bit_proxy.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
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 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
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 ****************************************************************************/
 
#ifndef VCL_SPACE_CORE_BIT_SET_BIT_PROXY_H
#define VCL_SPACE_CORE_BIT_SET_BIT_PROXY_H
 
#include <vclib/base.h>
 
#include <concepts>
#include <functional>
 
namespace vcl {
 
// See: https://stackoverflow.com/a/10145050/5851101
 
template<std::integral T>
class BitProxy
{
    std::reference_wrapper<T> mMask;
    const uint                mIndex;
 
public:
    using UnderlyingType = T;
 
    BitProxy(T& mask, uint index) : mMask(mask), mIndex(index) {}
 
    operator bool() const { return mMask.get() & (1 << mIndex); }
 
    void operator=(bool bit)
    {
        mMask.get() = (mMask.get() & ~(1 << mIndex)) | (bit << mIndex);
    }
 
    BitProxy& operator|=(bool bit)
    {
        mMask.get() |= (bit << mIndex);
        return *this;
    }
 
    BitProxy& operator&=(bool bit)
    {
        mMask.get() &= ~(bit << mIndex);
        return *this;
    }
 
    BitProxy& operator/=(bool bit)
    {
        mMask.get() ^= (bit << mIndex);
        return *this;
    }
};
 
/* Concepts */
 
template<typename T>
concept BitProxyConcept = std::derived_from< // same type or derived type
    std::remove_cvref_t<T>,
    BitProxy<typename RemoveRef<T>::UnderlyingType>>;
 
} // namespace vcl
 
#endif // VCL_SPACE_CORE_BIT_SET_BIT_PROXY_H