/* run tests against the c_rbtree_find*() helpers */
static void test_map(void) {
CRBNode **slot, *p;
CRBTree t = {};
Node *nodes[2048];
unsigned long i;
/* allocate and initialize all nodes */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
nodes[i] = malloc(sizeof(*nodes[i]));
assert(nodes[i]);
nodes[i]->key = i;
c_rbnode_init(&nodes[i]->rb);
}
/* shuffle nodes */
shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
/* add all nodes, and verify that each node is linked */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
assert(!c_rbnode_is_linked(&nodes[i]->rb));
assert(!c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
slot = c_rbtree_find_slot(&t, compare, (void *)nodes[i]->key, &p);
assert(slot);
c_rbtree_add(&t, p, slot, &nodes[i]->rb);
assert(c_rbnode_is_linked(&nodes[i]->rb));
assert(nodes[i] == c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
}
/* shuffle nodes again */
shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
/* remove all nodes (in different order) */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
assert(c_rbnode_is_linked(&nodes[i]->rb));
assert(nodes[i] == c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
c_rbtree_remove_init(&t, &nodes[i]->rb);
assert(!c_rbnode_is_linked(&nodes[i]->rb));
assert(!c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
}
/* free nodes again */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i)
free(nodes[i]);
}
static void test_parent_middle(TestContext *ctx) {
size_t i;
shuffle(ctx->nodes, ctx->n_nodes);
for (i = 0; i < ctx->n_nodes; ++i)
child_assert(c_rbnode_is_linked(ctx->nodes[i]));
}
static void test_child2(TestContext *ctx) {
size_t i;
for (i = 0; i < ctx->n_nodes; ++i) {
child_assert(c_rbnode_is_linked(ctx->nodes[i]));
c_rbnode_unlink(ctx->nodes[i]);
}
}
static void test_child1(TestContext *ctx) {
CRBNode *p, **slot;
size_t i;
for (i = 0; i < ctx->n_nodes; ++i) {
child_assert(!c_rbnode_is_linked(ctx->nodes[i]));
slot = c_rbtree_find_slot(ctx->tree, compare, ctx->nodes[i], &p);
c_rbtree_add(ctx->tree, p, slot, ctx->nodes[i]);
}
}
static void test_parent_end(TestContext *ctx) {
size_t i;
int r;
for (i = 0; i < ctx->n_nodes; ++i)
c_assert(!c_rbnode_is_linked(ctx->nodes[i]));
r = munmap(ctx->map, ctx->mapsize);
c_assert(r >= 0);
}
/**
* c_rbnode_next_postorder() - return next node in post-order
* @n: current node, or NULL
*
* This returns the next node to @n, based on a left-to-right post-order
* traversal. If @n is NULL, the root node, or unlinked, this returns NULL.
*
* This implements a left-to-right post-order traversal: First visit the left
* child of a node, then the right, and lastly the node itself. Children are
* traversed recursively.
*
* This function can be used to implement a left-to-right post-order traversal:
*
* for (n = c_rbtree_first_postorder(t); n; n = c_rbnode_next_postorder(n))
* visit(n);
*
* Worst case runtime (n: number of elements in tree): O(log(n))
*
* Return: Pointer to next node, or NULL.
*/
_c_public_ CRBNode *c_rbnode_next_postorder(CRBNode *n) {
CRBNode *p;
if (!c_rbnode_is_linked(n))
return NULL;
p = c_rbnode_parent(n);
if (p && n == p->left && p->right)
return c_rbnode_leftdeepest(p->right);
return p;
}
/* verify that all API calls are exported */
static void test_api(void) {
CRBTree t = {};
CRBNode n = C_RBNODE_INIT(n);
assert(!c_rbnode_is_linked(&n));
/* init, is_linked, add, remove, remove_init */
c_rbtree_add(&t, NULL, &t.root, &n);
assert(c_rbnode_is_linked(&n));
c_rbtree_remove_init(&t, &n);
assert(!c_rbnode_is_linked(&n));
c_rbtree_add(&t, NULL, &t.root, &n);
assert(c_rbnode_is_linked(&n));
c_rbtree_remove(&t, &n);
assert(c_rbnode_is_linked(&n)); /* @n wasn't touched */
c_rbnode_init(&n);
assert(!c_rbnode_is_linked(&n));
/* first, last, leftmost, rightmost, next, prev */
assert(!c_rbtree_first(&t));
assert(!c_rbtree_last(&t));
assert(&n == c_rbnode_leftmost(&n));
assert(&n == c_rbnode_rightmost(&n));
assert(!c_rbnode_next(&n));
assert(!c_rbnode_prev(&n));
}
/**
* c_rbnode_prev() - return previous node
* @n: current node, or NULL
*
* An RB-Tree always defines a linear order of its elements. This function
* returns the logically previous node to @n. If @n is NULL, the first node or
* unlinked, this returns NULL.
*
* Worst case runtime (n: number of elements in tree): O(log(n))
*
* Return: Pointer to previous node, or NULL.
*/
_c_public_ CRBNode *c_rbnode_prev(CRBNode *n) {
CRBNode *p;
if (!c_rbnode_is_linked(n))
return NULL;
if (n->left)
return c_rbnode_rightmost(n->left);
while ((p = c_rbnode_parent(n)) && n == p->left)
n = p;
return p;
}
/**
* c_rbnode_prev_postorder() - return previous node in post-order
* @n: current node, or NULL
*
* This returns the previous node to @n, based on a left-to-right post-order
* traversal. That is, it is the inverse operation to c_rbnode_next_postorder().
* If @n is NULL, the left-deepest node, or unlinked, this returns NULL.
*
* This function returns the logical previous node in a directed post-order
* traversal. That is, it effectively does a pre-order traversal (since a
* reverse post-order traversal is a pre-order traversal). This function does
* NOT do a right-to-left post-order traversal! In other words, the following
* invariant is guaranteed, if c_rbnode_next_postorder(n) is non-NULL:
*
* n == c_rbnode_prev_postorder(c_rbnode_next_postorder(n))
*
* This function can be used to implement a right-to-left pre-order traversal,
* using the fact that a reverse post-order traversal is also a valid pre-order
* traversal:
*
* for (n = c_rbtree_last_postorder(t); n; n = c_rbnode_prev_postorder(n))
* visit(n);
*
* This would effectively perform a right-to-left pre-order traversal: first
* visit a parent, then its right child, then its left child. Both children are
* traversed recursively.
*
* Worst case runtime (n: number of elements in tree): O(log(n))
*
* Return: Pointer to previous node in post-order, or NULL.
*/
_c_public_ CRBNode *c_rbnode_prev_postorder(CRBNode *n) {
CRBNode *p;
if (!c_rbnode_is_linked(n))
return NULL;
if (n->right)
return n->right;
if (n->left)
return n->left;
while ((p = c_rbnode_parent(n))) {
if (p->left && n != p->left)
return p->left;
n = p;
}
return NULL;
}
static void insert(CRBTree *t, CRBNode *n) {
CRBNode **i, *p;
assert(t);
assert(n);
assert(!c_rbnode_is_linked(n));
i = &t->root;
p = NULL;
while (*i) {
p = *i;
if (n < *i) {
i = &(*i)->left;
} else {
assert(n > *i);
i = &(*i)->right;
}
}
c_rbtree_add(t, p, i, n);
}