mirror of
https://github.com/matrix-construct/construct
synced 2024-12-28 00:14:07 +01:00
85 lines
1.8 KiB
C++
85 lines
1.8 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_JSON_TUPLE__KEY_TRANSFORM_H
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namespace ircd {
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namespace json {
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template<class tuple,
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class it_a,
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class it_b,
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size_t i,
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class closure>
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constexpr typename std::enable_if<i == tuple::size(), it_a>::type
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_key_transform(it_a it,
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const it_b &end,
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closure&& lambda)
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{
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return it;
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}
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template<class tuple,
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class it_a,
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class it_b,
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size_t i = 0,
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class closure>
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constexpr typename std::enable_if<i < tuple::size(), it_a>::type
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_key_transform(it_a it,
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const it_b &end,
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closure&& lambda)
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{
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if(it != end)
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{
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*it = lambda(key<tuple, i>());
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++it;
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}
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return _key_transform<tuple, it_a, it_b, i + 1>(it, end, std::forward<closure>(lambda));
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}
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template<class tuple,
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class it_a,
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class it_b>
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constexpr auto
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_key_transform(it_a it,
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const it_b &end)
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{
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return _key_transform<tuple>(it, end, []
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(auto&& key)
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{
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return key;
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});
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}
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template<class it_a,
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class it_b,
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class... T>
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auto
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_key_transform(const tuple<T...> &tuple,
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it_a it,
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const it_b &end)
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{
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for_each(tuple, [&it, &end]
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(const auto &key, const auto &val)
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{
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if(it != end)
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{
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*it = key;
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++it;
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}
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});
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return it;
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}
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} // namespace json
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} // namespace ircd
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