apply.h

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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)...);
          }
      };
 
  }
 
 
 
 
  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));
    }
 
  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