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67 lines
1.7 KiB
67 lines
1.7 KiB
3 months ago
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// David Eberly, Geometric Tools, Redmond WA 98052
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// Copyright (c) 1998-2021
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// Distributed under the Boost Software License, Version 1.0.
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// https://www.boost.org/LICENSE_1_0.txt
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// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
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// Version: 4.0.2019.08.13
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#pragma once
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#include <iterator>
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#include <type_traits>
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// For information on range-based for-loops, see
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// http://en.cppreference.com/w/cpp/language/range-for
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namespace gte
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{
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// The function gte::reverse supports reverse iteration in range-based
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// for-loops using the auto keyword. For example,
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//
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// std::vector<int> numbers(4);
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// int i = 0;
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// for (auto& number : numbers)
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// {
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// number = i++;
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// std::cout << number << ' ';
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// }
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// // Output: 0 1 2 3
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//
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// for (auto& number : gte::reverse(numbers))
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// {
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// std::cout << number << ' ';
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// }
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// // Output: 3 2 1 0
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template <typename Iterator>
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class ReversalObject
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{
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public:
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ReversalObject(Iterator begin, Iterator end)
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:
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mBegin(begin),
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mEnd(end)
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{
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}
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Iterator begin() const { return mBegin; }
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Iterator end() const { return mEnd; }
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private:
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Iterator mBegin, mEnd;
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};
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template
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<
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typename Iterable,
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typename Iterator = decltype(std::begin(std::declval<Iterable>())),
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typename ReverseIterator = std::reverse_iterator<Iterator>
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>
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ReversalObject<ReverseIterator> reverse(Iterable && range)
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{
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return ReversalObject<ReverseIterator>(
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ReverseIterator(std::end(range)),
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ReverseIterator(std::begin(range)));
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}
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}
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