Elton's Blog

@interface ClassA : NSObject
{
         ClassB *objB;
}
 
-(ClassB *) getObjB;
-(void) setObjB:(ClassB *) value;
@end
 
@implementation ClassA
-(ClassB*) getObjB
{
         return objB;
}
 
-(void) setObjB:(ClassB*) value
{
         if (objB != value)
         {
                   [objB release];
                   objB = [value retain];
         }
}

-(void) dealloc
{
         [objB release];
         [super dealloc];
}

ClassA *obj1 = [[ClassA alloc] init];

ClassA *obj1 = [[[ClassA alloc] init] autorelease];

[obj1 release];
obj1 = nil;

ClassA *obj2 = obj1;
[obj2 retain];
//do something
[obj2 release];
obj2 = nil;

ClassA *Func1()
{
  ClassA *obj = [[[ClassA alloc]init]autorelease];
  return obj;
}

-(void) dealloc
{
         …
         [super dealloc];
}

ClassB *objB;

@property (retain) ClassB* objB;

@synthesize objB;

[objB release];

@interface ClassA : NSObject
{
         ClassB* objB;
}
 
@property (retain) ClassB* objB;
@end
 
@implementation ClassA
@synthesize objB;
-(void) dealloc
{
         [objB release];
         [super dealloc];
}
@end

void funcNoAutorelease()
{
         ClassB *objB1 = [[ClassB alloc]init];
         ClassA *objA = [[ClassA alloc]init];
         objA.objB = objB1;
         [objB1 release];
         [objA release];
}
 
void funcAutorelease()
{
         ClassB *objB1 = [[[ClassB alloc]init] autorelease];
         ClassA *objA = [[[ClassA alloc]init] autorelease];
         objA.objB = objB1;
}

ClassA *obj1 = [[ClassA alloc] init];

[obj1 dealloc];

ClassA *obj1 = [[ClassA alloc] init];
ClassA *obj2 = obj1;
[obj1 hello]; //输出hello
[obj1 dealloc];
[obj2 hello]; //能够执行这一行和下一行吗？
[obj2 dealloc];

ClassA *obj1 = [[ClassA alloc] init]; //对象生成时，retain count = 1
[obj1 release]; //release使retain count减1，retain count = 0，dealloc自动被调用,对象被销毁

ClassA *obj1 = [[ClassA alloc] init]; //retain count = 1
ClassA *obj2 = obj1; //retain count = 1
[obj1 hello]; //输出hello
[obj1 release]; //retain count = 0，对象被销毁
[obj2 hello];
[obj2 release];

ClassA *obj1 = [[ClassA alloc] init]; //retain count = 1
ClassA *obj2 = obj1; //retain count = 1
[obj2 retain]; //retain count = 2
[obj1 hello]; //输出hello
[obj1 release]; //retain count = 2 – 1 = 1
[obj2 hello]; //输出hello
[obj2 release]; //retain count = 0，对象被销毁

ClassA *obj1 = [[[ClassA alloc] init] autorelease]; //retain count = 1 但无需调用release

ClassA *obj1 = [[[ClassA alloc] init] autorelease]; //retain count = 1
ClassA *obj2 = obj1; //retain count = 1
[obj2 retain]; //retain count = 2
[obj1 hello]; //输出hello
//对于obj1，无需调用（实际上不能调用）release
[obj2 hello]; //输出hello
[obj2 release]; //retain count = 2-1 = 1

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

ClassA *obj1 = [[[ClassA alloc] init] autorelease]; //retain count = 1，把此对象加入autorelease pool中

int main (int argc, const char *argv[])
{
NSAutoreleasePool *pool;
pool = [[NSAutoreleasePool alloc] init];
 
// do something
 
[pool release];
return (0);
} // main

int main (int argc, const char *argv[])
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
int i, j;
for (i = 0; i < 100; i++ )
{
 for (j = 0; j < 100000; j++ )
    [NSString stringWithFormat:@"1234567890"];//产生的对象是autorelease的。
}
[pool release];
return (0);
} // main

int main (int argc, const char *argv[])
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
int i, j;
for (i = 0; i < 100; i++ )
{
 NSAutoreleasePool *loopPool = [[NSAutoreleasePool alloc] init];
 for (j = 0; j < 100000; j++ )
    [NSString stringWithFormat:@"1234567890"];//产生的对象是autorelease的。
 [loopPool release];
}
[pool release];
return (0);
} // main

