/// <summary>
/// Parses a custom time zone identifier and returns a corresponding zone.
/// This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
/// </summary>
/// <param name="id"> a string of the <a href="#CustomID">custom ID form</a>. </param>
/// <returns> a newly created TimeZone with the given offset and
/// no daylight saving time, or null if the id cannot be parsed. </returns>
private static TimeZone ParseCustomTimeZone(String id)
{
int length;
// Error if the length of id isn't long enough or id doesn't
// start with "GMT".
if ((length = id.Length()) < (GMT_ID_LENGTH + 2) || id.IndexOf(GMT_ID) != 0)
{
return(null);
}
ZoneInfo zi;
// First, we try to find it in the cache with the given
// id. Even the id is not normalized, the returned ZoneInfo
// should have its normalized id.
zi = ZoneInfoFile.getZoneInfo(id);
if (zi != null)
{
return(zi);
}
int index = GMT_ID_LENGTH;
bool negative = false;
char c = id.CharAt(index++);
if (c == '-')
{
negative = true;
}
else if (c != '+')
{
return(null);
}
int hours = 0;
int num = 0;
int countDelim = 0;
int len = 0;
while (index < length)
{
c = id.CharAt(index++);
if (c == ':')
{
if (countDelim > 0)
{
return(null);
}
if (len > 2)
{
return(null);
}
hours = num;
countDelim++;
num = 0;
len = 0;
continue;
}
if (c < '0' || c > '9')
{
return(null);
}
num = num * 10 + (c - '0');
len++;
}
if (index != length)
{
return(null);
}
if (countDelim == 0)
{
if (len <= 2)
{
hours = num;
num = 0;
}
else
{
hours = num / 100;
num %= 100;
}
}
else
{
if (len != 2)
{
return(null);
}
}
if (hours > 23 || num > 59)
{
return(null);
}
int gmtOffset = (hours * 60 + num) * 60 * 1000;
if (gmtOffset == 0)
{
zi = ZoneInfoFile.getZoneInfo(GMT_ID);
if (negative)
{
zi.ID = "GMT-00:00";
}
else
{
zi.ID = "GMT+00:00";
}
}
else
{
zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset);
}
return(zi);
}
