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diff --git a/ffmpeg/libavutil/tree.h b/ffmpeg/libavutil/tree.h
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+/*
+ * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * A tree container.
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#ifndef AVUTIL_TREE_H
+#define AVUTIL_TREE_H
+
+#include "attributes.h"
+#include "version.h"
+
+/**
+ * @addtogroup lavu_tree AVTree
+ * @ingroup lavu_data
+ *
+ * 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.
+ * @{
+ */
+
+
+struct AVTreeNode;
+extern const int av_tree_node_size;
+
+/**
+ * Allocate an AVTreeNode.
+ */
+struct AVTreeNode *av_tree_node_alloc(void);
+
+/**
+ * Find an element.
+ * @param root a pointer to the root node of the tree
+ * @param 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.
+ * @return An element with cmp(key, elem)==0 or NULL if no such element exists in
+ *         the tree.
+ */
+void *av_tree_find(const struct AVTreeNode *root, void *key, int (*cmp)(void *key, const void *b), void *next[2]);
+
+/**
+ * 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.
+ *
+ * @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 key  pointer to the element key to insert in the tree
+ * @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_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:
+ *             @code
+ *             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);
+ *             }
+ *             @endcode
+ * @param cmp compare function used to compare elements in the tree
+ * @return 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.
+ */
+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);
+
+/**
+ * Apply enu(opaque, &elem) to all the elements in the tree in a given range.
+ *
+ * @param 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.
+ */
+void av_tree_enumerate(struct AVTreeNode *t, void *opaque, int (*cmp)(void *opaque, void *elem), int (*enu)(void *opaque, void *elem));
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_TREE_H */