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 *     * Redistributions of source code must retain the above copyright
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#pragma once

#include <cub/config.cuh>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cub/agent/agent_three_way_partition.cuh>
#include <cub/agent/single_pass_scan_operators.cuh>
#include <cub/block/block_load.cuh>
#include <cub/block/block_scan.cuh>
#include <cub/util_device.cuh>
#include <cub/util_math.cuh>
#include <cub/util_type.cuh>

CUB_NAMESPACE_BEGIN

namespace detail
{

namespace three_way_partition
{

enum class input_size
{
  _1,
  _2,
  _4,
  _8,
  _16,
  unknown
};

enum class offset_size
{
  _4,
  _8,
  unknown
};

template <class InputT>
constexpr input_size classify_input_size()
{
  return sizeof(InputT) == 1 ? input_size::_1
       : sizeof(InputT) == 2 ? input_size::_2
       : sizeof(InputT) == 4 ? input_size::_4
       : sizeof(InputT) == 8 ? input_size::_8
       : sizeof(InputT) == 16
         ? input_size::_16
         : input_size::unknown;
}

template <class OffsetT>
constexpr offset_size classify_offset_size()
{
  return sizeof(OffsetT) == 4 ? offset_size::_4 : sizeof(OffsetT) == 8 ? offset_size::_8 : offset_size::unknown;
}

template <class InputT,
          class OffsetT,
          input_size InputSize   = classify_input_size<InputT>(),
          offset_size OffsetSize = classify_offset_size<OffsetT>()>
struct sm90_tuning
{
  static constexpr int threads = 256;
  static constexpr int items   = Nominal4BItemsToItems<InputT>(9);

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using AccumPackHelperT  = detail::three_way_partition::accumulator_pack_t<OffsetT>;
  using AccumPackT        = typename AccumPackHelperT::pack_t;
  using delay_constructor = detail::default_delay_constructor_t<AccumPackT>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_1, offset_size::_4>
{
  static constexpr int threads = 256;
  static constexpr int items   = 12;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using delay_constructor = detail::no_delay_constructor_t<445>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_2, offset_size::_4>
{
  static constexpr int threads = 256;
  static constexpr int items   = 12;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using delay_constructor = detail::fixed_delay_constructor_t<104, 512>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_4, offset_size::_4>
{
  static constexpr int threads = 320;
  static constexpr int items   = 12;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using delay_constructor = detail::no_delay_constructor_t<1105>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_8, offset_size::_4>
{
  static constexpr int threads = 384;
  static constexpr int items   = 7;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::fixed_delay_constructor_t<464, 1165>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_16, offset_size::_4>
{
  static constexpr int threads = 128;
  static constexpr int items   = 7;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<1040>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_1, offset_size::_8>
{
  static constexpr int threads = 256;
  static constexpr int items   = 24;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using delay_constructor = detail::fixed_delay_constructor_t<4, 285>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_2, offset_size::_8>
{
  static constexpr int threads = 640;
  static constexpr int items   = 24;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<245>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_4, offset_size::_8>
{
  static constexpr int threads = 256;
  static constexpr int items   = 23;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<910>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_8, offset_size::_8>
{
  static constexpr int threads = 256;
  static constexpr int items   = 18;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<1145>;
};

template <class Input, class OffsetT>
struct sm90_tuning<Input, OffsetT, input_size::_16, offset_size::_8>
{
  static constexpr int threads = 256;
  static constexpr int items   = 11;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<1050>;
};

template <class InputT,
          class OffsetT,
          input_size InputSize   = classify_input_size<InputT>(),
          offset_size OffsetSize = classify_offset_size<OffsetT>()>
struct sm80_tuning
{
  static constexpr int threads = 256;
  static constexpr int items   = Nominal4BItemsToItems<InputT>(9);

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_DIRECT;

  using AccumPackHelperT  = detail::three_way_partition::accumulator_pack_t<OffsetT>;
  using AccumPackT        = typename AccumPackHelperT::pack_t;
  using delay_constructor = detail::default_delay_constructor_t<AccumPackT>;
};

template <class Input, class OffsetT>
struct sm80_tuning<Input, OffsetT, input_size::_2, offset_size::_4>
{
  static constexpr int threads = 256;
  static constexpr int items   = 12;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<910>;
};

template <class Input, class OffsetT>
struct sm80_tuning<Input, OffsetT, input_size::_4, offset_size::_4>
{
  static constexpr int threads = 256;
  static constexpr int items   = 11;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::no_delay_constructor_t<1120>;
};

template <class Input, class OffsetT>
struct sm80_tuning<Input, OffsetT, input_size::_8, offset_size::_4>
{
  static constexpr int threads = 224;
  static constexpr int items   = 11;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::fixed_delay_constructor_t<264, 1080>;
};

template <class Input, class OffsetT>
struct sm80_tuning<Input, OffsetT, input_size::_16, offset_size::_4>
{
  static constexpr int threads = 128;
  static constexpr int items   = 10;

  static constexpr BlockLoadAlgorithm load_algorithm = BLOCK_LOAD_WARP_TRANSPOSE;

  using delay_constructor = detail::fixed_delay_constructor_t<672, 1120>;
};

} // namespace three_way_partition

template <class InputT, class OffsetT>
struct device_three_way_partition_policy_hub
{
  struct DefaultTuning
  {
    static constexpr int ITEMS_PER_THREAD = Nominal4BItemsToItems<InputT>(9);

    using ThreeWayPartitionPolicy =
      cub::AgentThreeWayPartitionPolicy<256,
                                        ITEMS_PER_THREAD,
                                        cub::BLOCK_LOAD_DIRECT,
                                        cub::LOAD_DEFAULT,
                                        cub::BLOCK_SCAN_WARP_SCANS>;
  };

  /// SM35
  struct Policy350
      : DefaultTuning
      , ChainedPolicy<350, Policy350, Policy350>
  {};

  struct Policy800 : ChainedPolicy<800, Policy800, Policy350>
  {
    using tuning = detail::three_way_partition::sm80_tuning<InputT, OffsetT>;

    using ThreeWayPartitionPolicy =
      AgentThreeWayPartitionPolicy<tuning::threads,
                                   tuning::items,
                                   tuning::load_algorithm,
                                   cub::LOAD_DEFAULT,
                                   cub::BLOCK_SCAN_WARP_SCANS,
                                   typename tuning::delay_constructor>;
  };

  struct Policy860
      : DefaultTuning
      , ChainedPolicy<860, Policy860, Policy800>
  {};

  /// SM90
  struct Policy900 : ChainedPolicy<900, Policy900, Policy860>
  {
    using tuning = detail::three_way_partition::sm90_tuning<InputT, OffsetT>;

    using ThreeWayPartitionPolicy =
      AgentThreeWayPartitionPolicy<tuning::threads,
                                   tuning::items,
                                   tuning::load_algorithm,
                                   cub::LOAD_DEFAULT,
                                   cub::BLOCK_SCAN_WARP_SCANS,
                                   typename tuning::delay_constructor>;
  };

  using MaxPolicy = Policy900;
};

} // namespace detail

CUB_NAMESPACE_END