mirror of
https://github.com/matrix-construct/construct
synced 2024-08-17 15:14:43 +02:00
435 lines
9.5 KiB
C++
435 lines
9.5 KiB
C++
/*
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* charybdis: 21st Century IRC++d
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* util.h: Miscellaneous utilities
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*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 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.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#define HAVE_IRCD_TUPLE_H
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//
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// Utilities for std::tuple
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//
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namespace ircd::util
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{
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template<class tuple>
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constexpr bool
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is_tuple()
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{
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return is_specialization_of<tuple, std::tuple>::value;
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}
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template<class tuple>
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constexpr typename std::enable_if<is_tuple<tuple>(), size_t>::type
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size()
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{
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return std::tuple_size<tuple>::value;
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}
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template<class... args>
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constexpr size_t
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size(const std::tuple<args...> &t)
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{
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return size<std::tuple<args...>>();
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}
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//
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// Iteration of a tuple
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//
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// for_each(tuple, [](auto&& elem) { ... });
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template<size_t i,
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class func,
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class... args>
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constexpr typename std::enable_if<i == std::tuple_size<std::tuple<args...>>::value, void>::type
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for_each(std::tuple<args...> &t,
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func&& f)
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{}
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template<size_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == std::tuple_size<std::tuple<args...>>::value, void>::type
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for_each(const std::tuple<args...> &t,
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func&& f)
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{}
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template<size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i < std::tuple_size<std::tuple<args...>>::value, void>::type
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for_each(const std::tuple<args...> &t,
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func&& f)
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{
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f(std::get<i>(t));
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for_each<i+1>(t, std::forward<func>(f));
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}
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template<size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i < std::tuple_size<std::tuple<args...>>::value, void>::type
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for_each(std::tuple<args...> &t,
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func&& f)
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{
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f(std::get<i>(t));
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for_each<i+1>(t, std::forward<func>(f));
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}
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//
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// Circuits for reverse iteration of a tuple
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//
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// rfor_each(tuple, [](auto&& elem) { ... });
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == 0, void>::type
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rfor_each(const std::tuple<args...> &t,
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func&& f)
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{}
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == 0, void>::type
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rfor_each(std::tuple<args...> &t,
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func&& f)
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{}
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i > 0), void>::type
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rfor_each(const std::tuple<args...> &t,
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func&& f)
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{
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f(std::get<i - 1>(t));
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rfor_each<i - 1>(t, std::forward<func>(f));
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}
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i > 0), void>::type
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rfor_each(std::tuple<args...> &t,
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func&& f)
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{
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f(std::get<i - 1>(t));
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rfor_each<i - 1>(t, std::forward<func>(f));
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}
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template<ssize_t i = -1,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i == -1), void>::type
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rfor_each(const std::tuple<args...> &t,
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func&& f)
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{
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constexpr const ssize_t size
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{
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std::tuple_size<std::tuple<args...>>::value
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};
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rfor_each<size>(t, std::forward<func>(f));
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}
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template<ssize_t i = -1,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i == -1), void>::type
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rfor_each(std::tuple<args...> &t,
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func&& f)
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{
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constexpr const ssize_t size
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{
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std::tuple_size<std::tuple<args...>>::value
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};
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rfor_each<size>(t, std::forward<func>(f));
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}
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//
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// Iteration of a tuple until() style: your closure returns true to continue, false
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// to break. until() then remains true to the end, or returns false if not.
