From d59b54811f8d2557b4b2fa47ea6ea867584e1c53 Mon Sep 17 00:00:00 2001
From: Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
Date: Sun, 29 Apr 2018 01:02:05 +0200
Subject: [PATCH] utility: Code for using enumerations as flags/bitsets

It baffles me that this is not just part of the language itself from the beginning, it's used nearly everywhere and is needed for type safety.
---
 CMakeLists.txt     |  2 ++
 source/utility.cpp | 21 ++++++++++++++++++++
 source/utility.h   | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+)
 create mode 100644 source/utility.cpp
 create mode 100644 source/utility.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4e089467..7bf018e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,6 +112,7 @@ SET(obs-stream-effects_HEADERS
 	"${PROJECT_SOURCE_DIR}/source/obs-audio-capture.h"
 	"${PROJECT_BINARY_DIR}/source/version.h"
 	"${PROJECT_SOURCE_DIR}/source/strings.h"
+	"${PROJECT_SOURCE_DIR}/source/utility.h"
 	"${PROJECT_SOURCE_DIR}/source/util-math.h"
 	"${PROJECT_SOURCE_DIR}/source/util-memory.h"
 )
@@ -135,6 +136,7 @@ SET(obs-stream-effects_SOURCES
 	"${PROJECT_SOURCE_DIR}/source/gs-vertex.cpp"
 	"${PROJECT_SOURCE_DIR}/source/gs-vertexbuffer.cpp"
 	"${PROJECT_SOURCE_DIR}/source/obs-audio-capture.cpp"
+	"${PROJECT_SOURCE_DIR}/source/utility.cpp"
 	"${PROJECT_SOURCE_DIR}/source/util-math.cpp"
 	"${PROJECT_SOURCE_DIR}/source/util-memory.cpp"
 )
diff --git a/source/utility.cpp b/source/utility.cpp
new file mode 100644
index 00000000..e6b83c40
--- /dev/null
+++ b/source/utility.cpp
@@ -0,0 +1,21 @@
+/*
+ * Modern effects for a modern Streamer
+ * Copyright (C) 2018 Michael Fabian Dirks
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+*/
+
+#include "utility.h"
+
diff --git a/source/utility.h b/source/utility.h
new file mode 100644
index 00000000..dbbf0a54
--- /dev/null
+++ b/source/utility.h
@@ -0,0 +1,48 @@
+/*
+ * Modern effects for a modern Streamer
+ * Copyright (C) 2018 Michael Fabian Dirks
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+*/
+
+#pragma once
+#include <type_traits>
+
+template<typename Enum>
+struct enable_bitmask_operators {
+	static const bool enable = false;
+};
+
+template<typename Enum>
+typename std::enable_if<enable_bitmask_operators<Enum>::enable, Enum>::type
+operator |(Enum lhs, Enum rhs) {
+	using underlying = typename std::underlying_type<Enum>::type;
+	return static_cast<Enum> (
+		static_cast<underlying>(lhs) |
+		static_cast<underlying>(rhs)
+		);
+}
+
+template<typename Enum>
+typename std::enable_if<enable_bitmask_operators<Enum>::enable, Enum>::type
+operator &(Enum lhs, Enum rhs) {
+	using underlying = typename std::underlying_type<Enum>::type;
+	return static_cast<Enum> (
+		static_cast<underlying>(lhs) &
+		static_cast<underlying>(rhs)
+		);
+}
+
+#define ENABLE_BITMASK_OPERATORS(x) template<> struct enable_bitmask_operators<x> { static const bool enable = true; };