utils.h

/** Copyright 2022 Alibaba Group Holding Limited.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#ifndef GAR_UTILS_UTILS_H_
#define GAR_UTILS_UTILS_H_

#include <memory>
#include <numeric>
#include <string>
#include <utility>
#include <vector>

#include "gar/utils/result.h"

#define REGULAR_SEPERATOR "_"

// forward declarations
namespace arrow {
class Table;
class ChunkedArray;
class Array;
}  // namespace arrow

namespace GAR_NAMESPACE_INTERNAL {

/** Type of vertex id or vertex index. */
using IdType = int64_t;

namespace util {

struct IndexConverter {
  explicit IndexConverter(std::vector<IdType>&& edge_chunk_nums)
      : edge_chunk_nums_(std::move(edge_chunk_nums)) {}
  IdType IndexPairToGlobalChunkIndex(IdType vertex_chunk_index,
                                     IdType edge_chunk_index) {
    IdType global_edge_chunk_index = 0;
    for (IdType i = 0; i < vertex_chunk_index; ++i) {
      global_edge_chunk_index += edge_chunk_nums_[i];
    }
    return global_edge_chunk_index + edge_chunk_index;
  }

  // covert edge global chunk index to <vertex_chunk_index, edge_chunk_index>
  std::pair<IdType, IdType> GlobalChunkIndexToIndexPair(IdType global_index) {
    std::pair<IdType, IdType> index_pair(0, 0);
    for (size_t i = 0; i < edge_chunk_nums_.size(); ++i) {
      if (global_index < edge_chunk_nums_[i]) {
        index_pair.first = static_cast<IdType>(i);
        index_pair.second = global_index;
        break;
      }
      global_index -= edge_chunk_nums_[i];
    }
    return index_pair;
  }

 private:
  std::vector<IdType> edge_chunk_nums_;
};

static inline IdType IndexPairToGlobalChunkIndex(
    const std::vector<IdType>& edge_chunk_nums, IdType vertex_chunk_index,
    IdType edge_chunk_index) {
  IdType global_edge_chunk_index = 0;
  for (IdType i = 0; i < vertex_chunk_index; ++i) {
    global_edge_chunk_index += edge_chunk_nums[i];
  }
  return global_edge_chunk_index + edge_chunk_index;
}

// covert edge global chunk index to <vertex_chunk_index, edge_chunk_index>
static inline std::pair<IdType, IdType> GlobalChunkIndexToIndexPair(
    const std::vector<IdType>& edge_chunk_nums, IdType global_index) {
  std::pair<IdType, IdType> index_pair(0, 0);
  for (size_t i = 0; i < edge_chunk_nums.size(); ++i) {
    if (global_index < edge_chunk_nums[i]) {
      index_pair.first = static_cast<IdType>(i);
      index_pair.second = global_index;
      break;
    }
    global_index -= edge_chunk_nums[i];
  }
  return index_pair;
}

std::shared_ptr<arrow::ChunkedArray> GetArrowColumnByName(
    std::shared_ptr<arrow::Table> const& table, const std::string& name);

std::shared_ptr<arrow::Array> GetArrowArrayByChunkIndex(
    std::shared_ptr<arrow::ChunkedArray> const& chunk_array,
    int64_t chunk_index);

Result<const void*> GetArrowArrayData(
    std::shared_ptr<arrow::Array> const& array);

static inline std::string ConcatStringWithDelimiter(
    const std::vector<std::string>& str_vec, const std::string& delimiter) {
  return std::accumulate(
      std::begin(str_vec), std::end(str_vec), std::string(),
      [&delimiter](const std::string& ss, const std::string& s) {
        return ss.empty() ? s : ss + delimiter + s;
      });
}

template <typename T>
struct ValueGetter {
  inline static T Value(const void* data, int64_t offset) {
    return reinterpret_cast<const T*>(data)[offset];
  }
};

template <>
struct ValueGetter<std::string> {
  static std::string Value(const void* data, int64_t offset);
};

}  // namespace util

}  // namespace GAR_NAMESPACE_INTERNAL
#endif  // GAR_UTILS_UTILS_H_