Function __lengthForIndex

system/lib/libcxx/src/ryu/d2fixed.cpp:230–233

}

[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __lengthForIndex(const uint32_t __idx) {
  // +1 for ceil, +16 for mantissa, +8 to round up when dividing by 9
  return (__log10Pow2(16 * static_cast<int32_t>(__idx)) + 1 + 16 + 8) / 9;
}

[[nodiscard]] to_chars_result __d2fixed_buffered_n(char* _First, char* const _Last, const double __d,
  const uint32_t __precision) {