2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
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.
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.
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
24 * @author Michael Niedermayer <michaelni@gmx.at>
30 #include "attributes.h"
34 * @addtogroup lavu_tree AVTree
37 * Low complexity tree container
39 * Insertion, removal, finding equal, largest which is smaller than and
40 * smallest which is larger than, all have O(log n) worst case complexity.
46 #if FF_API_CONTEXT_SIZE
47 extern attribute_deprecated const int av_tree_node_size;
51 * Allocate an AVTreeNode.
53 struct AVTreeNode *av_tree_node_alloc(void);
57 * @param root a pointer to the root node of the tree
58 * @param next If next is not NULL, then next[0] will contain the previous
59 * element and next[1] the next element. If either does not exist,
60 * then the corresponding entry in next is unchanged.
61 * @return An element with cmp(key, elem)==0 or NULL if no such element exists in
64 void *av_tree_find(const struct AVTreeNode *root, void *key, int (*cmp)(void *key, const void *b), void *next[2]);
67 * Insert or remove an element.
69 * If *next is NULL, then the supplied element will be removed if it exists.
70 * If *next is non-NULL, then the supplied element will be inserted, unless
71 * it already exists in the tree.
73 * @param rootp A pointer to a pointer to the root node of the tree; note that
74 * the root node can change during insertions, this is required
75 * to keep the tree balanced.
76 * @param key pointer to the element key to insert in the tree
77 * @param next Used to allocate and free AVTreeNodes. For insertion the user
78 * must set it to an allocated and zeroed object of at least
79 * av_tree_node_size bytes size. av_tree_insert() will set it to
80 * NULL if it has been consumed.
81 * For deleting elements *next is set to NULL by the user and
82 * av_tree_insert() will set it to the AVTreeNode which was
83 * used for the removed element.
84 * This allows the use of flat arrays, which have
85 * lower overhead compared to many malloced elements.
86 * You might want to define a function like:
88 * void *tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b), AVTreeNode **next){
89 * if(!*next) *next= av_mallocz(av_tree_node_size);
90 * return av_tree_insert(rootp, key, cmp, next);
92 * void *tree_remove(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b, AVTreeNode **next)){
94 * return av_tree_insert(rootp, key, cmp, next);
97 * @param cmp compare function used to compare elements in the tree
98 * @return If no insertion happened, the found element; if an insertion or
99 * removal happened, then either key or NULL will be returned.
100 * Which one it is depends on the tree state and the implementation. You
101 * should make no assumptions that it's one or the other in the code.
103 void *av_tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b), struct AVTreeNode **next);
104 void av_tree_destroy(struct AVTreeNode *t);
107 * Apply enu(opaque, &elem) to all the elements in the tree in a given range.
109 * @param cmp a comparison function that returns < 0 for a element below the
110 * range, > 0 for a element above the range and == 0 for a
111 * element inside the range
113 * @note The cmp function should use the same ordering used to construct the
116 void av_tree_enumerate(struct AVTreeNode *t, void *opaque, int (*cmp)(void *opaque, void *elem), int (*enu)(void *opaque, void *elem));
122 #endif /* AVUTIL_TREE_H */