BitRef.h

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#pragma once
// SPDX-FileCopyrightText: 2025 Nessan Fitzmaurice <nzznfitz+gh@icloud.com>
// SPDX-License-Identifier: MIT

 
#include <gf2/BitStore.h>
 
namespace gf2 {

template<BitStore Store>
class BitRef {
private:
    // The bit-store we are referencing.
    Store* m_store;
 
    // The index of the bit of interest within that bit-store
    usize m_index;
 
public:
    BitRef(Store* store, usize index) : m_store(store), m_index(index) {}
 
    // The default compiler generator implementations for most "rule of 5" methods will be fine ...
    constexpr BitRef() = default;
    constexpr BitRef(BitRef const&) = default;
    constexpr BitRef(BitRef&&) noexcept = default;
    ~BitRef() = default;

    constexpr operator bool() const { return gf2::get(*m_store, m_index); }

    constexpr BitRef& operator=(bool rhs) {
        gf2::set(*m_store, m_index, rhs);
        return *this;
    }

    constexpr BitRef& operator=(BitRef const& rhs) {
        gf2::set(*m_store, m_index, static_cast<bool>(rhs));
        return *this;
    }

    constexpr BitRef& flip() {
        gf2::flip(*m_store, m_index);
        return *this;
    }

    constexpr BitRef& operator&=(bool rhs) {
        if (!rhs) gf2::set(*m_store, m_index, false);
        return *this;
    }

    constexpr BitRef& operator&=(BitRef const& rhs) {
        if (!static_cast<bool>(rhs)) gf2::set(*m_store, m_index, false);
        return *this;
    }

    constexpr BitRef& operator|=(bool rhs) {
        if (rhs) gf2::set(*m_store, m_index);
        return *this;
    }

    constexpr BitRef& operator|=(BitRef const& rhs) {
        if (static_cast<bool>(rhs)) gf2::set(*m_store, m_index);
        return *this;
    }

    constexpr BitRef& operator^=(bool rhs) {
        if (rhs) gf2::flip(*m_store, m_index);
        return *this;
    }

    constexpr BitRef& operator^=(BitRef const& rhs) {
        if (static_cast<bool>(rhs)) gf2::flip(*m_store, m_index);
        return *this;
    }
};
 
} // namespace gf2
 
namespace std {

template<gf2::BitStore Store>
struct formatter<gf2::BitRef<Store>> : formatter<bool> {
    template<typename FormatContext>
    auto format(gf2::BitRef<Store> const& bit, FormatContext& ctx) const {
        return formatter<bool>::format(static_cast<bool>(bit), ctx);
    }
};
 
} // namespace std