Golang Buffer.Write0方法代碼示例

// Handles the message "gosa_get_log_file_by_date_and_mac".
//  xmlmsg: the decrypted and parsed message
// Returns:
//  unencrypted reply
func gosa_get_log_file_by_date_and_mac(xmlmsg *xml.Hash) *xml.Hash {
	macaddress := xmlmsg.Text("mac")
	lmac := strings.ToLower(macaddress)
	subdir := xmlmsg.Text("date")
	log_file := xmlmsg.Text("log_file")

	header := "get_log_file_by_date_and_mac"
	x := xml.NewHash("xml", "header", header)
	x.Add(header)
	x.Add("source", config.ServerSourceAddress)
	x.Add("target", "GOSA")
	x.Add("session_id", "1")

	if !macAddressRegexp.MatchString(macaddress) {
		emsg := fmt.Sprintf("Illegal or missing <mac> element in message: %v", xmlmsg)
		util.Log(0, "ERROR! %v", emsg)
		return ErrorReplyXML(emsg)
	}

	// As a precaution, make sure subdir and log_file contain no slashes.
	subdir = strings.Replace(subdir, "/", "_", -1)
	log_file = strings.Replace(log_file, "/", "_", -1)

	if subdir == "" {
		// When you open the installation logs in GOsa for the first time, GOsa sends
		// a broken request that is characterized by an empty <date> and log_file==0.
		// If we return an error, GOsa presents it to the user which
		// gives a bad experience. So we instead return an empty reply in this special case.
		if log_file == "0" {
			return x
		}
		emsg := fmt.Sprintf("Missing or empty <date> element in message: %v", xmlmsg)
		util.Log(0, "ERROR! %v", emsg)
		return ErrorReplyXML(emsg)
	}

	if log_file == "" {
		emsg := fmt.Sprintf("Missing or empty <log_file> element in message: %v", xmlmsg)
		util.Log(0, "ERROR! %v", emsg)
		return ErrorReplyXML(emsg)
	}

	f, err := os.Open(path.Join(config.FAILogPath, lmac, subdir, log_file))
	if err != nil {
		emsg := fmt.Sprintf("gosa_get_log_file_by_date_and_mac: %v", err)
		util.Log(0, "ERROR! %v", emsg)
		return ErrorReplyXML(emsg)
	}
	defer f.Close()

	var b bytes.Buffer
	defer b.Reset()
	buffy := make([]byte, 65536)
	for {
		n, err := f.Read(buffy)
		b.Write(buffy[0:n])
		if err == io.EOF {
			break
		}
		if err != nil {
			emsg := fmt.Sprintf("gosa_get_log_file_by_date_and_mac: %v", err)
			util.Log(0, "ERROR! %v", emsg)
			return ErrorReplyXML(emsg)
		}
		if n == 0 {
			util.Log(0, "WARNING! Read returned 0 bytes but no error. Assuming EOF")
			break
		}
	}

	idx := (((b.Len() + 2) / 3) << 2) - b.Len()
	b.Write0(idx)
	data := b.Bytes()
	copy(data[idx:], data)
	data = util.Base64EncodeInPlace(data, idx)

	data_element := x.Add(log_file)

	// To reduce memory leak potential, we append in pieces rather than as one large string
	end := xml.MaxFragmentLength
	for ; end < len(data); end += xml.MaxFragmentLength {
		data_element.AppendString(string(data[end-xml.MaxFragmentLength : end]))
	}
	data_element.AppendString(string(data[end-xml.MaxFragmentLength:]))

	return x
}

//.........這裏部分代碼省略.........
	check(b.Len(), 0)
	check(b.Capacity(), 0)
	check(b.Pointer(), nil)

	b.WriteString("Der Cottbuser Postkutscher kotzt in den Cottbuser Postkotzkasten")
	b.Trim(4, 4)
	check(b.Len(), 0)
	check(b.Capacity(), 0)
	check(b.Pointer(), nil)

	b.WriteString("Der Cottbuser Postkutscher kotzt in den Cottbuser Postkotzkasten")
	n = b.Len()
	c = b.Capacity()
	p = b.Pointer()
	b.Trim(0, b.Len()-6)
	check(b.Len(), n-6)
	check(b.Capacity(), c)
	check(b.Pointer(), p)
	check(b.String(), "Der Cottbuser Postkutscher kotzt in den Cottbuser Postkotz")

	b.Trim(27, b.Len())
	check(b.Len(), n-6-27)
	check(b.Capacity(), c)
	check(b.Pointer(), p)
	check(b.String(), "kotzt in den Cottbuser Postkotz")

	b.Trim(1, b.Len()-1)
	check(b.Len(), n-6-27-2)
	check(b.Capacity(), c)
	check(b.Pointer(), p)
	check(b.String(), "otzt in den Cottbuser Postkot")

	b.Reset()
	b.Write0(-1)
	b.Write0(-100)
	b.Write0(0)
	check(b.Len(), 0)
	check(b.Capacity(), 0)
	check(b.Pointer(), nil)

	b.Write0(1)
	check(b.Len(), 1)
	check(b.Capacity(), 1)
	check(b.Bytes(), []byte{0})

	b.WriteByte(111)
	b.Write0(1)
	b.WriteByte(222)
	b.Write0(2)
	b.WriteByte(99)
	check(b.Len(), 7)
	check(b.Bytes(), []byte{0, 111, 0, 222, 0, 0, 99})

	b2.Reset()
	slices := [][]byte{}
	total := 0
	numfakeerrs := 0
	for total < 100000 {
		c = rand.Intn(30000)
		total += c

		sl := make([]byte, c)
		for i := range sl {
			sl[i] = byte(rand.Intn(256))
		}
		slices = append(slices, sl)