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 * Modifications Copyright (c) 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.
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 *       notice, this list of conditions and the following disclaimer in the
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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_HIP
#include <thrust/detail/cstdint.h>
#include <thrust/detail/temporary_array.h>
#include <thrust/binary_search.h>
#include <thrust/distance.h>
#include <thrust/system/hip/detail/par_to_seq.h>
#include <thrust/system/hip/execution_policy.h>

#include <rocprim/rocprim.hpp>

THRUST_NAMESPACE_BEGIN
namespace hip_rocprim
{
namespace __binary_search
{
    template <typename Derived, typename HaystackIt, typename NeedlesIt, typename OutputIt, typename CompareOp>
    THRUST_HIP_RUNTIME_FUNCTION OutputIt
    lower_bound(execution_policy<Derived>& policy,
                HaystackIt                 haystack_begin,
                HaystackIt                 haystack_end,
                NeedlesIt                  needles_begin,
                NeedlesIt                  needles_end,
                OutputIt                   result,
                CompareOp                  compare_op)
    {
        using size_type = typename iterator_traits<NeedlesIt>::difference_type;

        const size_type needles_size  = thrust::distance(needles_begin, needles_end);
        const size_type haystack_size = thrust::distance(haystack_begin, haystack_end);

        if(needles_size == 0)
            return result;

        size_t      storage_size = 0;
        hipStream_t stream       = hip_rocprim::stream(policy);
        bool        debug_sync   = THRUST_HIP_DEBUG_SYNC_FLAG;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::lower_bound(NULL,
                                                         storage_size,
                                                         haystack_begin,
                                                         needles_begin,
                                                         result,
                                                         haystack_size,
                                                         needles_size,
                                                         compare_op,
                                                         stream,
                                                         debug_sync),
                                    "lower_bound: failed on 1st call");

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

        hip_rocprim::throw_on_error(rocprim::lower_bound(ptr,
                                                         storage_size,
                                                         haystack_begin,
                                                         needles_begin,
                                                         result,
                                                         haystack_size,
                                                         needles_size,
                                                         compare_op,
                                                         stream,
                                                         debug_sync),
                                    "lower_bound: failed on 2nt call");



        return result + needles_size;
    }

    template <typename Derived, typename HaystackIt, typename NeedlesIt, typename OutputIt, typename CompareOp>
    THRUST_HIP_RUNTIME_FUNCTION OutputIt
    upper_bound(execution_policy<Derived>& policy,
                HaystackIt                 haystack_begin,
                HaystackIt                 haystack_end,
                NeedlesIt                  needles_begin,
                NeedlesIt                  needles_end,
                OutputIt                   result,
                CompareOp                  compare_op)
    {
        using size_type = typename iterator_traits<NeedlesIt>::difference_type;

        const size_type needles_size  = thrust::distance(needles_begin, needles_end);
        const size_type haystack_size = thrust::distance(haystack_begin, haystack_end);

        if(needles_size == 0)
            return result;

        size_t      storage_size = 0;
        hipStream_t stream       = hip_rocprim::stream(policy);
        bool        debug_sync   = THRUST_HIP_DEBUG_SYNC_FLAG;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::upper_bound(NULL,
                                                         storage_size,
                                                         haystack_begin,
                                                         needles_begin,
                                                         result,
                                                         haystack_size,
                                                         needles_size,
                                                         compare_op,
                                                         stream,
                                                         debug_sync),
                                    "upper_bound: failed on 1st call");

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

        hip_rocprim::throw_on_error(rocprim::upper_bound(ptr,
                                                         storage_size,
                                                         haystack_begin,
                                                         needles_begin,
                                                         result,
                                                         haystack_size,
                                                         needles_size,
                                                         compare_op,
                                                         stream,
                                                         debug_sync),
                                    "upper_bound: failed on 2nt call");



        return result + needles_size;
    }

    template <typename Derived, typename HaystackIt, typename NeedlesIt, typename OutputIt, typename CompareOp>
    THRUST_HIP_RUNTIME_FUNCTION OutputIt
    binary_search(execution_policy<Derived>& policy,
                  HaystackIt                 haystack_begin,
                  HaystackIt                 haystack_end,
                  NeedlesIt                  needles_begin,
                  NeedlesIt                  needles_end,
                  OutputIt                   result,
                  CompareOp                  compare_op)
    {
        using size_type = typename iterator_traits<NeedlesIt>::difference_type;

