/// <summary>
/// Check if the given variant subtags separated by the given
/// separator(s) are valid.
/// </summary>
private int CheckVariants(string variants, string sep)
{
StringTokenEnumerator itr = new StringTokenEnumerator(variants, sep);
while (itr.MoveNext())
{
string s = itr.Current;
if (!LanguageTag.IsVariant(s))
{
return(itr.CurrentStart);
}
}
return(-1);
}