Golang bytes.Fields函数代码示例

// Read a single sequence and return it or an error.
// TODO: Does not read multi-line fastq.
func (self *Reader) Read() (s seq.Sequence, err error) {
	var (
		buff, line, label []byte
		isPrefix          bool
		seqBuff           []alphabet.QLetter
		t                 seqio.SequenceAppender
	)

	inQual := false

	for {
		if buff, isPrefix, err = self.r.ReadLine(); err == nil {
			if isPrefix {
				line = append(line, buff...)
				continue
			} else {
				line = buff
			}

			line = bytes.TrimSpace(line)
			if len(line) == 0 {
				continue
			}
			switch {
			case !inQual && line[0] == '@':
				t = self.readHeader(line)
				label, line = line, nil
			case !inQual && line[0] == '+':
				if len(label) == 0 {
					return nil, bio.NewError("fastq: no header line parsed before +line in fastq format", 0)
				}
				if len(line) > 1 && bytes.Compare(label[1:], line[1:]) != 0 {
					return nil, bio.NewError("fastq: quality header does not match sequence header", 0)
				}
				inQual = true
			case !inQual:
				line = bytes.Join(bytes.Fields(line), nil)
				seqBuff = make([]alphabet.QLetter, len(line))
				for i := range line {
					seqBuff[i].L = alphabet.Letter(line[i])
				}
			case inQual:
				line = bytes.Join(bytes.Fields(line), nil)
				if len(line) != len(seqBuff) {
					return nil, bio.NewError("fastq: sequence/quality length mismatch", 0)
				}
				for i := range line {
					seqBuff[i].Q = alphabet.DecodeToQphred(line[i], self.enc)
				}
				t.AppendQLetters(seqBuff...)

				return t, nil
			}
		} else {
			return
		}
	}

	panic("cannot reach")
}

func ram() string {
	f, err := os.Open("/proc/meminfo")
	if err != nil {
		return fmt.Sprint(err)
	}
	defer f.Close()

	bufReader := bufio.NewReader(f)
	b := make([]byte, 100)
	var free, total string
	for line, isPrefix, err := bufReader.ReadLine(); err != io.EOF; line, isPrefix, err = bufReader.ReadLine() {
		b = append(b, line...)

		if !isPrefix {
			switch {
			case bytes.Contains(b, []byte("MemFree")):
				s := bytes.Fields(b)
				free = string(s[1])
			case bytes.Contains(b, []byte("MemTotal")):
				s := bytes.Fields(b)
				total = string(s[1])
			}
			b = b[:0]
		}
	}
	return fmt.Sprintf("%s/%s", free, total)
}

func ram() interface{} {
	f, err := os.Open("/proc/meminfo")
	if err != nil {
		return "Unsupported"
	}
	defer f.Close()

	bufReader := bufio.NewReader(f)
	b := make([]byte, 0, 100)
	var free, total int

	for line, isPrefix, err := bufReader.ReadLine(); err != io.EOF; line, isPrefix, err = bufReader.ReadLine() {
		if err != nil {
			log.Fatal("bufReader.ReadLine: ", err)
		}
		b = append(b, line...)

		if !isPrefix {
			switch {
			case bytes.Contains(b, []byte("MemFree")):
				free = toInt(bytes.Fields(b)[1])
			case bytes.Contains(b, []byte("MemTotal")):
				total = toInt(bytes.Fields(b)[1])
			}
			b = b[:0]
		}
	}
	return Ram{free, total}
}

func readDataSetFile(filename string) (d *DataSet) {
	d = new(DataSet)
	data, err := ioutil.ReadFile(filename)
	if err != nil {
		fmt.Println("Error opening file: ", filename)
		return
	}
	lines := bytes.Split(data, []byte{'\n'})
	names := bytes.Fields(lines[0])
	for i := 0; i < len(names)-1; i++ {
		d.var_names = append(d.var_names, string(names[i]))
	}
	d.out_name = string(names[len(names)-1])

	for i := 1; i < len(lines); i++ {
		val_strs := bytes.Fields(lines[i])
		if len(val_strs) < len(d.var_names)+1 {
			break
		}
		input := make([]float64, len(d.var_names))

		for p := 0; p < len(d.var_names); p++ {
			var val float64
			fmt.Sscanf(string(val_strs[p]), "%f", &val)
			input[p] = val
		}
		d.input = append(d.input, input)
		var out float64
		fmt.Sscanf(string(val_strs[len(val_strs)-1]), "%f", &out)
		d.output = append(d.output, out)
	}

	return
}

func New(r io.Reader) (*Grammar, error) {
	buf := bufio.NewReader(r)
	g := &Grammar{data: make(map[string][][]string)}
	start, err := buf.Peek(80)
	if err != nil {
		return nil, err
	}
	g.start = string(bytes.Fields(start)[0])
	line, err := buf.ReadSlice('.')
	for ; err == nil; line, err = buf.ReadSlice('.') {
		splat := bytes.Fields(line) // First field is left side, last is ".".
		stringified := make([]string, len(splat)-2)
		for i, word := range splat[1 : len(splat)-1] {
			stringified[i] = string(word)
		}
		key := string(splat[0])
		g.data[key] = append(g.data[key], stringified)
	}
	if err != io.EOF {
		return g, err
	}
	for _, c := range line { // leftovers
		if !unicode.IsSpace(rune(c)) { // i.e. there's something after the last '.':
			return g, io.ErrUnexpectedEOF
		}
	}
	return g, nil
}

