Function safe_strto64

tensorflow/core/lib/strings/numbers.cc:223–262

}  // namespace

bool safe_strto64(StringPiece str, int64* value) {
  SkipSpaces(&str);

  int64 vlimit = kint64max;
  int sign = 1;
  if (absl::ConsumePrefix(&str, "-")) {
    sign = -1;
    // Different limit for positive and negative integers.
    vlimit = kint64min;
  }

  if (!isdigit(SafeFirstChar(str))) return false;

  int64 result = 0;
  if (sign == 1) {
    do {
      int digit = SafeFirstChar(str) - '0';
      if ((vlimit - digit) / 10 < result) {
        return false;
      }
      result = result * 10 + digit;
      str.remove_prefix(1);
    } while (isdigit(SafeFirstChar(str)));
  } else {
    do {
      int digit = SafeFirstChar(str) - '0';
      if ((vlimit + digit) / 10 > result) {
        return false;
      }
      result = result * 10 - digit;
      str.remove_prefix(1);
    } while (isdigit(SafeFirstChar(str)));
  }

  SkipSpaces(&str);
  if (!str.empty()) return false;

  *value = result;
  return true;
}

bool safe_strtou64(StringPiece str, uint64* value) {
  SkipSpaces(&str);