Set implementation for strongly-typed enums.

src/Set.h

@@ -0,0 +1,119 @@
+#ifndef Magnum_Set_h
+#define Magnum_Set_h
+/*
+    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum 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 Lesser General Public License version 3 for more details.
+*/
+
+/** @file
+ * @brief Class Magnum::Set
+ */
+
+namespace Magnum {
+
+/** @ingroup utility
+@brief %Set
+@tparam T Enum type
+@tparam U Underlying type of the enum
+
+Provides strongly-typed set-like functionality for strongly typed enums, such
+as binary OR and AND operations. The only requirement for enum type is that
+all the values must be binary exclusive.
+
+Desired usage is via typedef'ing and then calling SET_OPERATORS() macro with
+the resulting type as parameter to have all the operators implemented.
+@code
+enum class State: unsigned char {
+    Ready = 0x01,
+    Waiting = 0x02,
+    Done = 0x04
+};
+
+typedef Set<State, unsigned char> States;
+SET_OPERATORS(States)
+@endcode
+*/
+template<class T, class U> class Set {
+    public:
+        typedef T Type;             /**< @brief Enum type */
+        typedef U UnderlyingType;   /**< @brief Underlying type of the enum */
+
+        /** @brief Create empty set */
+        constexpr inline Set(): value() {}
+
+        /** @brief Create set from one value */
+        constexpr inline Set(T value): value(static_cast<UnderlyingType>(value)) {}
+
+        /** @brief Add value to the set */
+        constexpr inline Set<T, U> operator|(T other) const {
+            return Set<T, U>(value | static_cast<UnderlyingType>(other));
+        }
+
+        /** @brief Union of two sets */
+        constexpr inline Set<T, U> operator|(Set<T, U> other) const {
+            return Set<T, U>(value | other.value);
+        }
+
+        /** @brief Add value to the set and assign */
+        inline Set<T, U>& operator|=(T other) {
+            value |= static_cast<UnderlyingType>(other);
+            return *this;
+        }
+
+        /** @brief Union two sets and assign */
+        inline Set<T, U>& operator|=(Set<T, U> other) {
+            value |= other.value;
+            return *this;
+        }
+
+        /** @brief Check if given value is in the set */
+        constexpr inline T operator&(T other) const {
+            return static_cast<T>(value & static_cast<UnderlyingType>(other));
+        }
+
+        /** @brief Intersection of two sets */
+        constexpr inline Set<T, U> operator&(Set<T, U> other) const {
+            return Set<T, U>(value & other.value);
+        }
+
+        /** @brief Intersect two sets and assign */
+        inline Set<T, U>& operator&=(Set<T, U> other) const {
+            value &= other.value;
+            return *this;
+        }
+
+        /** @brief Value in underlying type */
+        constexpr inline UnderlyingType toUnderlyingType() const {
+            return value;
+        }
+
+    private:
+        constexpr inline explicit Set(UnderlyingType type): value(type) {}
+
+        UnderlyingType value;
+};
+
+/** @hideinitializer
+@brief Define out-of-class operators for given Set implementation
+*/
+#define SET_OPERATORS(class)                                                \
+    inline constexpr class operator|(class::Type a, class b) {              \
+        return b | a;                                                       \
+    }                                                                       \
+    inline constexpr class operator&(class::Type a, class b) {              \
+        return b & a;                                                       \
+    }
+
+}
+
+#endif