rtmp: add message reader / writer

internal/rtmp/message/msg_setwindowacksize.go

@@ -0,0 +1,40 @@
+package message
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/aler9/rtsp-simple-server/internal/rtmp/chunk"
+	"github.com/aler9/rtsp-simple-server/internal/rtmp/rawmessage"
+)
+
+// MsgSetWindowAckSize is a set window acknowledgement message.
+type MsgSetWindowAckSize struct {
+	Value uint32
+}
+
+// Unmarshal implements Message.
+func (m *MsgSetWindowAckSize) Unmarshal(raw *rawmessage.Message) error {
+	if raw.ChunkStreamID != ControlChunkStreamID {
+		return fmt.Errorf("unexpected chunk stream ID")
+	}
+
+	if len(raw.Body) != 4 {
+		return fmt.Errorf("unexpected body size")
+	}
+
+	m.Value = binary.BigEndian.Uint32(raw.Body)
+	return nil
+}
+
+// Marshal implements Message.
+func (m *MsgSetWindowAckSize) Marshal() (*rawmessage.Message, error) {
+	body := make([]byte, 4)
+	binary.BigEndian.PutUint32(body, m.Value)
+
+	return &rawmessage.Message{
+		ChunkStreamID: ControlChunkStreamID,
+		Type:          chunk.MessageTypeSetWindowAckSize,
+		Body:          body,
+	}, nil
+}