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 *       names of its contributors may be used to endorse or promote products
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#pragma once

#if THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_HCC
#include <thrust/system/hip/config.h>

#include <thrust/detail/config.h>
#include <thrust/pair.h>

#include <thrust/detail/alignment.h>
#include <thrust/detail/cstdint.h>
#include <thrust/detail/minmax.h>
#include <thrust/detail/raw_reference_cast.h>
#include <thrust/detail/temporary_array.h>
#include <thrust/detail/type_traits/iterator/is_output_iterator.h>
#include <thrust/device_vector.h>
#include <thrust/distance.h>
#include <thrust/functional.h>
#include <thrust/system/hip/detail/get_value.h>
#include <thrust/system/hip/detail/par_to_seq.h>
#include <thrust/system/hip/detail/util.h>

// rocprim include
#include <rocprim/rocprim.hpp>

BEGIN_NS_THRUST

template <typename DerivedPolicy,
          typename InputIterator1,
          typename InputIterator2,
          typename OutputIterator1,
          typename OutputIterator2,
          typename BinaryPredicate>
thrust::pair<OutputIterator1, OutputIterator2> __host__ __device__
reduce_by_key(const thrust::detail::execution_policy_base<DerivedPolicy>& exec,
              InputIterator1                                              keys_first,
              InputIterator1                                              keys_last,
              InputIterator2                                              values_first,
              OutputIterator1                                             keys_output,
              OutputIterator2                                             values_output,
              BinaryPredicate                                             binary_pred);

namespace hip_rocprim
{
namespace __reduce_by_key
{
    template <class Derived,
              class KeysInputIt,
              class ValuesInputIt,
              class KeysOutputIt,
              class ValuesOutputIt,
              class EqualityOp,
              class ReductionOp>
    pair<KeysOutputIt, ValuesOutputIt> THRUST_HIP_RUNTIME_FUNCTION
    reduce_by_key(execution_policy<Derived>& policy,
                  KeysInputIt                keys_first,
                  KeysInputIt                keys_last,
                  ValuesInputIt              values_first,
                  KeysOutputIt               keys_output,
                  ValuesOutputIt             values_output,
                  EqualityOp                 equality_op,
                  ReductionOp                reduction_op)
    {
        typedef size_t size_type;
        size_type   num_items = static_cast<size_type>(thrust::distance(keys_first, keys_last));
        void*       d_temp_storage     = NULL;
        size_t      temp_storage_bytes = 0;
        hipStream_t stream             = hip_rocprim::stream(policy);
        size_type*  d_num_runs_out     = NULL;
        bool        debug_sync         = THRUST_HIP_DEBUG_SYNC_FLAG;

        if(num_items == 0)
            return thrust::make_pair(keys_output, values_output);

        hip_rocprim::throw_on_error(rocprim::reduce_by_key(d_temp_storage,
                                                           temp_storage_bytes,
                                                           keys_first,
                                                           values_first,
                                                           num_items,
                                                           keys_output,
                                                           values_output,
                                                           d_num_runs_out,
                                                           reduction_op,
                                                           equality_op,
                                                           stream,
                                                           debug_sync),
                                    "reduce_by_key failed on 1st step");

        // Allocate temporary storage.
        d_temp_storage
            = hip_rocprim::get_memory_buffer(policy, sizeof(size_type) + temp_storage_bytes);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "reduce_by_key failed to get memory buffer");

        d_num_runs_out = reinterpret_cast<size_type*>(reinterpret_cast<char*>(d_temp_storage)
                                                      + temp_storage_bytes);

        hip_rocprim::throw_on_error(rocprim::reduce_by_key(d_temp_storage,
                                                           temp_storage_bytes,
                                                           keys_first,
                                                           values_first,
                                                           num_items,
                                                           keys_output,
                                                           values_output,
                                                           d_num_runs_out,
                                                           reduction_op,
                                                           equality_op,
                                                           stream,
                                                           debug_sync),
                                    "reduce_by_key failed on 2nd step");

        size_type num_runs_out = hip_rocprim::get_value(policy, d_num_runs_out);

        hip_rocprim::return_memory_buffer(policy, d_temp_storage);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "reduce_by_key failed to return memory buffer");

        return thrust::make_pair(keys_output + num_runs_out, values_output + num_runs_out);
    }