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template<size_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == std::tuple_size<std::tuple<args...>>::value, bool>::type
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until(std::tuple<args...> &t,
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func&& f)
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{
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return true;
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}
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template<size_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == std::tuple_size<std::tuple<args...>>::value, bool>::type
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until(const std::tuple<args...> &t,
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func&& f)
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{
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return true;
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}
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template<size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i < std::tuple_size<std::tuple<args...>>::value, bool>::type
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until(std::tuple<args...> &t,
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func&& f)
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{
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using value_type = typename std::tuple_element<i, std::tuple<args...>>::type;
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return f(static_cast<value_type &>(std::get<i>(t)))? until<i+1>(t, f) : false;
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}
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template<size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i < std::tuple_size<std::tuple<args...>>::value, bool>::type
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until(const std::tuple<args...> &t,
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func&& f)
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{
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using value_type = typename std::tuple_element<i, std::tuple<args...>>::type;
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return f(static_cast<const value_type &>(std::get<i>(t)))? until<i+1>(t, f) : false;
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}
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//
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// Circuits for reverse iteration of a tuple
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//
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// runtil(tuple, [](auto&& elem) -> bool { ... });
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == 0, bool>::type
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runtil(const std::tuple<args...> &t,
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func&& f)
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{
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return true;
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}
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == 0, bool>::type
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runtil(std::tuple<args...> &t,
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func&& f)
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{
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return true;
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}
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template<ssize_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i > 0), bool>::type
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runtil(const std::tuple<args...> &t,
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func&& f)
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{
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return f(std::get<i - 1>(t))? runtil<i - 1>(t, f) : false;
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}
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template<ssize_t i,
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class func,
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class... args>
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constexpr typename std::enable_if<(i > 0), bool>::type
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runtil(std::tuple<args...> &t,
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func&& f)
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{
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return f(std::get<i - 1>(t))? runtil<i - 1>(t, f) : false;
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}
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template<ssize_t i = -1,
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class func,
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class... args>
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constexpr typename std::enable_if<(i == -1), bool>::type
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runtil(const std::tuple<args...> &t,
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func&& f)
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{
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constexpr const auto size
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{
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std::tuple_size<std::tuple<args...>>::value
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};
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return runtil<size>(t, std::forward<func>(f));
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}
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template<ssize_t i = -1,
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class func,
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class... args>
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constexpr typename std::enable_if<(i == -1), bool>::type
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runtil(std::tuple<args...> &t,
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func&& f)
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{
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constexpr const auto size
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{
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std::tuple_size<std::tuple<args...>>::value
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};
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return runtil<size>(t, std::forward<func>(f));
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}
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//
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// test() is a logical inversion of until() for intuitive find()-like
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// boolean semantics.
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//
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template<size_t i,
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class func,
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class... args>
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constexpr auto
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test(std::tuple<args...> &t,
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func&& f)
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{
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return !until(t, [&f](auto&& arg)
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{
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return !f(arg);
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});
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}
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template<size_t i,
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class func,
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class... args>
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constexpr auto
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rtest(std::tuple<args...> &t,
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func&& f)
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{
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return !runtil(t, [&f](auto&& arg)
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{
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return !f(arg);
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});
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}
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//
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// Kronecker delta
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//
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template<size_t j,
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size_t i,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == j, void>::type
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kronecker_delta(const std::tuple<args...> &t,
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func&& f)
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{
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using value_type = typename std::tuple_element<i, std::tuple<args...>>::type;
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f(static_cast<const value_type &>(std::get<i>(t)));
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}
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template<size_t i,
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size_t j,
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class func,
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class... args>
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constexpr
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typename std::enable_if<i == j, void>::type
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kronecker_delta(std::tuple<args...> &t,
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func&& f)
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{
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using value_type = typename std::tuple_element<i, std::tuple<args...>>::type;
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f(static_cast<value_type &>(std::get<i>(t)));
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}
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template<size_t j,
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size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i < j), void>::type
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kronecker_delta(const std::tuple<args...> &t,
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func&& f)
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{
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kronecker_delta<j, i + 1>(t, std::forward<func>(f));
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}
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template<size_t j,
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size_t i = 0,
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class func,
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class... args>
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constexpr
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typename std::enable_if<(i < j), void>::type
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kronecker_delta(std::tuple<args...> &t,
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func&& f)
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{
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kronecker_delta<j, i + 1>(t, std::forward<func>(f));
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}
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//
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// Get the index of a tuple element by address at runtime
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//
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template<class tuple>
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size_t
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indexof(tuple &t, const void *const &ptr)
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{
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size_t ret(0);
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const auto closure([&ret, &ptr]
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(auto &elem)
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{
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if(reinterpret_cast<const void *>(std::addressof(elem)) == ptr)
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return false;
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++ret;
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return true;
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});
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if(unlikely(until(t, closure)))
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throw std::out_of_range("no member of this tuple with that address");
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return ret;
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}
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//
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// Tuple layouts are not standard layouts; we can only do this at runtime
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//
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template<size_t index,
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class tuple>
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off_t
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tuple_offset(const tuple &t)
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{
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return
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{
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reinterpret_cast<const uint8_t *>(std::addressof(std::get<index>(t))) -
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reinterpret_cast<const uint8_t *>(std::addressof(t))
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};
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}
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} // namespace ircd::util
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