {
}
/* ********** END extension of BigBlock ********** */
} // end public class BATBlock
public static class BATBlockAndIndex {
private final int index;
private final BATBlock block;
private BATBlockAndIndex(int index, BATBlock block) {
this.index = index;
this.block = block;
}
public int getIndex() {
return index;
}
public BATBlock getBlock() {
return block;
}
}
}

174
src/testcases/org/apache/poi/poifs/storage/TestBATBlock.java
View File

@ -19,7 +19,10 @@ package org.apache.poi.poifs.storage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.poi.poifs.common.POIFSConstants;
@ -208,4 +211,175 @@ public final class TestBATBlock extends TestCase {
public void testGetXBATChainOffset() {
assertEquals(508, POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS.getNextXBATChainOffset());
}
public void testCalculateMaximumSize() throws Exception {
// Zero fat blocks isn't technically valid, but it'd be header only
assertEquals(
512,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 0, 0)
);
assertEquals(
4096,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 0, 0)
);
// A single FAT block can address 128/1024 blocks
assertEquals(
512 + 512*128,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 1, 0)
);
assertEquals(
4096 + 4096*1024,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 1, 0)
);
assertEquals(
512 + 4*512*128,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 4, 0)
);
assertEquals(
4096 + 4*4096*1024,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 4, 0)
);
// Once we get into XBAT blocks, they address a little bit less
assertEquals(
512 + 109*512*128,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 0)
);
assertEquals(
4096 + 109*4096*1024,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 0)
);
assertEquals(
512 + 109*512*128 + 512*127,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 1)
);
assertEquals(
4096 + 109*4096*1024 + 4096*1023,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 1)
);
assertEquals(
512 + 109*512*128 + 3*512*127,
BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 3)
);
assertEquals(
4096 + 109*4096*1024 + 3*4096*1023,
BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 3)
);
}
public void testGetBATBlockAndIndex() throws Exception {
HeaderBlock header = new HeaderBlock(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
List<BATBlock> blocks = new ArrayList<BATBlock>();
int offset;
// First, try a one BAT block file
header.setBATCount(1);
blocks.add(
BATBlock.createBATBlock(header.getBigBlockSize(), ByteBuffer.allocate(512))
);
offset = 0;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1;
assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 127;
assertEquals(127, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
// Now go for one with multiple BAT blocks
header.setBATCount(2);
blocks.add(
BATBlock.createBATBlock(header.getBigBlockSize(), ByteBuffer.allocate(512))
);
offset = 0;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 127;
assertEquals(127, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 128;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 129;
assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
// And finally one with XBATs too
// This is a naughty file, but we should be able to cope...
// (We'll decide everything is XBAT not BAT)
header.setBATCount(0);
offset = 0;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 126;
assertEquals(126, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 127;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 128;
assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 129;
assertEquals(2, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
// Check with the bigger block size too
header = new HeaderBlock(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS);
offset = 0;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1022;
assertEquals(1022, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1023;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1024;
assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
// Biggr block size, back to real BATs
header.setBATCount(2);
offset = 0;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1022;
assertEquals(1022, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1023;
assertEquals(1023, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
offset = 1024;
assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
}
}