allow writing primitives to static buffers

pkg/base/interleavedframe.go

@@ -105,16 +105,28 @@ func (f *InterleavedFrame) Read(maxPayloadSize int, br *bufio.Reader) error {
 	return nil
 }
 
-// Write writes an InterleavedFrame into a buffered writer.
-func (f InterleavedFrame) Write(w io.Writer) error {
-	buf := []byte{0x24, byte(f.Channel), 0x00, 0x00}
-	binary.BigEndian.PutUint16(buf[2:], uint16(len(f.Payload)))
-
-	_, err := w.Write(buf)
-	if err != nil {
-		return err
-	}
-
-	_, err = w.Write(f.Payload)
-	return err
+// WriteSize returns the size of an InterleavedFrame.
+func (f InterleavedFrame) WriteSize() int {
+	return 4 + len(f.Payload)
+}
+
+// WriteTo writes an InterleavedFrame.
+func (f InterleavedFrame) WriteTo(buf []byte) (int, error) {
+	pos := 0
+
+	pos += copy(buf[pos:], []byte{0x24, byte(f.Channel)})
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(f.Payload)))
+	pos += 2
+
+	pos += copy(buf[pos:], f.Payload)
+
+	return pos, nil
+}
+
+// Write writes an InterleavedFrame.
+func (f InterleavedFrame) Write() ([]byte, error) {
+	buf := make([]byte, f.WriteSize())
+	_, err := f.WriteTo(buf)
+	return buf, err
 }