怎样推断 ios设备的类型（iphone，ipod，ipad）

-(bool)checkDevice:(NSString*)name
{
	NSString* deviceType = [UIDevice currentDevice].model;
	NSLog(@"deviceType = %@", deviceType);
	
	NSRange range = [deviceType rangeOfString:name];
	return range.location != NSNotFound;
}

		NSString *  nsStrIphone=@"iPhone";
		NSString *  nsStrIpod=@"iPod";
		NSString *  nsStrIpad=@"iPad";
		bool  bIsiPhone=false;
		bool  bIsiPod=false;
		bool  bIsiPad=false;
		bIsiPhone=[self  checkDevice:nsStrIphone];
		bIsiPod=[self checkDevice:nsStrIpod];
		bIsiPad=[self checkDevice:nsStrIpad];