calculate the date at the start and end of a given week

gistfile1.m

- (NSDate *)dateAtStartOfWeek
{
    NSCalendar *calendar = [NSDate AZ_currentCalendar];
    NSDateComponents *components = [calendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekdayCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit fromDate:self];
//    NSRange range = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSWeekdayCalendarUnit forDate:self];
    components.day -= components.weekday;
    return [calendar dateFromComponents:components];
}

- (NSDate *)dateAtEndOfWeek
{
    NSCalendar *calendar = [NSDate AZ_currentCalendar];
    NSDateComponents *components = [calendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekdayCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit fromDate:self];
    NSRange range = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSWeekCalendarUnit forDate:self];
    components.day += range.length - components.weekday;
    return [calendar dateFromComponents:components];
}