utility.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
 
// SPDX-FileCopyrightText: Copyright © DUNE Project contributors, see file AUTHORS.md
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception OR LGPL-3.0-or-later
 
#ifndef DUNE_FUNCTIONS_COMMON_UTILITY_HH
#define DUNE_FUNCTIONS_COMMON_UTILITY_HH
 
 
#include <utility>
#include <type_traits>
 
#include <dune/common/overloadset.hh>
#include <dune/common/indices.hh>
 
#include <dune/functions/common/functionconcepts.hh>
 
namespace Dune {
namespace Functions {
 
 
namespace Imp {
 
  template<template<class...> class T, class List>
  struct ExpandTupleHelper
  {};
 
  template<template<class...> class T, template<class...> class ListType, class... Args>
  struct ExpandTupleHelper<T, ListType<Args...>>
  {
    using Type = T<Args...>;
  };
 
} // end namespace Imp
 
template<template<class...> class T, class ArgTuple>
using ExpandTuple = typename Imp::ExpandTupleHelper<T, ArgTuple>::Type;
 
 
 
namespace Imp {
 
  template<template<class...> class T, class... Tuple>
  struct TransformTupleHelper
  {};
 
  template<template<class...> class T, class... Args1>
  struct TransformTupleHelper<T, typename std::tuple<Args1...>>
  {
    using Type = std::tuple<T<Args1>...>;
  };
 
  template<template<class...> class T, class... Args1, class... Args2>
  struct TransformTupleHelper<T, typename std::tuple<Args1...>, typename std::tuple<Args2...>>
  {
    using Type = std::tuple<T<Args1, Args2>...>;
  };
 
} // end namespace Imp
 
template<template<class...> class F, class... Tuples>
using TransformTuple = typename Imp::TransformTupleHelper<F, Tuples...>::Type;
 
 
 
namespace Imp {
 
  template<class F, class... T, std::size_t... k>
  auto transformTupleHelper(F&& f, const std::tuple<T...>& tuple, std::index_sequence<k...>)
    -> decltype(std::make_tuple(f(std::get<k>(tuple))...))
  {
    return std::make_tuple(f(std::get<k>(tuple))...);
  }
 
  template<class F, class... T1, class...T2, std::size_t... k>
  auto transformTupleHelper(F&& f, const std::tuple<T1...>& tuple1, const std::tuple<T2...>& tuple2, std::index_sequence<k...>)
    -> decltype(std::make_tuple(f(std::get<k>(tuple1), std::get<k>(tuple2))...))
  {
    return std::make_tuple(f(std::get<k>(tuple1), std::get<k>(tuple2))...);
  }
 
} // end namespace Imp
 
template<class F, class... T>
auto transformTuple(F&& f, const std::tuple<T...>& tuple)
  -> decltype(Imp::transformTupleHelper(std::forward<F>(f), tuple, std::index_sequence_for<T...>{}))
{
  return Imp::transformTupleHelper(std::forward<F>(f), tuple, std::index_sequence_for<T...>{});
}
 
template<class F, class... T1, class... T2>
auto transformTuple(F&& f, const std::tuple<T1...>& tuple1, const std::tuple<T2...>& tuple2)
  -> decltype(Imp::transformTupleHelper(std::forward<F>(f), tuple1, tuple2, std::index_sequence_for<T1...>{}))
{
  return Imp::transformTupleHelper(std::forward<F>(f), tuple1, tuple2, std::index_sequence_for<T1...>{});
}
 
 
 
namespace Imp {
 
  template<class IntegerSequence>
  struct IntegerSequenceTupleHelper
  {};
 
  template<class I, I... k>
  struct IntegerSequenceTupleHelper<std::integer_sequence<I, k...>>
  {
    using Type = std::tuple<std::integral_constant<I, k>...>;
  };
 
} // end namespace Imp
 
template<class IntegerSequence>
using IntegerSequenceTuple= typename Imp::IntegerSequenceTupleHelper<IntegerSequence>::Type;
 
 
 
template<class... T>
struct LastType
{
  using type = std::tuple_element_t<sizeof...(T)-1, std::tuple<T...>>;
};
 
 
 
namespace Imp {
 
template<class T, class I>
struct RotateHelper;
 
template<class... T, std::size_t... I>
struct RotateHelper<std::tuple<T...>, std::index_sequence<I...> >
{
  using type = typename std::tuple<typename LastType<T...>::type, std::tuple_element_t<I,std::tuple<T...>>...>;
};
 
} // end namespace Imp
 
 
template<class... T>
struct RotateTuple
{
  using type = typename Imp::RotateHelper<std::tuple<T...>, std::make_index_sequence<sizeof...(T)-1>>::type;
};
 
 
 
template<class Expression>
auto callableCheck(Expression f)
{
  return [f](auto&&... args){
    return Functions::Concept::isCallable(f, std::forward<decltype(args)>(args)...);
  };
}
 
 
 
template<class Check>
auto negatePredicate(Check check)
{
  return [check](auto&&... args){
    auto negate = overload(
        [](std::true_type) { return std::false_type{};},
        [](std::false_type) { return std::true_type{};},
        [](bool v) { return not v;});
    return negate(check(std::forward<decltype(args)>(args)...));
  };
}
 
 
namespace Impl {
 
  // Wrapper to capture values in a lambda for perfect forwarding.
  // This captures value types by value and reference types by reference.
  template <typename T>
  struct ForwardCaptureWrapper;
 
  template <typename T>
  struct ForwardCaptureWrapper
  {
    template <typename TT>
    ForwardCaptureWrapper(TT&& t) : t_{std::forward<TT>(t)} {}
 
    auto forward() const { return std::move(t_); }
 
    T t_;
  };
 
  template <typename T>
  struct ForwardCaptureWrapper<T&>
  {
    ForwardCaptureWrapper(T& t) : t_{t} {}
 
    T& forward() const { return t_; };
 
    T& t_;
  };
 
  template <typename T>
  struct ForwardCaptureWrapper<const T&>
  {
    ForwardCaptureWrapper(const T& t) : t_{t} {}
 
    const T& forward() const { return t_; };
 
    const T& t_;
  };
 
} // end namespace Dune::Functions::Impl
 
 
 
template <class T>
auto forwardCapture(T&& t)
{
    return Impl::ForwardCaptureWrapper<T>(std::forward<T>(t));
}
 
 
 
} // namespace Dune::Functions
} // namespace Dune
 
 
#endif // DUNE_FUNCTIONS_COMMON_UTILITY_HH