public static byte [] padHead(final byte [] a, final int length) {
    byte [] padding = new byte[length];
    for (int i = 0; i < length; i++) {
      padding[i] = 0;
    }
    return add(padding, a);
  }
public static byte [ ] padHead ( final byte [ ] a , final int length ) { byte [ ] padding = new byte [ length ] ; for ( int i = 0 ; i < length ; i ++ ) { padding [ i ] = 0 ; } return add ( padding , a ) ; }
Return a byte array with value in <code>a</code> plus <code>length</code> prepended 0 bytes.
@param a array
@param length new array size
@return Value in <code>a</code> plus <code>length</code> prepended 0 bytes