Re: Assigning Binary Data From Network To Variables

FROM : Nick Zitzmann
DATE : Sat Jan 05 23:03:42 2008

On Jan 5, 2008, at 12:27 AM, Bridger Maxwell wrote:

> I am very new to Cocoa, so I apologize if this question seems very 
> basic.
> Right now I am trying to read data from a program that is sending 
> data in
> the "TUIO" protocol.  I have read the data from the socket, and 
> assigned it
> to a NSData object with this code:
>    NSData *messageData = [[notification userInfo]
>                        objectForKey:NSFileHandleNotificationDataItem];
> Now how do I translate that data to integer and float values?



Try something like this (warning, written in Mail, untested, use at 
your own risk, but this ought to work):

long long offset = 0;
int32_t someIntValue;
float32_t someFloatValue;

[messageData getBytes:&someIntValue range:NSMakeRange(offset, 
sizeof(int32_t))];
offset += sizeof(int32_t);
[messageData getBytes:&someFloatValue range:NSMakeRange(offset, 
sizeof(float32_t))];
offset += sizeof(float32_t);

Don't forget to flip those bits around on the appropriate 
architectures if you're building a universal binary. There are some 
NSSwap... functions in Foundation that will do that.

Nick Zitzmann
<http://www.chronosnet.com/>