code: private void verifyBufferSize(int sz)
  	{
  		if (sz > buf.length)
  		{
  			byte[] old = buf;
  			buf = new byte[Math.max(sz, 2 * buf.length)];
  			System.arraycopy(old, 0, buf, 0, old.length);
  			old = null;
  		}
  	}
docs: Ensures that we have a large enough buffer for the given size.