1 files changed, 86 insertions, 4 deletions

diff --git a/core/templates/set.h b/core/templates/set.h
index d0ac71a710..0a80ceefb5 100644
--- a/core/templates/set.h
+++ b/core/templates/set.h
@@ -5,8 +5,8 @@
 /*                           GODOT ENGINE                                */
 /*                      https://godotengine.org                          */
 /*************************************************************************/
-/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
-/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
 /*                                                                       */
 /* Permission is hereby granted, free of charge, to any person obtaining */
 /* a copy of this software and associated documentation files (the       */
@@ -35,7 +35,7 @@
 #include "core/typedefs.h"
 
 // based on the very nice implementation of rb-trees by:
-// https://web.archive.org/web/20120507164830/http://web.mit.edu/~emin/www/source_code/red_black_tree/index.html
+// https://web.archive.org/web/20120507164830/https://web.mit.edu/~emin/www/source_code/red_black_tree/index.html
 
 template <class T, class C = Comparator<T>, class A = DefaultAllocator>
 class Set {
@@ -71,12 +71,94 @@ public:
 		Element *prev() {
 			return _prev;
 		}
+		T &get() {
+			return value;
+		}
 		const T &get() const {
 			return value;
 		};
 		Element() {}
 	};
 
+	typedef T ValueType;
+
+	struct Iterator {
+		_FORCE_INLINE_ T &operator*() const {
+			return E->get();
+		}
+		_FORCE_INLINE_ T *operator->() const { return &E->get(); }
+		_FORCE_INLINE_ Iterator &operator++() {
+			E = E->next();
+			return *this;
+		}
+		_FORCE_INLINE_ Iterator &operator--() {
+			E = E->prev();
+			return *this;
+		}
+
+		_FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; }
+		_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; }
+
+		Iterator(Element *p_E) { E = p_E; }
+		Iterator() {}
+		Iterator(const Iterator &p_it) { E = p_it.E; }
+
+	private:
+		Element *E = nullptr;
+	};
+
+	struct ConstIterator {
+		_FORCE_INLINE_ const T &operator*() const {
+			return E->get();
+		}
+		_FORCE_INLINE_ const T *operator->() const { return &E->get(); }
+		_FORCE_INLINE_ ConstIterator &operator++() {
+			E = E->next();
+			return *this;
+		}
+		_FORCE_INLINE_ ConstIterator &operator--() {
+			E = E->prev();
+			return *this;
+		}
+
+		_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; }
+		_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; }
+
+		_FORCE_INLINE_ ConstIterator(const Element *p_E) { E = p_E; }
+		_FORCE_INLINE_ ConstIterator() {}
+		_FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) { E = p_it.E; }
+
+	private:
+		const Element *E = nullptr;
+	};
+
+	_FORCE_INLINE_ Iterator begin() {
+		return Iterator(front());
+	}
+	_FORCE_INLINE_ Iterator end() {
+		return Iterator(nullptr);
+	}
+
+#if 0
+	//to use when replacing find()
+	_FORCE_INLINE_ Iterator find(const K &p_key) {
+		return Iterator(find(p_key));
+	}
+#endif
+
+	_FORCE_INLINE_ ConstIterator begin() const {
+		return ConstIterator(front());
+	}
+	_FORCE_INLINE_ ConstIterator end() const {
+		return ConstIterator(nullptr);
+	}
+
+#if 0
+	//to use when replacing find()
+	_FORCE_INLINE_ ConstIterator find(const K &p_key) const {
+		return ConstIterator(find(p_key));
+	}
+#endif
 private:
 	struct _Data {
 		Element *_root = nullptr;
@@ -576,7 +658,7 @@ public:
 		return e;
 	}
 
-	inline bool empty() const { return _data.size_cache == 0; }
+	inline bool is_empty() const { return _data.size_cache == 0; }
 	inline int size() const { return _data.size_cache; }
 
 	int calculate_depth() const {