Fixed the sigsegv bug in binary tree

src/BinaryTree/BinaryTree.c

@@ -150,18 +150,18 @@ static int _BinaryTree_DestroyNode(BinaryTree* tree, BinaryTreeNode* node)
 	return EXIT_SUCCESS;
 }
 
-static BinaryTreeNode** _BinaryTreeNode_SmallestNodeLocation(BinaryTreeNode* node)
+static BinaryTreeNode* _BinaryTreeNode_SmallestNodeParent(BinaryTreeNode* node)
 {
 	if (node->left == NULL) {
 		return NULL;
 	}
 	
-	BinaryTreeNode** smallest_location = &node->left;
-	do {
-		smallest_location = &(*smallest_location)->left;
-	} while (smallest_location != NULL);
+	BinaryTreeNode* parent = node;
+	while (parent->left != NULL && (parent->left->left != NULL)) {
+		parent = parent->left;
+	}
 
-	return smallest_location;
+	return parent;
 }
 
 static int _BinaryTreeNode_UnlinkNode(BinaryTreeNode** nodep)
@@ -179,11 +179,15 @@ static int _BinaryTreeNode_UnlinkNode(BinaryTreeNode** nodep)
 			*nodep = (*nodep)->left;
 		} else {
 			// both right and left node active
-			BinaryTreeNode** smallest_subnode = _BinaryTreeNode_SmallestNodeLocation(*nodep);
-			BinaryTreeNode* right_branch = (*nodep)->right;
-			*nodep = *smallest_subnode;
-			*smallest_subnode = (*smallest_subnode)->right;
-			(*nodep)->right = right_branch;
+			BinaryTreeNode* smallest_parent = _BinaryTreeNode_SmallestNodeParent(*nodep);
+			BinaryTreeNode* smallest_node   = smallest_parent->left;
+
+			smallest_parent->left = smallest_node->right;
+			smallest_node->right  = (*nodep)->right;
+			smallest_node->left   = (*nodep)->left;
+			*nodep = smallest_node;
+
+			_BinaryTreeNode_UpdateDepth(smallest_parent);
 		}
 	}
 
@@ -225,6 +229,7 @@ static int _BinaryTree_Remove(BinaryTree* self, void* value)
 
 		bottom_walker->position = BINARYTREENODEPOSITION_SELF;
         }
+	DynamicArray_Remove(&self->walker_stack, self->walker_stack.reserved - 1);
 
 	_BinaryTree_DestroyNode(self, preserved_pointer);
 

tests/BinaryTree.test.c

@@ -216,6 +216,34 @@ void testMany(void)
 	return;
 }
 
+void testRanges(void)
+{
+	allocator_t allocator;
+	Allocator_CreateSystemAllocator(&allocator);
+	BinaryTree tree;
+
+	assert(EXIT_SUCCESS == BinaryTree_Create(
+		&tree,
+		(BinaryTreeComparator) doublecomparator,
+		(void*) 0xDEADBEEF,
+		sizeof(double),
+		&allocator)
+	);
+
+	for (double value = 0; value < 300; value++) {
+		assert(EXIT_SUCCESS == 	BinaryTree_Insert(&tree, &value));
+	}
+
+	for (double value = 150; value <= 200; value++) {
+		assert(EXIT_SUCCESS == 	BinaryTree_Remove(&tree, &value));
+	}
+
+	BinaryTree_Destroy(&tree);
+	assert(allocator.reserved == 0);
+
+	return;
+}
+
 int main()
 {
 	testLifetime();
@@ -223,5 +251,6 @@ int main()
 	testEqual();
 	testMany();
 	testRemoval();
+	testRanges();
 	return 0;
 }