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Initial NPOIFS low level stream reader and writer. Still needs unit tests, but should allow reading and writing to a basic stream of (big) blocks 

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1051795 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nick Burch 2010-12-22 08:52:17 +00:00
parent c0a0faf9c5
commit 39f533b4d0
3 changed files with 260 additions and 23 deletions
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52
src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
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@ -56,6 +56,7 @@ import org.apache.poi.poifs.storage.HeaderBlockWriter;
import org.apache.poi.poifs.storage.RawDataBlockList;
import org.apache.poi.poifs.storage.SmallBlockTableReader;
import org.apache.poi.poifs.storage.SmallBlockTableWriter;
import org.apache.poi.poifs.storage.BATBlock.BATBlockAndIndex;
import org.apache.poi.util.CloseIgnoringInputStream;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.LongField;
@ -81,10 +82,10 @@ public class NPOIFSFileSystem
return new CloseIgnoringInputStream(is);
}
private PropertyTable _property_table;
private List<BATBlock> _blocks;
private HeaderBlock _header;
private DirectoryNode _root;
private PropertyTable _property_table;
private List<BATBlock> _bat_blocks;
private HeaderBlock _header;
private DirectoryNode _root;
private DataSource _data;
@ -104,7 +105,7 @@ public class NPOIFSFileSystem
{
_header = new HeaderBlock(bigBlockSize);
_property_table = new PropertyTable(_header);// TODO Needs correct type
_blocks = new ArrayList<BATBlock>();
_bat_blocks = new ArrayList<BATBlock>();
_root = null;
}
@ -187,11 +188,7 @@ public class NPOIFSFileSystem
// We need to buffer the whole file into memory when
// working with an InputStream.
// The max possible size is when each BAT block entry is used
int maxSize =
_header.getBATCount() *
_header.getBigBlockSize().getBATEntriesPerBlock() *
_header.getBigBlockSize().getBigBlockSize()
;
int maxSize = BATBlock.calculateMaximumSize(_header);
ByteBuffer data = ByteBuffer.allocate(maxSize);
// Copy in the header
data.put(headerBuffer);
@ -275,7 +272,7 @@ public class NPOIFSFileSystem
for(int fatAt : _header.getBATArray()) {
loopDetector.claim(fatAt);
ByteBuffer fatData = getBlockAt(fatAt);
_blocks.add(BATBlock.createBATBlock(bigBlockSize, fatData));
_bat_blocks.add(BATBlock.createBATBlock(bigBlockSize, fatData));
}
// Now read the XFAT blocks
@ -287,7 +284,7 @@ public class NPOIFSFileSystem
xfat = BATBlock.createBATBlock(bigBlockSize, fatData);
nextAt = xfat.getValueAt(bigBlockSize.getNextXBATChainOffset());
_blocks.add(xfat);
_bat_blocks.add(xfat);
}
// We're now able to load steams
@ -305,10 +302,41 @@ public class NPOIFSFileSystem
long startAt = (offset+1) * bigBlockSize.getBigBlockSize();
return _data.read(bigBlockSize.getBigBlockSize(), startAt);
}
/**
* Returns the BATBlock that handles the specified offset,
* and the relative index within it
*/
protected BATBlockAndIndex getBATBlockAndIndex(final int offset) {
return BATBlock.getBATBlockAndIndex(
offset, _header, _bat_blocks
);
}
/**
* Works out what block follows the specified one.
*/
protected int getNextBlock(final int offset) {
BATBlockAndIndex bai = getBATBlockAndIndex(offset);
return bai.getBlock().getValueAt( bai.getIndex() );
}
/**
* Changes the record of what block follows the specified one.
*/
protected void setNextBlock(final int offset, final int nextBlock) {
BATBlockAndIndex bai = getBATBlockAndIndex(offset);
bai.getBlock().setValueAt(
bai.getIndex(), nextBlock
);
}
/**
* Finds a free block, and returns its offset.
* This method will extend the file if needed, and if doing
* so, allocate new FAT blocks to address the extra space.
*/
protected int getFreeBlock() {
// TODO
return -1;
}

