format/pktline: review and improving coverage

1 files changed, 63 insertions, 0 deletions

diff --git a/formats/pktline/encoder.go b/formats/pktline/encoder.go
new file mode 100644
index 0000000..dfa53e2
--- /dev/null
+++ b/formats/pktline/encoder.go
@@ -0,0 +1,63 @@
+package pktline
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var (
+	ErrOverflow = errors.New("unexpected string length (overflow)")
+)
+
+// Encoder implements a pkt-line format encoder
+type Encoder struct {
+	lines []string
+}
+
+// NewEncoder returns a new Encoder
+func NewEncoder() *Encoder {
+	return &Encoder{make([]string, 0)}
+}
+
+// AddLine encode and adds a line to the encoder
+func (e *Encoder) AddLine(line string) error {
+	le, err := EncodeFromString(line + "\n")
+	if err != nil {
+		return err
+	}
+
+	e.lines = append(e.lines, le)
+	return nil
+}
+
+// AddFlush adds a flush-pkt to the encoder
+func (e *Encoder) AddFlush() {
+	e.lines = append(e.lines, "0000")
+}
+
+// Reader returns a string.Reader over the encoder
+func (e *Encoder) Reader() *strings.Reader {
+	data := strings.Join(e.lines, "")
+
+	return strings.NewReader(data)
+}
+
+// EncodeFromString encodes a string to pkt-line format
+func EncodeFromString(line string) (string, error) {
+	return Encode([]byte(line))
+}
+
+// Encode encodes a byte slice to pkt-line format
+func Encode(line []byte) (string, error) {
+	if line == nil {
+		return "0000", nil
+	}
+
+	l := len(line) + HeaderLength
+	if l > MaxLength {
+		return "", ErrOverflow
+	}
+
+	return fmt.Sprintf("%04x%s", l, line), nil
+}