iOS - receiving binary data from server only works in debug mode - iphone

Question

I have a question concerning my last post
But I think at first I should provide some code:
This is the function to handle my created object
- (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;
}
}
And I here I receive the data from a stream
- (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;
}
It all works just fine with the simulator or if I debug the application on the iPhone, but if try to run it on the device I always get BAD_EXCESS, because the value of packetLength is wrong and so I try to read too much byte into my buffer.
Now to my question: How can it be that all values are right in debug mode, but get totally messed up in run mode? Is there anything I could to avoid that problem or I should be aware of?
Your help is much appreciated
Here is my BytesToInt Function, but I think it works as it should, if the received values are correct
- (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;
}

Answer 1

I finally did it by looping the received data until I reached my maxLength value. It wasn't too hard to fix, but I wasn't acting quite smart...
Well, here is how I did it:
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];
}

Answer 2

Check the return value of your [NSInputStream read]. Specifying maxLength does not mean that actually that many bytes will be really read. It can be less, or even 0. If the stream reads only 2 bytes, I guess you will have to issue a second read with a pointer that points behind the bytes already read in your buffer, and with maxLength of the remaining bytes in the buffer.