} // namespace __reduce_by_key

//-------------------------
// Thrust API entry points
//-------------------------

__thrust_exec_check_disable__ template <class Derived,
                                        class KeyInputIt,
                                        class ValInputIt,
                                        class KeyOutputIt,
                                        class ValOutputIt,
                                        class BinaryPred,
                                        class BinaryOp>
pair<KeyOutputIt, ValOutputIt> THRUST_HIP_FUNCTION
reduce_by_key(execution_policy<Derived>& policy,
              KeyInputIt                 keys_first,
              KeyInputIt                 keys_last,
              ValInputIt                 values_first,
              KeyOutputIt                keys_output,
              ValOutputIt                values_output,
              BinaryPred                 binary_pred,
              BinaryOp                   binary_op)
{
    pair<KeyOutputIt, ValOutputIt> ret = thrust::make_pair(keys_output, values_output);

    THRUST_HIP_PRESERVE_KERNELS_WORKAROUND(
        (__reduce_by_key::reduce_by_key<Derived,
                                        KeyInputIt,
                                        ValInputIt,
                                        KeyOutputIt,
                                        ValOutputIt,
                                        BinaryPred,
                                        BinaryOp>)
    );
#if __THRUST_HAS_HIPRT__
    ret = __reduce_by_key::reduce_by_key(policy,
                                         keys_first,
                                         keys_last,
                                         values_first,
                                         keys_output,
                                         values_output,
                                         binary_pred,
                                         binary_op);
#else // __THRUST_HAS_HIPRT__
    ret = thrust::reduce_by_key(cvt_to_seq(derived_cast(policy)),
                                keys_first,
                                keys_last,
                                values_first,
                                keys_output,
                                values_output,
                                binary_pred,
                                binary_op);
#endif // __THRUST_HAS_HIPRT__
    return ret;
}

__thrust_exec_check_disable__ template <class Derived,
                                        class KeyInputIt,
                                        class ValInputIt,
                                        class KeyOutputIt,
                                        class ValOutputIt,
                                        class BinaryPred>
pair<KeyOutputIt, ValOutputIt> THRUST_HIP_FUNCTION
reduce_by_key(execution_policy<Derived>& policy,
              KeyInputIt                 keys_first,
              KeyInputIt                 keys_last,
              ValInputIt                 values_first,
              KeyOutputIt                keys_output,
              ValOutputIt                values_output,
              BinaryPred                 binary_pred)
{
    typedef typename thrust::detail::eval_if<thrust::detail::is_output_iterator<ValOutputIt>::value,
                                             thrust::iterator_value<ValInputIt>,
                                             thrust::iterator_value<ValOutputIt>>::type value_type;

    return hip_rocprim::reduce_by_key(policy,
                                      keys_first,
                                      keys_last,
                                      values_first,
                                      keys_output,
                                      values_output,
                                      binary_pred,
                                      plus<value_type>());
}

__thrust_exec_check_disable__ template <class Derived,
                                        class KeyInputIt,
                                        class ValInputIt,
                                        class KeyOutputIt,
                                        class ValOutputIt>
pair<KeyOutputIt, ValOutputIt> THRUST_HIP_FUNCTION
reduce_by_key(execution_policy<Derived>& policy,
              KeyInputIt                 keys_first,
              KeyInputIt                 keys_last,
              ValInputIt                 values_first,
              KeyOutputIt                keys_output,
              ValOutputIt                values_output)
{
    typedef typename thrust::iterator_value<KeyInputIt>::type KeyT;
    return hip_rocprim::reduce_by_key(policy,
                                      keys_first,
                                      keys_last,
                                      values_first,
                                      keys_output,
                                      values_output,
                                      equal_to<KeyT>());
}

} // namespace  hip_rocprim
END_NS_THRUST

#endif