simd_bitset.h

/* SPDX-License-Identifier: LGPL-3.0-or-later */
/* Copyright © 2022–2024 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
 *                       Matthias Kretz <m.kretz@gsi.de>
 */
 
#ifndef VIR_SIMD_BITSET_H_
#define VIR_SIMD_BITSET_H_
 
#include <bitset>
#include "simd.h"
#include "detail.h"
 
namespace vir
{
  template <typename T, typename A>
    std::bitset<stdx::simd_size_v<T, A>>
    to_bitset(const stdx::simd_mask<T, A>& k)
    {
#if VIR_GLIBCXX_STDX_SIMD
      return k.__to_bitset();
#else
      if constexpr (stdx::simd_size_v<T, A> == 1)
        return k[0];
      else
        {
          constexpr int N = stdx::simd_size_v<T, A>;
          std::bitset<N> bits;
          for (int i = 0; i < N; ++i)
            bits[i] = k[i];
          return bits;
        }
#endif
    }
 
  template <typename M>
    std::enable_if_t<stdx::is_simd_mask_v<M>, M>
    to_simd_mask(std::bitset<M::size()> bits)
    {
#if VIR_GLIBCXX_STDX_SIMD
      return M::__from_bitset(bits);
#else
      if constexpr (M::size() == 1)
        return M(bits[0]);
      else
        return M([bits](size_t i) -> bool { return bits[i]; });
#endif
    }
 
  template <typename T, typename A>
    auto
    to_simd_mask(std::bitset<stdx::simd_size_v<T, A>> bits)
    -> decltype(to_simd_mask<stdx::simd_mask<T, A>>(bits))
    { return to_simd_mask<stdx::simd_mask<T, A>>(bits); }
 
  template <typename T, std::size_t N>
    auto
    to_simd_mask(std::bitset<N> bits)
    -> decltype(to_simd_mask<stdx::simd_mask<T, stdx::simd_abi::deduce_t<T, N>>>(bits))
    { return to_simd_mask<stdx::simd_mask<T, stdx::simd_abi::deduce_t<T, N>>>(bits); }
}
 
#endif // VIR_SIMD_BITSET_H_