func parseCommit(r io.Reader, resultSize string, name SHA) (Commit, error) {
	var commit = Commit{_type: "commit", size: resultSize}

	scnr := bufio.NewScanner(r)
	scnr.Split(ScanLinesNoTrim)

	var commitMessageLines [][]byte
	for scnr.Scan() {
		line := scnr.Bytes()
		trimmedLine := bytes.TrimRight(line, "\r\n")
		if commitMessageLines == nil && len(bytes.Fields(trimmedLine)) == 0 {
			// Everything after the first empty line is the commit message
			commitMessageLines = [][]byte{}
			continue
		}

		if commitMessageLines != nil {
			// We have already seen an empty line
			commitMessageLines = append(commitMessageLines, line)
			continue
		}

		parts := bytes.Fields(trimmedLine)
		key := parts[0]
		switch keyType(key) {
		case treeKey:
			commit.Tree = string(parts[1])
		case parentKey:
			commit.Parents = append(commit.Parents, SHA(string(parts[1])))
		case authorKey:
			authorline := string(bytes.Join(parts[1:], []byte(" ")))
			author, date, err := parseAuthorString(authorline)
			if err != nil {
				return commit, err
			}
			commit.Author = author
			commit.AuthorDate = date
		case committerKey:
			committerline := string(bytes.Join(parts[1:], []byte(" ")))
			committer, date, err := parseCommitterString(committerline)
			if err != nil {
				return commit, err
			}
			commit.Committer = committer
			commit.CommitterDate = date
		default:
			err := fmt.Errorf("encountered unknown field in commit: %s", key)
			return commit, err
		}
	}
	commit.Name = name
	commit.Message = bytes.Join(commitMessageLines, []byte("\n"))
	return commit, nil
}

// Read a single sequence and return it or an error.
// TODO: Does not read interleaved fastq.
func (self *Reader) Read() (sequence *seq.Seq, err error) {
	if self.r == nil {
		self.r = bufio.NewReader(self.f)
	}
	var line, label, seqBody, qualBody []byte
	sequence = &seq.Seq{}

	inQual := false
READ:
	for {
		if line, err = self.r.ReadBytes('\n'); err == nil {
			if len(line) > 0 && line[len(line)-1] == '\r' {
				line = line[:len(line)-1]
			}
			line = bytes.TrimSpace(line)
			if len(line) == 0 {
				continue
			}
			switch {
			case !inQual && line[0] == '@':
				label = line[1:]
			case !inQual && line[0] == '+':
				if len(label) == 0 {
					return nil, errors.New("No ID line parsed at +line in fastq format")
				}
				if len(line) > 1 && bytes.Compare(label, line[1:]) != 0 {
					return nil, errors.New("Quality ID does not match sequence ID")
				}
				inQual = true
			case !inQual:
				line = bytes.Join(bytes.Fields(line), nil)
				seqBody = append(seqBody, line...)
			case inQual:
				line = bytes.Join(bytes.Fields(line), nil)
				qualBody = append(qualBody, line...)
				if len(qualBody) >= len(seqBody) {
					break READ
				}
			}
		} else {
			return
		}
	}

	if len(seqBody) != len(qualBody) {
		return nil, errors.New("Quality length does not match sequence length")
	}
	sequence = seq.New(label, seqBody, qualBody)

	return
}

func discoverGatewayUsingRoute() (ip net.IP, err error) {
	routeCmd := exec.Command("route", "-n")
	stdOut, err := routeCmd.StdoutPipe()
	if err != nil {
		return
	}
	if err = routeCmd.Start(); err != nil {
		return
	}
	output, err := ioutil.ReadAll(stdOut)
	if err != nil {
		return
	}

	// Linux route out format is always like this:
	// Kernel IP routing table
	// Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
	// 0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth0
	outputLines := bytes.Split(output, []byte("\n"))
	for _, line := range outputLines {
		if bytes.Contains(line, []byte("0.0.0.0")) {
			ipFields := bytes.Fields(line)
			ip = net.ParseIP(string(ipFields[1]))
			break
		}
	}
	err = routeCmd.Wait()
	return
}

func discoverGatewayUsingIp() (ip net.IP, err error) {
	routeCmd := exec.Command("ip", "route", "show")
	stdOut, err := routeCmd.StdoutPipe()
	if err != nil {
		return
	}
	if err = routeCmd.Start(); err != nil {
		return
	}
	output, err := ioutil.ReadAll(stdOut)
	if err != nil {
		return
	}

