lib: add iterative node traversal methods in red-black trees.

lib: add release code for rb_tree_clear.

src/structures/red_black_tree.c

@@ -52,13 +52,24 @@ rb_node_new(enum RBNodeColor color, struct RBNode* parent, const_pointer entry)
 }
 
 
+static rb_subtree_free(struct RBNode* node, cry_free_funptr fun)
+{
+	if(node == 0)
+		return;
+
+	rb_subtree_free(node->left, fun);
+	rb_subtree_free(node->right, fun);
+
+	rb_node_free(node, fun);
+}
+
+
 void
-rb_tree_clear(struct RBTree* tree, cry_free_funptr free_entry)
+rb_tree_clear(struct RBTree* tree, cry_free_funptr fun)
 {
 	assert(tree != 0);
 
-	// free elements
-
+	rb_subtree_free(tree->root, fun);
         
         tree->root = 0;
         tree->nodes = 0;
@@ -401,3 +412,95 @@ rb_tree_remove(struct RBTree* tree, const_pointer entry)
 	return data_node;
 }
 
+
+struct RBNode*          
+rb_node_first(struct RBTree* tree)
+{
+	assert(tree != 0);
+
+	if(tree->root == 0) 
+		return 0;
+
+	struct RBNode* node = tree->root;
+
+	while(node->left != 0) {
+		node = node->left;
+	}
+
+	return node;
+}
+
+
+struct RBNode*          
+rb_node_last(struct RBTree* tree)
+{
+	assert(tree != 0);
+
+	if(tree->root == 0) 
+		return 0;
+
+	struct RBNode* node = tree->root;
+
+	while(node->right != 0) {
+		node = node->right;
+	}
+
+	return node;
+}
+
+
+
+struct RBNode*          
+rb_node_next(struct RBNode* node)
+{
+	assert(node != 0);
+
+	struct RBNode* tmp = 0;
+
+	if(node->right != 0) {
+		tmp = node->right;
+
+		while(tmp->left != 0)
+			tmp = tmp->left;
+
+		return tmp;
+	}
+
+	tmp = node->parent;
+
+	while(tmp != 0 && node == tmp->right) {
+		node = tmp;
+		tmp = tmp->parent; 
+	}
+
+	return tmp;
+}
+
+
+struct RBNode*          
+rb_node_prev(struct RBNode* node)
+{
+	assert(node != 0);
+
+	struct RBNode* tmp = 0;
+
+	if(node->left != 0) {
+		tmp = node->left;
+
+		while(tmp->right != 0)
+			tmp = tmp->right;
+
+		return tmp;
+	}
+
+	tmp = node->parent;
+
+	while(tmp != 0 && node == tmp->left) {
+		node = tmp;
+		tmp = tmp->parent; 
+	}
+
+	return tmp;
+}
+
+

src/structures/red_black_tree.h

@@ -44,14 +44,19 @@ struct RBTree {
 
 
 struct RBTree*          rb_tree_new(cry_ordering_funptr compare);
-void			rb_tree_clear(struct RBTree* tree, cry_free_funptr free_key);
+void			rb_tree_clear(struct RBTree* tree, cry_free_funptr fun);
 
 struct RBNode*          rb_tree_lookup(struct RBTree* tree, const_pointer entry);
 struct RBNode*          rb_tree_insert(struct RBTree* tree, const_pointer entry);
 struct RBNode*          rb_tree_remove(struct RBTree* tree, const_pointer entry);
 
 struct RBNode*          rb_node_new(enum RBNodeColor color, struct RBNode* parent, const_pointer entry);
-void			rb_node_free(struct RBNode* node, cry_free_funptr entry_key);
+void			rb_node_free(struct RBNode* node, cry_free_funptr fun);
+
+struct RBNode*          rb_node_first(struct RBTree* tree);
+struct RBNode*          rb_node_last(struct RBTree* tree);
+struct RBNode*          rb_node_next(struct RBNode* node);
+struct RBNode*          rb_node_prev(struct RBNode* node);