comparison: src/functional.h
src/functional.h
- changeset 63
- f7dd937667a5
- child 106
- 128efb9d148b
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| 1 /* | |
| 2 * LDForge: LDraw parts authoring CAD | |
| 3 * Copyright (C) 2020 Teemu Piippo | |
| 4 * | |
| 5 * This program is free software: you can redistribute it and/or modify | |
| 6 * it under the terms of the GNU General Public License as published by | |
| 7 * the Free Software Foundation, either version 3 of the License, or | |
| 8 * (at your option) any later version. | |
| 9 * | |
| 10 * This program is distributed in the hope that it will be useful, | |
| 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 13 * GNU General Public License for more details. | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License | |
| 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 17 */ | |
| 18 | |
| 19 #pragma once | |
| 20 #include <algorithm> | |
| 21 #include <functional> | |
| 22 #include <QVector> | |
| 23 #include <QSet> | |
| 24 #include <QList> | |
| 25 | |
| 26 namespace fn | |
| 27 { | |
| 28 template<typename C> | |
| 29 class InsertIterator; | |
| 30 } | |
| 31 | |
| 32 /** | |
| 33 * Like std::back_inserter but calls x.insert(v) instead | |
| 34 */ | |
| 35 template<typename C> | |
| 36 class fn::InsertIterator | |
| 37 { | |
| 38 public: | |
| 39 InsertIterator(C& container) : | |
| 40 container{container} {} | |
| 41 auto operator*() | |
| 42 { | |
| 43 return *this; | |
| 44 } | |
| 45 auto operator++() | |
| 46 { | |
| 47 return *this; | |
| 48 } | |
| 49 auto operator++(int) | |
| 50 { | |
| 51 return *this; | |
| 52 } | |
| 53 template<typename T> | |
| 54 auto operator=(T&& value) | |
| 55 { | |
| 56 this->container.insert(std::forward<T>(value)); | |
| 57 return *this; | |
| 58 } | |
| 59 private: | |
| 60 C& container; | |
| 61 }; | |
| 62 | |
| 63 namespace fn | |
| 64 { | |
| 65 // Constructs a fn::InsertIterator | |
| 66 template<typename C> | |
| 67 InsertIterator<C> makeInsertIterator(C& container) | |
| 68 { | |
| 69 return InsertIterator<C>{container}; | |
| 70 } | |
| 71 | |
| 72 // Constructs a back_inserter for std::vector | |
| 73 template<typename T> | |
| 74 auto makeDefaultInserter(std::vector<T>& vec) | |
| 75 { | |
| 76 return std::back_inserter(vec); | |
| 77 } | |
| 78 | |
| 79 // Constructs a back_inserter for QVector | |
| 80 template<typename T> | |
| 81 auto makeDefaultInserter(QVector<T>& vec) | |
| 82 { | |
| 83 return std::back_inserter(vec); | |
| 84 } | |
| 85 | |
| 86 // Constructs a back_inserter for QList | |
| 87 template<typename T> | |
| 88 auto makeDefaultInserter(QList<T>& vec) | |
| 89 { | |
| 90 return std::back_inserter(vec); | |
| 91 } | |
| 92 | |
| 93 // Constructs an fn::InsertIterator for QSet | |
| 94 template<typename T> | |
| 95 auto makeDefaultInserter(QSet<T>& vec) | |
| 96 { | |
| 97 return InsertIterator(vec); | |
| 98 } | |
| 99 | |
| 100 // Changes the value type of C | |
| 101 template<typename C, typename TT> | |
| 102 struct ChangeContainerValueType | |
| 103 { | |
| 104 }; | |
| 105 | |
| 106 // Changes the value type of std::vector | |
| 107 template<typename T, typename TT> | |
| 108 struct ChangeContainerValueType<std::vector<T>, TT> | |
| 109 { | |
| 110 using type = std::vector<TT>; | |
| 111 }; | |
| 112 | |
| 113 // Changes the value type of QVector | |
| 114 template<typename T, typename TT> | |
| 115 struct ChangeContainerValueType<QVector<T>, TT> | |
| 116 { | |
| 117 using type = QVector<TT>; | |
| 118 }; | |
| 119 | |
| 120 // Changes the value type of QSet | |
| 121 template<typename T, typename TT> | |
| 122 struct ChangeContainerValueType<QSet<T>, TT> | |
| 123 { | |
| 124 using type = QSet<TT>; | |
| 125 }; | |
| 126 | |
| 127 // Changes the value type of QList | |
| 128 template<typename T, typename TT> | |
| 129 struct ChangeContainerValueType<QList<T>, TT> | |
| 130 { | |
| 131 using type = QList<TT>; | |
| 132 }; | |
| 133 | |
| 134 // Changes the value type of C | |
| 135 template<typename C, typename TT> | |
| 136 using ChangeContainerValueType_t = typename ChangeContainerValueType<C, TT>::type; | |
| 137 | |
| 138 /** | |
| 139 * \brief Applies \c function to all elements of \c container | |
| 140 * \param container Container to iterate | |
| 141 * \param function Function to apply | |
| 142 * \param Rt result type. If not provided, a suitable result type is deduced from inputs | |
| 143 * \returns mapped result container | |
| 144 */ | |
| 145 template<typename Rt = void, typename C, typename Fn> | |
| 146 auto map(C&& container, Fn&& function) | |
| 147 { | |
| 148 using value_t = decltype(*std::declval<C>().begin()); | |
| 149 using newvalue_t = std::result_of_t<Fn(value_t)>; | |
| 150 using result_t = std::conditional_t< | |
| 151 std::is_same_v<Rt, void>, | |
| 152 ChangeContainerValueType_t<std::remove_reference_t<C>, newvalue_t>, | |
| 153 Rt>; | |
| 154 result_t result; | |
| 155 result.reserve(std::end(container) - std::begin(container)); | |
| 156 std::transform(std::begin(container), std::end(container), makeDefaultInserter(result), function); | |
| 157 return result; | |
| 158 } | |
| 159 } |
