49 lines
1.2 KiB
C++
49 lines
1.2 KiB
C++
#pragma once
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#include "utils/iterator/composable.hpp"
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#include "utils/iterator/iterator_base.hpp"
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namespace iter
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{
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// Wraps lambda into interator with next().
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// T - type of return value
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// F - type of wraped lambda
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template <class T, class F>
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class LambdaIterator : public IteratorBase<T>,
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public Composable<T, LambdaIterator<T, F>>
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{
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public:
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LambdaIterator(F &&f, size_t count) : func(std::move(f)), _count(count) {}
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LambdaIterator(LambdaIterator &&other)
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: func(std::move(other.func)), _count(other._count)
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{
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}
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~LambdaIterator() final {}
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Option<T> next() final
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{
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_count = _count > 0 ? _count - 1 : 0;
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return func();
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}
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Count count() final { return Count(_count); }
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private:
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F func;
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size_t _count;
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};
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// Wraps lambda which returns options as an iterator.
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template <class F>
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auto make_iterator(F &&f, size_t count)
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{
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// Because function isn't receving or in any way using type T from
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// FunctionIterator compiler can't deduce it thats way there is decltype in
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// construction of FunctionIterator. Resoulting type of iter.next().take()
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// is T.
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return LambdaIterator<decltype(f().take()), F>(std::move(f), count);
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}
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}
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