Core/Misc: Improve enum flags with type safe operators

1 files changed, 126 insertions, 0 deletions

diff --git a/src/common/Utilities/EnumFlag.h b/src/common/Utilities/EnumFlag.h
new file mode 100644
index 00000000000..bd9a991daed
--- /dev/null
+++ b/src/common/Utilities/EnumFlag.h
@@ -0,0 +1,126 @@
+/*
+ * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef EnumFlag_h__
+#define EnumFlag_h__
+
+#include <type_traits>
+
+namespace EnumFlag
+{
+    template<typename T>
+    struct IsFlag : std::false_type { };
+}
+
+template<typename T, std::enable_if_t<EnumFlag::IsFlag<T>::value, std::nullptr_t> = nullptr>
+inline constexpr T operator&(T left, T right)
+{
+    return static_cast<T>(static_cast<std::underlying_type_t<T>>(left) & static_cast<std::underlying_type_t<T>>(right));
+}
+
+template<typename T, std::enable_if_t<EnumFlag::IsFlag<T>::value, std::nullptr_t> = nullptr>
+inline constexpr T& operator&=(T& left, T right)
+{
+    return left = left & right;
+}
+
+template<typename T, std::enable_if_t<EnumFlag::IsFlag<T>::value, std::nullptr_t> = nullptr>
+inline constexpr T operator|(T left, T right)
+{
+    return static_cast<T>(static_cast<std::underlying_type_t<T>>(left) | static_cast<std::underlying_type_t<T>>(right));
+}
+
+template<typename T, std::enable_if_t<EnumFlag::IsFlag<T>::value, std::nullptr_t> = nullptr>
+inline constexpr T& operator|=(T& left, T right)
+{
+    return left = left | right;
+}
+
+template<typename T, std::enable_if_t<EnumFlag::IsFlag<T>::value, std::nullptr_t> = nullptr>
+inline constexpr T operator~(T value)
+{
+    return static_cast<T>(~static_cast<std::underlying_type_t<T>>(value));
+}
+
+template<typename T>
+class EnumFlag_t
+{
+    static_assert(EnumFlag::IsFlag<T>::value, "EnumFlag_t must be used only with enums that are specify EnumFlag::IsFlag");
+
+public:
+    /*implicit*/ constexpr EnumFlag_t(T value) : _value(value)
+    {
+    }
+
+    constexpr EnumFlag_t& operator&=(EnumFlag_t right)
+    {
+        _value &= right._value;
+        return *this;
+    }
+
+    constexpr friend EnumFlag_t operator&(EnumFlag_t left, EnumFlag_t right)
+    {
+        return left &= right;
+    }
+
+    constexpr EnumFlag_t& operator|=(EnumFlag_t right)
+    {
+        _value |= right._value;
+        return *this;
+    }
+
+    constexpr friend EnumFlag_t operator|(EnumFlag_t left, EnumFlag_t right)
+    {
+        return left |= right;
+    }
+
+    constexpr EnumFlag_t operator~() const
+    {
+        return static_cast<T>(~static_cast<std::underlying_type_t<T>>(_value));
+    }
+
+    constexpr void RemoveFlag(EnumFlag_t flag)
+    {
+        _value &= ~flag._value;
+    }
+
+    constexpr bool HasFlag(T flag) const
+    {
+        using i = std::underlying_type_t<T>;
+        return static_cast<i>(_value & flag) != static_cast<i>(0);
+    }
+
+    constexpr bool HasAllFlags(T flags) const
+    {
+        return (_value & flags) == flags;
+    }
+
+    constexpr operator T() const
+    {
+        return _value;
+    }
+
+    constexpr std::underlying_type_t<T> AsUnderlyingType() const
+    {
+        return static_cast<std::underlying_type_t<T>>(_value);
+    }
+
+private:
+    T _value;
+};
+
+#endif // EnumFlag_h__