From 7fd978449e87c9fec02e789598032d596f3587b2 Mon Sep 17 00:00:00 2001
From: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Date: Sun, 3 Apr 2022 17:50:04 +0200
Subject: [PATCH] datatypes: draft interface RB-Tree

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
---
 vlib/datatypes/rbtree.v      | 86 ++++++++++++++++++++++++++++++++++++
 vlib/datatypes/rbtree_test.v |  6 +++
 2 files changed, 92 insertions(+)
 create mode 100644 vlib/datatypes/rbtree.v
 create mode 100644 vlib/datatypes/rbtree_test.v

diff --git a/vlib/datatypes/rbtree.v b/vlib/datatypes/rbtree.v
new file mode 100644
index 0000000000..2dfc3cdc6a
--- /dev/null
+++ b/vlib/datatypes/rbtree.v
@@ -0,0 +1,86 @@
+module datatypes
+
+/// Internal rapresentation of the tree node
+[heap]
+struct RBTreeNode<T> {
+mut:
+	is_init bool // mark node as initialized
+	value   T    // value of the node
+	parent  &RBTreeNode<T> = 0
+	left    &RBTreeNode<T> = 0
+	right   &RBTreeNode<T> = 0
+	color   bool // mark the node as red or black
+}
+
+// new_root_node create new root rbt node
+fn new_rbt_root_node<T>(value &T) &RBTreeNode<T> {
+	return &RBTreeNode<T>{
+		is_init: true
+		value: value
+		color: false
+		parent: new_rbt_none_node<T>(true)
+		left: new_rbt_none_node<T>(true)
+		right: new_rbt_none_node<T>(true)
+	}
+}
+
+// new_node create a new rb node with a parante
+fn new_rbt_node<T>(parent &RBTreeNode<T>, value &T) &RBTreeNode<T> {
+	return &RBTreeNode<T>{
+		is_init: true
+		value: value
+		parent: parant
+	}
+}
+
+// new_none_node create a dummy node.
+fn new_rbt_none_node<T>(init bool) &RBTreeNode<T> {
+	return &RBTreeNode<T>{
+		is_init: init
+	}
+}
+
+// set_to_red set the color of the node to red
+fn (mut node RBTreeNode<T>) set_to_red() {
+	node.color = true
+}
+
+// set_to_black set the color of the node to black
+fn (mut node RBTreeNode<T>) set_to_black() {
+	node.color = false
+}
+
+// Pure Red-Black Tree implementation
+//
+// Pure V implementation of the RB-Tree
+// Time complexity on main operation O(N log N)
+// in the wrost case still O(N log N)
+// Space complexity O(N)
+pub struct RBTree<T> {
+mut:
+	root &RBTreeNode<T> = 0
+}
+
+pub fn (mut rbt RBTree<T>) insert(value &T) bool {
+	return false
+}
+
+pub fn (mut rbt RBTree<T>) contains(value &T) bool {
+	return false
+}
+
+pub fn (mut rbt RBTree<T>) remove(value &T) bool {
+	return false
+}
+
+pub fn (rbt &RBTree<T>) is_empty() bool {
+	return rbt.root == 0
+}
+
+pub fn (rbt &RBTree<T>) max() ?&T {
+	return error('not implemented')
+}
+
+pub fn (rbt &RBTree<T>) min() ?&T {
+	return error('not implemented')
+}
diff --git a/vlib/datatypes/rbtree_test.v b/vlib/datatypes/rbtree_test.v
new file mode 100644
index 0000000000..9eee8abded
--- /dev/null
+++ b/vlib/datatypes/rbtree_test.v
@@ -0,0 +1,6 @@
+module datatypes
+
+fn test_init_rbtree() {
+	rbtree := RBTree<int>{}
+	assert rbtree.is_empty()
+}