/// <summary>
/// Returns the next string from the token stream.
/// </summary>
/// <param name="tokens">The tokens to parse from.</param>
/// <param name="name">The name of the expected value, for use in the exception if no value is available.</param>
private string NextString(Tokens tokens, string name)
{
if (!tokens.HasNextToken)
{
throw new InvalidDataException($"Missing zone info token: {name}");
}
return tokens.NextToken(name);
}
private static void AssertTokensEqual(IList<string> expectedTokens, Tokens tokens)
{
for (int i = 0; i < expectedTokens.Count; i++)
{
Assert.True(tokens.HasNextToken, "Not enough items in enumeration");
var actual = tokens.NextToken(i.ToString());
if (actual == null)
{
Assert.Fail("The enumeration item at index [" + i + "] is null");
}
Assert.AreEqual(expectedTokens[i], actual, "The enumeration item at index [" + i + "] is not correct");
}
Assert.False(tokens.HasNextToken, "Too many items in enumeration");
}
/// <summary> /// Returns the next token, which is optional, converting "-" to null. /// </summary> /// <param name="tokens">The tokens.</param> /// <param name="name">The name of the expected value, for use in the exception if no value is available.</param> private string NextOptional(Tokens tokens, string name) => ParserHelper.ParseOptional(NextString(tokens, name));
/// <summary> /// Parses the next token as an offset. /// </summary> /// <param name="tokens">The tokens.</param> /// <param name="name">The name of the expected value, for use in the exception if no value is available.</param> private Offset NextOffset(Tokens tokens, string name) => ParserHelper.ParseOffset(NextString(tokens, name));
/// <summary>
/// Parses the next token as a month number (1-12).
/// </summary>
/// <param name="tokens">The tokens.</param>
/// <param name="name">The name of the expected value, for use in the exception if no value is available.</param>
private int NextMonth(Tokens tokens, string name)
{
var value = NextString(tokens, name);
return ParseMonth(value);
}
/// <summary>
/// Parses a time zone definition and returns the Zone object.
/// </summary>
/// <remarks>
/// # GMTOFF RULES FORMAT [ UntilYear [ UntilMonth [ UntilDay [ UntilTime [ ZoneCharacter ] ] ] ] ]
/// </remarks>
/// <param name="name">The name of the zone being parsed.</param>
/// <param name="tokens">The tokens to parse.</param>
/// <returns>The Zone object.</returns>
internal ZoneLine ParseZone(string name, Tokens tokens)
{
var offset = NextOffset(tokens, "Gmt Offset");
var rules = NextOptional(tokens, "Rules");
var format = NextString(tokens, "Format");
int year = NextYear(tokens, Int32.MaxValue);
if (tokens.HasNextToken)
{
var until = ParseDateTimeOfYear(tokens, false);
return new ZoneLine(name, offset, rules, format, year, until);
}
return new ZoneLine(name, offset, rules, format, year, ZoneYearOffset.StartOfYear);
}
/// <summary>
/// Parses a daylight savings rule and returns the Rule object.
/// </summary>
/// <remarks>
/// # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
/// </remarks>
/// <param name="tokens">The tokens to parse.</param>
/// <returns>The Rule object.</returns>
internal RuleLine ParseRule(Tokens tokens)
{
var name = NextString(tokens, "GetName");
int fromYear = NextYear(tokens, 0);
// This basically doesn't happen these days, but if we have any recurrent rules
// which start at the dawn of time, make them effective from 1900. This matches
// zic behaviour in the only cases of this that we've seen, e.g. the systemv rules
// prior to 2001a.
if (fromYear == int.MinValue)
{
fromYear = 1900;
}
int toYear = NextYear(tokens, fromYear);
if (toYear < fromYear)
{
throw new ArgumentException($"To year cannot be before the from year in a Rule: {toYear} < {fromYear}");
}
var type = NextOptional(tokens, "Type");
var yearOffset = ParseDateTimeOfYear(tokens, true);
var savings = NextOffset(tokens, "SaveMillis");
var daylightSavingsIndicator = NextOptional(tokens, "LetterS");
// The name of the zone recurrence is currently the name of the rule. Later (in ZoneRule.GetRecurrences)
// it will be replaced with the formatted name. It's not ideal, but it avoids a lot of duplication.
var recurrence = new ZoneRecurrence(name, savings, yearOffset, fromYear, toYear);
return new RuleLine(recurrence, daylightSavingsIndicator, type);
}
/// <summary>
/// Parses an alias link and returns the ZoneAlias object.
