makeContainer.h

/*  This file is part of the Vc library. {{{
Copyright © 2013-2015 Matthias Kretz <kretz@kde.org>
All rights reserved.

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      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the names of contributing organizations nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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}}}*/

#ifndef VC_COMMON_MAKECONTAINER_H_
#define VC_COMMON_MAKECONTAINER_H_

#include <Vc/vector.h>
#include <initializer_list>
#include "macros.h"

namespace Vc_VERSIONED_NAMESPACE
{

    namespace
    {
        template<typename Container, typename T> struct make_container_helper
        {
            static constexpr Container help(std::initializer_list<T> list) { return { list }; }
        };

        template <typename T_, typename Abi, typename Alloc,
                  template <class, class> class Container>
        struct make_container_helper<Container<Vector<T_, Abi>, Alloc>,
                                     typename Vector<T_, Abi>::EntryType> {
            typedef Vector<T_, Abi> V;
            typedef typename V::EntryType T;
            typedef Container<V, Alloc> C;
            static inline C help(std::initializer_list<T> list) {
                const std::size_t size = (list.size() + (V::Size - 1)) / V::Size;
                C v(size);
                auto containerIt = v.begin();
                auto init = std::begin(list);
                const auto initEnd = std::end(list);
                for (std::size_t i = 0; i < size - 1; ++i) {
                    *containerIt++ = V(init, Vc::Unaligned);
                    init += V::Size;
                }
                Vc_ASSERT(all_of(*containerIt == V::Zero()));
                int j = 0;
                while (init != initEnd) {
                    (*containerIt)[j++] = *init++;
                }
                return v;
            }
        };

        template <typename T_, typename Abi, std::size_t N,
                  template <class, std::size_t> class Container>
        struct make_container_helper<Container<Vector<T_, Abi>, N>,
                                     typename Vector<T_, Abi>::EntryType> {
            typedef Vector<T_, Abi> V;
            typedef typename V::EntryType T;
            static constexpr std::size_t size = (N + (V::Size - 1)) / V::Size;
            typedef Container<
                V,
#if defined Vc_CLANG && Vc_CLANG < 0x30700
                // clang before 3.7.0 has a bug when returning std::array<__m256x, 1>. So
                // increase it to std::array<__m256x, 2> and fill it with zeros. Better
                // than returning garbage.
                (size == 1 && std::is_same<Abi, VectorAbi::Avx>::value) ? 2 :
#endif
                                                                        size> C;
            static inline C help(std::initializer_list<T> list) {
                Vc_ASSERT(N == list.size())
                Vc_ASSERT(size == (list.size() + (V::Size - 1)) / V::Size)
                C v;
                auto containerIt = v.begin();
                auto init = std::begin(list);
                const auto initEnd = std::end(list);
                for (std::size_t i = 0; i < size - 1; ++i) {
                    *containerIt++ = V(init, Vc::Unaligned);
                    init += V::Size;
                }
                Vc_ASSERT(all_of(*containerIt == V::Zero()));
                int j = 0;
                while (init != initEnd) {
                    (*containerIt)[j++] = *init++;
                }
                return v;
            }
        };
    } // anonymous namespace

    template<typename Container, typename T>
    constexpr auto makeContainer(std::initializer_list<T> list) -> decltype(make_container_helper<Container, T>::help(list))
    {
        return make_container_helper<Container, T>::help(list);
    }

    template<typename Container, typename T>
    constexpr auto make_container(std::initializer_list<T> list) -> decltype(makeContainer<Container, T>(list))
    {
        return makeContainer<Container, T>(list);
    }

}  // namespace Vc

#endif // VC_COMMON_MAKECONTAINER_H_