Code dealing with messages moved to msg.cpp

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/msg.hpp

@@ -0,0 +1,52 @@
+/*
+    Copyright (c) 2007-2011 iMatix Corporation
+    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __ZMQ_MSG_HPP_INCLUDE__
+#define __ZMQ_MSG_HPP_INCLUDE__
+
+#include <stddef.h>
+
+#include "../include/zmq.h"
+
+#include "atomic_counter.hpp"
+
+namespace zmq
+{
+
+    //  Shared message buffer. Message data are either allocated in one
+    //  continuous block along with this structure - thus avoiding one
+    //  malloc/free pair or they are stored in used-supplied memory.
+    //  In the latter case, ffn member stores pointer to the function to be
+    //  used to deallocate the data. If the buffer is actually shared (there
+    //  are at least 2 references to it) refcount member contains number of
+    //  references.
+
+    struct msg_content_t
+    {
+        void *data;
+        size_t size;
+        zmq_free_fn *ffn;
+        void *hint;
+        zmq::atomic_counter_t refcnt;
+    };
+
+}
+
+#endif