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
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
/*
* 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.
* @param cmp compare function used to compare elements in the tree,
* API identical to that of Standard C's qsort
* @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, API identical
* to that of Standard C's qsort
* @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 */
|
