/* *   File:  ByteQueue.java * *   This Class queues up bits, then returns them later as needed. *   Used for storing truly random entropy from keystrokes of the user. * *   version 1.02 v1a *   Copyright 1998, 1999 by Hush Communications Corporation, BWI */package hushcode;import java.util.Vector;import hushcode.Conversions;final class ByteQueue{   private Vector bytes;   private int currentByte;   private int currentBit;   private int bitsEnqueued;   private Byte zero = new Byte((byte)0);   ByteQueue()   {      bytes = new Vector();      currentByte = 0;       currentBit = 7;      bytes.addElement(zero);   }   /*  This method accepts a number and enqueues the numBits least significant bits.    *  The number must be positive, and no more than 63 bits may be enqueued at a time.    */   void enqueueBits(long number, int numBits)   {         long p2 = (long)(Math.pow(2,(double)(numBits-1)));      if (number-p2 > p2) number = number%(p2*2);      for (long n=p2; ;n=n/2)      {         if (number%n==number) currentBit--;         else          {            byte newByte = (byte)               ((int)((Byte)(bytes.elementAt(currentByte))).byteValue() | (1<<currentBit--));            bytes.setElementAt(new Byte(newByte),currentByte);         }         if (currentBit<0)         {            currentBit = 7;            currentByte++;            bytes.setSize(currentByte);            bytes.addElement(zero);         }         number = number % n;         if (n==1) break;      }      bitsEnqueued = bitsEnqueued+numBits;       }   int bitsEnqueued() { return bitsEnqueued; }   int bytesAvailable() { return currentByte; }   int longsAvailable() { return currentByte/8; }   byte[] dequeueBytes(int numBytes)   {      byte[] returnBytes = new byte[numBytes];      for (int n=0; n<numBytes; n++)         returnBytes[n] = dequeueByte();      return returnBytes;    }   byte dequeueByte()   {      byte returnByte = ((Byte)bytes.firstElement()).byteValue();      bytes.removeElementAt(0);      currentByte--;      return returnByte;   }   long dequeueLong()   {      byte[] rBytes = new byte[8];      for (int n=0; n<8; n++)         rBytes[n] = dequeueByte();      return Conversions.bytesToLong(rBytes);    }}   //  end ByteQueue