two_dimensional_matrix_iterator_base.hpp

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// SPDX-FileCopyrightText: 2006-2024 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2024 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <concepts>
#include <ranges>
#include <type_traits>
 
#include <seqan3/alignment/matrix/detail/matrix_coordinate.hpp>
#include <seqan3/core/detail/iterator_traits.hpp>
#include <seqan3/utility/type_traits/basic.hpp>
 
namespace seqan3::detail
{
 
enum struct matrix_major_order : uint8_t
{
    column, 
    row     
};
 
template <typename derived_t, matrix_major_order order>
class two_dimensional_matrix_iterator_base
{
private:
    friend derived_t;
 
    template <typename other_derived_t, matrix_major_order other_order>
    friend class two_dimensional_matrix_iterator_base;
 
    constexpr two_dimensional_matrix_iterator_base() = default;
    constexpr two_dimensional_matrix_iterator_base(two_dimensional_matrix_iterator_base const &) = default;
    constexpr two_dimensional_matrix_iterator_base(two_dimensional_matrix_iterator_base &&) = default;
    constexpr two_dimensional_matrix_iterator_base & operator=(two_dimensional_matrix_iterator_base const &) = default;
    constexpr two_dimensional_matrix_iterator_base & operator=(two_dimensional_matrix_iterator_base &&) = default;
    ~two_dimensional_matrix_iterator_base() = default;
 
    template <typename _derived_t>
    using difference_type = typename _derived_t::difference_type;
 
    template <typename _derived_t>
    using reference = typename _derived_t::reference;
 
    template <typename _derived_t>
    using pointer = typename _derived_t::pointer;
 
public:
    template <typename dummy_t = derived_t>
    constexpr reference<dummy_t> operator*() const noexcept
    {
        return *as_derived().host_iter;
    }
 
    template <typename dummy_t = derived_t>
    constexpr reference<dummy_t> operator[](std::iter_difference_t<dummy_t> const offset) const noexcept
    {
        return *(as_derived() + offset);
    }
 
    template <typename dummy_t = derived_t>
    constexpr reference<dummy_t> operator[](matrix_offset const & offset) const noexcept
    {
        return *(as_derived() + offset);
    }
 
    template <typename dummy_t = derived_t>
    constexpr pointer<dummy_t> operator->() const noexcept
    {
        return std::addressof(*as_derived().host_iter);
    }
 
    SEQAN3_DOXYGEN_ONLY(constexpr seqan3::detail::matrix_coordinate coordinate() const noexcept {})
 
    SEQAN3_DOXYGEN_ONLY(constexpr derived_t & operator+=(matrix_offset const & offset) noexcept {})
 
    constexpr derived_t & operator++() noexcept
    {
        if constexpr (order == matrix_major_order::column)
            return as_derived() += matrix_offset{row_index_type{1}, column_index_type{0}};
        else
            return as_derived() += matrix_offset{row_index_type{0}, column_index_type{1}};
    }
 
    constexpr derived_t operator++(int) noexcept
    {
        derived_t previous{as_derived()};
        ++(*this);
        return previous;
    }
 
    template <typename dummy_t = derived_t>
    constexpr derived_t & operator+=(std::iter_difference_t<dummy_t> const offset) noexcept
    {
        if constexpr (order == matrix_major_order::column)
            return as_derived() += matrix_offset{row_index_type{offset}, column_index_type{0}};
        else
            return as_derived() += matrix_offset{row_index_type{0}, column_index_type{offset}};
    }
 
    template <typename dummy_t = derived_t>
    constexpr derived_t operator+(std::iter_difference_t<dummy_t> const offset) const noexcept
    {
        derived_t next{as_derived()};
        next += offset;
        return next;
    }
 
    template <typename dummy_t = derived_t>
    constexpr friend derived_t operator+(std::iter_difference_t<dummy_t> const offset, derived_t const iter)
    {
        return iter + offset;
    }
 
    constexpr derived_t operator+(matrix_offset const & offset) const noexcept
    {
        derived_t next{as_derived()};
        next += offset;
        return next;
    }
 
    constexpr friend derived_t operator+(matrix_offset const & offset, derived_t const iter)
    {
        return iter + offset;
    }
 
    constexpr derived_t & operator--() noexcept
    {
        if constexpr (order == matrix_major_order::column)
            return as_derived() += matrix_offset{row_index_type{-1}, column_index_type{0}};
        else
            return as_derived() += matrix_offset{row_index_type{0}, column_index_type{-1}};
    }
 
    constexpr derived_t operator--(int) noexcept
    {
        derived_t previous{as_derived()};
        --(*this);
        return previous;
    }
 
    template <typename dummy_t = derived_t>
    constexpr derived_t & operator-=(std::iter_difference_t<dummy_t> const offset) noexcept
    {
        return *this += -offset;
    }
 
    template <typename dummy_t = derived_t>
    constexpr derived_t operator-(std::iter_difference_t<dummy_t> const offset) const noexcept
    {
        derived_t next{as_derived()};
        next -= offset;
        return next;
    }
 
    constexpr derived_t & operator-=(matrix_offset const & offset) noexcept
    {
        return as_derived() += matrix_offset{row_index_type{-offset.row}, column_index_type{-offset.col}};
    }
 
    constexpr derived_t operator-(matrix_offset const & offset) const noexcept
    {
        derived_t next{as_derived()};
        next -= offset;
        return next;
    }
 
    template <typename dummy_t = derived_t>
    friend constexpr std::iter_difference_t<dummy_t> operator-(derived_t const lhs, derived_t const rhs) noexcept
    {
        return lhs.as_host_iter() - rhs.as_host_iter();
    }
 
    // What if the derived type is different?
    // How can make sure this is the same type?
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator==(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return as_derived().host_iter == rhs.as_derived().host_iter;
    }
 
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator!=(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return !(*this == rhs);
    }
 
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator<(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return as_derived().host_iter < rhs.as_derived().host_iter;
    }
 
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator<=(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return as_derived().host_iter <= rhs.as_derived().host_iter;
    }
 
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator>(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return as_derived().host_iter > rhs.as_derived().host_iter;
    }
 
    template <typename other_derived_t>
        requires std::constructible_from<derived_t, other_derived_t>
              || std::constructible_from<other_derived_t, derived_t>
    constexpr bool operator>=(two_dimensional_matrix_iterator_base<other_derived_t, order> const & rhs) const noexcept
    {
        return as_derived().host_iter >= rhs.as_derived().host_iter;
    }
 
private:
    constexpr auto const & as_host_iter() const
    {
        return as_derived().host_iter;
    }
 
    constexpr derived_t & as_derived()
    {
        return static_cast<derived_t &>(*this);
    }
 
    constexpr derived_t const & as_derived() const
    {
        return static_cast<derived_t const &>(*this);
    }
 
    // matrix_iterator_t host_iter{};    //!< The wrapped matrix iterator.
};
} // namespace seqan3::detail