1 files changed, 62 insertions, 0 deletions
diff --git a/Plugins/MonoGame.Extended/source/MonoGame.Extended/Math/Triangulation/IndexableCyclicalLinkedList.cs b/Plugins/MonoGame.Extended/source/MonoGame.Extended/Math/Triangulation/IndexableCyclicalLinkedList.cs
new file mode 100644
index 0000000..d84ee82
--- /dev/null
+++ b/Plugins/MonoGame.Extended/source/MonoGame.Extended/Math/Triangulation/IndexableCyclicalLinkedList.cs
@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace MonoGame.Extended.Triangulation
+{
+    /// <summary>
+	/// Implements a LinkedList that is both indexable as well as cyclical. Thus
+	/// indexing into the list with an out-of-bounds index will automatically cycle
+	/// around the list to find a valid node.
+	/// </summary>
+    /// MIT Licensed: https://github.com/nickgravelyn/Triangulator
+	class IndexableCyclicalLinkedList<T> : LinkedList<T>
+    {
+        /// <summary>
+        /// Gets the LinkedListNode at a particular index.
+        /// </summary>
+        /// <param name="index">The index of the node to retrieve.</param>
+        /// <returns>The LinkedListNode found at the index given.</returns>
+        public LinkedListNode<T> this[int index]
+        {
+            get
+            {
+                //perform the index wrapping
+                while (index < 0)
+                    index = Count + index;
+                if (index >= Count)
+                    index %= Count;
+
+                //find the proper node
+                LinkedListNode<T> node = First;
+                for (int i = 0; i < index; i++)
+                    node = node.Next;
+
+                return node;
+            }
+        }
+
+        /// <summary>
+        /// Removes the node at a given index.
+        /// </summary>
+        /// <param name="index">The index of the node to remove.</param>
+        public void RemoveAt(int index)
+        {
+            Remove(this[index]);
+        }
+
+        /// <summary>
+        /// Finds the index of a given item.
+        /// </summary>
+        /// <param name="item">The item to find.</param>
+        /// <returns>The index of the item if found; -1 if the item is not found.</returns>
+        public int IndexOf(T item)
+        {
+            for (int i = 0; i < Count; i++)
+                if (this[i].Value.Equals(item))
+                    return i;
+
+            return -1;
+        }
+    }
+}