Low-complexity tree container. More...

Functions
struct AVTreeNode *	av_tree_node_alloc (void)
	Allocate an AVTreeNode.

void *	av_tree_find (const struct AVTreeNode root, void key, int(cmp)(void key, const void b), void next[2])
	Find an element.

void *	av_tree_insert (struct AVTreeNode *rootp, void key, int(cmp)(void key, const void b), struct AVTreeNode *next)
	Insert or remove an element.

void	av_tree_destroy (struct AVTreeNode *t)

void	av_tree_enumerate (struct AVTreeNode t, void opaque, int(cmp)(void opaque, void elem), int(enu)(void opaque, void elem))
	Apply enu(opaque, &elem) to all the elements in the tree in a given range.

Variables
const int	av_tree_node_size

Detailed Description

Low-complexity tree container.

Insertion, removal, finding equal, largest which is smaller than and smallest which is larger than, all have O(log n) worst-case complexity.

Function Documentation

struct AVTreeNode* av_tree_node_alloc ( void )

read

Allocate an AVTreeNode.

Definition at line 34 of file tree.c.

Referenced by ff_nut_add_sp(), and load_glyph().

void* av_tree_find	(	const struct AVTreeNode *	root,
		void *	key,
		int()(void key, const void *b)	cmp,
		void *	next[2]
	)

Find an element.

Parameters

root	a pointer to the root node of the tree
next	If next is not NULL, then next[0] will contain the previous element and next[1] the next element. If either does not exist, then the corresponding entry in next is unchanged.

Returns: An element with cmp(key, elem) == 0 or NULL if no such element exists in the tree.

void* av_tree_insert	(	struct AVTreeNode **	rootp,
		void *	key,
		int()(void key, const void *b)	cmp,
		struct AVTreeNode **	next
	)

Insert or remove an element.

If *next is NULL, then the supplied element will be removed if it exists. If *next is non-NULL, then the supplied element will be inserted, unless it already exists in the tree.

Parameters

rootp	A pointer to a pointer to the root node of the tree; note that the root node can change during insertions, this is required to keep the tree balanced.
key	pointer to the element key to insert in the tree
next	Used to allocate and free AVTreeNodes. For insertion the user must set it to an allocated and zeroed object of at least av_tree_node_size bytes size. av_tree_insert() will set it to NULL if it has been consumed. For deleting elements next is set to NULL by the user and av_tree_insert() will set it to the AVTreeNode which was used for the removed element. This allows the use of flat arrays, which have lower overhead compared to many malloced elements. You might want to define a function like: void tree_insert(struct AVTreeNode *rootp, void key, int (cmp)(void key, const void b), AVTreeNode next) { if (!next) next = av_mallocz(av_tree_node_size); return av_tree_insert(rootp, key, cmp, next); } void tree_remove(struct AVTreeNode *rootp, void key, int (cmp)(void key, const void b, AVTreeNode *next)) { av_freep(next); return av_tree_insert(rootp, key, cmp, next); }
cmp	compare function used to compare elements in the tree

Returns: If no insertion happened, the found element; if an insertion or removal happened, then either key or NULL will be returned. Which one it is depends on the tree state and the implementation. You should make no assumptions that it's one or the other in the code.

Definition at line 59 of file tree.c.

Referenced by av_tree_insert(), ff_nut_add_sp(), and load_glyph().

void av_tree_destroy ( struct AVTreeNode * t )

Definition at line 146 of file tree.c.

Referenced by av_tree_destroy(), ff_nut_free_sp(), and uninit().