try {
            System.arraycopy(this.sbuf, 0, buffer, 0, 4 + SMB1_HEADER_LENGTH);
            int size = ( Encdec.dec_uint16be(buffer, 2) & 0xFFFF );
            if ( size < ( SMB1_HEADER_LENGTH + 1 ) || ( 4 + size ) > Math.min(0xFFFF, getContext().getConfig().getMaximumBufferSize()) ) {
                throw new IOException("Invalid payload size: " + size);
            }

	UTFMax    = 4            // maximum number of bytes of a UTF-8 encoded Unicode character.
)

// Code points in the surrogate range are not valid for UTF-8.
const (
	surrogateMin = 0xD800
	surrogateMax = 0xDFFF
)

const (
	t1 = 0b00000000
	tx = 0b10000000
	t2 = 0b11000000
	t3 = 0b11100000
	t4 = 0b11110000
	t5 = 0b11111000

	maskx = 0b00111111
	mask2 = 0b00011111
	mask3 = 0b00001111

	if !(Point{x, y}.In(p.Rect)) {
		return
	}
	r, g, b, a := uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
	if (a != 0) && (a != 0xffff) {
		r = (r * 0xffff) / a
		g = (g * 0xffff) / a
		b = (b * 0xffff) / a
	}
	i := p.PixOffset(x, y)
	s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
	s[0] = uint8(r >> 8)
	s[1] = uint8(g >> 8)

	IN_ACCESS                        = 0x1
	IN_ALL_EVENTS                    = 0xfff
	IN_ATTRIB                        = 0x4
	IN_CLASSA_HOST                   = 0xffffff
	IN_CLASSA_MAX                    = 0x80
	IN_CLASSA_NET                    = 0xff000000
	IN_CLASSA_NSHIFT                 = 0x18
	IN_CLASSB_HOST                   = 0xffff
	IN_CLASSB_MAX                    = 0x10000
	IN_CLASSB_NET                    = 0xffff0000

// does a -1 shadowRange, which is what sparsemap.get returns
// on a failed lookup).
type shadowRange int32

func (sr shadowRange) lo() int64 {
	return int64(sr & 0xffff)
}

func (sr shadowRange) hi() int64 {
	return int64((sr >> 16) & 0xffff)
}

// contains reports whether [lo:hi] is completely within sr.
func (sr shadowRange) contains(lo, hi int64) bool {
	return lo >= sr.lo() && hi <= sr.hi()
}

	SOCK_SEQPACKET                = 0x6
	SOCK_STREAM                   = 0x2
	SOCK_TYPE_MASK                = 0xffff
	SOL_FILTER                    = 0xfffc
	SOL_PACKET                    = 0xfffd
	SOL_ROUTE                     = 0xfffe
	SOL_SOCKET                    = 0xffff
	SOMAXCONN                     = 0x80
	SO_ACCEPTCONN                 = 0x2
	SO_ALL                        = 0x3f

	}
	*d = digest(byteorder.BeUint32(b[len(magic):]))
	return nil
}

// Add p to the running checksum d.
func update(d digest, p []byte) digest {
	s1, s2 := uint32(d&0xffff), uint32(d>>16)
	for len(p) > 0 {
		var q []byte
		if len(p) > nmax {
			p, q = p[:nmax], p[nmax:]
		}
		for len(p) >= 4 {
			s1 += uint32(p[0])
			s2 += s1
			s1 += uint32(p[1])
			s2 += s1

	}
	if rand.Intn(10) > 5 {
		m.extendedMasterSecret = true
	}
	for i := 0; i < rand.Intn(5); i++ {
		m.supportedVersions = append(m.supportedVersions, uint16(rand.Intn(0xffff)+1))
	}
	if rand.Intn(10) > 5 {
		m.cookie = randomBytes(rand.Intn(500)+1, rand)
	}
	for i := 0; i < rand.Intn(5); i++ {
		var ks keyShare
		ks.group = CurveID(rand.Intn(30000) + 1)

	SOCK_SEQPACKET                = 0x6
	SOCK_STREAM                   = 0x2
	SOCK_TYPE_MASK                = 0xffff
	SOL_FILTER                    = 0xfffc
	SOL_PACKET                    = 0xfffd
	SOL_ROUTE                     = 0xfffe
	SOL_SOCKET                    = 0xffff
	SOMAXCONN                     = 0x80
	SO_ACCEPTCONN                 = 0x2
	SO_ALL                        = 0x3f

						d[3] = 0
					} else if s[3] == 0xff {
						copy(d[:], s[:])
					} else {
						// This code does the same as color.NRGBAModel.Convert(
						// rgba.At(x, y)).(color.NRGBA) but with no extra memory
						// allocations or interface/function call overhead.
						//
						// The multiplier m combines 0x101 (which converts
						// 8-bit color to 16-bit color) and 0xffff (which, when