From: a bellenir <a@bellenir.com>
Date: Wed, 6 Aug 2014 21:12:35 +0000 (+0000)
Subject: handle more deletion cases & add tests
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=a2c30e75c163d69e2d1440fbc4151c952b0b535a;p=projs%2Flibcds.git

handle more deletion cases & add tests
---

diff --git a/source/rb/rb.c b/source/rb/rb.c
index b05515e..dccd0e2 100644
--- a/source/rb/rb.c
+++ b/source/rb/rb.c
@@ -175,11 +175,32 @@ static void rb_tree_delete_node(rb_tree_t* tree, rb_node_t* node){
 		//has two children. TODO
 	}else{
 		rb_node_t* parent = node->parent;
-		if(RED == node->color){
+		if(RED == node_color(node)){
 			if(node == parent->left) parent->left = NULL;
 			else parent->right = NULL;
 			node->parent = NULL;
 			mem_release(node);
+		} else if(RED == node_color(node->left) && BLACK == node_color(node->right)){
+			//single red child, to the left
+			rb_node_t* child = node->left;
+			child->parent = parent;
+			if(parent->left == node) parent->left = child;
+			else parent->right = child;
+			//safe to destroy node->right ; it is a NULL leaf
+			child->color = BLACK;
+			node->left = NULL;
+			node->parent = NULL;
+			mem_release(node);
+		} else if(RED == node_color(node->right) && BLACK == node_color(node->left)){
+			//single red child, to the right
+			rb_node_t* child = node->right;
+			child->parent = parent;
+			if(parent->left == node) parent->left = child;
+			else parent->right = child;
+			child->color = BLACK;
+			node->right = NULL;
+			node->parent = NULL;
+			mem_release(node);
 		}
 	}
 }
diff --git a/tests/test_rb.c b/tests/test_rb.c
index 4945391..e93fe86 100644
--- a/tests/test_rb.c
+++ b/tests/test_rb.c
@@ -310,7 +310,7 @@ TEST_SUITE(RB) {
 		mem_release(node4);
 		mem_release(tree);
     }
-    TEST(Verify_rb_delete_black_node_with_single_red_child){
+    TEST(Verify_rb_delete_left_black_node_with_single_red_left_child){
 		rb_tree_t* tree = rb_tree_new();
 		rb_node_t* node1 = rb_tree_insert(tree, 42);
 		rb_node_t* node2 = rb_tree_insert(tree, 33);
@@ -337,7 +337,87 @@ TEST_SUITE(RB) {
 		mem_release(node2);
 		mem_release(tree);
     }
-
+    TEST(Verify_rb_delete_left_black_node_with_single_red_right_child){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* node1 = rb_tree_insert(tree, 42);
+		rb_node_t* node2 = rb_tree_insert(tree, 33);
+		rb_node_t* node3 = rb_tree_insert(tree, 88);
+		rb_node_t* node4 = rb_tree_insert(tree, 38);
+		mem_retain(node2);
+		//delete node 2
+		rb_tree_delete(tree, 33);
+		CHECK(1 == mem_num_references(node2));
+		CHECK(node1 == tree->root);
+		CHECK(node4 == node1->left);
+		CHECK(node3 == node1->right);
+		CHECK(NULL == node4->left);
+		CHECK(NULL == node4->right);
+		CHECK(node1 == node4->parent);
+		CHECK(BLACK == node1->color);
+		CHECK(BLACK == node3->color);
+		CHECK(BLACK == node4->color);
+		//check node2 pointers are nulld
+		CHECK(NULL == node2->parent);
+		CHECK(NULL == node2->left);
+		CHECK(NULL == node2->right);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(node2);
+		mem_release(tree);
+    }
+    TEST(Verify_rb_delete_right_black_node_with_single_red_right_child){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* node1 = rb_tree_insert(tree, 42);
+		rb_node_t* node2 = rb_tree_insert(tree, 33);
+		rb_node_t* node3 = rb_tree_insert(tree, 88);
+		rb_node_t* node4 = rb_tree_insert(tree, 98);
+		mem_retain(node3);
+		//delete node 3
+		rb_tree_delete(tree, 88);
+		CHECK(1 == mem_num_references(node3));
+		CHECK(node1 == tree->root);
+		CHECK(node2 == node1->left);
+		CHECK(node4 == node1->right);
+		CHECK(NULL == node4->left);
+		CHECK(NULL == node4->right);
+		CHECK(node1 == node4->parent);
+		CHECK(BLACK == node1->color);
+		CHECK(BLACK == node2->color);
+		CHECK(BLACK == node4->color);
+		//check node3 pointers are nulld
+		CHECK(NULL == node3->parent);
+		CHECK(NULL == node3->left);
+		CHECK(NULL == node3->right);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(node3);
+		mem_release(tree);
+    }
+    TEST(Verify_rb_delete_right_black_node_with_single_red_left_child){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* node1 = rb_tree_insert(tree, 42);
+		rb_node_t* node2 = rb_tree_insert(tree, 33);
+		rb_node_t* node3 = rb_tree_insert(tree, 88);
+		rb_node_t* node4 = rb_tree_insert(tree, 68);
+		mem_retain(node3);
+		//delete node 3
+		rb_tree_delete(tree, 88);
+		CHECK(1 == mem_num_references(node3));
+		CHECK(node1 == tree->root);
+		CHECK(node2 == node1->left);
+		CHECK(node4 == node1->right);
+		CHECK(NULL == node4->left);
+		CHECK(NULL == node4->right);
+		CHECK(node1 == node4->parent);
+		CHECK(BLACK == node1->color);
+		CHECK(BLACK == node2->color);
+		CHECK(BLACK == node4->color);
+		//check node3 pointers are nulld
+		CHECK(NULL == node3->parent);
+		CHECK(NULL == node3->left);
+		CHECK(NULL == node3->right);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(node3);
+		mem_release(tree);
+    }
 	//second class: deleting nodes that have two children
 	//third class: special cases
 	TEST(Verify_rb_delete_root){}