NSDate zero out seconds without rounding up

Question

I would like to know if anyone can help me with my method. I have the following method, which will zero out the seconds value of a NSDate object:

- (NSDate *)dateWithZeroSeconds:(NSDate *)date {
    NSTimeInterval time = round([date timeIntervalSinceReferenceDate] / 60.0) * 60.0;
    return  [NSDate dateWithTimeIntervalSinceReferenceDate:time];
}

The problem is when passed a date such as:

2011-03-16 18:21:43 +0000

it returns:

2011-03-16 18:22:00 +0000

I do not want this rounding to occur, as it is a user who is actually specifying the date, so it needs to be exact to the minute they request.

Any help is greatly appreciated.

Answer 1

To be complete, here is the code referenced to iOS SDK 8.1 using NSCalendar and NSDateComponents.

+ (NSDate *)truncateSecondsForDate:(NSDate *)fromDate;
{
     NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
     NSCalendarUnit unitFlags = NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute;
     NSDateComponents *fromDateComponents = [gregorian components:unitFlags fromDate:fromDate ];
     return [gregorian dateFromComponents:fromDateComponents];
}

Note that as of iOS 8 the calendar unit names have changed.