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/* Copyright (c) 2008-2022 the MRtrix3 contributors.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Covered Software is provided under this License on an "as is"
* basis, without warranty of any kind, either expressed, implied, or
* statutory, including, without limitation, warranties that the
* Covered Software is free of defects, merchantable, fit for a
* particular purpose or non-infringing.
* See the Mozilla Public License v. 2.0 for more details.
*
* For more details, see http://www.mrtrix.org/.
*/
#ifndef __apply_h__
#define __apply_h__
#include <tuple>
#include <type_traits>
#include "types.h" // For FORCE_INLINE
namespace MR {
namespace {
template<size_t N>
struct Apply { NOMEMALIGN
template<typename F, typename T>
static FORCE_INLINE void apply (F && f, T && t)
{
Apply<N-1>::apply (::std::forward<F>(f), ::std::forward<T>(t));
::std::forward<F>(f) (::std::get<N> (::std::forward<T>(t)));
}
};
template<>
struct Apply<0> { NOMEMALIGN
template<typename F, typename T>
static FORCE_INLINE void apply (F && f, T && t)
{
::std::forward<F>(f) (::std::get<0> (::std::forward<T>(t)));
}
};
template<size_t N>
struct Unpack { NOMEMALIGN
template<typename F, typename T, typename... A>
static FORCE_INLINE auto unpack (F && f, T && t, A &&... a)
-> decltype(Unpack<N-1>::unpack (
::std::forward<F>(f), ::std::forward<T>(t),
::std::get<N-1>(::std::forward<T>(t)), ::std::forward<A>(a)...
))
{
return Unpack<N-1>::unpack (::std::forward<F>(f), ::std::forward<T>(t),
::std::get<N-1>(::std::forward<T>(t)), ::std::forward<A>(a)...
);
}
};
template<>
struct Unpack<0> { NOMEMALIGN
template<typename F, typename T, typename... A>
static FORCE_INLINE auto unpack (F && f, T &&, A &&... a)
-> decltype(::std::forward<F>(f)(::std::forward<A>(a)...))
{
return ::std::forward<F>(f)(::std::forward<A>(a)...);
}
};
}
//! invoke \c f(x) for each entry in \c t
template <class F, class T>
FORCE_INLINE void apply (F && f, T && t)
{
Apply< ::std::tuple_size<
typename ::std::decay<T>::type
>::value-1>::apply (::std::forward<F>(f), ::std::forward<T>(t));
}
//! if \c t is a tuple of elements \c a..., invoke \c f(a...)
template<typename F, typename T>
FORCE_INLINE auto unpack (F && f, T && t)
-> decltype(Unpack< ::std::tuple_size<
typename ::std::decay<T>::type
>::value>::unpack (::std::forward<F>(f), ::std::forward<T>(t)))
{
return Unpack< ::std::tuple_size<
typename ::std::decay<T>::type
>::value>::unpack (::std::forward<F>(f), ::std::forward<T>(t));
}
}
#endif
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