        const size_type needles_size  = thrust::distance(needles_begin, needles_end);
        const size_type haystack_size = thrust::distance(haystack_begin, haystack_end);

        if(needles_size == 0)
            return result;

        size_t      storage_size = 0;
        hipStream_t stream       = hip_rocprim::stream(policy);
        bool        debug_sync   = THRUST_HIP_DEBUG_SYNC_FLAG;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::binary_search(NULL,
                                                           storage_size,
                                                           haystack_begin,
                                                           needles_begin,
                                                           result,
                                                           haystack_size,
                                                           needles_size,
                                                           compare_op,
                                                           stream,
                                                           debug_sync),
                                    "binary_search: failed on 1st call");

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

        hip_rocprim::throw_on_error(rocprim::binary_search(ptr,
                                                           storage_size,
                                                           haystack_begin,
                                                           needles_begin,
                                                           result,
                                                           haystack_size,
                                                           needles_size,
                                                           compare_op,
                                                           stream,
                                                           debug_sync),
                                    "binary_search: failed on 2nt call");

        return result + needles_size;
    }

} // namespace __binary_search

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

// Vector functions

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt, class CompareOp>
OutputIt THRUST_HIP_FUNCTION
lower_bound(execution_policy<Derived>& policy,
            HaystackIt                 first,
            HaystackIt                 last,
            NeedlesIt                  values_first,
            NeedlesIt                  values_last,
            OutputIt                   result,
            CompareOp                  compare_op)
{
  struct workaround
  {
      __host__
      static OutputIt par(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        #if __HCC__ && __HIP_DEVICE_COMPILE__
          THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
          (__binary_search::lower_bound<Derived,
                                        HaystackIt,
                                        NeedlesIt,
                                        OutputIt,
                                        CompareOp>);
          return first;
        #else
        return __binary_search::lower_bound(
            policy, first, last, values_first, values_last, result, compare_op
        );
        #endif
      }


      __device__
      static OutputIt seq(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        return thrust::lower_bound(cvt_to_seq(derived_cast(policy)),
                                   first,
                                   last,
                                   values_first,
                                   values_last,
                                   result,
                                   compare_op);
      }
  };

  #if __THRUST_HAS_HIPRT__
    return workaround::par(policy, first, last, values_first, values_last, result, compare_op);
  #else
    return workaround::seq(policy, first, last, values_first, values_last, result, compare_op);
  #endif



}

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt>
OutputIt THRUST_HIP_FUNCTION
lower_bound(execution_policy<Derived>& policy,
            HaystackIt                 first,
            HaystackIt                 last,
            NeedlesIt                  values_first,
            NeedlesIt                  values_last,
            OutputIt                   result)
{
    return hip_rocprim::lower_bound(
        policy, first, last, values_first, values_last, result, rocprim::less<>()
    );
}

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt, class CompareOp>
OutputIt THRUST_HIP_FUNCTION
upper_bound(execution_policy<Derived>& policy,
            HaystackIt                 first,
            HaystackIt                 last,
            NeedlesIt                  values_first,
            NeedlesIt                  values_last,
            OutputIt                   result,
            CompareOp                  compare_op)
{
  struct workaround
  {
      __host__
      static OutputIt par(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        #if __HCC__ && __HIP_DEVICE_COMPILE__
          THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
          (__binary_search::upper_bound<Derived,
                                        HaystackIt,
                                        NeedlesIt,
                                        OutputIt,
                                        CompareOp>);
          return first;

        #else
        return __binary_search::upper_bound(
            policy, first, last, values_first, values_last, result, compare_op
        );
        #endif
      }


      __device__
      static OutputIt seq(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        return thrust::upper_bound(cvt_to_seq(derived_cast(policy)),
                                   first,
                                   last,
                                   values_first,
                                   values_last,
                                   result,
                                   compare_op);
      }
  };

  #if __THRUST_HAS_HIPRT__
    return workaround::par(policy, first, last, values_first, values_last, result, compare_op);
  #else
    return workaround::seq(policy, first, last, values_first, values_last, result, compare_op);
  #endif

