Edited since the question was changed:
If you need to concatenate multiple NSData
objects into one then something like this will work:
NSData *data1 = ... // the 1st NSData object
NSData *data2 = ... // the 2nd NSData object
NSData *data3 = ... // the 3rd NSData object
NSMutableData *completeData = [data1 mutableCopy];
[completeData appendData:data2];
[completeData appendData:data3];
Call appendData:
for each NSData
you need to append.