From ba066c34dde204aa192d03a23a81356374d93731 Mon Sep 17 00:00:00 2001
From: chatty
Date: Wed, 7 Apr 1993 11:50:31 +0000
Subject: Initial revision

---
 comm/Message.cc | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 comm/Message.cc

(limited to 'comm/Message.cc')

diff --git a/comm/Message.cc b/comm/Message.cc
new file mode 100644
index 0000000..54cd771
--- /dev/null
+++ b/comm/Message.cc
@@ -0,0 +1,98 @@
+/*
+ *	The Unix Channel
+ *
+ *	by Michel Beaudouin-Lafon
+ *
+ *	Copyright 1990-1993
+ *	Laboratoire de Recherche en Informatique (LRI)
+ *
+ *	Messages
+ *
+ *	$Id$
+ *	$CurLog$
+ */
+
+#include "cplus_bugs.h"
+
+#include "Message.h"
+
+/*?class UchMessage
+\typ{UchMessage} is the virtual base class for messages.
+Each subclass must redefine the virtual functions \fun{WriteTo} and \fun{ReadFrom}.
+Messages can be added to buffers and can be retrieved from buffers.
+?*/
+
+/*?nodoc?*/
+UchMessage :: UchMessage ()
+{
+	// nothing
+}
+
+/*?nodoc?*/
+UchMessage :: ~UchMessage ()
+{
+}
+
+/*?
+This virtual function must write a message into a buffer.
+Usually, the implementation of this function in a derived class starts by calling
+the same function of its base class, because a derived class inherits the fields
+of its base class and adds its own fields.
+Data is usually appended to the buffer by the \fun{UchMsgBuffer::Append} functions or operator <<.
+In class \typ{UchMessage}, this function does nothing.
+?*/
+void
+UchMessage :: WriteTo (UchMsgBuffer&)
+{
+	// nothing
+}
+
+/*?
+This virtual function must extract data from the buffer to create the message.
+At most \var{len} bytes should be read from the buffer.
+Usually, the implementation of this function in a derived class starts by calling
+the same function of its base class, because a derived class inherits the fields
+of its base class and adds its own fields.
+Data is usually retrieved from the buffer by the \fun{UchMsgBuffer::Get} functions or operator >>.
+In class \typ{UchMessage}, this function does nothing.
+?*/
+void
+UchMessage :: ReadFrom (UchMsgBuffer&, lword)
+{
+}
+
+/*?
+This virtual function can be redefined in derived classes to support the handling of messages
+after they have been loaded from a buffer. The function \typ{MyClient}::\fun{NewMessage}
+may then look like:
+\begin{ccode}
+void
+MyClient :: NewMessage (UchMsgBuffer& buffer, bool ask)
+{
+    MyRequest* m = 0;
+    lword type;
+    buffer.MsgPeek (&type);
+    switch (type) {
+    case MyFirstReqType:
+        m = new MyFirstRequest;
+        break;
+    case ...
+       ...
+    }
+    if (m) {
+        buffer.Get (m);
+        m->Activate ();
+        return TRUE;
+    }
+    return FALSE;
+}
+\end{ccode}
+However, this virtual function is only provided as a facility and is not used
+by \uch. Redefining it is not mandatory.
+?*/
+void
+UchMessage :: Activate ()
+{
+}
+
+
-- 
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