/**
* Does the same thing as <code>readFully</code> do but without copying data (thread safe)
*
* @param length length of the bytes to read
* @return buffer with portion of file content
* @throws IOException on any fail of I/O operation
*/
public synchronized ByteBuffer readBytes(int length) throws IOException {
int remaining = buffer.remaining() - position;
if (length > remaining)
throw new IOException(
String.format(
"mmap segment underflow; remaining is %d but %d requested", remaining, length));
if (length == 0) return ByteBufferUtil.EMPTY_BYTE_BUFFER;
ByteBuffer bytes = buffer.duplicate();
bytes.position(buffer.position() + position).limit(buffer.position() + position + length);
position += length;
// we have to copy the data in case we unreference the underlying sstable. See CASSANDRA-3179
ByteBuffer clone = ByteBuffer.allocate(bytes.remaining());
clone.put(bytes);
clone.flip();
return clone;
}
