private void writeChunkHeader(BTreeChunk chunk) {
StringBuilder buff = chunk.asStringBuilder();
byte[] bytes = buff.toString().getBytes(DataUtils.LATIN);
int checksum = DataUtils.getFletcher32(bytes, bytes.length);
DataUtils.appendMap(buff, "fletcher", checksum);
buff.append("\n");
bytes = buff.toString().getBytes(DataUtils.LATIN);
ByteBuffer header = ByteBuffer.allocate(CHUNK_HEADER_SIZE);
header.put(bytes);
header.position(BLOCK_SIZE);
header.put(bytes);
header.rewind();
write(chunk.fileStorage, 0, header);
}
private synchronized BTreeChunk readChunkHeader(int chunkId) {
FileStorage fileStorage = getFileStorage(chunkId);
BTreeChunk chunk = null;
ByteBuffer chunkHeaderBlocks = fileStorage.readFully(0, CHUNK_HEADER_SIZE);
byte[] buff = new byte[BLOCK_SIZE];
for (int i = 0; i <= BLOCK_SIZE; i += BLOCK_SIZE) {
chunkHeaderBlocks.get(buff);
try {
String s = new String(buff, 0, BLOCK_SIZE, DataUtils.LATIN).trim();
HashMap<String, String> m = DataUtils.parseMap(s);
int blockSize = DataUtils.readHexInt(m, "blockSize", BLOCK_SIZE);
if (blockSize != BLOCK_SIZE) {
throw DataUtils.newIllegalStateException(
DataUtils.ERROR_UNSUPPORTED_FORMAT,
"Block size {0} is currently not supported",
blockSize);
}
int check = DataUtils.readHexInt(m, "fletcher", 0);
m.remove("fletcher");
s = s.substring(0, s.lastIndexOf("fletcher") - 1);
byte[] bytes = s.getBytes(DataUtils.LATIN);
int checksum = DataUtils.getFletcher32(bytes, bytes.length);
if (check != checksum) {
continue;
}
chunk = BTreeChunk.fromString(s);
break;
} catch (Exception e) {
continue;
}
}
if (chunk == null) {
throw DataUtils.newIllegalStateException(
DataUtils.ERROR_FILE_CORRUPT, "Storage header is corrupt: {0}", fileStorage);
}
chunk.fileStorage = fileStorage;
chunks.put(chunk.id, chunk);
return chunk;
}