}
	}

	n = len(b0) - len(b)
	switch {
	case err == io.EOF:
		return n, errMissData // Less data in dense file than sparse file
	case err != nil:
		return n, err
	case sr.logicalRemaining() == 0 && sr.physicalRemaining() > 0:
		return n, errUnrefData // More data in dense file than sparse file
	case finished:
		return n, io.EOF
	default:
		return n, nil
	}
}

	return err
}

// Peek returns the next n bytes without advancing the reader. The bytes stop
// being valid at the next read call. If Peek returns fewer than n bytes, it
// also returns an error explaining why the read is short. The error is
// [ErrBufferFull] if n is larger than b's buffer size.
//
// Calling Peek prevents a [Reader.UnreadByte] or [Reader.UnreadRune] call from succeeding
// until the next read operation.

			break
		}
	}
	if got, want := scanner.Err(), ErrBadReadCount; got != want {
		t.Errorf("scanner.Err: got %v, want %v", got, want)
	}
}

// largeReader returns an invalid count that is larger than the number
// of bytes requested.
type largeReader struct{}

func (largeReader) Read(p []byte) (int, error) {
	return len(p) + 1, nil
}

// Test that the scanner doesn't panic and returns ErrBadReadCount

	}

	return w.writeDataDescriptor()
}

func (w *fileWriter) writeDataDescriptor() error {
	if !w.hasDataDescriptor() {
		return nil
	}
	// Write data descriptor. This is more complicated than one would
	// think, see e.g. comments in zipfile.c:putextended() and
	// https://bugs.openjdk.org/browse/JDK-7073588.
	// The approach here is to write 8 byte sizes if needed without