package parser import ( "bytes" "strconv" ) // IsCallout detects a callout in the following format: <<N>> Where N is a integer > 0. func IsCallout(data []byte) (id []byte, consumed int) { if !bytes.HasPrefix(data, []byte("<<")) { return nil, 0 } start := 2 end := bytes.Index(data[start:], []byte(">>")) if end < 0 { return nil, 0 } b := data[start : start+end] b = bytes.TrimSpace(b) i, err := strconv.Atoi(string(b)) if err != nil { return nil, 0 } if i <= 0 { return nil, 0 } return b, start + end + 2 // 2 for >> }