bitset_reference.hpp

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// Copyright 2024 Man Group Operations Limited
//
// 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.
 
#pragma once
 
namespace sparrow
{
    template <class B, bool is_const>
    class bitset_iterator;

    template <class B>
    class bitset_reference
    {
    public:
 
        using self_type = bitset_reference<B>;  
 
        constexpr bitset_reference(const bitset_reference&) noexcept = default;
        constexpr bitset_reference(bitset_reference&&) noexcept = default;

        constexpr self_type& operator=(const self_type& rhs) noexcept;

        constexpr self_type& operator=(self_type&& rhs) noexcept;

        constexpr self_type& operator=(bool value) noexcept;

        constexpr operator bool() const noexcept;

        constexpr bool operator~() const noexcept;

        constexpr self_type& operator&=(bool rhs) noexcept;

        constexpr self_type& operator|=(bool rhs) noexcept;

        constexpr self_type& operator^=(bool rhs) noexcept;
 
    private:
 
        using block_type = typename B::block_type;  
        using bitset_type = B;                      
        using size_type = typename B::size_type;    

        bitset_reference(bitset_type& bitset, size_type index);

        constexpr void assign(bool value) noexcept;

        constexpr void set() noexcept;

        constexpr void reset() noexcept;
 
        bitset_type* p_bitset;  
        size_type m_index;      
 
        friend class bitset_iterator<B, false>;  
        template <typename RAR>
            requires std::ranges::random_access_range<std::remove_pointer_t<RAR>>
        friend class dynamic_bitset_base;  
    };

    template <class B1, class B2>
    bool operator==(const bitset_reference<B1>& lhs, const bitset_reference<B2>& rhs);

    template <class B>
    bool operator==(const bitset_reference<B>& lhs, bool rhs);
 
    template <class B>
    constexpr auto bitset_reference<B>::operator=(const self_type& rhs) noexcept -> self_type&
    {
        assign(rhs);
        return *this;
    }
 
    template <class B>
    constexpr auto bitset_reference<B>::operator=(self_type&& rhs) noexcept -> self_type&
    {
        assign(rhs);
        return *this;
    }
 
    template <class B>
    constexpr auto bitset_reference<B>::operator=(bool rhs) noexcept -> self_type&
    {
        assign(rhs);
        return *this;
    }
 
    template <class B>
    constexpr bitset_reference<B>::operator bool() const noexcept
    {
        return p_bitset->test(m_index);
    }
 
    template <class B>
    constexpr bool bitset_reference<B>::operator~() const noexcept
    {
        return !p_bitset->test(m_index);
    }
 
    template <class B>
    constexpr auto bitset_reference<B>::operator&=(bool rhs) noexcept -> self_type&
    {
        if (!rhs)
        {
            reset();
        }
        return *this;
    }
 
    template <class B>
    constexpr auto bitset_reference<B>::operator|=(bool rhs) noexcept -> self_type&
    {
        if (rhs)
        {
            set();
        }
        return *this;
    }
 
    template <class B>
    constexpr auto bitset_reference<B>::operator^=(bool rhs) noexcept -> self_type&
    {
        if (rhs)
        {
            p_bitset->set(m_index, !p_bitset->test(m_index));
        }
        return *this;
    }
 
    template <class B>
    bitset_reference<B>::bitset_reference(bitset_type& bitset, size_type index)
        : p_bitset(&bitset)
        , m_index(index)
    {
    }
 
    template <class B>
    constexpr void bitset_reference<B>::assign(bool rhs) noexcept
    {
        rhs ? set() : reset();
    }
 
    template <class B>
    constexpr void bitset_reference<B>::set() noexcept
    {
        p_bitset->set(m_index, true);
    }
 
    template <class B>
    constexpr void bitset_reference<B>::reset() noexcept
    {
        p_bitset->set(m_index, false);
    }
 
    template <class B1, class B2>
    bool operator==(const bitset_reference<B1>& lhs, const bitset_reference<B2>& rhs)
    {
        return bool(lhs) == bool(rhs);
    }
 
    template <class B>
    bool operator==(const bitset_reference<B>& lhs, bool rhs)
    {
        return bool(lhs) == rhs;
    }
}
 
#if defined(__cpp_lib_format)
#    include <format>
 
template <class B>
struct std::formatter<sparrow::bitset_reference<B>>
{
    constexpr auto parse(std::format_parse_context& ctx)
    {
        return ctx.begin();
    }
 
    auto format(const sparrow::bitset_reference<B>& b, std::format_context& ctx) const
    {
        bool val = b;
        return std::format_to(ctx.out(), "{}", val);
    }
};
 
#endif