public final long getBeUlong40(final int pos) {
        final int position = origin + pos;

        if (pos + 4 >= limit || pos < 0) throw new IllegalArgumentException("limit excceed: "
                                                                            + (pos < 0 ? pos : (pos + 4)));

        byte[] buf = buffer;
        return ((long) (0xff & buf[position + 4])) | ((long) (0xff & buf[position + 3]) << 8)
               | ((long) (0xff & buf[position + 2]) << 16) | ((long) (0xff & buf[position + 1]) << 24)
               | ((long) (0xff & buf[position]) << 32);
    }
public final long getBeUlong40 ( final int pos ) { final int position = origin + pos ; if ( pos + 4 >= limit || pos < 0 ) throw new IllegalArgumentException ( "limit excceed: " + ( pos < 0 ? pos : ( pos + 4 ) ) ) ; byte [ ] buf = buffer ; return ( ( long ) ( 0xff & buf [ position + 4 ] ) ) | ( ( long ) ( 0xff & buf [ position + 3 ] ) << 8 ) | ( ( long ) ( 0xff & buf [ position + 2 ] ) << 16 ) | ( ( long ) ( 0xff & buf [ position + 1 ] ) << 24 ) | ( ( long ) ( 0xff & buf [ position ] ) << 32 ) ; }
Return 40-bit unsigned int from buffer. (big-endian)

@see mysql-5.6.10/include/myisampack.h - mi_uint5korr