// Protect against e.cur wraparound.
	if e.cur >= bufferReset {
		e.shiftOffsets()
	}
}

// shiftOffsets will shift down all match offset.
// This is only called in rare situations to prevent integer overflow.
//
// See https://golang.org/issue/18636 and https://github.com/golang/go/issues/34121.
func (e *deflateFast) shiftOffsets() {
	if len(e.prev) == 0 {
		// We have no history; just clear the table.