# define AVL_INLINE inline __attribute__((always_inline))
#else
# define AVL_INLINE inline
+# warning "AVL tree functions may not be inlined as intended"
#endif
/* Node in an AVL tree. Embed this in some other data structure. */
* 11 => undefined
*
* The rest of the bits are the pointer to the parent node. It must be
- * 4-byte aligned, and it will be NULL if this is the root note and
+ * 4-byte aligned, and it will be NULL if this is the root node and
* therefore has no parent. */
uintptr_t parent_balance;
};
#define avl_tree_entry(entry, type, member) \
((type*) ((char *)(entry) - offsetof(type, member)))
-/* Extracts the parent pointer from the specified AVL tree node.
- * Returns the parent pointer, or NULL if @node is the root node. */
+/* Returns a pointer to the parent of the specified AVL tree node, or NULL if it
+ * is already the root of the tree. */
static AVL_INLINE struct avl_tree_node *
avl_get_parent(const struct avl_tree_node *node)
{
return (struct avl_tree_node *)(node->parent_balance & ~3);
}
-/* Mark the node as unlinked from any tree. */
+/* Marks the specified AVL tree node as unlinked from any tree. */
static AVL_INLINE void
avl_tree_node_set_unlinked(struct avl_tree_node *node)
{
node->parent_balance = (uintptr_t)node;
}
-/* Returns true iff the specified node has been marked with
+/* Returns true iff the specified AVL tree node has been marked with
* avl_tree_node_set_unlinked() and has not subsequently been inserted into a
* tree. */
static AVL_INLINE bool
return node->parent_balance == (uintptr_t)node;
}
-/* Internal use only */
+/* (Internal use only) */
extern void
avl_tree_rebalance_after_insert(struct avl_tree_node **root_ptr,
struct avl_tree_node *inserted);
/*
- * Look up an item in an AVL tree.
+ * Looks up an item in the specified AVL tree.
*
* @root
* Pointer to the root of the AVL tree. (This can be NULL --- that just
* means the tree is empty.)
*
* @cmp_ctx
- * First argument to pass to the comparison callback --- generally a
- * pointer to an object equal to the one being searched for.
+ * First argument to pass to the comparison callback. This generally
+ * should be a pointer to an object equal to the one being searched for.
*
* @cmp
* Comparison callback. Must return < 0, 0, or > 0 if the first argument
* respectively. The first argument will be @cmp_ctx and the second
* argument will be a pointer to the AVL tree node of an item in the tree.
*
- * Returns a pointer to the AVL tree node embedded in the resulting item, or
- * NULL if the item was not found.
+ * Returns a pointer to the AVL tree node of the resulting item, or NULL if the
+ * item was not found.
*/
static AVL_INLINE struct avl_tree_node *
avl_tree_lookup(const struct avl_tree_node *root,
return (struct avl_tree_node*)cur;
}
-/* Same as avl_tree_lookup(), just uses a more specific type for the comparison
- * function. Specifically, the item being searched for is expected to be in the
- * same format as those already in the tree, with an embedded 'struct
- * avl_tree_node'. */
+/* Same as avl_tree_lookup(), but uses a more specific type for the comparison
+ * function. Specifically, with this function the item being searched for is
+ * expected to be in the same format as those already in the tree, with an
+ * embedded 'struct avl_tree_node'. */
static AVL_INLINE struct avl_tree_node *
avl_tree_lookup_node(const struct avl_tree_node *root,
const struct avl_tree_node *node,
}
/*
- * Insert an item into an AVL tree.
+ * Inserts an item into the specified AVL tree.
*
* @root_ptr
- * Pointer to the pointer to the root of the AVL tree. (Indirection is
- * needed because the root node may change.) Initialize *root_ptr to NULL
- * for an empty tree.
+ * Location of the AVL tree's root pointer. Indirection is needed because
+ * the root node may change as a result of rotations caused by the
+ * insertion. Initialize *root_ptr to NULL for an empty tree.
*
* @item
* Pointer to the `struct avl_tree_node' embedded in the item to insert.
* is less than, equal to, or greater than the second argument,
* respectively. The first argument will be @item and the second
* argument will be a pointer to an AVL tree node embedded in some
- * previously-inserted item that @item is being compared with.
+ * previously-inserted item to which @item is being compared.
*
- * Returns NULL if the item was successfully inserted, otherwise the node of a
- * previously-inserted item which compared equal to @item and prevented the new
- * insertion of @item.
+ * If no item in the tree is comparatively equal (via @cmp) to @item, inserts
+ * @item and returns NULL. Otherwise does nothing and returns a pointer to the
+ * AVL tree node embedded in the previously-inserted item which compared equal
+ * to @item.
*/
static AVL_INLINE struct avl_tree_node *
avl_tree_insert(struct avl_tree_node **root_ptr,
return NULL;
}
+/* Removes an item from the specified AVL tree.
+ * See implementation for details. */
extern void
avl_tree_remove(struct avl_tree_node **root_ptr, struct avl_tree_node *node);
git://wimlib.net / wimlib / blobdiff