/*
     1 1
     2 10
     3 11
     4 100
     5 101
     6 110
     7 111
     8 1000
     */
    
    
    
    
    NSLog(@"%d", 1 & 2); //01 10 -> 00 ->0
    NSLog(@"%d", 1 | 2);//01 10 ->11 ->3
    NSLog(@"%d", 1 ^ 2); //01 10 -11 ->3
    NSLog(@"%d", 1 << 1);  //00001 00010 -> 2
    NSLog(@"%d", 1 << 2); //00001 00100 ->4
    NSLog(@"%d", 2 >> 1);  //10 01 -> 1
    NSLog(@"%d", 4 >> 2); //100 -001 -> 1
    
    NSLog(@"%lu",(unsigned long)StreamEventNone); //0
    NSLog(@"%lu",(unsigned long)StreamEventOpenCompleted);//01
    NSLog(@"%lu",(unsigned long)StreamEventHasBytesAvailable);//10
    
    NSLog(@"%d %d",1 & 1, 2&2);
    NSLog(@"%d",1 & 2);
    //NSLog(@"%d",1 & 3);
    NSLog(@"%d",1 & 4);
    //因为是位移的没有3  所以&可以保证就是自己
    NSLog(@"%d",4 ^ 4); // 100 100  //不同为1 相同为为0
    NSLog(@"%d",5 ^ 5); //使得相同的值为0

    StreamEvent direction = StreamEventOpenCompleted|StreamEventHasBytesAvailable|StreamEventHasSpaceAvailable;
    
    
    if (direction & StreamEventOpenCompleted) {
        NSLog(@"StreamEventOpenCompleted");
    }
    NSLog(@"%lu",(unsigned long)direction);
    

一个字 2个字节 一个字节8位
word  = 2byte  1byte = 8bit
1字节     uint8_t
2字节     uint16_t
4字节     uint32_t
8字节     uint64_t