add stat for streams

1 files changed, 57 insertions, 0 deletions

diff --git a/pkg/pack/pack.go b/pkg/pack/pack.go
new file mode 100644
index 0000000..e186773
--- /dev/null
+++ b/pkg/pack/pack.go
@@ -0,0 +1,57 @@
+package pack
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+type Reader interface {
+	io.Reader
+	io.ByteReader
+}
+
+type Encoder struct {
+	w io.Writer
+}
+
+type Decoder struct {
+	r Reader
+}
+
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{w: w}
+}
+
+func NewDecoder(r Reader) *Decoder {
+	return &Decoder{r: r}
+}
+
+func (e *Encoder) Lps(b []byte) error {
+	buf := make([]byte, binary.MaxVarintLen64)
+	n := binary.PutVarint(buf, int64(len(b)))
+
+	if _, err := e.w.Write(buf[:n]); err != nil {
+		return err
+	}
+
+	_, err := e.w.Write(b)
+	return err
+}
+
+func (d *Decoder) Lps() ([]byte, error) {
+	if n, err := binary.ReadVarint(d.r); err != nil {
+		return nil, fmt.Errorf("lps: %w", err)
+	} else {
+		buf := make([]byte, n)
+
+		if _, err := io.ReadFull(d.r, buf); err != nil {
+			if err == io.EOF {
+				err = io.ErrUnexpectedEOF
+			}
+			return nil, fmt.Errorf("lps: %w", err)
+		}
+
+		return buf, nil
+	}
+}