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
parent
c3c4e4f2f7
commit
c0a0faf9c5
@ -21,6 +21,7 @@ import java.io.IOException;
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import java.io.OutputStream;
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import java.nio.ByteBuffer;
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import java.util.Arrays;
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import java.util.List;
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import org.apache.poi.poifs.common.POIFSBigBlockSize;
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import org.apache.poi.poifs.common.POIFSConstants;
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@ -194,7 +195,6 @@ public final class BATBlock extends BigBlock {
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*
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* @return the number of BATBlocks needed
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*/
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public static int calculateStorageRequirements(final POIFSBigBlockSize bigBlockSize, final int entryCount)
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{
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int _entries_per_block = bigBlockSize.getBATEntriesPerBlock();
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@ -209,14 +209,62 @@ public final class BATBlock extends BigBlock {
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*
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* @return the number of XBATBlocks needed
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*/
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public static int calculateXBATStorageRequirements(final POIFSBigBlockSize bigBlockSize, final int entryCount)
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{
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int _entries_per_xbat_block = bigBlockSize.getXBATEntriesPerBlock();
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return (entryCount + _entries_per_xbat_block - 1)
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/ _entries_per_xbat_block;
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}
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/**
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* Calculates the maximum size of a file which is addressable given the
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* number of FAT (BAT and XBAT) sectors specified.
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* The actual file size will be between [size of fatCount-1 blocks] and
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* [size of fatCount blocks].
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* For 512 byte block sizes, this means we may over-estimate by up to 65kb.
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* For 4096 byte block sizes, this means we may over-estimate by up to 4mb
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*/
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public static int calculateMaximumSize(final POIFSBigBlockSize bigBlockSize,
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final int numBAT, final int numXBAT) {
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int size = 1; // Header isn't FAT addressed
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size += (numBAT * bigBlockSize.getBATEntriesPerBlock());
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size += (numXBAT * bigBlockSize.getXBATEntriesPerBlock());
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return size * bigBlockSize.getBigBlockSize();
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}
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public static int calculateMaximumSize(final HeaderBlock header)
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{
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return calculateMaximumSize(header.getBigBlockSize(), header.getBATCount(), header.getXBATCount());
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}
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/**
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* Returns the BATBlock that handles the specified offset,
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* and the relative index within it.
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* The List of BATBlocks must be in sequential order
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*/
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public static BATBlockAndIndex getBATBlockAndIndex(final int offset,
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final HeaderBlock header, final List<BATBlock> blocks) {
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POIFSBigBlockSize bigBlockSize = header.getBigBlockSize();
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// Are we in the BAT or XBAT range
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int batRangeEndsAt = bigBlockSize.getBATEntriesPerBlock() *
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header.getBATCount();
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if(offset < batRangeEndsAt) {
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int whichBAT = (int)Math.floor(offset / bigBlockSize.getBATEntriesPerBlock());
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int index = offset % bigBlockSize.getBATEntriesPerBlock();
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return new BATBlockAndIndex( index, blocks.get(whichBAT) );
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}
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// XBATs hold slightly less
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int relOffset = offset - batRangeEndsAt;
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int whichXBAT = (int)Math.floor(relOffset / bigBlockSize.getXBATEntriesPerBlock());
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int index = relOffset % bigBlockSize.getXBATEntriesPerBlock();
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return new BATBlockAndIndex(
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index,
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blocks.get(header.getBATCount() + whichXBAT)
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);
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}
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private void setXBATChain(final POIFSBigBlockSize bigBlockSize, int chainIndex)
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{
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int _entries_per_xbat_block = bigBlockSize.getXBATEntriesPerBlock();
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@ -277,5 +325,21 @@ public final class BATBlock extends BigBlock {
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}
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/* ********** END extension of BigBlock ********** */
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} // end public class BATBlock
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public static class BATBlockAndIndex {
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private final int index;
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private final BATBlock block;
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private BATBlockAndIndex(int index, BATBlock block) {
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this.index = index;
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this.block = block;
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}
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public int getIndex() {
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return index;
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}
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public BATBlock getBlock() {
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return block;
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}
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}
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}
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@ -19,7 +19,10 @@ package org.apache.poi.poifs.storage;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import org.apache.poi.poifs.common.POIFSConstants;
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@ -208,4 +211,175 @@ public final class TestBATBlock extends TestCase {
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public void testGetXBATChainOffset() {
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assertEquals(508, POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS.getNextXBATChainOffset());
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}
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public void testCalculateMaximumSize() throws Exception {
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// Zero fat blocks isn't technically valid, but it'd be header only
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assertEquals(
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512,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 0, 0)
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);
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assertEquals(
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4096,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 0, 0)
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);
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// A single FAT block can address 128/1024 blocks
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assertEquals(
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512 + 512*128,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 1, 0)
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);
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assertEquals(
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4096 + 4096*1024,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 1, 0)
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);
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assertEquals(
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512 + 4*512*128,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 4, 0)
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);
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assertEquals(
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4096 + 4*4096*1024,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 4, 0)
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);
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// Once we get into XBAT blocks, they address a little bit less
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assertEquals(
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512 + 109*512*128,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 0)
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);
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assertEquals(
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4096 + 109*4096*1024,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 0)
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);
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assertEquals(
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512 + 109*512*128 + 512*127,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 1)
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);
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assertEquals(
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4096 + 109*4096*1024 + 4096*1023,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 1)
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);
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assertEquals(
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512 + 109*512*128 + 3*512*127,
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BATBlock.calculateMaximumSize(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS, 109, 3)
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);
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assertEquals(
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4096 + 109*4096*1024 + 3*4096*1023,
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BATBlock.calculateMaximumSize(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS, 109, 3)
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);
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}
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public void testGetBATBlockAndIndex() throws Exception {
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HeaderBlock header = new HeaderBlock(POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS);
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List<BATBlock> blocks = new ArrayList<BATBlock>();
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int offset;
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// First, try a one BAT block file
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header.setBATCount(1);
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blocks.add(
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BATBlock.createBATBlock(header.getBigBlockSize(), ByteBuffer.allocate(512))
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);
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offset = 0;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1;
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assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 127;
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assertEquals(127, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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// Now go for one with multiple BAT blocks
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header.setBATCount(2);
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blocks.add(
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BATBlock.createBATBlock(header.getBigBlockSize(), ByteBuffer.allocate(512))
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);
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offset = 0;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 127;
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assertEquals(127, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 128;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 129;
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assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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// And finally one with XBATs too
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// This is a naughty file, but we should be able to cope...
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// (We'll decide everything is XBAT not BAT)
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header.setBATCount(0);
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offset = 0;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 126;
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assertEquals(126, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 127;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 128;
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assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 129;
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assertEquals(2, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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// Check with the bigger block size too
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header = new HeaderBlock(POIFSConstants.LARGER_BIG_BLOCK_SIZE_DETAILS);
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offset = 0;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1022;
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assertEquals(1022, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1023;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1024;
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assertEquals(1, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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// Biggr block size, back to real BATs
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header.setBATCount(2);
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offset = 0;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1022;
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assertEquals(1022, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1023;
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assertEquals(1023, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(0, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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offset = 1024;
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assertEquals(0, BATBlock.getBATBlockAndIndex(offset, header, blocks).getIndex());
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assertEquals(1, blocks.indexOf( BATBlock.getBATBlockAndIndex(offset, header, blocks).getBlock() ));
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}
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}
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