EnumFlag.h

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/*
 * 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>
 
template<typename T>
constexpr bool IsEnumFlag(T) { return false; }
 
#define DEFINE_ENUM_FLAG(enumType) constexpr bool IsEnumFlag(enumType) { return true; }
 
namespace EnumTraits
{
 template<typename T>
 using IsFlag = std::conjunction<std::is_enum<T>, std::integral_constant<bool, IsEnumFlag(T{})>>;
}
 
template<typename T, std::enable_if_t<EnumTraits::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<EnumTraits::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<EnumTraits::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<EnumTraits::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<EnumTraits::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
{
 static_assert(EnumTraits::IsFlag<T>::value, "EnumFlag must be used only with enums that are marked as flags by DEFINE_ENUM_FLAG macro");
 
public:
 /*implicit*/ constexpr EnumFlag(T value) : _value(value)
 {
 }
 
 constexpr EnumFlag& operator&=(EnumFlag right)
 {
 _value &= right._value;
 return *this;
 }
 
 constexpr friend EnumFlag operator&(EnumFlag left, EnumFlag right)
 {
 return left &= right;
 }
 
 constexpr EnumFlag& operator|=(EnumFlag right)
 {
 _value |= right._value;
 return *this;
 }
 
 constexpr friend EnumFlag operator|(EnumFlag left, EnumFlag right)
 {
 return left |= right;
 }
 
 constexpr EnumFlag operator~() const
 {
 return static_cast<T>(~static_cast<std::underlying_type_t<T>>(_value));
 }
 
 constexpr void RemoveFlag(EnumFlag 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__