// This file is part of OpenCV project.
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// It is subject to the license terms in the LICENSE file found in the top-level directory
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// of this distribution and at http://opencv.org/license.html.
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//
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// Copyright (C) 2018-2019 Intel Corporation
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#ifndef OPENCV_GAPI_UTIL_HPP
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#define OPENCV_GAPI_UTIL_HPP
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#include <tuple>
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// \cond HIDDEN_SYMBOLS
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// This header file contains some generic utility functions which are
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// used in other G-API Public API headers.
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//
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// PLEASE don't put any stuff here if it is NOT used in public API headers!
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namespace cv
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{
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namespace detail
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{
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// Recursive integer sequence type, useful for enumerating elements of
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// template parameter packs.
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template<int... I> struct Seq { using next = Seq<I..., sizeof...(I)>; };
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template<int Sz> struct MkSeq { using type = typename MkSeq<Sz-1>::type::next; };
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template<> struct MkSeq<0>{ using type = Seq<>; };
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// Checks if elements of variadic template satisfy the given Predicate.
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// Implemented via tuple, with an interface to accept plain type lists
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template<template<class> class, typename, typename...> struct all_satisfy;
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template<template<class> class F, typename T, typename... Ts>
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struct all_satisfy<F, std::tuple<T, Ts...> >
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{
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static const constexpr bool value = F<T>::value
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&& all_satisfy<F, std::tuple<Ts...> >::value;
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};
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template<template<class> class F, typename T>
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struct all_satisfy<F, std::tuple<T> >
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{
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static const constexpr bool value = F<T>::value;
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};
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template<template<class> class F, typename T, typename... Ts>
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struct all_satisfy: public all_satisfy<F, std::tuple<T, Ts...> > {};
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// Permute given tuple type C with given integer sequence II
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// Sequence may be less than tuple C size.
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template<class, class> struct permute_tuple;
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template<class C, int... IIs>
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struct permute_tuple<C, Seq<IIs...> >
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{
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using type = std::tuple< typename std::tuple_element<IIs, C>::type... >;
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};
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// Given T..., generates a type sequence of sizeof...(T)-1 elements
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// which is T... without its last element
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// Implemented via tuple, with an interface to accept plain type lists
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template<typename T, typename... Ts> struct all_but_last;
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template<typename T, typename... Ts>
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struct all_but_last<std::tuple<T, Ts...> >
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{
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using C = std::tuple<T, Ts...>;
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using S = typename MkSeq<std::tuple_size<C>::value - 1>::type;
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using type = typename permute_tuple<C, S>::type;
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};
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template<typename T, typename... Ts>
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struct all_but_last: public all_but_last<std::tuple<T, Ts...> > {};
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template<typename... Ts>
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using all_but_last_t = typename all_but_last<Ts...>::type;
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// NB.: This is here because there's no constexpr std::max in C++11
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template<std::size_t S0, std::size_t... SS> struct max_of_t
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{
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static constexpr const std::size_t rest = max_of_t<SS...>::value;
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static constexpr const std::size_t value = rest > S0 ? rest : S0;
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};
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template<std::size_t S> struct max_of_t<S>
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{
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static constexpr const std::size_t value = S;
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};
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template <typename...>
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struct contains : std::false_type{};
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template <typename T1, typename T2, typename... Ts>
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struct contains<T1, T2, Ts...> : std::integral_constant<bool, std::is_same<T1, T2>::value ||
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contains<T1, Ts...>::value> {};
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template<typename T, typename... Types>
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struct contains<T, std::tuple<Types...>> : std::integral_constant<bool, contains<T, Types...>::value> {};
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template <typename...>
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struct all_unique : std::true_type{};
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template <typename T1, typename... Ts>
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struct all_unique<T1, Ts...> : std::integral_constant<bool, !contains<T1, Ts...>::value &&
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all_unique<Ts...>::value> {};
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template<typename>
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struct tuple_wrap_helper;
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template<typename T> struct tuple_wrap_helper
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{
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using type = std::tuple<T>;
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static type get(T&& obj) { return std::make_tuple(std::move(obj)); }
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};
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template<typename... Objs>
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struct tuple_wrap_helper<std::tuple<Objs...>>
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{
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using type = std::tuple<Objs...>;
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static type get(std::tuple<Objs...>&& objs) { return std::forward<std::tuple<Objs...>>(objs); }
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};
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} // namespace detail
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} // namespace cv
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// \endcond
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#endif // OPENCV_GAPI_UTIL_HPP
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