libavutil/tree.h

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file tree.h
  23  * A tree container.
  24  * @author Michael Niedermayer <michaelni@gmx.at>
  25  */
  26
  27 #ifndef TREE_H
  28 #define TREE_H
  29
  30 struct AVTreeNode;
  31
  32 /**
  33  * Finds an element.
  34  * @param root a pointer to the root node of the tree
  35  * @param next If next is not NULL then next[0] will contain the previous
  36  *             element and next[1] the next element if either does not exist
  37  *             then the corresponding entry in next is unchanged.
  38  * @return An element with cmp(key, elem)==0 or NULL if no such element exists in
  39  *         the tree.
  40  */
  41 void *av_tree_find(const struct AVTreeNode *root, void *key, int (*cmp)(void *key, const void *b), void *next[2]);
  42
  43 /**
  44  * Finds a element for which cmp(key, elem)==0, if no such element is found key
  45  * is inserted into the tree.
  46  * @param rootp A pointer to a pointer to the root node of the tree. Note that
  47  *              the root node can change during insertions, this is required
  48  *              to keep the tree balanced.
  49  *
  50  * @return If no insertion happened, the found element.
  51  *         If an insertion happened, then either key or NULL will be returned.
  52  *         Which one it is depends on the tree state and the implementation. You
  53  *         should make no assumptions that it's one or the other in the code.
  54  */
  55 void *av_tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b));
  56 void av_tree_destroy(struct AVTreeNode *t);
  57
  58 #endif /* TREE_H */