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我有一个关于我上一篇文章的问题

但我认为首先我应该提供一些代码：

这是处理我创建的对象的函数

- (void)handleObject:(NSMutableData *)object {

NSLog(@"[object length] = %d", [object length]);
Byte *byteArray;
byteArray = (Byte *)[object bytes];

switch (byteArray[5]) {

    case 0: NSLog(@"Login OK"); 
        break;

    case 1: NSLog(@"Exit. Server disconnect");
        break;

    case 2: NSLog(@"Ping erhalten");
        break;

    case 4: NSLog(@"Points received");
        break;

    case 6: NSLog(@"transfer of POLYLINE vector objects");
        break;

    case 8: NSLog(@"transfer of POLYGON vector objects");
        break;

    case 9: NSLog(@"transfer of Render Rule");
        break;

    case 10: {

        NSLog(@"end of response for RequestVectorObjects");                                 
        isLoading = FALSE;
    }
        break;

    case 11: NSLog(@"Background Colorcode: %d", (byteArray[6] & 0xFF));
        break;    

    default: NSLog(@"From server: default value");
        break;
}

}

我在这里接收来自流的数据

- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {

switch(eventCode) {

    case NSStreamEventHasBytesAvailable:
    {
        isLoading = YES; 

        while (isLoading) {               

            uint8_t bufSize[4];            

            int packetLength = 0; 

            [(NSInputStream *)stream read:bufSize maxLength:4];
            packetLength = [self bytesToInt:bufSize withOffset:0];
            NSLog(@"packetLength: %d", packetLength);

            [tempStore appendBytes:bufSize length:4];

            if (packetLength == 25600) {

                loggedIn = YES;
                uint8_t buf[4];
                [(NSInputStream *)stream read:buf maxLength:4];
                [tempStore appendBytes:buf length:4];
                [self handleObject:tempStore];
            }
            else {

                uint8_t buf[packetLength];
                [(NSInputStream *)stream read:buf maxLength:packetLength];
                [tempStore appendBytes:buf length:packetLength];
                [self handleObject:tempStore];                    
            }
            [tempStore resetBytesInRange:NSMakeRange(0, [tempStore length])];
            [tempStore setLength:0];
        }           
        NSLog(@"Finished loading objects");                 

    } break;

}

这一切都适用于模拟器，或者如果我在 iPhone 上调试应用程序，但如果尝试在设备上运行它，我总是得到 BAD_EXCESS，因为 packetLength 的值是错误的，所以我尝试将太多字节读入我的缓冲。

现在我的问题是：为什么所有值在调试模式下都是正确的，但在运行模式下却完全搞砸了？有什么我可以避免这个问题或我应该注意的吗？

非常感谢您的帮助

这是我的 BytesToInt 函数，但如果接收到的值正确，我认为它可以正常工作

- (int)bytesToInt:(Byte *)b withOffset:(int)offset {

int ret = 0;
for (int i = 0; i < 4; i++) {

    ret |= (b[offset + i] & 0xFF) << (3-i)*8;
}    
return ret;

}

4

2 回答 2

2

我最终通过循环接收到的数据直到达到我的 maxLength 值来做到这一点。解决起来并不难，但我表现得不太聪明......

好吧，这就是我的做法：

isLoading = YES; 

        while (isLoading) {               

            uint8_t bufSize[4];            

            int packetLength , maxLength, len;

            maxLength = 4;
            len = [(NSInputStream *)stream read:bufSize maxLength:maxLength];
            NSLog(@"len = %d", len);
            packetLength = [self bytesToInt:bufSize withOffset:0];
            NSLog(@"packetLength: %d", packetLength);

            [tempStore appendBytes:bufSize length:maxLength];

            if (packetLength == 25600) {

                loggedIn = YES;
                maxLength = 4;
                uint8_t buf[maxLength];                    
                len = [(NSInputStream *)stream read:buf maxLength:maxLength];
                NSLog(@"len = %d", len);
                [tempStore appendBytes:buf length:maxLength];
            }
            else {
                maxLength = packetLength;
                BOOL allDataReceived = NO;

                while (!allDataReceived) {

                    uint8_t buf[maxLength];                    
                    len = [(NSInputStream *)stream read:buf maxLength:maxLength];                                                                    
                    NSLog(@"len = %d", len);                       

                    if (len < maxLength) {

                        maxLength -= len;
                        [tempStore appendBytes:buf length:len];
                    }
                    else {

                        allDataReceived = YES;
                        [tempStore appendBytes:buf length:len];
                    }                            
                }                    
            }
            [self handleObject:tempStore];
            [tempStore resetBytesInRange:NSMakeRange(0, [tempStore length])];
            [tempStore setLength:0];
        }
于 2012-03-16T09:39:16.960 回答
1

检查您的[NSInputStream read]. 指定 maxLength 并不意味着实际上会真正读取那么多字节。它可以更少，甚至为 0。如果流仅读取 2 个字节，我想您将不得不使用指向缓冲区中已读取字节后面的指针以及剩余字节的 maxLength 发出第二次读取缓冲。

于 2012-03-15T15:59:25.133 回答