 /usr/bin/openssl sha1 [full path to file]
 /usr/bin/openssl md5 [full path to file]

 /usr/bin/openssl md5 sample.iso 
MD5(sample.iso)= 3be75df53e0cfb3905af0b4f4471c9f3

#import <UIKit/UIKit.h>
#import <iAd/ADBannerView.h>
@interface TabViewController : UIViewController<ADBannerViewDelegate> {
    ADBannerView *adView;
    UILabel *adStatus;  
}
- (void)bannerViewDidLoadAd:(ADBannerView *)banner;
- (BOOL)bannerViewActionShouldBegin:(ADBannerView *)banner willLeaveApplication:(BOOL)willLeave;
- (void)bannerViewActionDidFinish:(ADBannerView *)banner;
- (void)bannerView:(ADBannerView *) didFailToReceiveAdWithError:(NSError *)error;
- (void)adAvailabilityDidChange;
@property (nonatomic, retain) ADBannerView *adView;
@property (nonatomic, retain) UILabel *adStatus;
@end

#import "TabViewController.h"
@implementation TabViewController
@synthesize adStatus;
@synthesize adView;
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
 
    adView = [[ADBannerView alloc] initWithFrame:CGRectMake(0, 250, 320, 50)];
    self.adView.delegate = self;
    self.adView.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:adView];
 
    adStatus = [[UILabel alloc] initWithFrame:CGRectMake(10, 20, 200, 30)];
    [self.view addSubview:adStatus];
 
    NSLog(@"Trying to change the ad status");
}
- (void)adAvailabilityDidChange {
    NSLog(@"[iAd]: Ads are available! Let's display one!");
 
    //    if([ADManager sharedAdManager].canPresentModalAd == YES)
    //        [[ADManager sharedAdManager] presentModalAdFromViewController:self];
}
- (void)cancelBannerViewAction {
    NSLog(@"Banner was cancelled!");
 
    self.adStatus.text = @"[iAd]: Bannes was closed.";
}
- (void)bannerViewDidLoadAd:(ADBannerView *)banner {
    NSLog(@"[iAd]: Ad did load.");
    self.adStatus.text = @"[iAd]: Ad did load.";
}
- (BOOL)bannerViewActionShouldBegin:(ADBannerView *)banner willLeaveApplication:(BOOL)willLeave {
    NSLog(@"[iAd]: An action was started from the banner. Application will quit: %d", willLeave);
 
    self.adStatus.text = @"[iAd]: An action was started from the banner. Application will quit: %d", willLeave;
 
    return YES;
}
- (void)bannerViewActionDidFinish:(ADBannerView *)banner {
    NSLog(@"[iAd]: Action finished.");
 
    self.adStatus.text = @"[iAd]: Action finished.";
}
- (void)bannerView:(ADBannerView *) didFailToReceiveAdWithError:(NSError *)error {
    NSLog(@"[iAd]: Faild to load the banner: %@", error);
 
    self.adStatus.text = @"[iAd]: Faild to load the banner: %@", error;
}
- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
 
    // Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}
- (void)dealloc {
    [super dealloc];
}
@end

ioreg -l -p IODeviceTree | grep "firmware-abi" | sed -e 's/[^0-9A-Z]//g'

sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
		<dict>
		        <key>Kernel</key>
		        <string>mach_kernel</string>
		        <key>Kernel Flags</key>
		        <string>arch=x86_64</string>
		</dict>
	</plist>

#import "TFHpple.h"
 
NSData *data = [[NSData alloc] initWithContentsOfFile:@"example.html"];
 
// Create parser
xpathParser = [[TFHpple alloc] initWithHTMLData:data];
 
//Get all the cells of the 2nd row of the 3rd table 
NSArray *elements  = [xpathParser search:@"//table[3]/tr[2]/td"];
 
// Access the first cell
TFHppleElement *element = [elements objectAtIndex:0];
 
// Get the text within the cell tag
NSString *content = [element content];  
 
[xpathParser release];
[data release];