mirror of
https://github.com/matrix-construct/construct
synced 2024-07-10 20:48:34 +02:00
57 lines
1.2 KiB
C++
57 lines
1.2 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_H
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namespace ircd {
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namespace json {
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template<class tuple,
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size_t i>
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constexpr enable_if_tuple<tuple, const char *>
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key()
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noexcept
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{
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return tuple_element<tuple, i>::key;
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}
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template<class tuple,
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size_t i>
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constexpr typename std::enable_if<i == tuple::size(), const char *>::type
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key(const size_t &j)
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noexcept
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{
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return nullptr;
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}
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template<class tuple,
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size_t i = 0>
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constexpr typename std::enable_if<i < tuple::size(), const char *>::type
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key(const size_t &j)
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noexcept
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{
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return j == i?
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tuple_element<tuple, i>::key:
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key<tuple, i + 1>(j);
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}
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template<size_t i,
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class tuple>
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enable_if_tuple<tuple, const char *>
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key(const tuple &t)
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noexcept
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{
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return std::get<i>(t).key;
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}
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} // namespace json
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} // namespace ircd
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