2 files changed, 30 insertions, 21 deletions

diff --git a/src/btree.c b/src/btree.c
index 21db8d6..4a8c4f6 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -115,13 +115,15 @@ zix_btree_new(const ZixComparator cmp, const void* const cmp_data)
 }
 
 static void
-zix_btree_free_children(ZixBTree* const     t,
-                        ZixBTreeNode* const n,
-                        ZixDestroyFunc      destroy)
+zix_btree_free_children(ZixBTree* const      t,
+                        ZixBTreeNode* const  n,
+                        const ZixDestroyFunc destroy,
+                        const void* const    destroy_user_data)
 {
   if (!n->is_leaf) {
     for (ZixShort i = 0; i < n->n_vals + 1u; ++i) {
-      zix_btree_free_children(t, zix_btree_child(n, i), destroy);
+      zix_btree_free_children(
+        t, zix_btree_child(n, i), destroy, destroy_user_data);
       free(zix_btree_child(n, i));
     }
   }
@@ -129,30 +131,34 @@ zix_btree_free_children(ZixBTree* const     t,
   if (destroy) {
     if (n->is_leaf) {
       for (ZixShort i = 0u; i < n->n_vals; ++i) {
-        destroy(n->data.leaf.vals[i]);
+        destroy(n->data.leaf.vals[i], destroy_user_data);
       }
     } else {
       for (ZixShort i = 0u; i < n->n_vals; ++i) {
-        destroy(n->data.inode.vals[i]);
+        destroy(n->data.inode.vals[i], destroy_user_data);
       }
     }
   }
 }
 
 void
-zix_btree_free(ZixBTree* const t, ZixDestroyFunc destroy)
+zix_btree_free(ZixBTree* const      t,
+               const ZixDestroyFunc destroy,
+               const void* const    destroy_user_data)
 {
   if (t) {
-    zix_btree_clear(t, destroy);
+    zix_btree_clear(t, destroy, destroy_user_data);
     free(t->root);
     free(t);
   }
 }
 
 void
-zix_btree_clear(ZixBTree* const t, ZixDestroyFunc destroy)
+zix_btree_clear(ZixBTree* const t,
+                ZixDestroyFunc  destroy,
+                const void*     destroy_user_data)
 {
-  zix_btree_free_children(t, t->root, destroy);
+  zix_btree_free_children(t, t->root, destroy, destroy_user_data);
 
   memset(t->root, 0, sizeof(ZixBTreeNode));
   t->root->is_leaf = true;
diff --git a/src/tree.c b/src/tree.c
index 9faf13c..f26ff90 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -27,6 +27,7 @@ typedef struct ZixTreeNodeImpl ZixTreeNode;
 struct ZixTreeImpl {
   ZixTreeNode*   root;
   ZixDestroyFunc destroy;
+  const void*    destroy_user_data;
   ZixComparator  cmp;
   void*          cmp_data;
   size_t         size;
@@ -69,15 +70,17 @@ ZixTree*
 zix_tree_new(bool           allow_duplicates,
              ZixComparator  cmp,
              void*          cmp_data,
-             ZixDestroyFunc destroy)
+             ZixDestroyFunc destroy,
+             const void*    destroy_user_data)
 {
-  ZixTree* t          = (ZixTree*)malloc(sizeof(ZixTree));
-  t->root             = NULL;
-  t->destroy          = destroy;
-  t->cmp              = cmp;
-  t->cmp_data         = cmp_data;
-  t->size             = 0;
-  t->allow_duplicates = allow_duplicates;
+  ZixTree* t           = (ZixTree*)malloc(sizeof(ZixTree));
+  t->root              = NULL;
+  t->destroy           = destroy;
+  t->destroy_user_data = destroy_user_data;
+  t->cmp               = cmp;
+  t->cmp_data          = cmp_data;
+  t->size              = 0;
+  t->allow_duplicates  = allow_duplicates;
   return t;
 }
 
@@ -88,7 +91,7 @@ zix_tree_free_rec(ZixTree* t, ZixTreeNode* n)
     zix_tree_free_rec(t, n->left);
     zix_tree_free_rec(t, n->right);
     if (t->destroy) {
-      t->destroy(n->data);
+      t->destroy(n->data, t->destroy_user_data);
     }
     free(n);
   }
@@ -451,7 +454,7 @@ zix_tree_remove(ZixTree* t, ZixTreeIter* ti)
   if ((n == t->root) && !n->left && !n->right) {
     t->root = NULL;
     if (t->destroy) {
-      t->destroy(n->data);
+      t->destroy(n->data, t->destroy_user_data);
     }
     free(n);
     --t->size;
@@ -583,7 +586,7 @@ zix_tree_remove(ZixTree* t, ZixTreeIter* ti)
   DUMP(t);
 
   if (t->destroy) {
-    t->destroy(n->data);
+    t->destroy(n->data, t->destroy_user_data);
   }
   free(n);