Extend the foreach implementation

src/set/extra.c

@@ -76,17 +76,23 @@ _Bool libcdsb_vset_insert(set_t* x, const void* v, vtype t) {
 /*#####################################################################################################################*/
 
 
-int libcdsb_vset_foreach(const vtype_set* x, int (*callback)(const void* value, vtype type)) {
-    rbiter_t i;
-    int      r;
+int libcdsb_vset_foreach(const set_t* x, void* data, int (*callback)(const void* value, vtype type, void* data)) {
+    stack_t   s = { .prev = 0, .value = x->root };
+    int       r = 0;
     rbnode_t* c;
 
-    if (rbiter_init(&i, &x->root, 0)) {
-        while (!rbnode_is_empty(c = rbiter_next(&i))) {
-            if ((r = callback(vnode_peek(&c->value, x->type), x->type)))
-                return r;
+    if (rbnode_is_empty(x->root)) return 0;
+
+    while ((c = stack_pop(&s))) {
+        if ((r = callback(vnode_peek(&c->value, x->type), x->type, data))) {
+            stack_flush(&s);
+            break;
         }
+        if (!rbnode_is_empty(c->left))
+            stack_push(&s, c->left);
+        if (!rbnode_is_empty(c->right))
+            stack_push(&s, c->right);
     }
 
-    return 0;
+    return r;
 }