private final byte[] zeroExtend(byte[] dataToPad){
  assert null != dataToPad;
  final int targetLength=4;
  if (targetLength <= dataToPad.length)   return dataToPad;
  byte padded[]=new byte[targetLength];
  for (int i=0; i < dataToPad.length; i++)   padded[i]=dataToPad[i];
  for (int i=dataToPad.length; i < padded.length; i++)   padded[i]=(byte)0;
  return padded;
}

private final byte [ ] zeroExtend ( byte [ ] dataToPad ) { assert null != dataToPad ; final int targetLength = 4 ; if ( targetLength <= dataToPad . length ) return dataToPad ; byte padded [ ] = new byte [ targetLength ] ; for ( int i = 0 ; i < dataToPad . length ; i ++ ) padded [ i ] = dataToPad [ i ] ; for ( int i = dataToPad . length ; i < padded . length ; i ++ ) padded [ i ] = ( byte ) 0 ; return padded ; }
if the parameter is shorter than 4 bytes , then create and return a new 4 byte array with the input array ' s bytes followed by zero bytes . otherwise return the parameter .
