gistfile1.m

// NSDate#descriptionWithTwitterStyle

@interface NSDate(TwitterStyle)
- (NSString*)descriptionWithTwitterStyle;
@end

@implementation NSDate(TwitterStyle) 
- (NSString*)descriptionWithTwitterStyle {
	time_t now = [[NSDate date] timeIntervalSince1970];
	time_t t = [self timeIntervalSince1970];
	
	int d = now - t;
	
	if (d < 5) {
		return @"less than 5 seconds ago";
	} else if (d < 10) {
		return @"less than 10 seconds ago";
	} else if (d < 15) {
		return @"less than 15 seconds ago";
	} else if (d < 20) {
		return @"less than 20 seconds ago";
	} else if (d < 30) {
		return @"half a minute ago";
	} else if (d < 60) {
		return @"less than a minute ago";
	} else if (d < 45*60 ) {
		return [NSString stringWithFormat:@"about %d minute ago", d/60];
	} else if (d < 24*60*60) {
		int h = d/3600;
		if (h < 1) h = 1;
		return [NSString stringWithFormat:@"about %d hour ago",h];
	}
	
	char tmp[80];
	struct tm *tm_ = localtime(&t);
	strftime(tmp, sizeof(tmp), "%I:%M %p %b %dth", tm_);
	return [NSString stringWithUTF8String:tmp];
}
@end