Beefy2D updates, file pack support

BeefLibs/Beefy2D/src/utils/StableIndexedList.bf

@@ -0,0 +1,60 @@
+using System.Collections;
+namespace utils;
+
+class StableIndexedList<T>
+{
+	public List<T> mList = new .() ~ delete _;
+	public List<int32> mFreeIndices = new .() ~ delete _;
+
+	public this()
+	{
+		mList.Add(default); // Reserve idx 0
+	}
+
+	public ref T this[int idx]
+	{
+		get
+		{
+			return ref mList[idx];
+		}
+
+		set
+		{
+			mList[idx] = value;
+		}
+	}
+
+	public int Add(T val)
+	{
+		if (!mFreeIndices.IsEmpty)
+		{
+			int32 idx = mFreeIndices.PopBack();
+			mList[idx] = val;
+			return idx;
+		}
+		mList.Add(val);
+		return mList.Count - 1;
+	}
+
+	public void RemoveAt(int idx)
+	{
+		if (idx == mList.Count - 1)
+		{
+			mList.PopBack();
+		}
+		else
+		{
+			mList[idx] = default;
+			mFreeIndices.Add((.)idx);
+		}
+	}
+
+	public List<T>.Enumerator GetEnumerator() => mList.GetEnumerator();
+
+	public T SafeGet(int idx)
+	{
+		if ((idx < 0) || (idx > mList.Count))
+			return default;
+		return mList[idx];
+	}
+}