changes to HilberCurve

gistfile1.txt

static BigInteger toIndex(int bits, long... transposedIndex) {
        int length = bits * transposedIndex.length;
        byte[] b = new byte[length / 8 + 1];
        int bIndex = length - 1;
        long mask = 1L << (bits - 1);
        for (int i = 0; i < bits; i++) {
            for (int j = 0; j < transposedIndex.length; j++) {
                if ((transposedIndex[j] & mask) != 0) {
                    b[b.length - 1 - bIndex / 8] |= 1 << (bIndex % 8);
                }
                bIndex--;
            }
            mask >>>= 1;
        }
        // b is expected to be BigEndian
        return new BigInteger(1, b);
    }

    static long[] transposedIndex(int bits, long... unsignedPoint) {
        final long M = 1L << (bits - 1);
        final int n = unsignedPoint.length; // n: Number of dimensions
        final long[] x = Arrays.copyOf(unsignedPoint, n);
        long p;
        long q;
        long t;
        int i;
        // Inverse undo
        for (q = M; q != 1; q >>>= 1) {
            p = q - 1;
            for (i = 0; i < n; i++) {
                if ((x[i] & q) != 0) {
                    x[0] ^= p; // invert
                } else {
                    t = (x[0] ^ x[i]) & p;
                    x[0] ^= t;
                    x[i] ^= t;
                }
            }
        } // exchange
        // Gray encode
        for (i = 1; i < n; i++) {
            x[i] ^= x[i - 1];
        }
        t = 0;
        for (q = M; q != 1; q >>>= 1) {
            if ((x[n - 1] & q) != 0) {
                t ^= q - 1;
            }
        }
        for (i = 0; i < n; i++) {
            x[i] ^= t;
        }

        return x;
    }