gistfile1.m

@implementation NSDate (PKDateUtils)

+ (NSDate *)dateAtMidnightWithDaysAgo:(int)numDaysAgo
{
	NSDate *today = [NSDate date];
	NSCalendar *gregorianCal = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
	NSDateComponents *todayComponents = [gregorianCal components:NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit fromDate:today];
	todayComponents.day -= numDaysAgo;
	todayComponents.hour = 0;
	todayComponents.minute = 0;
	return [gregorianCal dateFromComponents:todayComponents];
	
}

+ (NSDate *)dateWithTotalCrossString:(NSString *)totalCrossString {
	if ([@"0" isEqualToString:totalCrossString]) {
		return nil;
	}
	else {
		return [[DataFormatter sharedDataFormatter] dateForValue:totalCrossString];
	}
}

- (NSDate *)dateAtMidnight {
	NSCalendar *gregorianCal = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
	NSDateComponents *components = [gregorianCal components:NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit fromDate:self];
	components.hour = 0;
	components.minute = 0;
	return [gregorianCal dateFromComponents:components];
	
}

- (NSString *)toTotalCrossFormat {
	return [[DataFormatter sharedDataFormatter] formatDate:self format:FORMAT_TOTAL_CROSS];
}

- (NSInteger)numDaysAgo {
	NSCalendar *gregorianCal = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
	NSDateComponents *components = [gregorianCal components:NSDayCalendarUnit fromDate:[self dateAtMidnight] toDate:[NSDate dateAtMidnightWithDaysAgo:0] options:0];
	return components.day;
}

- (NSDate *)dateByAddingDays:(NSInteger)numDays {
	NSCalendar *gregorianCal = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
	NSDateComponents *components = [gregorianCal components:NSYearCalendarUnit | NSMonthCalendarUnit | 
									NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit 
												   fromDate:self];
	components.day += numDays;
	return [gregorianCal dateFromComponents:components];
}

- (NSInteger)daysSince:(NSDate *)pastDate {
	NSCalendar *gregorianCal = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
	NSDateComponents *components = [gregorianCal components:NSDayCalendarUnit fromDate:[pastDate dateAtMidnight] toDate:[self dateAtMidnight] options:0];
	return components.day;
}