Method Slice

cpp/src/arrow/chunked_array.cc:176–200

}

std::shared_ptr<ChunkedArray> ChunkedArray::Slice(int64_t offset, int64_t length) const {
  ARROW_CHECK_LE(offset, length_) << "Slice offset greater than array length";
  bool offset_equals_length = offset == length_;
  int curr_chunk = 0;
  while (curr_chunk < num_chunks() && offset >= chunk(curr_chunk)->length()) {
    offset -= chunk(curr_chunk)->length();
    curr_chunk++;
  }

  ArrayVector new_chunks;
  if (num_chunks() > 0 && (offset_equals_length || length == 0)) {
    // Special case the zero-length slice to make sure there is at least 1 Array
    // in the result. When there are zero chunks we return zero chunks
    new_chunks.push_back(chunk(std::min(curr_chunk, num_chunks() - 1))->Slice(0, 0));
  } else {
    while (curr_chunk < num_chunks() && length > 0) {
      new_chunks.push_back(chunk(curr_chunk)->Slice(offset, length));
      length -= chunk(curr_chunk)->length() - offset;
      offset = 0;
      curr_chunk++;
    }
  }

  return std::make_shared<ChunkedArray>(new_chunks, type_);
}

std::shared_ptr<ChunkedArray> ChunkedArray::Slice(int64_t offset) const {
  return Slice(offset, length_);