Russ Cox <******@****.***> 1643915146 -0500

// To rotate x right by k bits, call RotateLeft8(x, -k).
//
// This function's execution time does not depend on the inputs.
func RotateLeft8(x uint8, k int) uint8 {
	const n = 8
	s := uint(k) & (n - 1)
	return x<<s | x>>(n-s)
}

// RotateLeft16 returns the value of x rotated left by (k mod 16) bits.
// To rotate x right by k bits, call RotateLeft16(x, -k).
//

func test32(a, b float32) {
	abits := math.Float32bits(a)
	bbits := math.Float32bits(b)
	if abits != bbits {
		panic(fmt.Sprintf("%08x != %08x\n", abits, bbits))
	}
}

func test64(a, b float64) {
	abits := math.Float64bits(a)
	bbits := math.Float64bits(b)
	if abits != bbits {
		panic(fmt.Sprintf("%016x != %016x\n", abits, bbits))
	}

}

// emit emits the least significant nBits bits of bits to the bit-stream.
// The precondition is bits < 1<<nBits && nBits <= 16.
func (e *encoder) emit(bits, nBits uint32) {
	nBits += e.nBits
	bits <<= 32 - nBits
	bits |= e.bits
	for nBits >= 8 {
		b := uint8(bits >> 24)
		e.writeByte(b)
		if b == 0xff {
			e.writeByte(0x00)
		}
		bits <<= 8
		nBits -= 8
	}
	e.bits, e.nBits = bits, nBits
}

	if w.err != nil {
		return
	}
	w.bits |= uint64(b) << w.nbits
	w.nbits += nb
	if w.nbits >= 48 {
		bits := w.bits
		w.bits >>= 48
		w.nbits -= 48
		n := w.nbytes
		bytes := w.bytes[n : n+6]
		bytes[0] = byte(bits)
		bytes[1] = byte(bits >> 8)
		bytes[2] = byte(bits >> 16)
		bytes[3] = byte(bits >> 24)
		bytes[4] = byte(bits >> 32)
		bytes[5] = byte(bits >> 40)
		n += 6
		if n >= bufferFlushSize {

}

// writeLSB writes the code c for "Least Significant Bits first" data.
func (w *Writer) writeLSB(c uint32) error {
	w.bits |= c << w.nBits
	w.nBits += w.width
	for w.nBits >= 8 {
		if err := w.w.WriteByte(uint8(w.bits)); err != nil {
			return err
		}
		w.bits >>= 8
		w.nBits -= 8
	}
	return nil
}

// writeMSB writes the code c for "Most Significant Bits first" data.
func (w *Writer) writeMSB(c uint32) error {

	// table with the first 10 bits from the mantissa.
	xExp := int64((xBits>>52)&0x7FF) - 1023
	xManIndex := (xBits >> (52 - fastlogNumBits)) % (1 << fastlogNumBits)
	xManScale := (xBits >> (52 - fastlogNumBits - fastlogScaleBits)) % (1 << fastlogScaleBits)

	low, high := fastlog2Table[xManIndex], fastlog2Table[xManIndex+1]
	return float64(xExp) + low + (high-low)*float64(xManScale)*fastlogScaleRatio

}

// readLSB returns the next code for "Least Significant Bits first" data.
func (r *Reader) readLSB() (uint16, error) {
	for r.nBits < r.width {
		x, err := r.r.ReadByte()
		if err != nil {
			return 0, err
		}
		r.bits |= uint32(x) << r.nBits
		r.nBits += 8
	}
	code := uint16(r.bits & (1<<r.width - 1))
	r.bits >>= r.width
	r.nBits -= r.width
	return code, nil
}

	var p Bits
	for _, x := range x {
		for _, y := range y {
			p = append(p, x+y)
		}
	}
	return p
}

func TestMulBits(t *testing.T) {
	for _, test := range []struct {
		x, y, want Bits
	}{
		{nil, nil, nil},
		{Bits{}, Bits{}, nil},
		{Bits{0}, Bits{0}, Bits{0}},
		{Bits{0}, Bits{1}, Bits{1}},
		{Bits{1}, Bits{1, 2, 3}, Bits{2, 3, 4}},
		{Bits{-1}, Bits{1}, Bits{0}},

		{11, 2048 - 1024},
		{12, 4096 - 2048},
	}
	nCodes, nBits := 0, 0
	for _, e := range iterations {
		nCodes += e.n
		nBits += e.n * e.width
	}
	if nCodes != 3839 {
		t.Fatalf("nCodes: got %v, want %v", nCodes, 3839)
	}
	if nBits != 43255 {
		t.Fatalf("nBits: got %v, want %v", nBits, 43255)
	}

	// Construct our input of 43255 zero bits (which gets d.hi and d.width up