comparison: src/transform.h
src/transform.h
- changeset 1017
- fc1c13db9618
- child 1072
- 9ce9496427f2
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| 1016:3b279b5e57d3 | 1017:fc1c13db9618 |
|---|---|
| 1 /* | |
| 2 * LDForge: LDraw parts authoring CAD | |
| 3 * Copyright (C) 2013 - 2016 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 <functional> | |
| 21 | |
| 22 // | |
| 23 // TransformingIterator | |
| 24 // | |
| 25 // Transforming iterator, calls Fn on iterated values before returning them. | |
| 26 // | |
| 27 template<typename T, typename Res, typename Arg> | |
| 28 struct TransformingIterator | |
| 29 { | |
| 30 using Iterator = decltype(T().begin()); | |
| 31 using Self = TransformingIterator<T, Res, Arg>; | |
| 32 Iterator it; | |
| 33 std::function<Res(Arg)> fn; | |
| 34 | |
| 35 TransformingIterator(Iterator it, std::function<Res(Arg)> fn) : | |
| 36 it(it), | |
| 37 fn(fn) {} | |
| 38 | |
| 39 Res operator*() | |
| 40 { | |
| 41 return fn(*it); | |
| 42 } | |
| 43 | |
| 44 bool operator!= (const Self& other) const | |
| 45 { | |
| 46 return other.it != it; | |
| 47 } | |
| 48 | |
| 49 void operator++() | |
| 50 { | |
| 51 ++it; | |
| 52 } | |
| 53 }; | |
| 54 | |
| 55 // | |
| 56 // TransformWrapper | |
| 57 // | |
| 58 // Transform object, only serves to produce transforming iterators | |
| 59 // | |
| 60 template<typename T, typename Res, typename Arg> | |
| 61 struct TransformWrapper | |
| 62 { | |
| 63 using Iterator = TransformingIterator<T, Res, Arg>; | |
| 64 | |
| 65 TransformWrapper(T& iterable, std::function<Res(Arg)> fn) : | |
| 66 iterable(iterable), | |
| 67 function(fn) {} | |
| 68 | |
| 69 Iterator begin() | |
| 70 { | |
| 71 return Iterator(iterable.begin(), function); | |
| 72 } | |
| 73 | |
| 74 Iterator end() | |
| 75 { | |
| 76 return Iterator(iterable.end(), function); | |
| 77 } | |
| 78 | |
| 79 T& iterable; | |
| 80 std::function<Res(Arg)> function; | |
| 81 }; | |
| 82 | |
| 83 template<typename T, typename Res, typename Arg> | |
| 84 TransformWrapper<T, Res, Arg> transform(T& iterable, Res(*fn)(Arg)) | |
| 85 { | |
| 86 return TransformWrapper<T, Res, Arg>(iterable, fn); | |
| 87 } | |
| 88 | |
| 89 template<typename T, typename Res, typename Arg> | |
| 90 TransformWrapper<T, Res, Arg> transform(T& iterable, std::function<Res(Arg)> fn) | |
| 91 { | |
| 92 return TransformWrapper<T, Res, Arg>(iterable, fn); | |
| 93 } |
