avl_tree: bug fix on chain insertion/deletion.

src/lol/algorithm/avl_tree.h

@@ -410,20 +410,28 @@ protected:
             this->m_parent_slot = nullptr;
             this->m_child[0] = nullptr;
             this->m_child[1] = nullptr;
-            this->m_chain[0] = nullptr;
-            this->m_chain[1] = nullptr;
         }
 
         void replace_chain(tree_node * replacement)
         {
             for (int i = 0 ; i < 2 ; ++i)
             {
-                if (this->m_chain[i])
+                if (replacement)
                 {
-                    this->m_chain[i]->m_chain[i ? 0 : 1] = replacement;
-                    if (replacement)
-                        replacement->m_chain[i ? 0 : 1] = this->m_chain[i];
+                    if (replacement->m_chain[i])
+                        replacement->m_chain[i]->m_chain[i ? 0 : 1] = replacement->m_chain[i ? 0 : 1];
+
+                    replacement->m_chain[i] = this->m_chain[i];
+                    if (replacement->m_chain[i])
+                        replacement->m_chain[i]->m_chain[i ? 0 : 1] = replacement;
                 }
+                else
+                {
+                    if (this->m_chain[i])
+                        this->m_chain[i]->m_chain[i ? 0 : 1] = this->m_chain[i ? 0 : 1];
+                }
+
+                this->m_chain[i] = nullptr;
             }
         }
 

src/t/algorithm/avl_tree.cpp

@@ -91,6 +91,15 @@ lolunit_declare_fixture(AvlTreeTest)
         lolunit_assert_equal(tree.get_count(), 3);
 
         lolunit_assert_equal(tree.erase(30), true);
+
+        int test = 0;
+
+        for (auto iterator : tree)
+        {
+            test += 10;
+            lolunit_assert_equal(iterator.key, test);
+        }
+
         lolunit_assert_equal(tree.get_count(), 2);
         lolunit_assert_equal(tree.insert(30, 1), true);
 
@@ -98,6 +107,13 @@ lolunit_declare_fixture(AvlTreeTest)
         lolunit_assert_equal(tree.insert(20, 1), true);
         lolunit_assert_equal(tree.exists(10), true);
 
+        test = 0;
+
+        for (auto iterator : tree)
+        {
+            test += 10;
+            lolunit_assert_equal(iterator.key, test);
+        }
     }
 
     lolunit_declare_test(AvlTreeExistence)