px4_platform_common: add bitmask.h for templated type safe bitmask operations

platforms/common/include/px4_platform_common/bitmask.h

@@ -0,0 +1,154 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2020 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file bitmask.h
+ * @brief Provides SFINAE for type safe templated bitmask operations
+ * @author Nuno Marques <nuno.marques@dronesolutions.io>
+ *
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+
+#include<type_traits>
+
+template<typename E>
+struct enable_bitmask_operators {
+	static const bool enable = false;
+};
+
+namespace px4
+{
+
+#define ENABLE_BIT_OPERATORS(E) \
+	template<> \
+	struct enable_bitmask_operators<E> \
+	{ \
+		static const bool enable = true; \
+	};
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E>::type
+operator==(E lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	return static_cast<E>(
+		       static_cast<underlying>(lhs) ==
+		       static_cast<underlying>(rhs)
+	       );
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E>::type
+operator~(E lhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	return static_cast<E>(
+		       ~static_cast<underlying>(lhs)
+	       );
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E>::type
+operator|(E lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	return static_cast<E>(
+		       static_cast<underlying>(lhs) |
+		       static_cast<underlying>(rhs)
+	       );
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E &>::type
+operator|=(E &lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	lhs = static_cast<E>(
+		      static_cast<underlying>(lhs) |
+		      static_cast<underlying>(rhs)
+	      );
+	return lhs;
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E>::type
+operator&(E lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	return static_cast<E>(
+		       static_cast<underlying>(lhs) &
+		       static_cast<underlying>(rhs)
+	       );
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E &>::type
+operator&=(E &lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	lhs = static_cast<E>(
+		      static_cast<underlying>(lhs) &
+		      static_cast<underlying>(rhs)
+	      );
+	return lhs;
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E>::type
+operator^(E lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	return static_cast<E>(
+		       static_cast<underlying>(lhs) ^
+		       static_cast<underlying>(rhs)
+	       );
+}
+
+template<typename E>
+typename std::enable_if<enable_bitmask_operators<E>::enable, E &>::type
+operator^=(E &lhs, E rhs)
+{
+	typedef typename std::underlying_type<E>::type underlying;
+	lhs = static_cast<E>(
+		      static_cast<underlying>(lhs) ^
+		      static_cast<underlying>(rhs)
+	      );
+	return lhs;
+}
+
+} /* namespace px4 */
+
+#endif /* __cplusplus */