1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* A 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.
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#ifndef AVUTIL_TREE_H
#define AVUTIL_TREE_H
struct AVTreeNode;
extern const int av_tree_node_size;
/**
* 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 not 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 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:
* @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
* @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 */
|
