public long [] readNextLongArray(int nElements) throws IOException {
        long [] l = readLongArray(currentIndex, nElements);
        currentIndex+=(SIZEOF_LONG*nElements);
        return l;
    }
Reads a long array of <code>nElements</code>
starting at the current index and then increments the current
index by <code>SIZEOF_LONG * nElements</code>.
@return the long array starting at the current index
@exception IOException if an I/O error occurs
GPL/DMG/src/dmg/java/mobiledevices/dmg/ghidra/GBinaryReader.java