install go2rtc on bob

installs_on_host/go2rtc/pkg/tutk/helpers.go

@@ -0,0 +1,71 @@
+package tutk
+
+import (
+	"encoding/binary"
+	"time"
+)
+
+func GenSessionID() []byte {
+	b := make([]byte, 8)
+	binary.LittleEndian.PutUint64(b, uint64(time.Now().UnixNano()))
+	return b
+}
+
+func ICAM(cmd uint32, args ...byte) []byte {
+	// 0   4943414d  ICAM
+	// 4   d807ff00  command
+	// 8   00000000000000
+	// 15  02        args count
+	// 16  00000000000000
+	// 23  0101      args
+	n := byte(len(args))
+	b := make([]byte, 23+n)
+	copy(b, "ICAM")
+	binary.LittleEndian.PutUint32(b[4:], cmd)
+	b[15] = n
+	copy(b[23:], args)
+	return b
+}
+
+func HL(cmdID uint16, payload []byte) []byte {
+	// 0-1   "HL"       magic
+	// 2     version    (typically 5)
+	// 3     reserved
+	// 4-5   cmdID      command ID (uint16 LE)
+	// 6-7   payloadLen payload length (uint16 LE)
+	// 8-15  reserved
+	// 16+   payload
+	const headerSize = 16
+	const version = 5
+
+	b := make([]byte, headerSize+len(payload))
+	copy(b, "HL")
+	b[2] = version
+	binary.LittleEndian.PutUint16(b[4:], cmdID)
+	binary.LittleEndian.PutUint16(b[6:], uint16(len(payload)))
+	copy(b[headerSize:], payload)
+	return b
+}
+
+func ParseHL(data []byte) (cmdID uint16, payload []byte, ok bool) {
+	if len(data) < 16 || data[0] != 'H' || data[1] != 'L' {
+		return 0, nil, false
+	}
+	cmdID = binary.LittleEndian.Uint16(data[4:])
+	payloadLen := binary.LittleEndian.Uint16(data[6:])
+	if len(data) >= 16+int(payloadLen) {
+		payload = data[16 : 16+payloadLen]
+	} else if len(data) > 16 {
+		payload = data[16:]
+	}
+	return cmdID, payload, true
+}
+
+func FindHL(data []byte, offset int) []byte {
+	for i := offset; i+16 <= len(data); i++ {
+		if data[i] == 'H' && data[i+1] == 'L' {
+			return data[i:]
+		}
+	}
+	return nil
+}