for (;;) { struct rb_node *x = pa[k - 1]->rb_link[da[k - 1]]; if (x != NULL && x->rb_color == RB_RED) { x->rb_color = RB_BLACK; break; } if (k < 2) break; if (da[k - 1] == 0) { struct rb_node *w = pa[k - 1]->rb_link[1]; if (w->rb_color == RB_RED) { w->rb_color = RB_BLACK; pa[k - 1]->rb_color = RB_RED; pa[k - 1]->rb_link[1] = w->rb_link[0]; w->rb_link[0] = pa[k - 1]; pa[k - 2]->rb_link[da[k - 2]] = w; pa[k] = pa[k - 1]; da[k] = 0; pa[k - 1] = w; k++; w = pa[k - 1]->rb_link[1]; } if ((w->rb_link[0] == NULL || w->rb_link[0]->rb_color == RB_BLACK) && (w->rb_link[1] == NULL || w->rb_link[1]->rb_color == RB_BLACK)) w->rb_color = RB_RED; else { if (w->rb_link[1] == NULL || w->rb_link[1]->rb_color == RB_BLACK) { struct rb_node *y = w->rb_link[0]; y->rb_color = RB_BLACK; w->rb_color = RB_RED; w->rb_link[0] = y->rb_link[1]; y->rb_link[1] = w; w = pa[k - 1]->rb_link[1] = y; } w->rb_color = pa[k - 1]->rb_color; pa[k - 1]->rb_color = RB_BLACK; w->rb_link[1]->rb_color = RB_BLACK; pa[k - 1]->rb_link[1] = w->rb_link[0]; w->rb_link[0] = pa[k - 1]; pa[k - 2]->rb_link[da[k - 2]] = w; break; } } else { struct rb_node *w = pa[k - 1]->rb_link[0]; if (w->rb_color == RB_RED) { w->rb_color = RB_BLACK; pa[k - 1]->rb_color = RB_RED; pa[k - 1]->rb_link[0] = w->rb_link[1]; w->rb_link[1] = pa[k - 1]; pa[k - 2]->rb_link[da[k - 2]] = w; pa[k] = pa[k - 1]; da[k] = 1; pa[k - 1] = w; k++; w = pa[k - 1]->rb_link[0]; } if ((w->rb_link[0] == NULL || w->rb_link[0]->rb_color == RB_BLACK) && (w->rb_link[1] == NULL || w->rb_link[1]->rb_color == RB_BLACK)) w->rb_color = RB_RED; else { if (w->rb_link[0] == NULL || w->rb_link[0]->rb_color == RB_BLACK) { struct rb_node *y = w->rb_link[1]; y->rb_color = RB_BLACK; w->rb_color = RB_RED; w->rb_link[1] = y->rb_link[0]; y->rb_link[0] = w; w = pa[k - 1]->rb_link[0] = y; } w->rb_color = pa[k - 1]->rb_color; pa[k - 1]->rb_color = RB_BLACK; w->rb_link[0]->rb_color = RB_BLACK; pa[k - 1]->rb_link[0] = w->rb_link[1]; w->rb_link[1] = pa[k - 1]; pa[k - 2]->rb_link[da[k - 2]] = w; break; } } k--; }