public bool Equals(DateTag obj)
{
if (obj == null)
{
return(false);
}
return(m_dateTicks == obj.m_dateTicks && TimeZone.Equals(obj.TimeZone) && Precision == obj.Precision);
}
/// <summary>
/// Parses a metadata date tag into a <see cref="DateTag"/> including <see cref="DateTime"/>, <see cref="TimeZoneTag"/>, and significant digits.
/// </summary>
/// <param name="dateTag">The value to be parsed in <see cref="https://www.w3.org/TR/NOTE-datetime">W3CDTF</see> format.</param>
/// <param name="result">The result of the parsing.</param>
/// <returns>True if successful, else false.</returns>
/// <remarks>
/// <para>The <see cref="https://www.w3.org/TR/NOTE-datetime">W3CDTF</see> format has date and timezone portions.
/// This method parses both.</para>
/// <para>If the timezone portion is not included in the input string then the resulting <paramref name="timezone"/>
/// will have <see cref="Kind"/> set to <see cref="TimeZoneKind.ForceLocal"/>.
/// </para>
/// <para>If the timezone portion is set to "Z" indicating UTC, then the resulting <paramref name="timezone"/>
/// will have <see cref="Kind"/> set to <see cref="TimeZoneKind.ForceUtc"/> and the <see cref="UtcOffset"/>
/// will be zero.
/// </para>
/// <para>The W2CDTF format permits partial date-time values. For example "2018" is just a year with no
/// other information. The <paramref name="precision"/> value indicates how much detail is included
/// as follows: 4 = year, 6 = month, 8 = day, 10 = hour, 12 = minute, 14 = second, 17 = millisecond, 20 = microsecond,
/// 21 = tick (100 nanoseconds).
/// </para>
/// </remarks>
public static bool TryParse(string dateTag, out DateTag result)
{
// Init values for failure case
result = new DateTag(ZeroDate, TimeZoneTag.Zero, 0);
// Init parts
int year = 0;
int month = 1;
int day = 1;
int hour = 12; // Noon
int minute = 0;
int second = 0;
long ticks = 0;
// Track position
int pos = 0;
if (dateTag.Length < 4)
{
return(false);
}
if (!int.TryParse(dateTag.Substring(0, 4), out year) ||
year < 1 || year > 9999)
{
return(false);
}
int precision = PrecisionYear;
pos = 4;
if (dateTag.Length > 5 && dateTag[4] == '-')
{
if (!int.TryParse(dateTag.Substring(5, 2), out month) ||
month < 1 || month > 12)
{
return(false);
}
precision = PrecisionMonth;
pos = 7;
if (dateTag.Length > 8 && dateTag[7] == '-')
{
if (!int.TryParse(dateTag.Substring(8, 2), out day) ||
day < 1 || day > DateTime.DaysInMonth(year, month))
{
return(false);
}
precision = PrecisionDay;
pos = 10;
if (dateTag.Length > 11 && (dateTag[10] == 'T' || dateTag[10] == ' ')) // Even though W3CDTF and ISO 8601 specify 'T' separating date and time, tolerate a space as an alternative.
{
if (!int.TryParse(dateTag.Substring(11, 2), out hour) ||
hour < 0 || hour > 23)
{
return(false);
}
precision = PrecisionHour;
pos = 13;
if (dateTag.Length > 14 && dateTag[13] == ':')
{
if (!int.TryParse(dateTag.Substring(14, 2), out minute) ||
minute < 0 || minute > 59)
{
return(false);
}
precision = PrecisionMinute;
pos = 16;
if (dateTag.Length > 17 && dateTag[16] == ':')
{
if (!int.TryParse(dateTag.Substring(17, 2), out second) ||
second < 0 || second > 59)
{
return(false);
}
precision = PrecisionSecond;
pos = 19;
if (dateTag.Length > 20 && dateTag[19] == '.')
{
++pos;
int anchor = pos;
while (pos < dateTag.Length && char.IsDigit(dateTag[pos]))
{
++pos;
}
precision = PrecisionSecond + (pos - anchor);
if (precision > PrecisionMax)
{
precision = PrecisionMax;
}
double d;
if (!double.TryParse(dateTag.Substring(anchor, pos - anchor), out d))
{
return(false);
}
ticks = (long)(d * Math.Pow(10.0, 7.0 - (pos - anchor)));
}
}
}
}
}
}
// Attempt to parse the timezone
TimeZoneTag timezone;
DateTimeKind dtk = DateTimeKind.Unspecified;
if (pos < dateTag.Length)
{
if (!TimeZoneTag.TryParse(dateTag.Substring(pos), out timezone))
{
return(false);
}
dtk = (timezone.Kind == TimeZoneKind.ForceUtc) ? DateTimeKind.Utc : DateTimeKind.Local;
}
else
{
timezone = TimeZoneTag.ForceLocal;
dtk = DateTimeKind.Local;
}
result = new DateTag(new DateTime(year, month, day, hour, minute, second, dtk).AddTicks(ticks),
timezone, precision);
return(true);
}
