}
        tot = 0;

        while( true ) {
            while( bip > 0 ) {
                n = in.read( b, off, Math.min( len, bip ));
                if( n == -1 ) {
                    return tot > 0 ? tot : -1;
                }
                tot += n;
                off += n;
                len -= n;
                bip -= n;
                if( len == 0 ) {
                    return tot;