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| 1 | // SPDX-FileCopyrightText: 2022-2023 Dennis Gläser <dennis.glaeser@iws.uni-stuttgart.de> | ||
| 2 | // SPDX-License-Identifier: MIT | ||
| 3 | /*! | ||
| 4 | * \file | ||
| 5 | * \ingroup Common | ||
| 6 | * \brief Iterator facades implemented by means of CRTP. | ||
| 7 | */ | ||
| 8 | #ifndef GRIDFORMAT_COMMON_ITERATOR_FACADES_HPP_ | ||
| 9 | #define GRIDFORMAT_COMMON_ITERATOR_FACADES_HPP_ | ||
| 10 | |||
| 11 | #include <compare> | ||
| 12 | #include <cstddef> | ||
| 13 | #include <iterator> | ||
| 14 | #include <type_traits> | ||
| 15 | |||
| 16 | #include <gridformat/common/concepts.hpp> | ||
| 17 | #include <gridformat/common/detail/crtp.hpp> | ||
| 18 | |||
| 19 | namespace GridFormat { | ||
| 20 | |||
| 21 | //! \addtogroup Common | ||
| 22 | //! @{ | ||
| 23 | |||
| 24 | /*! | ||
| 25 | * \brief Gateway for granting the iterator facades access to | ||
| 26 | * the iterator implementations. Iterator implementations | ||
| 27 | * are expected to provide a set of functions, depending | ||
| 28 | * on the type of iterator that is modeled. It is recommended | ||
| 29 | * to put these functions in private scope, and make IteratorAccess | ||
| 30 | * a friend of the implementation such that the facades can | ||
| 31 | * request access via this class. | ||
| 32 | */ | ||
| 33 | class IteratorAccess { | ||
| 34 | public: | ||
| 35 | template<typename IteratorImpl> | ||
| 36 | 924501 | static decltype(auto) dereference(IteratorImpl* impl) { | |
| 37 | 924501 | return impl->_dereference(); | |
| 38 | } | ||
| 39 | |||
| 40 | template<typename IteratorImpl> | ||
| 41 | 1231669 | static void increment(IteratorImpl* impl) { | |
| 42 | 1231669 | return impl->_increment(); | |
| 43 | } | ||
| 44 | |||
| 45 | template<typename IteratorImpl> | ||
| 46 | 2 | static void decrement(IteratorImpl* impl) { | |
| 47 | 2 | return impl->_decrement(); | |
| 48 | } | ||
| 49 | |||
| 50 | template<typename IteratorImpl> | ||
| 51 | 7 | static void advance(IteratorImpl* impl, std::signed_integral auto n) { | |
| 52 | 7 | return impl->_advance(n); | |
| 53 | } | ||
| 54 | |||
| 55 | template<std::signed_integral Difference, typename IteratorImpl1, typename IteratorImpl2> | ||
| 56 | 8 | static Difference distance(IteratorImpl1* lhs, IteratorImpl2* rhs) { | |
| 57 | 8 | return lhs->_distance_to(*rhs); | |
| 58 | } | ||
| 59 | |||
| 60 | template<typename IteratorImpl1, typename IteratorImpl2> | ||
| 61 | 676007 | static bool equal(IteratorImpl1* lhs, IteratorImpl2* rhs) { | |
| 62 | 676007 | return lhs->_is_equal(*rhs); | |
| 63 | } | ||
| 64 | }; | ||
| 65 | |||
| 66 | /*! | ||
| 67 | * \brief Base class for all iterator facades. | ||
| 68 | * \tparam Impl The derived (implementation) type | ||
| 69 | * \tparam IteratorTag The iterator category tag | ||
| 70 | * \tparam ValueType The type over which it is iterated | ||
| 71 | * \tparam Reference The reference type returned after dereferencing | ||
| 72 | * \tparam Difference The type to express differences between two iterators | ||
| 73 | */ | ||
| 74 | template<typename Impl, | ||
| 75 | typename IteratorTag, | ||
| 76 | typename ValueType, | ||
| 77 | typename Reference = ValueType&, | ||
| 78 | typename Pointer = std::remove_reference_t<Reference>*, | ||
| 79 | typename Difference = std::ptrdiff_t> | ||
| 80 | class IteratorFacade | ||
| 81 | : public Detail::CRTPBase<Impl> { | ||
| 82 | static constexpr bool is_bidirectional = std::derived_from<IteratorTag, std::bidirectional_iterator_tag>; | ||
| 83 | static constexpr bool is_random_access = std::derived_from<IteratorTag, std::random_access_iterator_tag>; | ||
| 84 | |||
| 85 | public: | ||
