/* Examines the binary tree rooted at |node|. Zeroes |*okay| if an error occurs. Otherwise, does not modify |*okay|. Sets |*count| to the number of nodes in that tree, including |node| itself if |node != NULL|. Sets |*height| to the tree's height. All the nodes in the tree are verified to be at least |min| but no greater than |max|. */ static void recurse_verify_tree (struct pavl_node *node, int *okay, size_t *count, int min, int max, int *height) { int d; /* Value of this node's data. */ size_t subcount[2]; /* Number of nodes in subtrees. */ int subheight[2]; /* Heights of subtrees. */ int i; if (node == NULL) { *count = 0; *height = 0; return; } d = *(int *) node->pavl_data; if (min > max) { printf (" Parents of node %d constrain it to empty range %d...%d.\n", d, min, max); *okay = 0; } else if (d < min || d > max) { printf (" Node %d is not in range %d...%d implied by its parents.\n", d, min, max); *okay = 0; } recurse_verify_tree (node->pavl_link[0], okay, &subcount[0], min, d - 1, &subheight[0]); recurse_verify_tree (node->pavl_link[1], okay, &subcount[1], d + 1, max, &subheight[1]); *count = 1 + subcount[0] + subcount[1]; *height = 1 + (subheight[0] > subheight[1] ? subheight[0] : subheight[1]); if (subheight[1] - subheight[0] != node->pavl_balance) { printf (" Balance factor of node %d is %d, but should be %d.\n", d, node->pavl_balance, subheight[1] - subheight[0]); *okay = 0; } else if (node->pavl_balance < -1 || node->pavl_balance > +1) { printf (" Balance factor of node %d is %d.\n", d, node->pavl_balance); *okay = 0; } for (i = 0; i < 2; i++) { if (node->pavl_link[i] != NULL && node->pavl_link[i]->pavl_parent != node) { printf (" Node %d has parent %d (should be %d).\n", *(int *) node->pavl_link[i]->pavl_data, (node->pavl_link[i]->pavl_parent != NULL ? *(int *) node->pavl_link[i]->pavl_parent->pavl_data : -1), d); *okay = 0; } } }