format/pktline: review and improving coverage

1 files changed, 106 insertions, 0 deletions

diff --git a/formats/pktline/decoder.go b/formats/pktline/decoder.go
new file mode 100644
index 0000000..a078475
--- /dev/null
+++ b/formats/pktline/decoder.go
@@ -0,0 +1,106 @@
+package pktline
+
+import (
+	"errors"
+	"io"
+	"strconv"
+)
+
+var (
+	ErrUnderflow     = errors.New("unexpected string length (underflow)")
+	ErrInvalidHeader = errors.New("invalid header")
+	ErrInvalidLen    = errors.New("invalid length")
+)
+
+// Decoder implements a pkt-line format decoder
+type Decoder struct {
+	r io.Reader
+}
+
+// NewDecoder returns a new Decoder
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{r}
+}
+
+// ReadLine reads and return one pkt-line line from the reader
+func (d *Decoder) ReadLine() (string, error) {
+	return d.readLine()
+}
+
+func (d *Decoder) readLine() (string, error) {
+	raw := make([]byte, HeaderLength)
+	if _, err := d.r.Read(raw); err != nil {
+		return "", err
+	}
+
+	header, err := strconv.ParseInt(string(raw), 16, 16)
+	if err != nil {
+		return "", ErrInvalidHeader
+	}
+
+	if header == 0 {
+		return "", nil
+	}
+
+	exp := int(header - HeaderLength)
+	if exp < 0 {
+		return "", ErrInvalidLen
+	}
+
+	line := make([]byte, exp)
+	if read, err := d.r.Read(line); err != nil {
+		return "", err
+	} else if read != exp {
+		return "", ErrUnderflow
+	}
+
+	return string(line), nil
+}
+
+// ReadBlock reads and return multiple pkt-line lines, it stops at the end
+// of the reader or if a flush-pkt is reached
+func (d *Decoder) ReadBlock() ([]string, error) {
+	var o []string
+
+	for {
+		line, err := d.readLine()
+		if err == io.EOF {
+			return o, nil
+		}
+
+		if err != nil {
+			return o, err
+		}
+
+		if err == nil && line == "" {
+			return o, nil
+		}
+
+		o = append(o, line)
+	}
+}
+
+// ReadAll read and returns all the lines
+func (d *Decoder) ReadAll() ([]string, error) {
+	result, err := d.ReadBlock()
+	if err != nil {
+		return result, err
+	}
+
+	for {
+		lines, err := d.ReadBlock()
+		if err == io.EOF {
+			return result, nil
+		}
+
+		if err != nil {
+			return result, err
+		}
+
+		if err == nil && len(lines) == 0 {
+			return result, nil
+		}
+
+		result = append(result, lines...)
+	}
+}