}

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt>
OutputIt THRUST_HIP_FUNCTION
upper_bound(execution_policy<Derived>& policy,
            HaystackIt                 first,
            HaystackIt                 last,
            NeedlesIt                  values_first,
            NeedlesIt                  values_last,
            OutputIt                   result)
{
    return hip_rocprim::upper_bound(
        policy, first, last, values_first, values_last, result, rocprim::less<>()
    );
}

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt, class CompareOp>
OutputIt THRUST_HIP_FUNCTION
binary_search(execution_policy<Derived>& policy,
              HaystackIt                 first,
              HaystackIt                 last,
              NeedlesIt                  values_first,
              NeedlesIt                  values_last,
              OutputIt                   result,
              CompareOp                  compare_op)
{
  struct workaround
  {
      __host__
      static OutputIt par(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        #if __HCC__ && __HIP_DEVICE_COMPILE__
          THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
          (__binary_search::binary_search<Derived,
                                        HaystackIt,
                                        NeedlesIt,
                                        OutputIt,
                                        CompareOp>);
          return first;

        #else
        return __binary_search::binary_search(
            policy, first, last, values_first, values_last, result, compare_op
        );
        #endif
      }


      __device__
      static OutputIt seq(execution_policy<Derived>& policy,
                          HaystackIt                 first,
                          HaystackIt                 last,
                          NeedlesIt                  values_first,
                          NeedlesIt                  values_last,
                          OutputIt                   result,
                          CompareOp                  compare_op)
      {
        return thrust::binary_search(cvt_to_seq(derived_cast(policy)),
                                   first,
                                   last,
                                   values_first,
                                   values_last,
                                   result,
                                   compare_op);
      }
  };

  #if __THRUST_HAS_HIPRT__
    return workaround::par(policy, first, last, values_first, values_last, result, compare_op);
  #else
    return workaround::seq(policy, first, last, values_first, values_last, result, compare_op);
  #endif

}

template <class Derived, class HaystackIt, class NeedlesIt, class OutputIt>
OutputIt THRUST_HIP_FUNCTION
binary_search(execution_policy<Derived>& policy,
              HaystackIt                 first,
              HaystackIt                 last,
              NeedlesIt                  values_first,
              NeedlesIt                  values_last,
              OutputIt                   result)
{
    return hip_rocprim::binary_search(
        policy, first, last, values_first, values_last, result, rocprim::less<>()
    );
}

// Scalar functions

// We use these custom implementations instead of thrust/system/detail/generic/binary_search.inl
// because HIP support of device-side memory allocation is under development
// (it is used in generic/binary_search.inl by thrust::detail::temporary_array).

template<typename Derived, typename HaystackIt, typename T, typename CompareOp>
THRUST_HIP_FUNCTION
HaystackIt lower_bound(execution_policy<Derived>& policy,
                       HaystackIt                 first,
                       HaystackIt                 last,
                       const T&                   value,
                       CompareOp                  compare_op)
{
    using difference_type = typename thrust::iterator_traits<HaystackIt>::difference_type;
    using values_type = typename thrust::detail::temporary_array<T, Derived>;
    using results_type = typename thrust::detail::temporary_array<difference_type, Derived>;

    struct workaround
    {
        __host__
        static HaystackIt par(execution_policy<Derived>& policy,
                              HaystackIt                 first,
                              HaystackIt                 last,
                              const T&                   value,
                              CompareOp                  compare_op)
        {
          #if __HCC__ && __HIP_DEVICE_COMPILE__
            THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
            (__binary_search::lower_bound<Derived,
                                          HaystackIt,
                                          typename values_type::iterator,
                                          typename results_type::iterator,
                                          CompareOp>);
            return first;
          #else
          values_type values(policy, 1);
          results_type result(policy, 1);

          values[0] = value;

          __binary_search::lower_bound(
              policy, first, last, values.begin(), values.end(), result.begin(), compare_op
          );

          return first + result[0];

          #endif
        }


        __device__
        static HaystackIt seq(execution_policy<Derived>& policy,
                            HaystackIt                 first,
                            HaystackIt                 last,
                            const T&                   value,
                            CompareOp                  compare_op)
        {
          difference_type result;
          thrust::lower_bound(cvt_to_seq(derived_cast(policy)),
                              first,
                              last,
                              &value,
                              &value + 1,
                              &result,
                              compare_op);
          return first + result;
        }
    };

