Function CIntFromPythonImpl

python/pyarrow/src/arrow/python/helpers.cc:196–228

// Extract C signed int from Python object
template <typename Int, enable_if_t<std::is_signed<Int>::value, Int> = 0>
Status CIntFromPythonImpl(PyObject* obj, Int* out, const std::string& overflow_message) {
  static_assert(sizeof(Int) <= sizeof(long long),  // NOLINT
                "integer type larger than long long");

  OwnedRef ref;
  if (!PyLong_Check(obj)) {
    ARROW_ASSIGN_OR_RAISE(ref, PyObjectToPyInt(obj));
    obj = ref.obj();
  }

  if (sizeof(Int) > sizeof(long)) {  // NOLINT
    const auto value = PyLong_AsLongLong(obj);
    if (ARROW_PREDICT_FALSE(value == -1)) {
      RETURN_IF_PYERROR();
    }
    if (ARROW_PREDICT_FALSE(value < std::numeric_limits<Int>::min() ||
                            value > std::numeric_limits<Int>::max())) {
      return IntegerOverflowStatus(obj, overflow_message);
    }
    *out = static_cast<Int>(value);
  } else {
    const auto value = PyLong_AsLong(obj);
    if (ARROW_PREDICT_FALSE(value == -1)) {
      RETURN_IF_PYERROR();
    }
    if (ARROW_PREDICT_FALSE(value < std::numeric_limits<Int>::min() ||
                            value > std::numeric_limits<Int>::max())) {
      return IntegerOverflowStatus(obj, overflow_message);
    }
    *out = static_cast<Int>(value);
  }
  return Status::OK();
}

// Extract C unsigned int from Python object
template <typename Int, enable_if_t<std::is_unsigned<Int>::value, Int> = 0>