poc.cpp

std::vector<Int64Builder> builders(num_chunks);

    ChunkResolver index_resolver(values.chunks());
    for (int64_t requested_index = 0; requested_index < num_indices; ++requested_index) {
      uint64_t index = poc_get_index(indices, requested_index);
      
      ChunkLocation resolved_index = index_resolver.Resolve(index);
      int64_t chunk_index = resolved_index.chunk_index;
      if (chunk_index < 0) {
        // ChunkResolver doesn't throw errors when the index is out of bounds
        // it will just return a chunk index that doesn't exist.
        return Status::IndexError("Index ", index, " is out of bounds");
      }
      ARROW_RETURN_NOT_OK(builders[chunk_index].Append(resolved_index.index_in_chunk));
    }

    std::vector<std::shared_ptr<arrow::Array>> looked_up_values;
    looked_up_values.reserve(num_chunks);
    for (int i = 0; i < num_chunks; ++i) {
      if (builders[i].length() == 0) {
        // No indices refer to this chunk, so we can skip it
        continue;
      }
      std::shared_ptr<Int64Array> indices_array;
      ARROW_RETURN_NOT_OK(builders[i].Finish(&indices_array));
      std::shared_ptr<ArrayData> looked_up_values_data;
      ARROW_ASSIGN_OR_RAISE(looked_up_values_data, TakeAA(values.chunk(i)->data(),
                                                          indices_array->data(), options, ctx));
      looked_up_values[i] = MakeArray(looked_up_values_data);
    }