From: a bellenir <a@bellenir.com>
Date: Tue, 5 Aug 2014 22:31:11 +0000 (+0000)
Subject: WIP; split insert & repaint functions
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=84302bf6723791b4d6e44f045b3099a0aab185f6;p=projs%2Flibcds.git

WIP; split insert & repaint functions
---

diff --git a/source/rb/rb.c b/source/rb/rb.c
index 9fa7ed3..e667cc0 100644
--- a/source/rb/rb.c
+++ b/source/rb/rb.c
@@ -32,12 +32,55 @@ rb_tree_t* rb_tree_new(){
 	return tree;
 }
 
+//leaves are NULL and black implicitly
+static rb_color_t node_color(rb_node_t* node){
+	return (node ? node->color : BLACK);
+}
+
+//NODE:the node to be inserted
+static void rb_tree_recolor(
+	rb_node_t* node, rb_node_t* parent,
+	rb_node_t* grandparent, rb_node_t* uncle
+){
+	if(NULL == parent){
+		node->color = BLACK;
+	}else if(BLACK == node_color(parent)){
+		/* dont need to do anything */
+	}else if(node_color(parent) == BLACK && node_color(uncle) == BLACK){
+		grandparent->color = RED;
+		parent->color = BLACK;
+		uncle->color = BLACK;
+	}else{
+		//TODO
+	}
+}
+static void rb_tree_insert_node(rb_tree_t* tree,
+	rb_node_t* node, rb_node_t* parent,
+	rb_node_t* grandparent, rb_node_t* uncle
+){
+	if(NULL == parent){ /* inserting root of the tree */
+		tree->root = node;
+		rb_tree_recolor(node, parent, grandparent, uncle);
+	}else if(node->contents < parent->contents){
+		if(parent->left){
+			rb_tree_insert_node(tree, node, parent->left, parent, parent->right);
+		}else{
+			parent->left = node;
+			rb_tree_recolor(node, parent, grandparent, uncle);
+		}
+	}else{
+		if(parent->right){
+			rb_tree_insert_node(tree, node, parent->right, parent, parent->left);
+		}else{
+			parent->right = node;
+			rb_tree_recolor(node, parent, grandparent, uncle);
+		}
+	}
+}
+
 rb_node_t* rb_tree_insert(rb_tree_t* tree, int value){
 	rb_node_t* new_node = rb_node_new(value);
-	if(NULL == tree->root){
-		new_node->color = BLACK;
-		tree->root = new_node;
-	}
+	rb_tree_insert_node(tree, new_node, tree->root, NULL, NULL);
 	return new_node;
 }
 
@@ -62,8 +105,8 @@ bool rb_node_is_valid(rb_node_t* node, int min_val, int max_val){
 	if(node){
 		ret &= (node->color == RED || node->color == BLACK);
 		if(node->color == RED){
-			ret &= (!node->left || node->left->color == BLACK);
-			ret &= (!node->right || node->right->color == BLACK);
+			ret &= ((node_color(node->left) == BLACK) && 
+					(node_color(node->right) == BLACK));
 		}
 		ret &= ( -1 == min_val || node->contents >= min_val);
 		ret &= ( -1 == max_val || node->contents <= max_val);
diff --git a/tests/test_rb.c b/tests/test_rb.c
index 3b75bce..e920c35 100644
--- a/tests/test_rb.c
+++ b/tests/test_rb.c
@@ -45,5 +45,51 @@ TEST_SUITE(RB) {
 		CHECK(rb_tree_is_valid(tree));
 		mem_release(tree);
     }
+    TEST(Verify_rb_insert_node_to_root_left_works){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* root = rb_tree_insert(tree, 42);
+		rb_node_t* node1 = rb_tree_insert(tree, 31);
+		CHECK(NULL != root);
+		CHECK(NULL != node1);
+		CHECK(tree->root == root);
+		CHECK(31 == node1->contents);
+		CHECK(node1 == root->left);
+		CHECK(NULL == root->right);
+		CHECK(RED == node1->color);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(tree);
+    }
+    TEST(Verify_rb_insert_node_to_root_right_works){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* root = rb_tree_insert(tree, 42);
+		rb_node_t* node2 = rb_tree_insert(tree, 64);
+		CHECK(NULL != root);
+		CHECK(NULL != node2);
+		CHECK(tree->root == root);
+		CHECK(64 == node2->contents);
+		CHECK(node2 == root->right);
+		CHECK(NULL == root->left);
+		CHECK(RED == node2->color);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(tree);
+    }
+    TEST(Verify_rb_insert_first_level_works){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* root = rb_tree_insert(tree, 42);
+		rb_node_t* node1 = rb_tree_insert(tree, 31);
+		rb_node_t* node2 = rb_tree_insert(tree, 64);
+		CHECK(NULL != root);
+		CHECK(NULL != node1);
+		CHECK(NULL != node2);
+		CHECK(tree->root == root);
+		CHECK(31 == node1->contents);
+		CHECK(64 == node2->contents);
+		CHECK(node1 == root->left);
+		CHECK(node2 == root->right);
+		CHECK(RED == node1->color);
+		CHECK(RED == node2->color);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(tree);
+    }
 }