public synchronized byte[] read(long pos, int length) throws IOException {
if (pos >= this.fileLength) return null;
this.offset = pos + length;
DataOutputX out = new DataOutputX();
int posOnBlock = (int) (pos % blockSize);
if (posOnBlock > 0) {
// long blockNum = (pos / blockSize);
byte[] blockBytes = getReadBlock(pos / blockSize);
if (blockBytes == null) {
return null;
}
if (blockBytes.length < blockSize) {
int readLen = Math.min(blockBytes.length - posOnBlock, length);
return DataInputX.get(blockBytes, posOnBlock, readLen);
}
int readLen = Math.min(blockSize - posOnBlock, length);
out.write(DataInputX.get(blockBytes, posOnBlock, readLen));
length -= readLen;
pos += readLen;
}
int blockCount = length / blockSize;
for (int i = 0; i < blockCount; i++) {
// long blockNum = (int) (pos / blockSize);
byte[] blockBytes = getReadBlock(pos / blockSize);
if (blockBytes == null) {
return out.toByteArray();
}
out.write(blockBytes);
pos += blockSize;
length -= blockSize;
}
if (length == 0) {
return out.toByteArray();
}
int remainder = length;
// long blockNum = (int) (pos / blockSize);
byte[] block = getReadBlock(pos / blockSize);
if (block != null) {
remainder = Math.min(block.length, remainder);
out.write(DataInputX.get(block, 0, remainder));
}
return out.toByteArray();
}
public short readShort(long pos) throws IOException {
byte[] buf = read(pos, 2);
return DataInputX.toShort(buf, 0);
}
public int readInt(long pos) throws IOException {
byte[] buf = read(pos, 4);
return DataInputX.toInt(buf, 0);
}