RandomByte.swift

// Swift 3, macos/Linux

#if os(Linux)
  import Glibc
#else
  import Darwin
#endif

class RandomByteGenerator {
  private let f = fopen("/dev/urandom","r")

  init() { }

  deinit {
    fclose(f)
  }
 
  /// random Int8
  func read() -> Int8 {
    var bytes:[Int8] = [0,0]
    fgets(&bytes,2,f)
    bytes.removeLast()
    return bytes[0]
  }

  /// random UInt32
  func rand() -> UInt32
  {
    let a:Int8 = read()
    let b:Int8 = read()
    let c:Int8 = read()
    let d:Int8 = read()
    
    let bytes: [Int8] = [a, b,c,d]
    let u32:UInt32 = UnsafePointer(bytes).withMemoryRebound(to: UInt32.self, capacity: 1) {
      $0.pointee
    }
    
    return u32
  }
}