/// </summary>
/// <param name="tokens">The tokens to parse.</param>
/// <returns>The ZoneAlias object.</returns>
internal Tuple<string, string> ParseLink(Tokens tokens)
{
var existing = NextString(tokens, "Existing");
var alias = NextString(tokens, "Alias");
return Tuple.Create(existing, alias);
}
/// <summary>
/// Nexts the month.
/// </summary>
/// <param name="tokens">The tokens.</param>
/// <param name="name">The name.</param>
private int NextMonth(Tokens tokens, string name)
{
var value = NextString(tokens, name);
int result = ParseMonth(value);
return result == 0 ? 1 : result;
}
/// <summary> /// Returns the next token, which is optional, converting "-" to null. /// </summary> /// <param name="tokens">The tokens.</param> /// <param name="name">The name of the expected value, for use in the exception if no value is available.</param> private string?NextOptional(Tokens tokens, string name) => ParserHelper.ParseOptional(NextString(tokens, name));
/// <summary> /// Parses the next token as an offset. /// </summary> /// <param name="tokens">The tokens.</param> /// <param name="name">The name of the expected value, for use in the exception if no value is available.</param> private Offset NextOffset(Tokens tokens, string name) => ParserHelper.ParseOffset(NextString(tokens, name));
/// <summary>
/// Parses the next token as a month number (1-12).
/// </summary>
/// <param name="tokens">The tokens.</param>
/// <param name="name">The name of the expected value, for use in the exception if no value is available.</param>
private int NextMonth(Tokens tokens, string name)
{
var value = NextString(tokens, name);
return(ParseMonth(value));
}
/// <summary>
/// Parses the ZoneYearOffset for a rule or zone. This is something like "3rd Sunday of October at 2am".
/// </summary>
/// <remarks>
/// IN ON AT
/// </remarks>
/// <param name="tokens">The tokens to parse.</param>
/// <param name="forRule">True if this is for a Rule line, in which case ON/AT are mandatory;
/// false for a Zone line, in which case it's part of "until" and they're optional</param>
/// <returns>The ZoneYearOffset object.</returns>
internal ZoneYearOffset ParseDateTimeOfYear(Tokens tokens, bool forRule)
{
var mode = ZoneYearOffset.StartOfYear.Mode;
var timeOfDay = ZoneYearOffset.StartOfYear.TimeOfDay;
int monthOfYear = NextMonth(tokens, "MonthOfYear");
int dayOfMonth = 1;
int dayOfWeek = 0;
bool advanceDayOfWeek = false;
bool addDay = false;
if (tokens.HasNextToken || forRule)
{
var on = NextString(tokens, "On");
if (on.StartsWith("last", StringComparison.Ordinal))
{
dayOfMonth = -1;
dayOfWeek = ParseDayOfWeek(on.Substring(4));
}
else
{
int index = on.IndexOf(">=", StringComparison.Ordinal);
if (index > 0)
{
dayOfMonth = Int32.Parse(on.Substring(index + 2), CultureInfo.InvariantCulture);
dayOfWeek = ParseDayOfWeek(on.Substring(0, index));
advanceDayOfWeek = true;
}
else
{
index = on.IndexOf("<=", StringComparison.Ordinal);
if (index > 0)
{
dayOfMonth = Int32.Parse(on.Substring(index + 2), CultureInfo.InvariantCulture);
dayOfWeek = ParseDayOfWeek(on.Substring(0, index));
}
else
{
try
{
dayOfMonth = Int32.Parse(on, CultureInfo.InvariantCulture);
dayOfWeek = 0;
}
catch (FormatException e)
{
throw new ArgumentException($"Unparsable ON token: {on}", e);
}
}
}
}
if (tokens.HasNextToken || forRule)
{
var atTime = NextString(tokens, "AT");
if (!string.IsNullOrEmpty(atTime))
{
if (Char.IsLetter(atTime[atTime.Length - 1]))
{
char zoneCharacter = atTime[atTime.Length - 1];
mode = ConvertModeCharacter(zoneCharacter);
atTime = atTime.Substring(0, atTime.Length - 1);
}
if (atTime == "24:00")
{
timeOfDay = LocalTime.Midnight;
addDay = true;
}
// As of TZDB 2018f, Japan's fallback transitions occur at 25:00. We can't
// represent this entirely accurately, but this is as close as we can approximate it.
else if (atTime == "25:00")
{
timeOfDay = new LocalTime(1, 0);
addDay = true;
}
else
{
timeOfDay = ParserHelper.ParseTime(atTime);
}
}
}
}
return(new ZoneYearOffset(mode, monthOfYear, dayOfMonth, dayOfWeek, advanceDayOfWeek, timeOfDay, addDay));
}
/// <summary>
/// Parses an alias link and returns the ZoneAlias object.
