private void parseTzName()
{
StringBuilder s = new StringBuilder();
while (pos < str.Length)
{
int ch = str[pos];
if (('a' <= ch && ch <= 'z') ||
('A' <= ch && ch <= 'Z') ||
('0' <= ch && ch <= '9') ||
ch == '+' || ch == '-' || ch == '_')
{
s.Append((char)ch);
pos++;
}
else break;
}
tzName = s.ToString();
}