subscripts.hpp

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// SPDX-License-Identifier: BSD-2-Clause
 
#ifndef pRC_CORE_CONTAINER_SUBSCRIPTS_H
#define pRC_CORE_CONTAINER_SUBSCRIPTS_H
 
#include <prc/core/basic/concepts.hpp>
#include <prc/core/basic/sequence.hpp>
#include <prc/core/container/declarations.hpp>
#include <prc/core/functors/add.hpp>
#include <prc/core/functors/div.hpp>
#include <prc/core/functors/mod.hpp>
#include <prc/core/functors/mul.hpp>
#include <prc/core/functors/sub.hpp>
#include <prc/core/log/log.hpp>
#include <prc/pragma.hpp>
 
namespace pRC
{
    template<Size... Ns>
    class Subscripts
    {
    public:
        using Sizes = pRC::Sizes<Ns...>;
 
        static constexpr auto Dimension = Sizes::Dimension;
 
        static constexpr auto size()
            requires requires { Sizes::size(); }
        {
            return Sizes::size();
        }
 
        static constexpr auto size(Index const dimension)
        {
            return Sizes::size(dimension);
        }
 
    public:
        ~Subscripts() = default;
        constexpr Subscripts() = default;
        constexpr Subscripts(Subscripts const &) = default;
        constexpr Subscripts(Subscripts &&) = default;
        constexpr Subscripts &operator=(Subscripts const &) & = default;
        constexpr Subscripts &operator=(Subscripts &&) & = default;
 
        template<IsConvertible<Index>... Ss>
            requires(sizeof...(Ss) == Dimension)
        explicit constexpr Subscripts(Ss const... subscripts)
            : mSubscripts(subscripts...)
        {
        }
 
        explicit constexpr Subscripts(Index const index)
            requires(Dimension == 0)
        {
            check(index);
        }
 
        explicit constexpr Subscripts(Index const index)
            requires(Dimension > 1) && requires { Sizes::size(); }
        {
            check(index);
 
            expand(
                makeSeries<Index, Dimension - 1>(),
                [this](auto index, auto const... seq)
                {
                    operator[](0) = index % size(0);
                    ((operator[](seq + 1) =
                             (index /= size(seq)) % size(seq + 1)),
                        ...);
                },
                index);
        }
 
        explicit constexpr operator Index() const
            requires requires { Sizes::size(); }
        {
            if constexpr(cDebugLevel >= DebugLevel::Low)
            {
                if(isOutOfRange())
                {
                    Logging::error("Subscripts out of range.");
                }
            }
 
            return expand(
                makeSeries<Index, Dimension>(),
                [](auto subscripts, auto const... seq)
                {
                    [[maybe_unused]] Index scale = 1;
                    ((subscripts[seq] *= scale, scale *= size(seq)), ...);
                    return (subscripts[seq] + ... + 0);
                },
                mSubscripts);
        }
 
        constexpr decltype(auto) operator[](Index const dimension) &&
        {
            return move(mSubscripts)[dimension];
        }
 
        constexpr decltype(auto) operator[](Index const dimension) const &&
        {
            return move(mSubscripts)[dimension];
        }
 
        constexpr decltype(auto) operator[](Index const dimension) &
        {
            return mSubscripts[dimension];
        }
 
        constexpr decltype(auto) operator[](Index const dimension) const &
        {
            return mSubscripts[dimension];
        }
 
        constexpr bool operator<(const Subscripts &rhs) const
        {
            for(std::size_t i = Dimension; i > 0; --i)
            {
 
                auto lhsE = mSubscripts[i - 1];
                auto rhsE = rhs[i - 1];
                if(lhsE < rhsE)
                {
                    return true;
                }
                if(lhsE > rhsE)
                {
                    return false;
                }
            }
            /*for(std::size_t dimension = 0; dimension < Dimension;
            ++dimension)
            {
                if(mSubscripts[dimension] < rhs[dimension])
                {
                    return true;
                }
                if(mSubscripts[dimension] > rhs[dimension])
                {
                    return false;
                }
            }*/
            return false;
        }
 
        constexpr auto isOutOfRange() const
        {
            return expand(makeSeries<Index, Dimension>(),
                [this](auto const... seq)
                {
                    return !((this->operator[](seq) < size(seq)) && ...);
                });
        }
 
        constexpr decltype(auto) periodize() &
        {
            return *this %= Sizes();
        }
 
        template<class X>
            requires IsInvocable<Add, Subscripts &, X>
        constexpr auto &operator+=(X &&rhs) &
        {
            return *this = *this + forward<X>(rhs);
        }
 
        template<class X>
            requires IsInvocable<Sub, Subscripts &, X>
        constexpr auto &operator-=(X &&rhs) &
        {
            return *this = *this - forward<X>(rhs);
        }
 
        template<class X>
            requires IsInvocable<Mul, Subscripts &, X>
        constexpr auto &operator*=(X &&rhs) &
        {
            return *this = *this * forward<X>(rhs);
        }
 
        template<class X>
            requires IsInvocable<Div, Subscripts &, X>
        constexpr auto &operator/=(X &&rhs) &
        {
            return *this = *this / forward<X>(rhs);
        }
 
        template<class X>
            requires IsInvocable<Mod, Subscripts &, X>
        constexpr auto &operator%=(X &&rhs) &
        {
            return *this = *this % forward<X>(rhs);
        }
 
