 /******************************************************************************
 * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
 *  Modifications Copyright© 2019 Advanced Micro Devices, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * 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.
 *     * Neither the name of the NVIDIA CORPORATION nor the
 *       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
 * ARE DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************/

#pragma once

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


#include <thrust/detail/cstdint.h>
#include <thrust/detail/temporary_array.h>
#include <thrust/system/hip/detail/par_to_seq.h>
#include <thrust/system/hip/detail/util.h>
#include <thrust/system/hip/detail/get_value.h>
#include <thrust/functional.h>
#include <thrust/detail/mpl/math.h>
#include <thrust/detail/minmax.h>
#include <thrust/distance.h>

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

THRUST_NAMESPACE_BEGIN

template <typename DerivedPolicy, typename ForwardIterator, typename BinaryPredicate>
ForwardIterator __host__ __device__
unique(const thrust::detail::execution_policy_base<DerivedPolicy>& exec,
       ForwardIterator                                             first,
       ForwardIterator                                             last,
       BinaryPredicate                                             binary_pred);

template <typename DerivedPolicy,
          typename InputIterator,
          typename OutputIterator,
          typename BinaryPredicate>
__host__ __device__ OutputIterator
unique_copy(const thrust::detail::execution_policy_base<DerivedPolicy>& exec,
            InputIterator                                               first,
            InputIterator                                               last,
            OutputIterator                                              result,
            BinaryPredicate                                             binary_pred);

namespace hip_rocprim
{
namespace __unique
{
    template <typename Derived,
	      typename ItemsInputIt,
	      typename ItemsOutputIt,
              typename BinaryPred>
    THRUST_HIP_RUNTIME_FUNCTION
    ItemsOutputIt unique(execution_policy<Derived>& policy,
                         ItemsInputIt               items_first,
                         ItemsInputIt               items_last,
                         ItemsOutputIt              items_result,
                         BinaryPred                 binary_pred)
    {
        typedef size_t size_type;

        size_type num_items = static_cast<size_type>(thrust::distance(items_first, items_last));
        size_t    temp_storage_bytes   = 0;
        hipStream_t stream             = hip_rocprim::stream(policy);
        bool        debug_sync         = THRUST_HIP_DEBUG_SYNC_FLAG;

        if(num_items == 0)
            return items_result;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::unique(NULL,
                                                    temp_storage_bytes,
                                                    items_first,
                                                    items_result,
                                                    reinterpret_cast<size_type*>(NULL),
                                                    num_items,
                                                    binary_pred,
                                                    stream,
                                                    debug_sync),
                                    "unique failed on 1st step");

        // Allocate temporary storage.
        thrust::detail::temporary_array<thrust::detail::uint8_t, Derived>
            tmp(policy, temp_storage_bytes + sizeof(size_type));
        void *ptr = static_cast<void*>(tmp.data().get());

        size_type* d_num_selected_out = reinterpret_cast<size_type*>(
            reinterpret_cast<char*>(ptr) + temp_storage_bytes);

        hip_rocprim::throw_on_error(rocprim::unique(ptr,
                                                    temp_storage_bytes,
                                                    items_first,
                                                    items_result,
                                                    d_num_selected_out,
                                                    num_items,
                                                    binary_pred,
                                                    stream,
                                                    debug_sync),
                                    "unique failed on 2nd step");

        size_type num_selected = get_value(policy, d_num_selected_out);

        return items_result + num_selected;
    }
} // namespace __unique

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

__thrust_exec_check_disable__ template <class Derived,
                                        class InputIt,
                                        class OutputIt,
                                        class BinaryPred>
OutputIt THRUST_HIP_FUNCTION
unique_copy(execution_policy<Derived>& policy,
            InputIt                    first,
            InputIt                    last,
            OutputIt                   result,
            BinaryPred                 binary_pred)
{
    // struct workaround is required for HIP-clang
    struct workaround
    {
        __host__ static OutputIt par(execution_policy<Derived>& policy,
                                     InputIt                    first,
                                     InputIt                    last,
                                     OutputIt                   result,
                                     BinaryPred                 binary_pred)
        {
            return __unique::unique(policy, first, last, result, binary_pred);
        }
        __device__ static OutputIt seq(execution_policy<Derived>& policy,
                                       InputIt                    first,
                                       InputIt                    last,
                                       OutputIt                   result,
                                       BinaryPred                 binary_pred)
        {
            return thrust::unique_copy(
                cvt_to_seq(derived_cast(policy)), first, last, result, binary_pred);
        }
  };
  #if __THRUST_HAS_HIPRT__
    return workaround::par(policy, first, last, result, binary_pred);
  #else
    return workaround::seq(policy, first, last, result, binary_pred);
  #endif
}

template <class Derived, class InputIt, class OutputIt>
OutputIt THRUST_HIP_FUNCTION
unique_copy(execution_policy<Derived>& policy, InputIt first, InputIt last, OutputIt result)
{
    typedef typename iterator_traits<InputIt>::value_type input_type;
    return hip_rocprim::unique_copy(policy, first, last, result, equal_to<input_type>());
}

__thrust_exec_check_disable__ template <class Derived, class InputIt, class BinaryPred>
InputIt THRUST_HIP_FUNCTION
unique(execution_policy<Derived>& policy,
       InputIt                    first,
       InputIt                    last,
       BinaryPred                 binary_pred)
{
    // struct workaround is required for HIP-clang
    struct workaround
    {
        __host__ static InputIt
        par(execution_policy<Derived>& policy, InputIt first, InputIt last, BinaryPred binary_pred)
        {
            return hip_rocprim::unique_copy(policy, first, last, first, binary_pred);
        }
        __device__ static InputIt
        seq(execution_policy<Derived>& policy, InputIt first, InputIt last, BinaryPred binary_pred)
        {
            return thrust::unique(cvt_to_seq(derived_cast(policy)), first, last, binary_pred);
        }
  };
  #if __THRUST_HAS_HIPRT__
      return workaround::par(policy, first, last, binary_pred);
  #else
      return workaround::seq(policy, first, last, binary_pred);
  #endif
}

template <class Derived, class InputIt>
InputIt THRUST_HIP_FUNCTION unique(execution_policy<Derived>& policy,
                                   InputIt                    first,
                                   InputIt                    last)
{
    typedef typename iterator_traits<InputIt>::value_type input_type;
    return hip_rocprim::unique(policy, first, last, equal_to<input_type>());
}

template <typename BinaryPred>
struct zip_adj_not_predicate {
  template <typename TupleType>
  bool __host__ __device__ operator()(TupleType&& tuple) {
      return !binary_pred(thrust::get<0>(tuple), thrust::get<1>(tuple));
  }
  
  BinaryPred binary_pred;
};

__thrust_exec_check_disable__
template <class Derived,
          class ForwardIt,
          class BinaryPred>
typename thrust::iterator_traits<ForwardIt>::difference_type
THRUST_HIP_FUNCTION
unique_count(execution_policy<Derived> &policy,
       ForwardIt                  first,
       ForwardIt                  last,
       BinaryPred                 binary_pred)
{
  if (first == last) {
    return 0;
  }
  auto size = thrust::distance(first, last);
  auto it = thrust::make_zip_iterator(thrust::make_tuple(first, thrust::next(first)));
  return 1 + thrust::count_if(policy, it, thrust::next(it, size - 1), zip_adj_not_predicate<BinaryPred>{binary_pred});
}

} // namespace hip_rocprim
THRUST_NAMESPACE_END

#include <thrust/memory.h>
#include <thrust/unique.h>
#endif
