avutil/tree: add additional const qualifier to the comparator

libc's qsort comparator has a const qualifier on both arguments. This
adds a missing const qualifier to exactly match the comparator API.

Existing usages of av_tree_find, av_tree_insert are appropriately
modified: type signature changes of the comparators, and removal of
unnecessary void * casts of function pointers.

Reviewed-by: Henrik Gramner <henrik@gramner.com>
Reviewed-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/libavutil/tree.h b/libavutil/tree.h
index f04f02d8ed..337a44c2d3 100644
--- a/libavutil/tree.h
+++ b/libavutil/tree.h
@@ -62,7 +62,7 @@ struct AVTreeNode *av_tree_node_alloc(void);
  *         exists in the tree.
  */
 void *av_tree_find(const struct AVTreeNode *root, void *key,
-                   int (*cmp)(void *key, const void *b), void *next[2]);
+                   int (*cmp)(const void *key, const void *b), void *next[2]);
 
 /**
  * Insert or remove an element.
@@ -109,7 +109,7 @@ void *av_tree_find(const struct AVTreeNode *root, void *key,
  *         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),
+                     int (*cmp)(const void *key, const void *b),
                      struct AVTreeNode **next);
 
 void av_tree_destroy(struct AVTreeNode *t);