key_remapping.hpp

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/*
 * SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 */
 
#pragma once
 
#include <cudf/column/column.hpp>
#include <cudf/table/table_view.hpp>
#include <cudf/types.hpp>
#include <cudf/utilities/default_stream.hpp>
#include <cudf/utilities/export.hpp>
#include <cudf/utilities/memory_resource.hpp>
 
#include <rmm/cuda_stream_view.hpp>
 
#include <memory>
 
namespace CUDF_EXPORT cudf {
 
enum class compute_metrics : bool { NO = false, YES = true };
 
namespace detail {
class key_remapping_impl;
}  // namespace detail
 
constexpr size_type KEY_REMAP_NOT_FOUND = -1;
 
constexpr size_type KEY_REMAP_RIGHT_NULL = -2;
 
[[deprecated("Use KEY_REMAP_RIGHT_NULL instead.")]] constexpr size_type KEY_REMAP_BUILD_NULL =
  KEY_REMAP_RIGHT_NULL;
 
class key_remapping {
 public:
  key_remapping() = delete;
  ~key_remapping();
  key_remapping(key_remapping const&)            = delete;
  key_remapping(key_remapping&&)                 = delete;
  key_remapping& operator=(key_remapping const&) = delete;
  key_remapping& operator=(key_remapping&&)      = delete;
 
  key_remapping(cudf::table_view const& right,
                null_equality compare_nulls   = null_equality::EQUAL,
                cudf::compute_metrics metrics = cudf::compute_metrics::YES,
                rmm::cuda_stream_view stream  = cudf::get_default_stream());
 
  [[nodiscard]] std::unique_ptr<cudf::column> remap_right_keys(
    rmm::cuda_stream_view stream      = cudf::get_default_stream(),
    rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()) const;
 
  [[deprecated("Use remap_right_keys instead.")]] [[nodiscard]] std::unique_ptr<cudf::column>
  remap_build_keys(
    rmm::cuda_stream_view stream      = cudf::get_default_stream(),
    rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()) const
  {
    return remap_right_keys(stream, mr);
  }
 
  [[nodiscard]] std::unique_ptr<cudf::column> remap_left_keys(
    cudf::table_view const& keys,
    rmm::cuda_stream_view stream      = cudf::get_default_stream(),
    rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()) const;
 
  [[deprecated("Use remap_left_keys instead.")]] [[nodiscard]] std::unique_ptr<cudf::column>
  remap_probe_keys(
    cudf::table_view const& keys,
    rmm::cuda_stream_view stream      = cudf::get_default_stream(),
    rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()) const
  {
    return remap_left_keys(keys, stream, mr);
  }
 
  [[nodiscard]] bool has_metrics() const;
 
  [[nodiscard]] size_type get_distinct_count() const;
 
  [[nodiscard]] size_type get_max_duplicate_count() const;
 
 private:
  using impl_type = cudf::detail::key_remapping_impl;
 
  std::unique_ptr<impl_type> _impl;
};
  // end of group
 
}  // namespace CUDF_EXPORT cudf