Converting NSData to Integer in Swift

Question

In Objective-C the code looked liked this and worked flawlessly,

NSInteger random = arc4random_uniform(99) + 1 
NSData *data = [NSData dataWithBytes:& ra         


        

Answer 1

For Swift 3, you can do this (little endian, but similar for big):

func getInt(fromData data: Data, start: Int) -> Int32 {
  let intBits = data.withUnsafeBytes({(bytePointer: UnsafePointer) -> Int32 in
    bytePointer.advanced(by: start).withMemoryRebound(to: Int32.self, capacity: 4) { pointer in
      return pointer.pointee
    }
  })
  return Int32(littleEndian: intBits)
}

You can modify this, add generics, etc. to fit other primitive types (and vary it depending on the endianness of the data bytes).