| 86 | using iterator_category = IteratorTag; | ||
| 87 | using value_type = ValueType; | ||
| 88 | using difference_type = Difference; | ||
| 89 | using pointer = Pointer; | ||
| 90 | using reference = Reference; | ||
| 91 | |||
| 92 | //! Test for equality against another iterator implementation | ||
| 93 | template<typename I, typename T, typename V, typename R, typename D> | ||
| 94 | 676007 | friend bool operator==(const IteratorFacade& lhs, const IteratorFacade<I, T, V, R, D>& rhs) { | |
| 95 | 676007 | return IteratorAccess::equal( | |
| 96 | lhs._pimpl(), | ||
| 97 | Detail::cast_to_impl_ptr<const I>(&rhs) | ||
| 98 | 676007 | ); | |
| 99 | } | ||
| 100 | |||
| 101 | //! Test for inequality against another iterator implementation | ||
| 102 | template<typename I, typename T, typename V, typename R, typename D> | ||
| 103 | 73491 | friend bool operator!=(const IteratorFacade& lhs, const IteratorFacade<I, T, V, R, D>& rhs) { | |
| 104 | 73491 | return !(lhs == rhs); | |
| 105 | } | ||
| 106 | |||
| 107 | 924491 | Reference operator*() const { | |
| 108 | 924491 | return IteratorAccess::dereference(this->_pimpl()); | |
| 109 | } | ||
| 110 | |||
| 111 | 5 | Pointer operator->() const { | |
| 112 | static_assert(std::is_lvalue_reference_v<Reference>); | ||
| 113 | 5 | return &(IteratorAccess::dereference(this->_pimpl())); | |
| 114 | } | ||
| 115 | |||
| 116 | 629750 | Impl& operator++() { | |
| 117 | 629750 | IteratorAccess::increment(this->_pimpl()); | |
| 118 | 629750 | return this->_impl(); | |
| 119 | } | ||
| 120 | |||
| 121 | 1 | Impl operator++(int) { | |
| 122 | 1 | auto cpy(this->_impl()); | |
| 123 | 1 | IteratorAccess::increment(this->_pimpl()); | |
| 124 | 1 | return cpy; | |
| 125 | } | ||
| 126 | |||
| 127 | 2 | Impl& operator--() requires(is_bidirectional) { | |
| 128 | 2 | IteratorAccess::decrement(this->_pimpl()); | |
| 129 | 2 | return this->_impl(); | |
| 130 | } | ||
| 131 | |||
| 132 | Impl operator--(int) requires(is_bidirectional) { | ||
| 133 | auto cpy(this->_impl()); | ||
| 134 | IteratorAccess::decrement(this->_pimpl()); | ||
| 135 | return cpy; | ||
| 136 | } | ||
| 137 | |||
| 138 | 2 | Reference operator[](Difference n) const requires(is_random_access) { | |
| 139 |
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2 | auto cpy(this->_impl()); |
| 140 |
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2 | cpy += n; |
| 141 |
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4 | return *cpy; |
| 142 | } | ||
| 143 | |||
| 144 | 5 | Impl& operator+=(Difference n) requires(is_random_access) { | |
| 145 | 5 | IteratorAccess::advance(this->_pimpl(), n); | |
| 146 | 5 | return this->_impl(); | |
| 147 | } | ||
| 148 | |||
| 149 | 2 | Impl& operator-=(Difference n) requires(is_random_access) { | |
| 150 | 2 | IteratorAccess::advance(this->_pimpl(), -n); | |
| 151 | 2 | return this->_impl(); | |
| 152 | } | ||
| 153 | |||
| 154 | 2 | Impl operator+(Difference n) const requires(is_random_access) { | |
| 155 | 2 | auto cpy(this->_impl()); | |
| 156 | 2 | cpy += n; | |
| 157 | 2 | return cpy; | |
| 158 | } | ||
| 159 | |||
| 160 | 1 | Impl operator-(Difference n) const requires(is_random_access) { | |
| 161 | 1 | auto cpy(this->_impl()); | |
| 162 | 1 | cpy -= n; | |
| 163 | 1 | return cpy; | |
| 164 | } | ||
| 165 | |||
| 166 | 1 | friend Impl operator+(Difference n, const IteratorFacade& it) requires(is_random_access) { | |
| 167 | 1 | return it + n; | |
| 168 | } | ||
| 169 | |||
| 170 | template<Concepts::Interoperable<Impl> I, typename T, typename V, typename R, typename D> | ||
| 171 | 8 | friend auto operator-(const IteratorFacade& lhs, | |
| 172 | const IteratorFacade<I, T, V, R, D>& rhs) requires(is_random_access) { | ||
