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Bit more on NPOIFSFileSystem, and some typo fixes in documentation 

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1050815 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nick Burch 2010-12-19 11:43:54 +00:00
parent aaddcfc655
commit adca67b937
3 changed files with 31 additions and 6 deletions
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33
src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
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@ -266,17 +266,22 @@ public class NPOIFSFileSystem
// Grab the block size
bigBlockSize = _header.getBigBlockSize();
// Each block should only ever be used by one of the
// FAT, XFAT or Property Table. Ensure it does
ChainLoopDetector loopDetector = new ChainLoopDetector();
// Read the FAT blocks
for(int fatAT : _header.getBATArray()) {
ByteBuffer fatData = getBlockAt(fatAT);
for(int fatAt : _header.getBATArray()) {
loopDetector.claim(fatAt);
ByteBuffer fatData = getBlockAt(fatAt);
_blocks.add(BATBlock.createBATBlock(bigBlockSize, fatData));
}
// Now read the XFAT blocks
// TODO Corrupt / Loop checking
BATBlock xfat;
int nextAt = _header.getXBATIndex();
for(int i=0; i<_header.getXBATCount(); i++) {
loopDetector.claim(nextAt);
ByteBuffer fatData = getBlockAt(nextAt);
xfat = BATBlock.createBATBlock(bigBlockSize, fatData);
nextAt = xfat.getValueAt(bigBlockSize.getNextXBATChainOffset());
@ -287,7 +292,6 @@ public class NPOIFSFileSystem
// We're now able to load steams
// Use this to read in the properties
// TODO
// TODO With loop checking
}
/**
@ -614,6 +618,27 @@ public class NPOIFSFileSystem
}
}
}
/**
* Used to detect if a chain has a loop in it, so
* we can bail out with an error rather than
* spinning away for ever...
*/
private class ChainLoopDetector {
private boolean[] used_blocks;
private ChainLoopDetector() throws IOException {
used_blocks = new boolean[(int)(_data.size()/bigBlockSize.getBigBlockSize())];
}
private void claim(int offset) {
if(used_blocks[offset]) {
throw new IllegalStateException(
"Potential loop detected - Block " + offset +
" was already claimed but was just requested again"
);
}
used_blocks[offset] = true;
}
}
/* ********** START begin implementation of POIFSViewable ********** */

2
src/java/org/apache/poi/poifs/property/PropertyFactory.java
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@ -28,7 +28,7 @@ import org.apache.poi.poifs.storage.ListManagedBlock;
/**
* Factory for turning an array of RawDataBlock instances containing
* Proprty data into an array of proper Property objects.
* Property data into an array of proper Property objects.
*
* The array produced may be sparse, in that any portion of data that
* should correspond to a Property, but which does not map to a proper

2
src/java/org/apache/poi/poifs/property/PropertyTable.java
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@ -32,7 +32,7 @@ import org.apache.poi.poifs.storage.RawDataBlockList;
/**
* This class embodies the Property Table for the filesystem; this is
* basically the dsirectory for all of the documents in the
* basically the directory for all of the documents in the
* filesystem.
*
* @author Marc Johnson (mjohnson at apache dot org)