Changing NSData byte order to little endian

Question

I am trying to figure out the best way to change the byte order of my NSData object that I have.

This is how I create it

NSData *pillowData = [manufData subdataWithRange:NSMakeRange(5, 4)];

This is the output of pillowData

41543138

This is what i want pillowData to be after conversion.

38315441

Essentially converting to little endian.

Answer 1

    NSData *manufData = [NSData dataWithBytes:"12345AT18" length:9];
    NSMutableData *pillowData = [[manufData subdataWithRange:NSMakeRange(5, 4)] mutableCopy];
    uint32_t *bytes = pillowData.mutableBytes;
    *bytes = CFSwapInt32(*bytes);
    NSLog(@"%@", pillowData);

Output:

2018-01-25 15:52:39.067805-0600 test[23520:1338453] <38315441>

Note that this doesn't change the contents of manufData. It only changes the copy of the bytes in pillowData.