/* Inserts |item| into |table|, replacing any duplicate item.
Returns |NULL| if |item| was inserted without replacing a duplicate,
or if a memory allocation error occurred.
Otherwise, returns the item that was replaced. */
void *
tavl_replace (struct tavl_table *table, void *item)
{
void **p = tavl_probe (table, item);
if (p == NULL || *p == item)
return NULL;
else
{
void *r = *p;
*p = item;
return r;
}
}
/* Attempts to insert |item| into |tree|.
If |item| is inserted successfully, it is returned and |trav| is
initialized to its location.
If a duplicate is found, it is returned and |trav| is initialized to
its location. No replacement of the item occurs.
If a memory allocation failure occurs, |NULL| is returned and |trav|
is initialized to the null item. */
void *tavl_t_insert(struct tavl_traverser *trav,
struct tavl_table *tree, void *item)
{
void **p;
assert(trav != NULL && tree != NULL && item != NULL);
p = tavl_probe(tree, item);
if (p != NULL) {
trav->tavl_table = tree;
trav->tavl_node = ((struct tavl_node *)
((char *)p -
offsetof(struct tavl_node, tavl_data)));
return *p;
}
/* Inserts |item| into |table|.
Returns |NULL| if |item| was successfully inserted
or if a memory allocation error occurred.
Otherwise, returns the duplicate item. */
void *tavl_insert(struct tavl_table *table, void *item)
{
void **p = tavl_probe(table, item);
return p == NULL || *p == item ? NULL : *p;
}
