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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.
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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.
 *
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#pragma once


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

BEGIN_NS_THRUST

namespace cuda_cub {

template <class Derived,
          class InputIt,
          class OutputIt,
          class TransformOp,
          class ScanOp>
OutputIt __host__ __device__
transform_inclusive_scan(execution_policy<Derived> &policy,
                         InputIt                    first,
                         InputIt                    last,
                         OutputIt                   result,
                         TransformOp                transform_op,
                         ScanOp                     scan_op)
{
  // the pseudocode for deducing the type of the temporary used below:
  // 
  // if UnaryFunction is AdaptableUnaryFunction
  //   TemporaryType = AdaptableUnaryFunction::result_type
  // else if OutputIterator is a "pure" output iterator
  //   TemporaryType = InputIterator::value_type
  // else
  //   TemporaryType = OutputIterator::value_type
  //
  // XXX upon c++0x, TemporaryType needs to be:
  // result_of_adaptable_function<UnaryFunction>::type
  typedef typename detail::eval_if<
    detail::has_result_type<TransformOp>::value,
    detail::result_type<TransformOp>,
    detail::eval_if<
      detail::is_output_iterator<OutputIt>::value,
      iterator_value<InputIt>,
      iterator_value<OutputIt>
    >
  >::type result_type;

  typedef typename iterator_traits<InputIt>::difference_type size_type;
  size_type num_items = static_cast<size_type>(thrust::distance(first, last));
  typedef transform_input_iterator_t<result_type,
                                     InputIt,
                                     TransformOp>
      transformed_iterator_t;

  return cuda_cub::inclusive_scan_n(policy,
                                 transformed_iterator_t(first, transform_op),
                                 num_items,
                                 result,
                                 scan_op);
}

template <class Derived,
          class InputIt,
          class OutputIt,
          class TransformOp,
          class T,
          class ScanOp>
OutputIt __host__ __device__
transform_exclusive_scan(execution_policy<Derived> &policy,
                         InputIt                    first,
                         InputIt                    last,
                         OutputIt                   result,
                         TransformOp                transform_op,
                         T                          init,
                         ScanOp                     scan_op)
{
  // the pseudocode for deducing the type of the temporary used below:
  // 
  // if UnaryFunction is AdaptableUnaryFunction
  //   TemporaryType = AdaptableUnaryFunction::result_type
  // else if OutputIterator is a "pure" output iterator
  //   TemporaryType = InputIterator::value_type
  // else
  //   TemporaryType = OutputIterator::value_type
  //
  // XXX upon c++0x, TemporaryType needs to be:
  // result_of_adaptable_function<UnaryFunction>::type

  typedef typename thrust::detail::eval_if<
    thrust::detail::has_result_type<TransformOp>::value,
    thrust::detail::result_type<TransformOp>,
    thrust::detail::eval_if<
      thrust::detail::is_output_iterator<OutputIt>::value,
      thrust::iterator_value<InputIt>,
      thrust::iterator_value<OutputIt>
    >
  >::type result_type;

  typedef typename iterator_traits<InputIt>::difference_type size_type;
  size_type num_items = static_cast<size_type>(thrust::distance(first, last));
  typedef transform_input_iterator_t<result_type,
                                     InputIt,
                                     TransformOp>
      transformed_iterator_t;

  return cuda_cub::exclusive_scan_n(policy,
                                 transformed_iterator_t(first, transform_op),
                                 num_items,
                                 result,
                                 init,
                                 scan_op);
}

}    // namespace cuda_cub

END_NS_THRUST
#endif