/*
	Copyright (C) 2012  fmaj7b5.info

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef FM7b5_MDVIEW_CUH
#define FM7b5_MDVIEW_CUH

#include <cstdint>
#include <type_traits>

namespace FM7b5
{
	namespace detail
	{
		//! copy const qualifier of From to To
		template <typename From, typename To> struct copy_const { typedef To type; };
		template <typename From, typename To> struct copy_const<const From, To> { typedef typename std::add_const<To>::type type; };

		//! array subscript access for multi dimentional data
		template <typename T, size_t D>
		class MDView
		{
		public:
			typedef T value_type;
			typedef typename copy_const<T, uint_fast8_t>::type* byte_pointer_type;
			typedef typename copy_const<T, void>::type* void_pointer_type;

		protected:
			//! temporal class for resolving the operator[]
			template <typename T, size_t D>
			class ref
			{
				byte_pointer_type const m_p;
				const size_t* const m_extent;

			public:
				typedef ref<T, D-1> result_type;

				__device__
				ref(void_pointer_type p, const size_t* extent)
					: m_p(static_cast<byte_pointer_type>(p)), m_extent(extent)
				{}

				__device__
				result_type operator[](size_t i) const
				{
					return result_type(m_p + *m_extent * i, m_extent + 1);
				}
			};

			template <typename T>
			class ref<T, 1>
			{
				byte_pointer_type const m_p;
				const size_t* const m_extent;

			public:
				typedef typename std::add_reference<T>::type result_type;

				__device__
				ref(void_pointer_type p, const size_t* extent)
					: m_p(static_cast<byte_pointer_type>(p)), m_extent(extent)
				{}

				__device__
				result_type operator[](size_t i) const
				{
					return *reinterpret_cast<T*>(m_p + *m_extent * i);
				}
			};

			byte_pointer_type m_data;
			size_t m_extent[D];

		public:
			MDView() {}

			MDView(void_pointer_type p, const size_t extent[D])
				: m_data(static_cast<byte_pointer_type>(p))
			{
				for (size_t i = 0; i < D; ++i) {
					m_extent[i] = extent[i];
				}
			}

			__device__
			typename ref<T, D>::result_type operator[](size_t i) const
			{
				ref<T, D> r(m_data, m_extent);
				return r[i];
			}
		};
	}

	using detail::MDView;
}

#endif /* FM7b5_MDVIEW_CUH */