Function round_up_bigint

source/extern/fast_float.h:3362–3368

}

fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
round_up_bigint(bigint &big, size_t &count) noexcept {
  // need to round-up the digits, but need to avoid rounding
  // ....9999 to ...10000, which could cause a false halfway point.
  add_native(big, 10, 1);
  count++;
}

// parse the significant digits into a big integer
template <typename UC>