/**
* Read and process the PropertiesTable and the FAT / XFAT blocks, so that we're ready to work
* with the file
*/
private void readCoreContents() throws IOException {
// 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 = getChainLoopDetector();
// Read the FAT blocks
for (int fatAt : _header.getBATArray()) {
readBAT(fatAt, loopDetector);
}
// Work out how many FAT blocks remain in the XFATs
int remainingFATs = _header.getBATCount() - _header.getBATArray().length;
// Now read the XFAT blocks, and the FATs within them
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);
xfat.setOurBlockIndex(nextAt);
nextAt = xfat.getValueAt(bigBlockSize.getXBATEntriesPerBlock());
_xbat_blocks.add(xfat);
// Process all the (used) FATs from this XFAT
int xbatFATs = Math.min(remainingFATs, bigBlockSize.getXBATEntriesPerBlock());
for (int j = 0; j < xbatFATs; j++) {
int fatAt = xfat.getValueAt(j);
if (fatAt == POIFSConstants.UNUSED_BLOCK || fatAt == POIFSConstants.END_OF_CHAIN) break;
readBAT(fatAt, loopDetector);
}
remainingFATs -= xbatFATs;
}
// We're now able to load steams
// Use this to read in the properties
_property_table = new NPropertyTable(_header, this);
// Finally read the Small Stream FAT (SBAT) blocks
BATBlock sfat;
List<BATBlock> sbats = new ArrayList<BATBlock>();
_mini_store = new NPOIFSMiniStore(this, _property_table.getRoot(), sbats, _header);
nextAt = _header.getSBATStart();
for (int i = 0; i < _header.getSBATCount(); i++) {
loopDetector.claim(nextAt);
ByteBuffer fatData = getBlockAt(nextAt);
sfat = BATBlock.createBATBlock(bigBlockSize, fatData);
sfat.setOurBlockIndex(nextAt);
sbats.add(sfat);
nextAt = getNextBlock(nextAt);
}
}
/** Constructor, intended for writing */
public NPOIFSFileSystem() {
this(true);
// Mark us as having a single empty BAT at offset 0
_header.setBATCount(1);
_header.setBATArray(new int[] {0});
_bat_blocks.add(BATBlock.createEmptyBATBlock(bigBlockSize, false));
setNextBlock(0, POIFSConstants.FAT_SECTOR_BLOCK);
// Now associate the properties with the empty block
_property_table.setStartBlock(1);
setNextBlock(1, POIFSConstants.END_OF_CHAIN);
}
private NPOIFSFileSystem(boolean newFS) {
_header = new HeaderBlock(bigBlockSize);
_property_table = new NPropertyTable(_header);
_mini_store =
new NPOIFSMiniStore(this, _property_table.getRoot(), new ArrayList<BATBlock>(), _header);
_xbat_blocks = new ArrayList<BATBlock>();
_bat_blocks = new ArrayList<BATBlock>();
_root = null;
if (newFS) {
// Data needs to initially hold just the header block,
// a single bat block, and an empty properties section
_data = new ByteArrayBackedDataSource(new byte[bigBlockSize.getBigBlockSize() * 3]);
}
}
/** Has our in-memory objects write their state to their backing blocks */
private void syncWithDataSource() throws IOException {
// HeaderBlock
HeaderBlockWriter hbw = new HeaderBlockWriter(_header);
hbw.writeBlock(getBlockAt(-1));
// BATs
for (BATBlock bat : _bat_blocks) {
ByteBuffer block = getBlockAt(bat.getOurBlockIndex());
BlockAllocationTableWriter.writeBlock(bat, block);
}
// SBATs
_mini_store.syncWithDataSource();
// Properties
_property_table.write(new NPOIFSStream(this, _header.getPropertyStart()));
}
/**
* remove an entry
*
* @param entry to be removed
*/
void remove(EntryNode entry) {
_property_table.removeProperty(entry.getProperty());
}
/**
* Get the root entry
*
* @return the root entry
*/
public DirectoryNode getRoot() {
if (_root == null) {
_root = new DirectoryNode(_property_table.getRoot(), this, null);
}
return _root;
}
/**
* add a new DirectoryProperty to the FileSystem
*
* @param directory the DirectoryProperty being added
*/
void addDirectory(final DirectoryProperty directory) {
_property_table.addProperty(directory);
}
/**
* add a new POIFSDocument to the FileSytem
*
* @param document the POIFSDocument being added
*/
void addDocument(final NPOIFSDocument document) {
_property_table.addProperty(document.getDocumentProperty());
}