long store_offset = first_piece_length + ((store_index-1)*(long)piece_size );
long swap_offset = first_piece_length + ((swap_index-1)*(long)piece_size );
delegate.read( raf, temp_buffers, swap_offset );
temp_buffer.position( SS_FILE, 0 );
delegate.write( raf, temp_buffers, store_offset );
piece_map[ store_index ] = store_index;
piece_reverse_map[ store_index ] = store_index;