| 173 | if constexpr (std::is_convertible_v<I, Impl>) | ||
| 174 | 8 | return IteratorAccess::distance<Difference>( | |
| 175 | Detail::cast_to_impl_ptr<const Impl>(&rhs), | ||
| 176 | lhs._pimpl() | ||
| 177 | 8 | ); | |
| 178 | else | ||
| 179 | return IteratorAccess::distance<D>( | ||
| 180 | rhs._pimpl(), | ||
| 181 | Detail::cast_to_impl_ptr<const I>(&lhs) | ||
| 182 | ); | ||
| 183 | } | ||
| 184 | |||
| 185 | template<Concepts::Interoperable<Impl> I, typename T, typename V, typename R, typename D> | ||
| 186 | 6 | friend std::strong_ordering operator<=>(const IteratorFacade& lhs, | |
| 187 | const IteratorFacade<I, T, V, R, D>& rhs) requires(is_random_access) { | ||
| 188 | 6 | const auto d = lhs - rhs; | |
| 189 |
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6 | return d <=> decltype(d){0}; |
| 190 | } | ||
| 191 | }; | ||
| 192 | |||
| 193 | /*! | ||
| 194 | * \brief Base class to turn a type into a forward iterator by means of CRTP. | ||
| 195 | * \tparam Impl The derived (implementation) type | ||
| 196 | * \tparam ValueType The type over which it is iterated | ||
| 197 | * \tparam Reference The reference type returned after dereferencing | ||
| 198 | * \tparam Difference The type to express differences between two iterators | ||
| 199 | */ | ||
| 200 | template<typename Impl, | ||
| 201 | typename ValueType, | ||
| 202 | typename Reference = ValueType&, | ||
| 203 | typename Pointer = std::remove_reference_t<Reference>*, | ||
| 204 | typename Difference = std::ptrdiff_t> | ||
| 205 | using ForwardIteratorFacade = IteratorFacade<Impl, | ||
| 206 | std::forward_iterator_tag, | ||
| 207 | ValueType, | ||
| 208 | Reference, | ||
| 209 | Pointer, | ||
| 210 | Difference>; | ||
| 211 | |||
| 212 | /*! | ||
| 213 | * \brief Base class to turn a type into a bidirectional iterator by means of CRTP. | ||
| 214 | * \tparam Impl The derived (implementation) type | ||
| 215 | * \tparam ValueType The type over which it is iterated | ||
| 216 | * \tparam Reference The reference type returned after dereferencing | ||
| 217 | * \tparam Difference The type to express differences between two iterators | ||
| 218 | */ | ||
| 219 | template<typename Impl, | ||
| 220 | typename ValueType, | ||
| 221 | typename Reference = ValueType&, | ||
| 222 | typename Pointer = std::remove_reference_t<Reference>*, | ||
| 223 | typename Difference = std::ptrdiff_t> | ||
| 224 | using BidirectionalIteratorFacade = IteratorFacade<Impl, | ||
| 225 | std::bidirectional_iterator_tag, | ||
| 226 | ValueType, | ||
| 227 | Reference, | ||
| 228 | Pointer, | ||
| 229 | Difference>; | ||
| 230 | |||
| 231 | /*! | ||
| 232 | * \brief Base class to turn a type into a random-access iterator by means of CRTP. | ||
| 233 | * \tparam Impl The derived (implementation) type | ||
| 234 | * \tparam ValueType The type over which it is iterated | ||
| 235 | * \tparam Reference The reference type returned after dereferencing | ||
| 236 | * \tparam Difference The type to express differences between two iterators | ||
| 237 | */ | ||
| 238 | template<typename Impl, | ||
| 239 | typename ValueType, | ||
| 240 | typename Reference = ValueType&, | ||
| 241 | typename Pointer = std::remove_reference_t<Reference>*, | ||
| 242 | typename Difference = std::ptrdiff_t> | ||
| 243 | using RandomAccessIteratorFacade = IteratorFacade<Impl, | ||
| 244 | std::random_access_iterator_tag, | ||
| 245 | ValueType, | ||
| 246 | Reference, | ||
| 247 | Pointer, | ||
| 248 | Difference>; | ||
| 249 | |||
| 250 | //! @} end Common group | ||
| 251 | |||
| 252 | } // end namespace GridFormat | ||
| 253 | |||
| 254 | #endif // GRIDFORMAT_COMMON_ITERATOR_FACADES_HPP_ | ||
| 255 |