美文网首页程序员iOS Developer
栅栏函数与迭代函数

栅栏函数与迭代函数

作者: 心情的蛊惑 | 来源:发表于2017-03-29 08:59 被阅读68次

    一, 栅栏函数

    -(void)barrier {
        // 获取全局并发队列
        // 栅栏函数不能使用全局并发队列dispatch_get_global_queue(0, 0)
    //    dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
        dispatch_queue_t queue= dispatch_queue_create("dhuui", DISPATCH_QUEUE_CONCURRENT);
        
        //异步函数
        dispatch_async(queue, ^{
          
            for (int i = 0; i <4 ; i++) {
                 NSLog(@"download1--%zd---%@---栅栏函数" ,i, [NSThread currentThread]);
            }
        });
        dispatch_async(queue, ^{
            for (int i = 0; i <4 ; i++) {
                NSLog(@"download2--%zd---%@---栅栏函数",i , [NSThread currentThread]);
            }
       });
        //栅栏函数
        dispatch_barrier_sync(queue, ^{
            NSLog(@"休息一会");
        });
        dispatch_async(queue, ^{
            for (int i = 0; i <4 ; i++) {
                NSLog(@"download3--%zd---%@---栅栏函数" ,i, [NSThread currentThread]);
            }
        });
        dispatch_async(queue, ^{
            for (int i = 0; i <4 ; i++) {
                NSLog(@"download4--%zd---%@---栅栏函数",i , [NSThread currentThread]);
            }
        });
    }
    

    二,迭代函数

    /*
         参数1,遍历的次数
         参数2,队列(并发队列)
         参数3,index 索引
         */
        dispatch_apply(10, dispatch_get_global_queue(0, 0), ^(size_t index) {
            NSLog(@"%zd----%@" ,index , [NSThread currentThread]);
        });
    
    #pragma mark - 利用移动文件,来说明迭代函数
    -(void)moveFile {
        //1,拿到文件路径,直接把from拖进来就可以了
        NSString *from = @"/Users/mac/Desktop/GCD/from";
        //2,获得目标文件路径
        NSString *to = @"/Users/mac/Desktop/GCD/to";
        //3,得到目录下面的所有文件
        NSArray *subPaths = [[NSFileManager defaultManager] subpathsAtPath:from];
        //4,遍历所有文件,然后执行剪切操作
        NSInteger count = subPaths.count;
        for (NSInteger i = 0; i <count; i++) {
            //4.1 拼接文件的全部路径
    //        NSString *fullPath = [from stringByAppendingString:subPaths[i]];
            //在拼接的时候会自动添加/
            NSString *fullPath  = [from stringByAppendingPathComponent:subPaths[i]];
            NSString *toFullpath = [to stringByAppendingPathComponent:subPaths[i]];
            //4.2 剪切
            /*
             参数1,要剪切的文件位置
             参数2,文件剪切到哪
             参数3,
             */
            [[NSFileManager defaultManager] moveItemAtPath:fullPath toPath:toFullpath error:nil];
     NSLog(@"%@ ---%@ ---%@" , fullPath , toFullpath , [NSThread currentThread]);
            
        }
        
    }
    -(void)moveFileWithGCD {
        //1,拿到文件路径,直接把from拖进来就可以了
        NSString *from = @"/Users/mac/Desktop/GCD/from";
        //2,获得目标文件路径
        NSString *to = @"/Users/mac/Desktop/GCD/to";
        //3,得到目录下面的所有文件
        NSArray *subPaths = [[NSFileManager defaultManager] subpathsAtPath:from];
        //4,遍历所有文件,然后执行剪切操作
        NSInteger count = subPaths.count;
        dispatch_apply(count, dispatch_get_global_queue(0, 0), ^(size_t i ) {
           
            //4.1 拼接文件的全部路径
            //        NSString *fullPath = [from stringByAppendingString:subPaths[i]];
            //在拼接的时候会自动添加/
            NSString *fullPath  = [from stringByAppendingPathComponent:subPaths[i]];
            NSString *toFullpath = [to stringByAppendingPathComponent:subPaths[i]];
            //4.2 剪切
            /*
             参数1,要剪切的文件位置
             参数2,文件剪切到哪
             参数3,
             */
            [[NSFileManager defaultManager] moveItemAtPath:fullPath toPath:toFullpath error:nil];
            NSLog(@"%@ ---%@ ---%@" , fullPath , toFullpath , [NSThread currentThread]);
        });
        
    }
    

    相关文章

      网友评论

        本文标题:栅栏函数与迭代函数

        本文链接:https://www.haomeiwen.com/subject/bgqeottx.html