172
src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java Normal file
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@ -0,0 +1,172 @@
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
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
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==================================================================== */
package org.apache.poi.poifs.filesystem;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Iterator;
import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.poifs.property.Property;
import org.apache.poi.poifs.storage.HeaderBlock;
/**
* This handles reading and writing a stream within a
* {@link NPOIFSFileSystem}. It can supply an iterator
* to read blocks, and way to write out to existing and
* new blocks.
* Most users will want a higher level version of this,
* which deals with properties to track which stream
* this is.
* This only works on big block streams, it doesn't
* handle small block ones.
* This uses the new NIO code
*/
public class NPOIFSStream implements Iterable<ByteBuffer>
{
private NPOIFSFileSystem filesystem;
private int startBlock;
/**
* Constructor for an existing stream. It's up to you
* to know how to get the start block (eg from a
* {@link HeaderBlock} or a {@link Property})
*/
public NPOIFSStream(NPOIFSFileSystem filesystem, int startBlock) {
this.filesystem = filesystem;
this.startBlock = startBlock;
}
/**
* Constructor for a new stream. A start block won't
* be allocated until you begin writing to it.
*/
public NPOIFSStream(NPOIFSFileSystem filesystem) {
this.filesystem = filesystem;
this.startBlock = POIFSConstants.END_OF_CHAIN;
}
/**
* What block does this stream start at?
* Will be {@link POIFSConstants#END_OF_CHAIN} for a
* new stream that hasn't been written to yet.
*/
public int getStartBlock() {
return startBlock;
}
/**
* Returns an iterator that'll supply one {@link ByteBuffer}
* per block in the stream.
*/
public Iterator<ByteBuffer> iterator() {
return getBlockIterator();
}
public Iterator<ByteBuffer> getBlockIterator() {
if(startBlock == POIFSConstants.END_OF_CHAIN) {
throw new IllegalStateException(
"Can't read from a new stream before it has been written to"
);
}
return new StreamBlockByteBufferIterator(startBlock);
}
/**
* Updates the contents of the stream to the new
* set of bytes.
* Note - if this is property based, you'll still
* need to
*/
public void updateContents(byte[] contents) throws IOException {
// How many blocks are we going to need?
int blocks = (int)Math.ceil(contents.length / filesystem.getBigBlockSize());
// Start writing
int prevBlock = POIFSConstants.END_OF_CHAIN;
int nextBlock = startBlock;
for(int i=0; i<blocks; i++) {
int thisBlock = nextBlock;
// Allocate a block if needed, otherwise figure
// out what the next block will be
if(thisBlock == POIFSConstants.END_OF_CHAIN) {
thisBlock = filesystem.getFreeBlock();
nextBlock = POIFSConstants.END_OF_CHAIN;
// Mark the previous block as carrying on
if(prevBlock != POIFSConstants.END_OF_CHAIN) {
filesystem.setNextBlock(prevBlock, thisBlock);
}
} else {
nextBlock = filesystem.getNextBlock(thisBlock);
}
// Write it
ByteBuffer buffer = filesystem.getBlockAt(thisBlock);
buffer.put(contents, i*filesystem.getBigBlockSize(), filesystem.getBigBlockSize());
// Update pointers
prevBlock = thisBlock;
}
// Mark the end of the stream
filesystem.setNextBlock(nextBlock, POIFSConstants.END_OF_CHAIN);
}
// TODO Streaming write too
/**
* Class that handles a streaming read of one stream
*/
protected class StreamBlockByteBufferIterator implements Iterator<ByteBuffer> {
private int nextBlock;
protected StreamBlockByteBufferIterator(int firstBlock) {
nextBlock = firstBlock;
}
public boolean hasNext() {
if(nextBlock == POIFSConstants.END_OF_CHAIN) {
return false;
}
return true;
}
public ByteBuffer next() {
if(nextBlock == POIFSConstants.END_OF_CHAIN) {
throw new IndexOutOfBoundsException("Can't read past the end of the stream");
}
try {
ByteBuffer data = filesystem.getBlockAt(nextBlock);
nextBlock = filesystem.getNextBlock(nextBlock);
return data;
} catch(IOException e) {
throw new RuntimeException(e);
}
}
public void remove() {
throw new UnsupportedOperationException();
}
}
}

59
src/testcases/org/apache/poi/poifs/filesystem/TestNPOIFSFileSystem.java
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@ -17,20 +17,10 @@
package org.apache.poi.poifs.filesystem;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import junit.framework.TestCase;
import org.apache.poi.POIDataSamples;
import org.apache.poi.hssf.HSSFTestDataSamples;
import org.apache.poi.poifs.common.POIFSBigBlockSize;
import org.apache.poi.poifs.storage.HeaderBlock;
import org.apache.poi.poifs.storage.RawDataBlockList;
import org.apache.poi.poifs.common.POIFSConstants;
/**
* Tests for the new NIO POIFSFileSystem implementation
@ -81,4 +71,51 @@ public final class TestNPOIFSFileSystem extends TestCase {
// TODO
}
}
/**
* Check that for a given block, we can correctly figure
* out what the next one is
*/
public void testNextBlock() throws Exception {
NPOIFSFileSystem fs = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
// 0 -> 21 are simple
for(int i=0; i<21; i++) {
assertEquals(i+1, fs.getNextBlock(i));
}
// 21 jumps to 89, then ends
assertEquals(89, fs.getNextBlock(21));
assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(89));
// 22 -> 88 simple sequential stream
for(int i=22; i<88; i++) {
assertEquals(i+1, fs.getNextBlock(i));
}
assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(88));
// 90 -> 96 is another stream
for(int i=90; i<96; i++) {
assertEquals(i+1, fs.getNextBlock(i));
}
assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(96));
// 97+98 is another
assertEquals(98, fs.getNextBlock(97));
assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(98));
// 99 is our FAT block
assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
// 100 onwards is free
for(int i=100; i<fs.getBigBlockSizeDetails().getBATEntriesPerBlock(); i++) {
assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(i));
}
}
/**
* Check we get the right data back for each block
*/
public void testGetBlock() throws Exception {
// TODO
}
}