Function ParseInt

src/literal.cc:718–749

template <typename U>
Result ParseInt(const char* s,
                const char* end,
                U* out,
                ParseIntType parse_type) {
  using S = typename std::make_signed<U>::type;
  uint64_t value;
  bool has_sign = false;
  if (*s == '-' || *s == '+') {
    if (parse_type == ParseIntType::UnsignedOnly) {
      return Result::Error;
    }
    if (*s == '-') {
      has_sign = true;
    }
    s++;
  }
  CHECK_RESULT(ParseUint64(s, end, &value));

  if (has_sign) {
    // abs(INTN_MIN) == INTN_MAX + 1.
    if (value > static_cast<uint64_t>(std::numeric_limits<S>::max()) + 1) {
      return Result::Error;
    }
    value = std::numeric_limits<U>::max() - value + 1;
  } else {
    if (value > static_cast<uint64_t>(std::numeric_limits<U>::max())) {
      return Result::Error;
    }
  }
  *out = static_cast<U>(value);
  return Result::Ok;
}

Result ParseInt8(const char* s,
                 const char* end,