libavutil/tree.c File Reference

#include "log.h"
#include "tree.h"

Go to the source code of this file.

Data Structures
struct	AVTreeNode
Functions
void *	av_tree_find (const AVTreeNode *t, void *key, int(*cmp)(void *key, const void *b), void *next[2])
void *	av_tree_insert (AVTreeNode **tp, void *key, int(*cmp)(void *key, const void *b), AVTreeNode **next)
	Inserts or removes an element.
void	av_tree_destroy (AVTreeNode *t)
void	av_tree_enumerate (AVTreeNode *t, void *opaque, int(*cmp)(void *opaque, void *elem), int(*enu)(void *opaque, void *elem))
	Applies enu(opaque, &elem) to all the elements in the tree in a given range.
Variables
const int	av_tree_node_size = sizeof(AVTreeNode)

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Function Documentation

void av_tree_destroy

(

AVTreeNode *

t

)

Definition at line 129 of file tree.c.

Referenced by av_tree_destroy(), and ff_nut_free_sp().

void av_tree_enumerate	(	struct AVTreeNode *	t,
		void *	opaque,
		int(*)(void *opaque, void *elem)	cmp,
		int(*)(void *opaque, void *elem)	enu
	)

Applies enu(opaque, &elem) to all the elements in the tree in a given range.

Parameters:

cmp

a comparison function that returns < 0 for a element below the range, > 0 for a element above the range and == 0 for a element inside the range

Note:

The cmp function should use the same ordering used to construct the tree.

Definition at line 137 of file tree.c.

Referenced by av_tree_enumerate(), and ff_nut_free_sp().

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

Definition at line 32 of file tree.c.

Referenced by av_tree_insert(), read_seek(), and write_packet().

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

Inserts or removes an element.

If *next is NULL, then the supplied element will be removed if it exists. If *next is not 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.
	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_node_size() 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)){ if(*next) av_freep(next); return av_tree_insert(rootp, key, cmp, next); }

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 49 of file tree.c.

Referenced by av_tree_insert(), and ff_nut_add_sp().

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Variable Documentation

const int av_tree_node_size = sizeof(AVTreeNode)

Definition at line 30 of file tree.c.

Referenced by ff_nut_add_sp().