Method tmToStringView

bolt/type/Timestamp.cpp:269–389

}

StringView Timestamp::tmToStringView(
    const std::tm& tmValue,
    uint64_t nanos,
    const TimestampToStringOptions& options,
    char* const startPosition) {
  BOLT_DCHECK_LT(nanos, 1'000'000'000);

  const auto appendDigits = [](const int value,
                               const std::optional<uint32_t> minWidth,
                               char* const position) {
    const auto numDigits = countDigits(value);
    uint32_t offset = 0;
    // Append leading zeros when there is the requirement for minimum width.
    if (minWidth.has_value() && numDigits < minWidth.value()) {
      const auto leadingZeros = minWidth.value() - numDigits;
      std::memset(position, '0', leadingZeros);
      offset += leadingZeros;
    }
    const auto [endPosition, errorCode] =
        std::to_chars(position + offset, position + offset + numDigits, value);
    std::ignore = endPosition;
    BOLT_DCHECK_EQ(
        errorCode,
        std::errc(),
        "Failed to convert value to varchar: {}.",
        std::make_error_code(errorCode).message());
    offset += numDigits;
    return offset;
  };

  char* writePosition = startPosition;
  if (options.mode != TimestampToStringOptions::Mode::kTimeOnly) {
    int year = kTmYearBase + tmValue.tm_year;
    const bool leadingPositiveSign = options.leadingPositiveSign && year > 9999;
    const bool negative = year < 0;

    // Sign.
    if (negative) {
      *writePosition++ = '-';
      year = -year;
    } else if (leadingPositiveSign) {
      *writePosition++ = '+';
    }

    // Year.
    writePosition += appendDigits(
        year,
        options.zeroPaddingYear ? std::optional<uint32_t>(4) : std::nullopt,
        writePosition);

    // Month.
    *writePosition++ = '-';
    writePosition += appendDigits(1 + tmValue.tm_mon, 2, writePosition);

    // Day.
    *writePosition++ = '-';
    writePosition += appendDigits(tmValue.tm_mday, 2, writePosition);