/// <summary>
/// Returns the string representation of this {@code FileTime}. The string
/// is returned in the <a
/// href="http://www.w3.org/TR/NOTE-datetime">ISO 8601</a> format:
/// <pre>
/// YYYY-MM-DDThh:mm:ss[.s+]Z
/// </pre>
/// where "{@code [.s+]}" represents a dot followed by one of more digits
/// for the decimal fraction of a second. It is only present when the decimal
/// fraction of a second is not zero. For example, {@code
/// FileTime.fromMillis(1234567890000L).toString()} yields {@code
/// "2009-02-13T23:31:30Z"}, and {@code FileTime.fromMillis(1234567890123L).toString()}
/// yields {@code "2009-02-13T23:31:30.123Z"}.
///
/// <para> A {@code FileTime} is primarily intended to represent the value of a
/// file's time stamp. Where used to represent <i>extreme values</i>, where
/// the year is less than "{@code 0001}" or greater than "{@code 9999}" then
/// this method deviates from ISO 8601 in the same manner as the
/// <a href="http://www.w3.org/TR/xmlschema-2/#deviantformats">XML Schema
/// language</a>. That is, the year may be expanded to more than four digits
/// and may be negative-signed. If more than four digits then leading zeros
/// are not present. The year before "{@code 0001}" is "{@code -0001}".
///
/// </para>
/// </summary>
/// <returns> the string representation of this file time </returns>
public override String ToString()
{
if (ValueAsString == null)
{
long secs = 0L;
int nanos = 0;
if (Instant == null && Unit.CompareTo(TimeUnit.SECONDS) >= 0)
{
secs = Unit.ToSeconds(Value);
}
else
{
secs = ToInstant().EpochSecond;
nanos = ToInstant().Nano;
}
LocalDateTime ldt;
int year = 0;
if (secs >= -SECONDS_0000_TO_1970)
{
// current era
long zeroSecs = secs - SECONDS_PER_10000_YEARS + SECONDS_0000_TO_1970;
long hi = Math.FloorDiv(zeroSecs, SECONDS_PER_10000_YEARS) + 1;
long lo = Math.FloorMod(zeroSecs, SECONDS_PER_10000_YEARS);
ldt = LocalDateTime.OfEpochSecond(lo - SECONDS_0000_TO_1970, nanos, ZoneOffset.UTC);
year = ldt.Year + (int)hi * 10000;
}
else
{
// before current era
long zeroSecs = secs + SECONDS_0000_TO_1970;
long hi = zeroSecs / SECONDS_PER_10000_YEARS;
long lo = zeroSecs % SECONDS_PER_10000_YEARS;
ldt = LocalDateTime.OfEpochSecond(lo - SECONDS_0000_TO_1970, nanos, ZoneOffset.UTC);
year = ldt.Year + (int)hi * 10000;
}
if (year <= 0)
{
year = year - 1;
}
int fraction = ldt.Nano;
StringBuilder sb = new StringBuilder(64);
sb.Append(year < 0 ? "-" : "");
year = System.Math.Abs(year);
if (year < 10000)
{
Append(sb, 1000, System.Math.Abs(year));
}
else
{
sb.Append(Convert.ToString(year));
}
sb.Append('-');
Append(sb, 10, ldt.MonthValue);
sb.Append('-');
Append(sb, 10, ldt.DayOfMonth);
sb.Append('T');
Append(sb, 10, ldt.Hour);
sb.Append(':');
Append(sb, 10, ldt.Minute);
sb.Append(':');
Append(sb, 10, ldt.Second);
if (fraction != 0)
{
sb.Append('.');
// adding leading zeros and stripping any trailing zeros
int w = 100000000;
while (fraction % 10 == 0)
{
fraction /= 10;
w /= 10;
}
Append(sb, w, fraction);
}
sb.Append('Z');
ValueAsString = sb.ToString();
}
return(ValueAsString);
}