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++;
}
}
/** @see org.jnode.fs.fat.FatFormatter#format(BlockDeviceAPI) */
public void format(BlockDeviceAPI api) throws IOException {
formatter.format(api);
GrubBootSector bs = (GrubBootSector) formatter.getBootSector();
/* Fixup the blocklist end the end of the first sector of stage2 */
LittleEndian.setInt32(stage2, 512 - 8, bootSectorOffset + 2);
/* Fixup the install partition */
LittleEndian.setInt32(stage2, 512 + 0x08, installPartition);
/* Fixup the config file */
if (configFile != null) {
int ofs = 512 + 0x12;
while (stage2[ofs] != 0) {
ofs++;
}
ofs++; /* Skip '\0' */
for (int i = 0; i < configFile.length(); i++) {
stage2[ofs++] = (byte) configFile.charAt(i);
}
stage2[ofs] = 0;
}
/* Write stage2 */
api.write(bs.getBytesPerSector(), ByteBuffer.wrap(stage2));
}
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++;
}
}
