Update internal FFmpeg copy.

1 files changed, 31 insertions, 7 deletions

diff --git a/contrib/ffmpeg/libavutil/tree.h b/contrib/ffmpeg/libavutil/tree.h
index be1735858..111ea81a0 100644
--- a/contrib/ffmpeg/libavutil/tree.h
+++ b/contrib/ffmpeg/libavutil/tree.h
@@ -21,13 +21,16 @@
 /**
  * @file tree.h
  * A tree container.
+ * Insertion, Removial, Finding equal, largest which is smaller than and
+ * smallest which is larger than all have O(log n) worst case time.
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 
-#ifndef TREE_H
-#define TREE_H
+#ifndef FFMPEG_TREE_H
+#define FFMPEG_TREE_H
 
 struct AVTreeNode;
+extern const int av_tree_node_size;
 
 /**
  * Finds an element.
@@ -41,18 +44,39 @@ struct AVTreeNode;
 void *av_tree_find(const struct AVTreeNode *root, void *key, int (*cmp)(void *key, const void *b), void *next[2]);
 
 /**
- * Finds a element for which cmp(key, elem)==0, if no such element is found key
- * is inserted into the tree.
+ * Inserts or removes an element.
+ * If *next is NULL then the element supplied will be removed, if no such
+ * element exists behavior is undefined.
+ * If *next is not NULL then the element supplied will be inserted, unless
+ * it already exists in the tree.
  * @param 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.
+ * @param 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);
+ *             }
  *
  * @return If no insertion happened, the found element.
- *         If an insertion happened, then either key or NULL will be returned.
+ *         If an insertion or removial 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.
  */
-void *av_tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b));
+void *av_tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b), struct AVTreeNode **next);
 void av_tree_destroy(struct AVTreeNode *t);
 
-#endif /* TREE_H */
+#endif /* FFMPEG_TREE_H */