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avltree: Exports bs_avltree_node_delete(), and adds extra safeguards. #100

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Merged
phkaeser merged 1 commit into from
Aug 24, 2026
Merged

avltree: Exports bs_avltree_node_delete(), and adds extra safeguards. #100

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8 changes: 8 additions & 0 deletions include/libbase/avltree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -138,6 +138,14 @@ bs_avltree_node_t *bs_avltree_node_next(bs_avltree_t *tree_ptr,
bs_avltree_node_t *bs_avltree_node_prev(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr);

/** Deletes the node. Must be part of tree_ptr. */
void bs_avltree_node_delete(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr);

/** @return whether |tree_ptr| contains |node_ptr. */
bool bs_avltree_contains_node(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr);

/**
* Helper: Comparator to compare two pointers.
*
Expand Down
32 changes: 28 additions & 4 deletions src/avltree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,8 +51,6 @@ static size_t bs_avltree_node_height(bs_avltree_t *tree_ptr,
static void bs_avltree_node_exchange(bs_avltree_t *tree_ptr,
bs_avltree_node_t *old_node_ptr,
bs_avltree_node_t *new_node_ptr);
static void bs_avltree_node_delete(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr);

static bool bs_avltree_rot_right(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr);
Expand Down Expand Up @@ -294,6 +292,15 @@ bs_avltree_node_t *bs_avltree_node_prev(__UNUSED__ bs_avltree_t *tree_ptr,
return node_ptr->parent_ptr;
}

/* ------------------------------------------------------------------------- */
bool bs_avltree_contains_node(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr)
{
if (NULL == node_ptr) return false;
while (NULL != node_ptr->parent_ptr) node_ptr = node_ptr->parent_ptr;
return tree_ptr->root_ptr == node_ptr;
}

/* ------------------------------------------------------------------------- */
int bs_avltree_cmp_ptr(const void *node_key_ptr,
const void *key_ptr)
Expand Down Expand Up @@ -511,6 +518,8 @@ void bs_avltree_node_exchange(bs_avltree_t *tree_ptr,
void bs_avltree_node_delete(bs_avltree_t *tree_ptr,
bs_avltree_node_t *node_ptr)
{
BS_ASSERT(bs_avltree_contains_node(tree_ptr, node_ptr));

bs_avltree_node_t *next_larger_node_ptr = NULL;

if ((NULL != node_ptr->left_ptr) && (NULL != node_ptr->right_ptr)) {
Expand Down Expand Up @@ -925,7 +934,14 @@ void bs_avltree_test_random(bs_test_t *test_ptr)

BS_TEST_VERIFY_NEQ(test_ptr, node_ptr, NULL);
if (NULL != node_ptr) {
BS_TEST_VERIFY_TRUE(
test_ptr,
bs_avltree_contains_node(tree_ptr, &node_ptr->node));
BS_TEST_VERIFY_EQ(test_ptr, node_ptr->value, value);
} else {
BS_TEST_VERIFY_FALSE(
test_ptr,
bs_avltree_contains_node(tree_ptr, &node_ptr->node));
}
}

Expand Down Expand Up @@ -960,8 +976,16 @@ void bs_avltree_test_random(bs_test_t *test_ptr)
for (value_idx = 0; value_idx < BS_AVLTREE_TEST_VALUES; value_idx++) {
value = random_values[value_idx];

node_ptr = (bs_avltree_test_node_t*)
bs_avltree_delete(tree_ptr, &value);
if (value & 0x1) {
node_ptr = (bs_avltree_test_node_t*)
bs_avltree_delete(tree_ptr, &value);
} else {
node_ptr = (bs_avltree_test_node_t*)
bs_avltree_lookup(tree_ptr, &value);
if (NULL != node_ptr) {
bs_avltree_node_delete(tree_ptr, &node_ptr->node);
}
}
if (node_ptr != NULL) {
BS_TEST_VERIFY_EQ(test_ptr, node_ptr->value, value);
bs_avltree_test_node_destroy(&node_ptr->node);
Expand Down
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