host_unique_ptr.h

#ifndef HeterogeneousCore_CUDAUtilities_interface_host_unique_ptr_h
#define HeterogeneousCore_CUDAUtilities_interface_host_unique_ptr_h

#include <memory>
#include <functional>

#include "allocate_host.h"

namespace cudautils {
  namespace host {
    namespace impl {
      // Additional layer of types to distinguish from host::unique_ptr
      class HostDeleter {
      public:
        void operator()(void *ptr) { cudautils::free_host(ptr); }
      };
    }

    template <typename T>
    using unique_ptr = std::unique_ptr<T, impl::HostDeleter>;

    namespace impl {
      template <typename T>
      struct make_host_unique_selector { using non_array = cudautils::host::unique_ptr<T>; };
      template <typename T>
      struct make_host_unique_selector<T[]> { using unbounded_array = cudautils::host::unique_ptr<T[]>; };
      template <typename T, size_t N>
      struct make_host_unique_selector<T[N]> { struct bounded_array {}; };
    }
  }

  // Allocate pinned host memory
  template <typename T>
  typename host::impl::make_host_unique_selector<T>::non_array
  make_host_unique(cudaStream_t stream) {
    static_assert(std::is_trivially_constructible<T>::value, "Allocating with non-trivial constructor on the pinned host memory is not supported");
    void *mem = allocate_host(sizeof(T), stream);
    return typename host::impl::make_host_unique_selector<T>::non_array{reinterpret_cast<T *>(mem)};
  }

  template <typename T>
  typename host::impl::make_host_unique_selector<T>::unbounded_array
  make_host_unique(size_t n, cudaStream_t stream) {
    using element_type = typename std::remove_extent<T>::type;
    static_assert(std::is_trivially_constructible<element_type>::value, "Allocating with non-trivial constructor on the pinned host memory is not supported");
    void *mem = allocate_host(n*sizeof(element_type), stream);
    return typename host::impl::make_host_unique_selector<T>::unbounded_array{reinterpret_cast<element_type *>(mem)};
  }

  template <typename T, typename ...Args>
  typename host::impl::make_host_unique_selector<T>::bounded_array
  make_host_unique(Args&&...) = delete;


  // No check for the trivial constructor, make it clear in the interface
  template <typename T>
  typename host::impl::make_host_unique_selector<T>::non_array
  make_host_unique_uninitialized(cudaStream_t stream) {
    void *mem = allocate_host(sizeof(T), stream);
    return typename host::impl::make_host_unique_selector<T>::non_array{reinterpret_cast<T *>(mem)};
  }

  template <typename T>
  typename host::impl::make_host_unique_selector<T>::unbounded_array
  make_host_unique_uninitialized(size_t n, cudaStream_t stream) {
    using element_type = typename std::remove_extent<T>::type;
    void *mem = allocate_host(n*sizeof(element_type), stream);
    return typename host::impl::make_host_unique_selector<T>::unbounded_array{reinterpret_cast<element_type *>(mem)};
  }

  template <typename T, typename ...Args>
  typename host::impl::make_host_unique_selector<T>::bounded_array
  make_host_unique_uninitialized(Args&&...) = delete;
}

#endif