buffer.h

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// SPDX-License-Identifier: BSD-3-Clause
#ifndef TTG_BUFFER_H
#define TTG_BUFFER_H
 
#include <memory>
 
#include "ttg/fwd.h"
#include "ttg/util/meta.h"
#include "ttg/serialization.h"
#include <memory>
 
namespace ttg {
 
template<typename T, typename Allocator = std::allocator<std::decay_t<T>>>
using Buffer = TTG_IMPL_NS::Buffer<T, Allocator>;
 
namespace meta {
 
  /* Specialize some traits */
 
  template<typename T, typename A>
  struct is_buffer<ttg::Buffer<T, A>> : std::true_type
  { };
 
  template<typename T, typename A>
  struct is_buffer<const ttg::Buffer<T, A>> : std::true_type
  { };
 
  /* buffers are const if their value types are const */
  template<typename T, typename A>
  struct is_const<ttg::Buffer<T, A>> : std::is_const<T>
  { };
 
} // namespace meta
 
namespace detail {
  template<typename T, typename Enabler = void>
  struct has_buffer_apply_helper : std::false_type
  { };
 
  template<typename T>
  struct has_buffer_apply : has_buffer_apply_helper<T>
  { };
 
  template<typename T>
  constexpr const bool has_buffer_apply_v = has_buffer_apply<T>::value;
 
} // namespace detail
 
} // namespace ttg
 
 
 
#ifdef TTG_SERIALIZATION_SUPPORTS_MADNESS
#include <madness/world/buffer_archive.h>
 
namespace madness {
  namespace archive {
    template<typename Fn>
    struct BufferVisitorArchive : public madness::archive::BaseOutputArchive {
    private:
      Fn m_fn;
 
    public:
      template<typename _Fn>
      BufferVisitorArchive(_Fn&& fn)
      : m_fn(fn)
      { }
 
 
      template <typename T, typename Allocator>
      void store(const ttg::Buffer<T, Allocator>* t, long n) const {
        /* invoke the function on each buffer */
        for (std::size_t i = 0; i < n; ++i) {
          m_fn(t[i]);
        }
      }
 
      template <typename T>
      void store(const T* t, long n) const {
        /* nothing to be done for other types */
      }
 
      void open(std::size_t /*hint*/) {}
 
      void close() {}
 
      void flush() {}
 
      std::size_t size() const {
          return 0;
      };
    };
 
    /* deduction guide */
    template<typename Fn>
    BufferVisitorArchive(Fn&&) -> BufferVisitorArchive<Fn>;
  } // namespace archive
 
  template <typename Fn>
  struct is_archive<archive::BufferVisitorArchive<Fn>> : std::true_type {};
 
  template <typename Fn>
  struct is_output_archive<archive::BufferVisitorArchive<Fn>> : std::true_type {};
 
  template <typename Fn, typename T>
  struct is_default_serializable_helper<archive::BufferVisitorArchive<Fn>, T,
                                        std::enable_if_t<is_trivially_serializable<T>::value>>
  : std::true_type {};
 
  template <typename Fn, typename T, typename Allocator>
  struct is_default_serializable_helper<archive::BufferVisitorArchive<Fn>, ttg::Buffer<T, Allocator>>
  : std::true_type {};
} // namespace madness
 
namespace ttg::detail {
  template<typename T, typename Fn>
  requires(madness::is_serializable_v<madness::archive::BufferVisitorArchive<Fn>, std::decay<T>>)
  void buffer_apply(T&& t, Fn&& fn) {
    madness::archive::BufferVisitorArchive ar(std::forward<Fn>(fn));
    ar & t;
  }
 
  /* dummy function type used to check whether buffer_apply is available */
  using buffer_apply_dummy_fn = decltype([]<typename T, typename A>(const ttg::Buffer<T, A>&){});
 
  template<typename T>
  struct has_buffer_apply_helper<T, std::enable_if_t<madness::is_serializable_v<madness::archive::BufferVisitorArchive<buffer_apply_dummy_fn>, std::decay_t<T>>>>
  : std::true_type
  { };
 
} // namespace ttg::detail
 
#else
 
namespace ttg::detail {
  template<typename T, typename Fn>
  void buffer_apply(T&& t, Fn&& fn) {
    static_assert(ttg::meta::is_void_v<Fn>, "Types using ttg::Buffer must be MADNESS serializable.");
  }
 
} // namespace ttg::detail
 
#endif // TTG_SERIALIZATION_SUPPORTS_MADNESS
 
#endif // TTG_buffer_H