title: Swap byte-order for double values
body: <p>I'm reading in binary data that might possibly consist of 64 bit floats ("doubles") in the Big Endian byte-order. I read them individually into a buffer of the type Float64 using the getBytes:range: method of NSData. Now I would like to change the byte order to Little Endian. For integers, this is easily possible using the Core-Foundation function CFSwapIntXX(), with XX being the number of bits. But there are no corresponding methods for floats. What is the preferred way to do this?</p>
  
  <p>I tried to "force" a 64bit double as an argument to the function CFSwapInt64() by previously memcopying it into an int64_t variable and then back again to the double value. It works correctly, but this seems rather brutal to me. Is there no method that comes with the standard framework?</p>