public Item evaluateItem(XPathContext context) throws XPathException {
AtomicValue av1 = (AtomicValue)argument[0].evaluateItem(context);
if (av1==null) {
return null;
}
CalendarValue in = (CalendarValue)av1;
int nargs = argument.length;
DayTimeDurationValue tz;
if (nargs==1) {
return in.adjustTimezone(context.getImplicitTimezone());
} else {
AtomicValue av2 = (AtomicValue)argument[1].evaluateItem(context);
if (av2==null) {
return in.removeTimezone();
}
tz = (DayTimeDurationValue)av2;
long microseconds = tz.getLengthInMicroseconds();
if (microseconds%60000000 != 0) {
dynamicError("Timezone is not an integral number of minutes", "FODT0003", context);
}
int tzminutes = (int)(microseconds / 60000000);
if (Math.abs(tzminutes) > 14*60) {
dynamicError("Timezone out of range (-14:00 to +14:00)", "FODT0003", context);
}
return in.adjustTimezone(tzminutes);
}
}