// newStreamingBitrotWriterBuffer returns streaming bitrot writer implementation.
// The output is written to the supplied writer w.
func newStreamingBitrotWriterBuffer(w io.Writer, algo BitrotAlgorithm, shardSize int64) io.Writer {
	return &streamingBitrotWriter{iow: ioutil.NopCloser(w), h: algo.New(), shardSize: shardSize, canClose: nil, closeWithErr: func(err error) {}}
}

// Returns streaming bitrot writer implementation.

func bitSetTest(x int) bool {
	// amd64:"ANDL\t[$]9, AX"
	// amd64:"CMPQ\tAX, [$]9"
	return x&9 == 9
}

// mask contiguous one bits
func cont1Mask64U(x uint64) uint64 {
	// s390x:"RISBGZ\t[$]16, [$]47, [$]0,"
	return x & 0x0000ffffffff0000
}

// mask contiguous zero bits
func cont0Mask64U(x uint64) uint64 {
	// s390x:"RISBGZ\t[$]48, [$]15, [$]0,"
	return x & 0xffff00000000ffff
}

	if err = config.CheckValidKeys(config.HealSubSys, kvs, DefaultKVS); err != nil {
		return cfg, err
	}

	bitrot := env.Get(EnvBitrot, kvs.GetWithDefault(Bitrot, DefaultKVS))
	if _, err = parseBitrotConfig(bitrot); err != nil {
		return cfg, fmt.Errorf("'heal:bitrotscan' value invalid: %w", err)
	}

	cfg.Bitrot = bitrot

	cfg.Sleep, err = time.ParseDuration(env.Get(EnvSleep, kvs.GetWithDefault(Sleep, DefaultKVS)))
	if err != nil {

	storageRESTDstPath       = "destination-path"
	storageRESTOffset        = "offset"
	storageRESTLength        = "length"
	storageRESTCount         = "count"
	storageRESTBitrotAlgo    = "bitrot-algo"
	storageRESTBitrotHash    = "bitrot-hash"
	storageRESTDiskID        = "disk-id"
	storageRESTForceDelete   = "force-delete"
	storageRESTGlob          = "glob"
	storageRESTMetrics       = "metrics"
	storageRESTDriveQuorum   = "drive-quorum"

	// ppc64x: -"ADDC", "ADDE", -"ADDZE"
	r[2], c = bits.Add64(p[2], p[2], c)
}

func Add64MSaveC(p, q, r, c *[2]uint64) {
	// ppc64x: "ADDC\tR", "ADDZE"
	r[0], c[0] = bits.Add64(p[0], q[0], 0)
	// ppc64x: "ADDC\t[$]-1", "ADDE", "ADDZE"
	r[1], c[1] = bits.Add64(p[1], q[1], c[0])
}

func Add64PanicOnOverflowEQ(a, b uint64) uint64 {
	r, c := bits.Add64(a, b, 0)
	// s390x:"BRC\t[$]3,",-"ADDE"

	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}},

		d = a + bits.RotateLeft32((a^b^c)+d+x4+0x4bdecfa9, 11)
		c = d + bits.RotateLeft32((d^a^b)+c+x7+0xf6bb4b60, 16)
		b = c + bits.RotateLeft32((c^d^a)+b+xa+0xbebfbc70, 23)
		a = b + bits.RotateLeft32((b^c^d)+a+xd+0x289b7ec6, 4)
		d = a + bits.RotateLeft32((a^b^c)+d+x0+0xeaa127fa, 11)
		c = d + bits.RotateLeft32((d^a^b)+c+x3+0xd4ef3085, 16)
		b = c + bits.RotateLeft32((c^d^a)+b+x6+0x04881d05, 23)

		b.set(i)
		return
	}
	// Set bits [i, j].
	j := i + n - 1
	if i/64 == j/64 {
		b[i/64] |= ((uint64(1) << n) - 1) << (i % 64)
		return
	}
	_ = b[j/64]
	// Set leading bits.
	b[i/64] |= ^uint64(0) << (i % 64)
	for k := i/64 + 1; k < j/64; k++ {
		b[k] = ^uint64(0)
	}
	// Set trailing bits.
	b[j/64] |= (uint64(1) << (j%64 + 1)) - 1
}

// setAll sets all the bits of b.
func (b *pageBits) setAll() {

	"hash"
)

// New224 creates a new SHA3-224 hash.
// Its generic security strength is 224 bits against preimage attacks,
// and 112 bits against collision attacks.
func New224() hash.Hash {
	return new224()
}

// New256 creates a new SHA3-256 hash.
// Its generic security strength is 256 bits against preimage attacks,
// and 128 bits against collision attacks.
func New256() hash.Hash {
	return new256()
}

	// state = state * mul + inc
	hi, lo = bits.Mul64(p.lo, mulLo)
	hi += p.hi*mulLo + p.lo*mulHi
	lo, c := bits.Add64(lo, incLo, 0)
	hi, _ = bits.Add64(hi, incHi, c)
	p.lo = lo
	p.hi = hi
	return hi, lo
}

// Uint64 return a uniformly-distributed random uint64 value.
func (p *PCG) Uint64() uint64 {
	hi, lo := p.next()

	// XSL-RR would be
	//	hi, lo := p.next()
	//	return bits.RotateLeft64(lo^hi, -int(hi>>58))