Add diplomatic actions skeleton

Add AnyRef for cheap "move only" reference
Add FunctionRef for cheap "move only" function reference
	Based on https://github.com/think-cell/think-cell-library/blob/main/tc/base/ref.h

1 files changed, 61 insertions, 0 deletions

diff --git a/src/openvic-simulation/types/AnyRef.hpp b/src/openvic-simulation/types/AnyRef.hpp
new file mode 100644
index 0000000..b50a039
--- /dev/null
+++ b/src/openvic-simulation/types/AnyRef.hpp
@@ -0,0 +1,61 @@
+#pragma once
+
+#include <memory>
+
+namespace OpenVic {
+	// Based on https://github.com/think-cell/think-cell-library/blob/b9c84dd7fc926fad80829ed49705fa51afe36e87/tc/base/ref.h
+	//     Boost Software License - Version 1.0 - August 17th, 2003
+
+	// Permission is hereby granted, free of charge, to any person or organization
+	// obtaining a copy of the software and accompanying documentation covered by
+	// this license (the "Software") to use, reproduce, display, distribute,
+	// execute, and transmit the Software, and to prepare derivative works of the
+	// Software, and to permit third-parties to whom the Software is furnished to
+	// do so, all subject to the following:
+
+	// The copyright notices in the Software and this entire statement, including
+	// the above license grant, this restriction and the following disclaimer,
+	// must be included in all copies of the Software, in whole or in part, and
+	// all derivative works of the Software, unless such copies or derivative
+	// works are solely in the form of machine-executable object code generated by
+	// a source language processor.
+
+	// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+	// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+	// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+	// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+	// DEALINGS IN THE SOFTWARE.
+	union AnyRef {
+		// Any pointer to function can be converted to a pointer to a different function type. Calling the
+		// function through a pointer to a different function type is undefined, but converting such pointer
+		// back to pointer to the original function type yields the pointer to the original function.
+		// https://en.cppreference.com/w/cpp/language/reinterpret_cast
+
+		template<typename T>
+		[[nodiscard]] static constexpr T* as_mutable_ptr(T const* pt) noexcept {
+			return const_cast<T*>(pt);
+		}
+
+		template<typename RefT>
+		explicit AnyRef(RefT& ref) noexcept : m_pvRef(std::addressof(ref)) {}
+
+		template<typename RefT>
+		requires std::is_function<RefT>::value
+		explicit AnyRef(RefT& ref) noexcept : m_fpvRef(reinterpret_cast<void (*)()>(std::addressof(ref))) {}
+
+		template<typename RefT> // may be const and/or volatile
+		RefT& get_ref() const& noexcept {
+			static_assert(!std::is_reference<RefT>::value);
+			if constexpr (std::is_function<RefT>::value) {
+				return *reinterpret_cast<RefT*>(m_fpvRef);
+			} else {
+				return *static_cast<RefT*>(as_mutable_ptr(m_pvRef));
+			}
+		}
+
+		void const* m_pvRef;
+		void (*m_fpvRef)();
+	};
+}