/// </summary>
/// <param name="tokens">The tokens to parse.</param>
/// <returns>The ZoneAlias object.</returns>
internal ZoneAlias ParseLink(Tokens tokens)
{
var existing = NextString(tokens, "Existing");
var alias = NextString(tokens, "Alias");
return new ZoneAlias(existing, alias);
}
/// <summary>
/// Parses the ZoneYearOffset for a rule or zone. This is something like "3rd Sunday of October at 2am".
/// </summary>
/// <remarks>
/// IN ON AT
/// </remarks>
/// <param name="tokens">The tokens to parse.</param>
/// <param name="forRule">True if this is for a Rule line, in which case ON/AT are mandatory;
/// false for a Zone line, in which case it's part of "until" and they're optional</param>
/// <returns>The ZoneYearOffset object.</returns>
internal ZoneYearOffset ParseDateTimeOfYear(Tokens tokens, bool forRule)
{
var mode = ZoneYearOffset.StartOfYear.Mode;
var timeOfDay = ZoneYearOffset.StartOfYear.TimeOfDay;
int monthOfYear = NextMonth(tokens, "MonthOfYear");
int dayOfMonth = 1;
int dayOfWeek = 0;
bool advanceDayOfWeek = false;
bool addDay = false;
if (tokens.HasNextToken || forRule)
{
var on = NextString(tokens, "On");
if (on.StartsWith("last", StringComparison.Ordinal))
{
dayOfMonth = -1;
dayOfWeek = ParseDayOfWeek(on.Substring(4));
}
else
{
int index = on.IndexOf(">=", StringComparison.Ordinal);
if (index > 0)
{
dayOfMonth = Int32.Parse(on.Substring(index + 2), CultureInfo.InvariantCulture);
dayOfWeek = ParseDayOfWeek(on.Substring(0, index));
advanceDayOfWeek = true;
}
else
{
index = on.IndexOf("<=", StringComparison.Ordinal);
if (index > 0)
{
dayOfMonth = Int32.Parse(on.Substring(index + 2), CultureInfo.InvariantCulture);
dayOfWeek = ParseDayOfWeek(on.Substring(0, index));
}
else
{
try
{
dayOfMonth = Int32.Parse(on, CultureInfo.InvariantCulture);
dayOfWeek = 0;
}
catch (FormatException e)
{
throw new ArgumentException($"Unparsable ON token: {on}", e);
}
}
}
}
if (tokens.HasNextToken || forRule)
{
var atTime = NextString(tokens, "AT");
if (!string.IsNullOrEmpty(atTime))
{
if (Char.IsLetter(atTime[atTime.Length - 1]))
{
char zoneCharacter = atTime[atTime.Length - 1];
mode = ConvertModeCharacter(zoneCharacter);
atTime = atTime.Substring(0, atTime.Length - 1);
}
if (atTime == "24:00")
{
timeOfDay = LocalTime.Midnight;
addDay = true;
}
else
{
timeOfDay = ParserHelper.ParseTime(atTime);
}
}
}
}
return new ZoneYearOffset(mode, monthOfYear, dayOfMonth, dayOfWeek, advanceDayOfWeek, timeOfDay, addDay);
}
/// <summary>
/// Parses the next string from the token stream as a year.
/// </summary>
/// <param name="tokens">The tokens.</param>
/// <param name="defaultValue">The default value to return if the year isn't specified.</param>
private static int NextYear(Tokens tokens, int defaultValue)
{
int result = defaultValue;
string text;
if (tokens.TryNextToken(out text))
{
result = ParserHelper.ParseYear(text, defaultValue);
}
return result;
}
/// <summary>
/// Parses a daylight savings rule and returns the Rule object.
/// </summary>
/// <remarks>
/// # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
/// </remarks>
/// <param name="tokens">The tokens to parse.</param>
/// <returns>The Rule object.</returns>
internal ZoneRule ParseRule(Tokens tokens)
{
var name = NextString(tokens, "GetName");
int fromYear = NextYear(tokens, "FromYear", 0);
int toYear = NextYear(tokens, "ToYear", fromYear);
if (toYear < fromYear)
{
throw new ArgumentException("To year cannot be before the from year in a Rule: " + toYear + " < " + fromYear);
}
/* string type = */
NextOptional(tokens, "Type");
var yearOffset = ParseDateTimeOfYear(tokens, true);
var savings = NextOffset(tokens, "SaveMillis");
var letterS = NextOptional(tokens, "LetterS");
var recurrence = new ZoneRecurrence(name, savings, yearOffset, fromYear, toYear);
return new ZoneRule(recurrence, letterS);
}
