From: a bellenir <a@bellenir.com>
Date: Tue, 5 Aug 2014 20:52:01 +0000 (+0000)
Subject: red/black check functions
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=413e8d65994620bef43632b1f91baa86f4727673;p=projs%2Flibcds.git

red/black check functions
---

diff --git a/source/rb/rb.c b/source/rb/rb.c
index 07de5f3..9fa7ed3 100644
--- a/source/rb/rb.c
+++ b/source/rb/rb.c
@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <stdbool.h>
 
 #include "mem.h"
 #include "rb.h"
@@ -16,7 +17,6 @@ static void rb_node_free(void* v_node){
 	}
 }
 
-
 rb_node_t* rb_node_new(int contents){
 	rb_node_t* node = mem_allocate(sizeof(rb_node_t), &rb_node_free);
 	node->left = NULL;
@@ -32,3 +32,55 @@ rb_tree_t* rb_tree_new(){
 	return tree;
 }
 
+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;
+	}
+	return new_node;
+}
+
+
+/* THE FOLLOWING FUNCTIONS (TO EOF) ARE USED FOR TESTING PURPOSES ONLY */
+
+//if path to the left != path to the right, return -1 (invalid)
+int count_black_nodes_to_leaf(rb_node_t* node){
+	int ret = 0;
+	if(node){
+		int leftcount = count_black_nodes_to_leaf(node->left);
+		int rightcount = count_black_nodes_to_leaf(node->right);
+		if(leftcount != rightcount) ret = -1;
+		else if(node->color == BLACK) ret = leftcount+1;
+		else ret = leftcount;
+	}
+	return ret;
+}
+
+bool rb_node_is_valid(rb_node_t* node, int min_val, int max_val){
+	bool ret = true;
+	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 &= ( -1 == min_val || node->contents >= min_val);
+		ret &= ( -1 == max_val || node->contents <= max_val);
+		ret &= rb_node_is_valid(node->left, min_val, node->contents);
+		ret &= rb_node_is_valid(node->right, node->contents, max_val);
+	}
+	return ret;
+}
+
+//check the contents of the given tree/node as valid
+bool rb_tree_is_valid(rb_tree_t* tree){
+	bool ret = true;
+	if(tree){
+		ret = rb_node_is_valid(tree->root, -1, -1);
+		if(tree->root) ret &= (tree->root->color == BLACK);
+		ret &= (count_black_nodes_to_leaf(tree->root) != -1);
+	}
+	return ret;
+}
+
diff --git a/source/rb/rb.h b/source/rb/rb.h
index 06dd293..73421d9 100644
--- a/source/rb/rb.h
+++ b/source/rb/rb.h
@@ -5,6 +5,8 @@
 extern "C" {
 #endif
 
+#include <stdbool.h>
+
 typedef enum {
 	RED = 0,
 	BLACK
@@ -24,6 +26,12 @@ typedef struct {
 
 rb_node_t* rb_node_new(int contents);
 rb_tree_t* rb_tree_new();
+//returns a pointer to the new node
+rb_node_t* rb_tree_insert(rb_tree_t* tree, int value);
+
+//TEST FUNCTIONS:
+bool rb_tree_is_valid(rb_tree_t* tree);
+bool rb_node_is_valid(rb_node_t* node, int min_val, int max_val);
 
 #ifdef __cplusplus
 }
diff --git a/tests/test_rb.c b/tests/test_rb.c
index e2440c6..3b75bce 100644
--- a/tests/test_rb.c
+++ b/tests/test_rb.c
@@ -10,7 +10,7 @@ static void test_setup(void) { }
 //-----------------------------------------------------------------------------
 TEST_SUITE(RB) {
     //-------------------------------------------------------------------------
-    // Test the rb_new functions
+    // Test the rb_node_new function
     //-------------------------------------------------------------------------
     TEST(Verify_rb_node_new_returns_a_new_node){
 		rb_node_t* node = rb_node_new(42);
@@ -18,15 +18,32 @@ TEST_SUITE(RB) {
 		CHECK(NULL == node->left);
 		CHECK(NULL == node->right);
 		CHECK(42 == node->contents);
+		CHECK(rb_node_is_valid(node, -1, -1));
 		mem_release(node);
     }
 
+    //-------------------------------------------------------------------------
+    // Test the rb_tree_new function
+    //-------------------------------------------------------------------------
 	TEST(Verify_rb_tree_new_returns_an_empty_red_black_tree){
-		rb_tree_t* rb = rb_tree_new();
-		CHECK(rb != NULL);
-		CHECK(rb->root == NULL);
-		mem_release(rb);
+		rb_tree_t* tree = rb_tree_new();
+		CHECK(NULL != tree);
+		CHECK(NULL == tree->root);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(tree);
 	}
 
+    //-------------------------------------------------------------------------
+    // Test insert functions
+    //-------------------------------------------------------------------------
+    TEST(Verify_rb_insert_to_an_empty_list_assigns_root){
+		rb_tree_t* tree = rb_tree_new();
+		rb_node_t* node = rb_tree_insert(tree, 42);
+		CHECK(NULL != node);
+		CHECK(tree->root == node);
+		CHECK(42 == node->contents);
+		CHECK(rb_tree_is_valid(tree));
+		mem_release(tree);
+    }
 }