public synchronized void read(long fileOffset, ByteBuffer destBuf) throws IOException {
int len = destBuf.remaining();
final long max = (isDir) ? getLengthOnDisk() : getLength();
if (fileOffset + len > max) {
throw new IOException("Cannot read beyond the EOF");
}
final FatFileSystem fs = getFatFileSystem();
final long[] chain = fs.getFat().getChain(startCluster);
final BlockDeviceAPI api = fs.getApi();
int chainIdx = (int) (fileOffset / clusterSize);
if (fileOffset % clusterSize != 0) {
int clusOfs = (int) (fileOffset % clusterSize);
int size = Math.min(len, (int) (clusterSize - (fileOffset % clusterSize) - 1));
destBuf.limit(destBuf.position() + size);
api.read(getDevOffset(chain[chainIdx], clusOfs), destBuf);
fileOffset += size;
len -= size;
chainIdx++;
}
while (len > 0) {
int size = Math.min(clusterSize, len);
destBuf.limit(destBuf.position() + size);
api.read(getDevOffset(chain[chainIdx], 0), destBuf);
len -= size;
chainIdx++;
}
}
/**
* Gets the size this file occupies on disk
*
* @return long
*/
public long getLengthOnDisk() {
if (this.length == 0) {
return 0;
} else {
final FatFileSystem fs = getFatFileSystem();
final long[] chain = fs.getFat().getChain(getStartCluster());
return ((long) chain.length) * fs.getClusterSize();
}
}
/**
* Sets the length.
*
* @param length The length to set
*/
public synchronized void setLength(long length) throws IOException {
if (getFileSystem().isReadOnly()) {
throw new ReadOnlyFileSystemException("setLength in readonly filesystem");
}
if (this.length == length) {
// Do nothing
return;
}
final FatFileSystem fs = getFatFileSystem();
final Fat fat = fs.getFat();
final int nrClusters = (int) ((length + clusterSize - 1) / clusterSize);
if (this.length == 0) {
final long[] chain = fat.allocNew(nrClusters);
this.startCluster = chain[0];
this.myEntry.setStartCluster((int) startCluster);
} else {
final long[] chain = fs.getFat().getChain(startCluster);
if (nrClusters != chain.length) {
if (nrClusters > chain.length) {
// Grow
int count = nrClusters - chain.length;
while (count > 0) {
fat.allocAppend(getStartCluster());
count--;
}
} else {
// Shrink
fat.setEof(chain[nrClusters - 1]);
for (int i = nrClusters; i < chain.length; i++) {
fat.setFree(chain[i]);
}
}
}
}
this.length = length;
this.myEntry.updateLength(length);
}
public static void printInfo(File file, PrintWriter out) throws IOException, FileSystemException {
FileDevice fd = new FileDevice(file, "r");
try {
final FileSystemService fSS = InitialNaming.lookup(FileSystemService.NAME);
FatFileSystemType type = fSS.getFileSystemType(FatFileSystemType.ID);
FatFileSystem fs = new FatFileSystem(fd, false, type);
try {
BootSector bs = fs.getBootSector();
bs.read(fd);
out.println("OEM name " + bs.getOemName());
out.println("bytes/sector " + bs.getBytesPerSector());
out.println("sectors/cluster " + bs.getSectorsPerCluster());
out.println("#reserved sectors " + bs.getNrReservedSectors());
out.println("#fats " + bs.getNrFats());
out.println("#rootdir entries " + bs.getNrRootDirEntries());
out.println("#logical sectors " + bs.getNrLogicalSectors());
out.println("Medium descriptor 0x" + Integer.toHexString(bs.getMediumDescriptor()));
out.println("sectors/fat " + bs.getSectorsPerFat());
out.println("sectors/track " + bs.getSectorsPerTrack());
out.println("#heads " + bs.getNrHeads());
out.println("#hidden sectors " + bs.getNrHiddenSectors());
fs.getFat().printTo(out);
fs.getRootDir().printTo(out);
try {
FatDirectory dir =
(FatDirectory) fs.getRootEntry().getDirectory().getEntry("AAP").getDirectory();
dir.printTo(out);
} catch (FileNotFoundException ex) {
out.println("No AAP directory");
}
try {
FatDirectory dir =
(FatDirectory) fs.getRootEntry().getDirectory().getEntry("boot").getDirectory();
dir.printTo(out);
} catch (FileNotFoundException ex) {
out.println("No boot directory");
}
} finally {
// fd.stop();
fd.close();
}
} catch (NameNotFoundException e) {
throw new FileSystemException(e);
}
}
public synchronized void write(long fileOffset, ByteBuffer srcBuf) throws IOException {
int len = srcBuf.remaining();
if (getFileSystem().isReadOnly()) {
throw new ReadOnlyFileSystemException("write in readonly filesystem");
}
final long max = (isDir) ? getLengthOnDisk() : getLength();
if (fileOffset > max) {
throw new IOException("Cannot write beyond the EOF");
}
if (fileOffset + len > max) { // this is too short increase the size
// of the file
setLength(fileOffset + len);
}
final FatFileSystem fs = getFatFileSystem();
final long[] chain = fs.getFat().getChain(getStartCluster());
final BlockDeviceAPI api = fs.getApi();
int chainIdx = (int) (fileOffset / clusterSize);
if (fileOffset % clusterSize != 0) {
int clusOfs = (int) (fileOffset % clusterSize);
int size = Math.min(len, (int) (clusterSize - (fileOffset % clusterSize) - 1));
srcBuf.limit(srcBuf.position() + size);
api.write(getDevOffset(chain[chainIdx], clusOfs), srcBuf);
fileOffset += size;
len -= size;
chainIdx++;
}
while (len > 0) {
int size = Math.min(clusterSize, len);
srcBuf.limit(srcBuf.position() + size);
api.write(getDevOffset(chain[chainIdx], 0), srcBuf);
len -= size;
chainIdx++;
}
}