    #if __THRUST_HAS_HIPRT__
      return workaround::par(policy, first, last, value, compare_op);
    #else
      return workaround::seq(policy, first, last, value, compare_op);
    #endif

}

template<typename Derived, typename HaystackIt, typename T, typename CompareOp>
THRUST_HIP_FUNCTION
HaystackIt upper_bound(execution_policy<Derived>& policy,
                       HaystackIt                 first,
                       HaystackIt                 last,
                       const T&                   value,
                       CompareOp                  compare_op)
{
    using difference_type = typename thrust::iterator_traits<HaystackIt>::difference_type;
    using values_type = typename thrust::detail::temporary_array<T, Derived>;
    using results_type = typename thrust::detail::temporary_array<difference_type, Derived>;

    struct workaround
    {
        __host__
        static HaystackIt par(execution_policy<Derived>& policy,
                              HaystackIt                 first,
                              HaystackIt                 last,
                              const T&                   value,
                              CompareOp                  compare_op)
        {
          #if __HCC__ && __HIP_DEVICE_COMPILE__
            THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
            (__binary_search::upper_bound<Derived,
                                          HaystackIt,
                                          typename values_type::iterator,
                                          typename results_type::iterator,
                                          CompareOp>);
            return first;

          #else
          values_type values(policy, 1);
          results_type result(policy, 1);

          values[0] = value;

          __binary_search::upper_bound(
              policy, first, last, values.begin(), values.end(), result.begin(), compare_op
          );

          return first + result[0];

          #endif
        }


        __device__
        static HaystackIt seq(execution_policy<Derived>& policy,
                            HaystackIt                 first,
                            HaystackIt                 last,
                            const T&                   value,
                            CompareOp                  compare_op)
        {
          difference_type result;
          thrust::upper_bound(cvt_to_seq(derived_cast(policy)),
                              first,
                              last,
                              &value,
                              &value + 1,
                              &result,
                              compare_op);
          return first + result;
        }
    };

    #if __THRUST_HAS_HIPRT__
      return workaround::par(policy, first, last, value, compare_op);
    #else
      return workaround::seq(policy, first, last, value, compare_op);
    #endif
}

template<typename Derived, typename HaystackIt, typename T, typename CompareOp>
THRUST_HIP_FUNCTION
bool binary_search(execution_policy<Derived>& policy,
                   HaystackIt                 first,
                   HaystackIt                 last,
                   const T&                   value,
                   CompareOp                  compare_op)
{
    using values_type = typename thrust::detail::temporary_array<T, Derived>;
    using results_type = typename thrust::detail::temporary_array<int, Derived>;

    struct workaround
    {
        __host__
        static bool par(execution_policy<Derived>& policy,
                              HaystackIt                 first,
                              HaystackIt                 last,
                              const T&                   value,
                              CompareOp                  compare_op)
        {
          #if __HCC__ && __HIP_DEVICE_COMPILE__
            THRUST_HIP_PRESERVE_KERNELS_WORKAROUND
            (__binary_search::binary_search<Derived,
                                          HaystackIt,
                                          typename values_type::iterator,
                                          typename results_type::iterator,
                                          CompareOp>);
            return first;
          #else
          values_type values(policy, 1);
          results_type result(policy, 1);

          values[0] = value;

          __binary_search::binary_search(
              policy, first, last, values.begin(), values.end(), result.begin(), compare_op
          );

          return result[0] != 0;
          #endif
        }


        __device__
        static bool seq(execution_policy<Derived>& policy,
                            HaystackIt                 first,
                            HaystackIt                 last,
                            const T&                   value,
                            CompareOp                  compare_op)
        {
          bool result;
          thrust::binary_search(cvt_to_seq(derived_cast(policy)),
                              first,
                              last,
                              &value,
                              &value + 1,
                              &result,
                              compare_op);
          return result;
        }
    };

    #if __THRUST_HAS_HIPRT__
      return workaround::par(policy, first, last, value, compare_op);
    #else
      return workaround::seq(policy, first, last, value, compare_op);
    #endif
}

} // namespace hip_rocprim
THRUST_NAMESPACE_END

#endif