Add src/protocol/MessageType.h

Author: petesramek

src/protocol/MessageType.h

@@ -0,0 +1,49 @@
+#ifndef TINYLINK_MESSAGETYPE_H
+#define TINYLINK_MESSAGETYPE_H
+
+#include <stdint.h>
+
+namespace tinylink {
+
+    // Wire message type identifiers used in TinyLink frames.
+    // Stored as single bytes on the wire (ASCII codes).
+    enum class MessageType : uint8_t {
+        Data  = 'D',
+        Debug = 'g',
+        Cmd   = 'C',  // renamed from Req -> Cmd; new outgoing frames use 'C'
+        Done  = 'K'
+    };
+
+    // Convert a wire byte to MessageType. Returns true on success.
+    // Accept both legacy 'R' (Req) and new 'C' (Cmd) for migration.
+    inline bool message_type_from_wire(uint8_t b, MessageType &out) {
+        switch (b) {
+            case static_cast<uint8_t>(MessageType::Data):  out = MessageType::Data;  return true;
+            case static_cast<uint8_t>(MessageType::Debug): out = MessageType::Debug; return true;
+            case static_cast<uint8_t>(MessageType::Cmd):   out = MessageType::Cmd;   return true;
+            case 'R': /* legacy: Req */                    out = MessageType::Cmd;   return true;
+            case static_cast<uint8_t>(MessageType::Done):  out = MessageType::Done;  return true;
+            default: return false;
+        }
+    }
+
+    // Small helper to get the wire byte for a MessageType.
+    // Emits the new 'C' value for commands.
+    inline uint8_t message_type_to_wire(MessageType t) {
+        return static_cast<uint8_t>(t);
+    }
+
+    // to-string helper for diagnostics.
+    inline const char* message_type_to_string(MessageType t) {
+        switch (t) {
+            case MessageType::Data:  return "Data";
+            case MessageType::Debug: return "Debug";
+            case MessageType::Cmd:   return "Cmd";
+            case MessageType::Done:  return "Done";
+            default:                 return "Unknown";
+        }
+    }
+
+} // namespace tinylink
+
+#endif // TINYLINK_MESSAGETYPE_H