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 * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       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.
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 *       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
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#pragma once


#if THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_NVCC
#include <iterator>
#include <thrust/distance.h>
#include <thrust/system/cuda/detail/execution_policy.h>
#include <thrust/system/cuda/detail/util.h>
#include <thrust/system/cuda/detail/parallel_for.h>

BEGIN_NS_THRUST

namespace cuda_cub {

namespace __uninitialized_copy {

  template <class InputIt, class OutputIt>
  struct functor
  {
    InputIt  input;
    OutputIt output;

    typedef typename iterator_traits<InputIt>::value_type  InputType;
    typedef typename iterator_traits<OutputIt>::value_type OutputType;

    THRUST_FUNCTION
    functor(InputIt input_, OutputIt output_)
        : input(input_), output(output_) {}

    template<class Size>
    void THRUST_DEVICE_FUNCTION operator()(Size idx)
    {
      InputType const &in  = raw_reference_cast(input[idx]);
      OutputType &     out = raw_reference_cast(output[idx]);

#if defined(__CUDA__) && defined(__clang__)
      // XXX unsafe, but clang is seemngly unable to call in-place new
      out = in;
#else
      ::new (static_cast<void *>(&out)) OutputType(in);
#endif
    }
  };    // struct functor

}    // namespace __uninitialized_copy

template <class Derived,
          class InputIt,
          class Size,
          class OutputIt>
OutputIt __host__ __device__
uninitialized_copy_n(execution_policy<Derived> &policy,
                     InputIt                    first,
                     Size                       count,
                     OutputIt                   result)
{
  typedef __uninitialized_copy::functor<InputIt,OutputIt> functor_t;

  cuda_cub::parallel_for(policy,
                         functor_t(first, result),
                         count);
  return result + count;
}

template <class Derived,
          class InputIt,
          class OutputIt>
OutputIt __host__ __device__
uninitialized_copy(execution_policy<Derived>& policy,
                   InputIt                    first,
                   InputIt                    last,
                   OutputIt                   result)
{
  return cuda_cub::uninitialized_copy_n(policy,
                                        first,
                                        thrust::distance(first, last),
                                        result);
}

}    // namespace cuda_

END_NS_THRUST
#endif