    private:
        constexpr auto check([[maybe_unused]] Index const index)
        {
            if constexpr(cDebugLevel >= DebugLevel::Low)
            {
                if(!(index < size()))
                {
                    Logging::error("Index out of range.");
                }
            }
        }
 
    private:
        BEGIN_IGNORE_DIAGNOSTIC_GCC("-Wpedantic")
        StackArray<Index, Dimension> mSubscripts = {};
        END_IGNORE_DIAGNOSTIC_GCC
    };
 
    template<class T>
    concept IsSubscripts = !IsReference<T> && requires {
        {
            []<Size... Ns>(Subscripts<Ns...> const &&)
            {
            }(std::declval<T>())
        };
    };
 
    template<Size... Ns>
    static inline constexpr auto operator+(Subscripts<Ns...> const &lhs,
        Subscripts<Ns...> const &rhs)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs, &rhs](auto const... seq)
            {
                return Subscripts<Ns...>((lhs[seq] + rhs[seq])...);
            });
    }
 
    template<Size... Ns>
    static inline constexpr auto operator-(Subscripts<Ns...> const &lhs,
        Subscripts<Ns...> const &rhs)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs, &rhs](auto const... seq)
            {
                return Subscripts<Ns...>((lhs[seq] - rhs[seq])...);
            });
    }
 
    template<Size... Ns, Size... Ss>
        requires(sizeof...(Ns) == sizeof...(Ss))
    static inline constexpr auto operator*(Subscripts<Ns...> const &lhs,
        Sizes<Ss...> const)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs](auto const... seq)
            {
                return Subscripts<(
                    Sizes<Ns...>::size(seq) * Sizes<Ss...>::size(seq))...>(
                    (lhs[seq] * Sizes<Ss...>::size(seq))...);
            });
    }
 
    template<Size... Ns, Size... Ss>
        requires(sizeof...(Ns) == sizeof...(Ss))
    static inline constexpr auto operator*(Sizes<Ss...> const,
        Subscripts<Ns...> const &rhs)
    {
        return rhs * Sizes<Ss...>();
    }
 
    template<Size... Ns, Size... Ss>
        requires(sizeof...(Ns) == sizeof...(Ss))
    static inline constexpr auto operator/(Subscripts<Ns...> const &lhs,
        Sizes<Ss...> const)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs](auto const... seq)
            {
                return Subscripts<(
                    Sizes<Ns...>::size(seq) / Sizes<Ss...>::size(seq))...>(
                    (lhs[seq] / Sizes<Ss...>::size(seq))...);
            });
    }
 
    template<Size... Ns, Size... Ss>
        requires(sizeof...(Ns) == sizeof...(Ss))
    static inline constexpr auto operator%(Subscripts<Ns...> const &lhs,
        Sizes<Ss...> const)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs](auto const... seq)
            {
                return Subscripts<Ss...>(
                    (lhs[seq] % Sizes<Ss...>::size(seq))...);
            });
    }
 
    template<Size... Ns>
    static inline constexpr auto operator==(Subscripts<Ns...> const &lhs,
        Subscripts<Ns...> const &rhs)
    {
        return expand(makeSeriesFor<Index, Ns...>(),
            [&lhs, &rhs](auto const... seq)
            {
                return ((lhs[seq] == rhs[seq]) && ...);
            });
    }
 
    template<Size... Ns>
    static inline constexpr auto operator!=(Subscripts<Ns...> const &lhs,
        Subscripts<Ns...> const &rhs)
    {
        return !(lhs == rhs);
    }
 
    template<Index... Ps, Size... Ns>
        requires requires { permute<Ps...>(makeSeriesFor<Index, Ns...>()); }
    static inline constexpr auto permute(Subscripts<Ns...> const &arg)
    {
        return expand(permute<Ps...>(makeSeriesFor<Index, Ns...>()),
            [&arg](auto const... seq)
            {
                return Subscripts<Sizes<Ns...>::size(seq)...>(arg[seq]...);
            });
    }
 
    template<Size... Ns>
    static inline constexpr auto reverse(Subscripts<Ns...> const &arg)
    {
        return expand(reverse(makeSeriesFor<Index, Ns...>()),
            [&arg](auto const... seq)
            {
                return permute<seq...>(arg);
            });
    }
 
    template<Direction D, Size Step, Size... Ns>
        requires requires { rotate<D, Step>(makeSeriesFor<Index, Ns...>()); }
    static inline constexpr auto rotate(Subscripts<Ns...> const &arg)
    {
        return expand(rotate<D, Step>(makeSeriesFor<Index, Ns...>()),
            [&arg](auto const... seq)
            {
                return permute<seq...>(arg);
            });
    }
 
    template<Index... Ds, Size... Ns>
        requires requires { chip<Ds...>(Sequence<Index, Ns...>()); }
    static inline constexpr auto chip(Subscripts<Ns...> const &arg)
    {
        return expand(chip<Ds...>(makeSeriesFor<Index, Ns...>()),
            [&arg](auto const... seq)
            {
                return Subscripts<Sizes<Ns...>::size(seq)...>(arg[seq]...);
            });
    }
}
#endif // pRC_CORE_CONTAINER_SUBSCRIPTS_H