question: public byte [ ] toZOrderByteArray ( final BigInteger bigInt ) { final int numDimensions = datatypeConfig . getNumDimensions ( ) ; final byte [ ] bigIntAsByteArr = bigInt . toByteArray ( ) ; final int paddedArraySize = numDimensions * BASE_SIZE + 1 ; final byte [ ] bigIntAsByteArrPad = new byte [ paddedArraySize ] ; int idx = 0 ; for ( int i = 0 ; i < paddedArraySize - bigIntAsByteArr . length ; i ++ ) { bigIntAsByteArrPad [ idx ++ ] = 0 ; } for ( int i = 0 ; i < bigIntAsByteArr . length ; i ++ ) { bigIntAsByteArrPad [ idx ++ ] = bigIntAsByteArr [ i ] ; } final byte [ ] bigIntAsByteArrUnsigned = unpadLeadingZero ( bigIntAsByteArrPad ) ; return bigIntAsByteArrUnsigned ; }
target:  Decodes a BigInteger into a zOrder byte[] (without leading zero). Implements transformation F->E.