Method consumeUnsignedInteger

ext/src/llvm/StringRef.cpp:416–462

}

bool llvm::consumeUnsignedInteger(StringRef &Str, unsigned Radix,
                                  unsigned long long &Result) {
  // Autosense radix if not specified.
  if (Radix == 0)
    Radix = GetAutoSenseRadix(Str);

  // Empty strings (after the radix autosense) are invalid.
  if (Str.empty()) return true;

  // Parse all the bytes of the string given this radix.  Watch for overflow.
  StringRef Str2 = Str;
  Result = 0;
  while (!Str2.empty()) {
    unsigned CharVal;
    if (Str2[0] >= '0' && Str2[0] <= '9')
      CharVal = Str2[0] - '0';
    else if (Str2[0] >= 'a' && Str2[0] <= 'z')
      CharVal = Str2[0] - 'a' + 10;
    else if (Str2[0] >= 'A' && Str2[0] <= 'Z')
      CharVal = Str2[0] - 'A' + 10;
    else
      break;

    // If the parsed value is larger than the integer radix, we cannot
    // consume any more characters.
    if (CharVal >= Radix)
      break;

    // Add in this character.
    unsigned long long PrevResult = Result;
    Result = Result * Radix + CharVal;

    // Check for overflow by shifting back and seeing if bits were lost.
    if (Result / Radix < PrevResult)
      return true;

    Str2 = Str2.substr(1);
  }

  // We consider the operation a failure if no characters were consumed
  // successfully.
  if (Str.size() == Str2.size())
    return true;

  Str = Str2;
  return false;
}

bool llvm::consumeSignedInteger(StringRef &Str, unsigned Radix,
                                long long &Result) {