entire width into PREV's trailing ones, e.g. 00001111
00001111 becomes 0000111111111111. */
int node_width = node->n_zeros + node->n_ones;
entire width into PREV's trailing ones, e.g. 00001111
00001111 becomes 0000111111111111. */
int node_width = node->n_zeros + node->n_ones;