55 lines
1.7 KiB
C++
55 lines
1.7 KiB
C++
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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
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#if !defined(CPPLINQ_LINQ_SELECT_HPP)
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#define CPPLINQ_LINQ_SELECT_HPP
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#pragma once
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#include <cstddef>
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namespace cpplinq
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{
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template <class Collection, class Selector>
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class linq_select
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{
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typedef typename Collection::cursor
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inner_cursor;
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public:
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struct cursor {
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typedef typename util::result_of<Selector(typename inner_cursor::element_type)>::type
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reference_type;
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typedef typename std::remove_reference<reference_type>::type
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element_type;
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typedef typename inner_cursor::cursor_category
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cursor_category;
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cursor(const inner_cursor& cur, Selector sel) : cur(cur), sel(std::move(sel)) {}
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void forget() { cur.forget(); }
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bool empty() const { return cur.empty(); }
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void inc() { cur.inc(); }
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reference_type get() const { return sel(cur.get()); }
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bool atbegin() const { return cur.atbegin(); }
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void dec() { cur.dec(); }
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void skip(std::size_t n) { cur.skip(n); }
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std::size_t position() const { return cur.position(); }
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std::size_t size() const { return cur.size(); }
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private:
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inner_cursor cur;
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Selector sel;
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};
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linq_select(const Collection& c, Selector sel) : c(c), sel(sel) {}
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cursor get_cursor() const { return cursor(c.get_cursor(), sel); }
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private:
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Collection c;
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Selector sel;
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};
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}
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#endif // defined(CPPLINQ_LINQ_SELECT_HPP)
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