Method convertFromHexadecimalString

ext/src/llvm/APFloat.cpp:2493–2585

}

Expected<IEEEFloat::opStatus>
IEEEFloat::convertFromHexadecimalString(StringRef s,
                                        roundingMode rounding_mode) {
  lostFraction lost_fraction = lfExactlyZero;

  category = fcNormal;
  zeroSignificand();
  exponent = 0;

  integerPart *significand = significandParts();
  unsigned partsCount = partCount();
  unsigned bitPos = partsCount * integerPartWidth;
  bool computedTrailingFraction = false;

  // Skip leading zeroes and any (hexa)decimal point.
  StringRef::iterator begin = s.begin();
  StringRef::iterator end = s.end();
  StringRef::iterator dot;
  auto PtrOrErr = skipLeadingZeroesAndAnyDot(begin, end, &dot);
  if (!PtrOrErr)
    return PtrOrErr.takeError();
  StringRef::iterator p = *PtrOrErr;
  StringRef::iterator firstSignificantDigit = p;

  while (p != end) {
    integerPart hex_value;

    if (*p == '.') {
      if (dot != end)
        return createError("String contains multiple dots");
      dot = p++;
      continue;
    }

    hex_value = hexDigitValue(*p);
    if (hex_value == -1U)
      break;

    p++;

    // Store the number while we have space.
    if (bitPos) {
      bitPos -= 4;
      hex_value <<= bitPos % integerPartWidth;
      significand[bitPos / integerPartWidth] |= hex_value;
    } else if (!computedTrailingFraction) {
      auto FractOrErr = trailingHexadecimalFraction(p, end, hex_value);
      if (!FractOrErr)
        return FractOrErr.takeError();
      lost_fraction = *FractOrErr;
      computedTrailingFraction = true;
    }
  }

  /* Hex floats require an exponent but not a hexadecimal point.  */
  if (p == end)
    return createError("Hex strings require an exponent");
  if (*p != 'p' && *p != 'P')