C_flag.hpp

/*
 * Copyright 2026 Guillaume Guillet
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#ifndef _FGE_C_FLAG_HPP_INCLUDED
#define _FGE_C_FLAG_HPP_INCLUDED
 
#include <type_traits>
 
namespace fge
{

class BooleanFlag
{
public:
    constexpr BooleanFlag(bool defaultValue = false) :
            g_flag(defaultValue)
    {}

    constexpr bool check(bool input)
    {
        if (!this->g_flag)
        {
            this->g_flag = input;
            return input;
        }
        if (!input)
        {
            this->g_flag = false;
        }
        return false;
    }

    constexpr void set(bool value) { this->g_flag = value; }
    [[nodiscard]] constexpr bool get() const { return this->g_flag; }

    constexpr bool operator=(bool value) { return this->g_flag = value; }

    constexpr operator bool() const { return this->g_flag; }
 
private:
    bool g_flag;
};

template<typename EnumType>
class EnumFlags
{
    static_assert(std::is_enum_v<EnumType>, "EnumFlags can only be used with enum types");
 
public:
    using Type = std::underlying_type_t<EnumType>;
 
    constexpr EnumFlags(Type value = Type{0}) :
            g_flags(static_cast<Type>(value))
    {}
 
    EnumFlags& set(Type flag)
    {
        this->g_flags |= static_cast<Type>(flag);
        return *this;
    }
    EnumFlags& unset(Type flag)
    {
        this->g_flags &= ~static_cast<Type>(flag);
        return *this;
    }
    EnumFlags& toggle(Type flag)
    {
        this->g_flags ^= static_cast<Type>(flag);
        return *this;
    }
 
    [[nodiscard]] constexpr bool has(Type flag) const { return (this->g_flags & static_cast<Type>(flag)) == flag; }
 
    [[nodiscard]] constexpr Type get() const { return this->g_flags; }
    constexpr EnumFlags& operator=(Type value)
    {
        this->g_flags = value;
        return *this;
    }
 
private:
    Type g_flags;
};
 
template<typename EnumType>
using EnumFlags_t = fge::EnumFlags<EnumType>::Type;
 
} // namespace fge
 
#endif // _FGE_C_FLAG_HPP_INCLUDED