    virtual char *	readMemoryMapped (int n)
    {

        if (n + current > end)
	{
		THROW (IEX_NAMESPACE::InputExc, "Early end of file: requesting " << end - (n+current) << " extra bytes after file\n");
	}
	const char* value = current;
        current += n;

        return const_cast<char*>(value);
    }
    virtual char *	readMemoryMapped (int n)
    {

        if (n + current > end)
	{
		THROW (IEX_NAMESPACE::InputExc, "Early end of file: requesting " << end - (n+current) << " extra bytes after file\n");
	}
	const char* value = current;
        current += n;

        return const_cast<char*>(value);
    }