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.
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.