code: private static void verifyArguments(byte[] source, int srcOffset, byte[] destination, int destOffset) {
          // Lots of error checking and exception throwing
          if( source == null ){
              throw new IllegalArgumentException( "Source array was null." );
          }   // end if
          if( destination == null ){
              throw new IllegalArgumentException( "Destination array was null." );
          }   // end if
          if( srcOffset < 0 || srcOffset + 3 >= source.length ){
              throw new IllegalArgumentException( String.format(
                      "Source array with length %d cannot have offset of %d and still process four bytes.", source.length, srcOffset ) );
          }   // end if
          if( destOffset < 0 || destOffset +2 >= destination.length ){
              throw new IllegalArgumentException( String.format(
                      "Destination array with length %d cannot have offset of %d and still store three bytes.", destination.length, destOffset ) );
          }   // end if
      }
docs: Check for argument validity