	// Linux 'ip route show' format looks like this:
	// default via 192.168.178.1 dev wlp3s0  metric 303
	// 192.168.178.0/24 dev wlp3s0  proto kernel  scope link  src 192.168.178.76  metric 303
	outputLines := bytes.Split(output, []byte("\n"))
	for _, line := range outputLines {
		if bytes.Contains(line, []byte("default")) {
			ipFields := bytes.Fields(line)
			ip = net.ParseIP(string(ipFields[2]))
			break
		}
	}
	err = routeCmd.Wait()
	return
}

// loadGoodTable can be used to parse string heap that
// headers and values are arranged in right order
func loadGoodTable(table []byte, dumpZeros bool) (map[string]interface{}, error) {
	entries := map[string]interface{}{}
	fields := bytes.Fields(table)
	var value int64
	var err error
	// iterate over two values each time
	// first value is header, second is value
	for i := 0; i < len(fields); i = i + 2 {
		// counter is zero
		if bytes.Equal(fields[i+1], zeroByte) {
			if !dumpZeros {
				continue
			} else {
				entries[string(fields[i])] = int64(0)
				continue
			}
		}
		// the counter is not zero, so parse it.
		value, err = strconv.ParseInt(string(fields[i+1]), 10, 64)
		if err == nil {
			entries[string(fields[i])] = value
		}
	}
	return entries, nil
}

// ValidatePacket validates a carbon message.
func ValidatePacket(buf []byte) error {
	fields := bytes.Fields(buf)
	if len(fields) != 3 {
		return errors.New("packet must consist of 3 fields")

	}

	version := GetVersionB(fields[0])
	err := InitialValidationB(fields[0], version)
	if err != nil {
		return err
	}

	_, err = strconv.ParseFloat(string(fields[1]), 32)
	if err != nil {
		return errors.New("value field is not a float or int")
	}

	_, err = strconv.ParseUint(string(fields[2]), 10, 0)
	if err != nil {
		return errors.New("timestamp field is not a unix timestamp")
	}

	return nil
}

func (s *Statements) Scan() {
	go s.Parser.Parse()

	scanner := bufio.NewScanner(s.Parser)

	depth := 0
	scanner.Split(func(data []byte, atEOF bool) (advance int, token []byte, err error) {
		if i := bytes.IndexAny(data, ";{}"); i >= 0 {
			if string(data[i]) == "{" {
				depth++
			} else if string(data[i]) == "}" {
				depth--
			}
			return i + 1, data[0:i], nil
		} else if atEOF {
			return len(data), nil, nil
		}
		return 0, nil, nil
	})

	for scanner.Scan() {
		stmt := string(bytes.Join(bytes.Fields(scanner.Bytes()), []byte{' '}))
		s.stmts <- &stmtMsg{stmt, depth}
	}
}

func (f Format) TheHour(n int, t time.Time) (b []byte) {
	b = make([]byte, 0, 64)
	for _, f := range bytes.Fields(f) {
		switch f[0] {
		case '#':
			b = append(b, Numbers[n]...)
		case 'h':
			b = append(b, []byte(`THE HOUR`)...)
		case 'm':
			m := t.Minute()
			b = append(b, Numbers[m]...)
			if len(f) == 2 && f[1] == '_' {
				b = append(b, Sminute...)
				if m != 1 {
					b = append(b, 'S')
				}
			}
		case 's':
			s := t.Second()
			b = append(b, Numbers[s]...)
			if len(f) == 2 && f[1] == '_' {
				b = append(b, Ssecond...)
				if s != 1 {
					b = append(b, 'S')
				}
			}
		default:
			b = append(b, f...)
		}
		b = append(b, ' ')
	}
	return b[:len(b)-1]
}

func TestCache(t *testing.T) {

	// Test data was generated from the python code
	f, err := os.Open("testdata/domains.txt")

	if err != nil {
		t.Fatal(err)
	}

	scanner := bufio.NewScanner(f)

	cache := New(200)

	for scanner.Scan() {
		fields := bytes.Fields(scanner.Bytes())

		key := string(fields[0])
		wantHit := fields[1][0] == 'h'

		var hit bool
		v := cache.Get(key)
		if v == nil {
			cache.Set(key, key)
		} else {
			hit = true
			if v.(string) != key {
				t.Errorf("cache returned bad data: got %+v , want %+v\n", v, key)
			}
		}
		if hit != wantHit {
			t.Errorf("cache hit mismatch: got %v, want %v\n", hit, wantHit)
		}
	}
}

func DiscoverGateway() (ip net.IP, err error) {
	routeCmd := exec.Command("route", "-n", "get", "0.0.0.0")
	stdOut, err := routeCmd.StdoutPipe()
	if err != nil {
		return
	}
	if err = routeCmd.Start(); err != nil {
		return
	}
	output, err := ioutil.ReadAll(stdOut)
	if err != nil {
		return
	}

	// Darwin route out format is always like this:
	//    route to: default
	// destination: default
	//        mask: default
	//     gateway: 192.168.1.1
	outputLines := bytes.Split(output, []byte("\n"))
	for _, line := range outputLines {
		if bytes.Contains(line, []byte("gateway:")) {
			gatewayFields := bytes.Fields(line)
			ip = net.ParseIP(string(gatewayFields[1]))
			break
		}
	}

	err = routeCmd.Wait()
	return
}