offset         int
	maxInsertIndex int
	err            error

	// hashMatch must be able to contain hashes for the maximum match length.
	hashMatch [maxMatchLength - 1]uint32
}

func (d *compressor) fillDeflate(b []byte) int {
	if d.index >= 2*windowSize-(minMatchLength+maxMatchLength) {
		// shift the window by windowSize
		copy(d.window, d.window[windowSize:2*windowSize])
		d.index -= windowSize
		d.windowEnd -= windowSize