From bedd6906eabdd513042d6a178d4dc56a3a41d1d3 Mon Sep 17 00:00:00 2001 From: Fox Caminiti Date: Fri, 16 Dec 2022 20:16:43 -0500 Subject: v3, file/build organization --- dependencies/include/libavutil/tree.h | 137 ++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 dependencies/include/libavutil/tree.h (limited to 'dependencies/include/libavutil/tree.h') diff --git a/dependencies/include/libavutil/tree.h b/dependencies/include/libavutil/tree.h new file mode 100644 index 0000000..bbb8fbb --- /dev/null +++ b/dependencies/include/libavutil/tree.h @@ -0,0 +1,137 @@ +/* + * copyright (c) 2006 Michael Niedermayer + * + * 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 + */ + +#ifndef AVUTIL_TREE_H +#define AVUTIL_TREE_H + +#include "attributes.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 + * It is guaranteed that the first and only the first argument to cmp() + * will be the key parameter to av_tree_find(), thus it could if the + * user wants, be a different type (like an opaque context). + * @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)(const 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)(const 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 an element below the + * range, > 0 for an element above the range and == 0 for an + * 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 */ -- cgit v1.2.3