protected virtual string OnFormatSpecifier(DateTimeSyntax syntax)
{
var specifier = new StringBuilder();
specifier.Append(syntax.HasFlag(DateTimeSyntax.WithDayName) ? "ddd, " : string.Empty);
specifier.Append(syntax.HasFlag(DateTimeSyntax.TwoDigitDay) ? "dd" : "d");
specifier.Append(" MMM");
specifier.Append(syntax.HasFlag(DateTimeSyntax.FourDigitYear) ? " yyyy" : " yy");
if (syntax.HasFlag(DateTimeSyntax.UseAmPm))
{
if (syntax.HasFlag(DateTimeSyntax.TwoDigitTime))
{
specifier.Append(syntax.HasFlag(DateTimeSyntax.WithSeconds) ? " hh:mm:ss tt" : " hh:mm tt");
}
else
{
specifier.Append(syntax.HasFlag(DateTimeSyntax.WithSeconds) ? " h:m:s tt" : " h:m tt");
}
}
else
{
if (syntax.HasFlag(DateTimeSyntax.TwoDigitTime))
{
specifier.Append(syntax.HasFlag(DateTimeSyntax.WithSeconds) ? " HH:mm:ss" : " HH:mm");
}
else
{
specifier.Append(syntax.HasFlag(DateTimeSyntax.WithSeconds) ? " H:m:s" : " H:m");
}
}
return(specifier.ToString());
}
/// <summary>
/// Formats a date time offset according to the RFC 822 syntax specified
/// in the syntax parameter.
/// </summary>
/// <param name="syntax">The syntax that is ued to format the date time.</param>
/// <returns>An RFC 822 formatted date time.</returns>
public string ToString(DateTimeSyntax syntax)
{
var format = new DateTimeFormat(syntax).FormatSpecifier;
string result;
if (syntax.HasFlag(DateTimeSyntax.NumericTimeZone))
{
result = Instant.DateTime.ToString(format, CultureInfo.InvariantCulture);
string timeZone = Instant.Offset.Ticks >= 0 ? "+" : "-";
timeZone += Instant.Offset.ToString("hhmm");
result += " " + timeZone;
}
else
{
result = Instant.UtcDateTime.ToString(format, CultureInfo.InvariantCulture);
result += " UT";
}
return(result);
}
/// <summary>
/// Converts the RFC 822 string representation of date and time to a
/// System.DateTime and saves it together with the time zone offset
/// in the Instant property.
/// </summary>
/// <param name="input">A date and time formatted according to RFC 822
/// syntax.</param>
/// <param name="syntax">The syntax rules that should be used when
/// interpreting the input.</param>
public DateTimeRfc822(string input, DateTimeSyntax syntax)
{
ITimeZoneMapper timeZoneMapper;
if (syntax.HasFlag(DateTimeSyntax.NumericTimeZone))
{
timeZoneMapper = new NumericTimeZoneMapper();
}
else
{
timeZoneMapper = new TimeZoneTable();
}
var timeZoneMap = timeZoneMapper.Map(input.Substring(input.LastIndexOf(' ') + 1));
var src = input.TrimEnd(timeZoneMap.Identifier.ToCharArray()).Trim();
var format = new DateTimeFormat(syntax);
var dateTime = DateTime.ParseExact(src, format.FormatSpecifier, CultureInfo.InvariantCulture,
DateTimeStyles.RoundtripKind | DateTimeStyles.AllowWhiteSpaces);
Instant = new DateTimeOffset(dateTime, timeZoneMap.Offset);
}