/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#ifndef TREE_H
-#define TREE_H
+/**
+ * @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;
+#if FF_API_CONTEXT_SIZE
+extern attribute_deprecated const int av_tree_node_size;
+#endif
/**
- * Finds an element.
+ * 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
+ * @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.
+ * @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]);
+void *av_tree_find(const struct AVTreeNode *root, void *key,
+ int (*cmp)(void *key, const void *b), void *next[2]);
/**
- * Finds a element for which cmp(key, elem)==0, if no such element is found key
- * is inserted into the tree.
- * @param rootp A pointer to a pointer to the root node of the tree. Note that
+ * 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.
- *
- * @return If no insertion happened, the found element.
- * If an insertion happened, then either key or NULL is 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).
+ * @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));
+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);
-#endif /* TREE_H */
+/**
+ * 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 */
projects / ffmpeg / blobdiff