/*
 *  Copyright 2008-2013 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#pragma once

#include <thrust/detail/config.h>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#if THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_NVCC
#  include <thrust/system/cuda/config.h>

#  include <thrust/detail/raw_pointer_cast.h>
#  include <thrust/iterator/iterator_traits.h>
#  include <thrust/system/cuda/detail/cross_system.h>

#  include <nv/target>

THRUST_NAMESPACE_BEGIN
namespace cuda_cub
{

namespace
{

template <typename DerivedPolicy, typename Pointer>
inline _CCCL_HOST_DEVICE typename thrust::iterator_value<Pointer>::type
get_value_msvc2005_war(execution_policy<DerivedPolicy>& exec, Pointer ptr)
{
  typedef typename thrust::iterator_value<Pointer>::type result_type;

  // XXX war nvbugs/881631
  struct war_nvbugs_881631
  {
    _CCCL_HOST inline static result_type host_path(execution_policy<DerivedPolicy>& exec, Pointer ptr)
    {
      // when called from host code, implement with assign_value
      // note that this requires a type with default constructor
      result_type result;

      thrust::host_system_tag host_tag;
      cross_system<thrust::host_system_tag, DerivedPolicy> systems(host_tag, exec);
      assign_value(systems, &result, ptr);

      return result;
    }

    _CCCL_DEVICE inline static result_type device_path(execution_policy<DerivedPolicy>&, Pointer ptr)
    {
      // when called from device code, just do simple deref
      return *thrust::raw_pointer_cast(ptr);
    }
  };

  NV_IF_TARGET(
    NV_IS_HOST, (return war_nvbugs_881631::host_path(exec, ptr);), (return war_nvbugs_881631::device_path(exec, ptr);))
} // end get_value_msvc2005_war()
} // namespace

template <typename DerivedPolicy, typename Pointer>
inline _CCCL_HOST_DEVICE typename thrust::iterator_value<Pointer>::type
get_value(execution_policy<DerivedPolicy>& exec, Pointer ptr)
{
  return get_value_msvc2005_war(exec, ptr);
} // end get_value()

} // namespace cuda_cub
THRUST_NAMESPACE_END

#endif
