SBigInt.scala

final class SBigInt private(final val signum: Int, final private[math] val arr: Array[Int]) {

  ...

  /**
   * Standard Serialization would work, but we have to make sure
   * that we sanitize the array to verify our invariant of no leading
   * “zeroes” in our magnitude.
   * 
   * Otherwise all methods depending on it will be broken.
   * 
   * TODO: It probably makes sense to write an independent sanitizing method,
   * which can be shared and call it from here...
   */
  @throws(classOf[java.io.IOException]) @throws(classOf[java.lang.ClassNotFoundException])
  private def readObject(in: java.io.ObjectInputStream): Unit = {
    @inline def setField(name: String, value: Any): Unit = {
      val field = this.getClass.getDeclaredField(name)
      field.setAccessible(true)
      field.set(this, value)
      field.setAccessible(false)
    }
    
    var sign = in.readByte
    if(sign > 1 || sign < -1) 
      throw new java.io.StreamCorruptedException 
    setField("signum", sign)
    var inArr = in.readObject.asInstanceOf[Array[UInt]]
    if(sign == 0 && inArr.length != 0)
      throw new java.io.StreamCorruptedException
    setField("arr", stripLeadingZeroes(inArr))
  }
  
  @throws(classOf[java.io.ObjectStreamException])
  private def readReplace(): Object = {
    if(signum == 0) return SBigInt.Zero
    else this
  }
  
  @throws(classOf[java.io.IOException])
  private def writeObject(out: java.io.ObjectOutputStream): Unit = {
    out.writeByte(signum)
    out.writeObject(arr)
    out.close()
  }
}