Consider this extension on NSData
which serializes an NSData
object into a hex String:
extension NSData { func base16EncodedString(uppercase uppercase: Bool = false) -> String { let buffer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(self.bytes), count: self.length) let hexFormat = uppercase ? "X" : "x" let formatString = "%02\(hexFormat)" let bytesAsHexStrings = buffer.map { String(format: formatString, $0) } return bytesAsHexStrings.joinWithSeparator("") } }
If an UnsafeBufferPointer
is a non-owning pointer, does that mean I don't need to (or am not able to) explicitly call destroy? If I'm creating an UnsafePointer
from the memory of the bytes of an NSData
object, do I need to make sure to destroy that pointer after the buffer is copied?
UnsafePointer(self.bytes)
is only a pointer conversion from UnsafePointer<Void>
to UnsafePointer<UInt8>
(like a "cast" in C). It does not allocate memory.
The memory is managed by the NSData
object. You did not alloc()
the
memory and therefore must not call dealloc()
on the pointer.
You also did not initialize()
the memory and therefore must not
destroy()
it.