Introduce abstract interface for message encoder/decoder

src/i_encoder.hpp

@@ -0,0 +1,54 @@
+/*
+    Copyright (c) 2007-2012 iMatix Corporation
+    Copyright (c) 2007-2012 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_I_ENCODER_HPP_INCLUDED__
+#define __ZMQ_I_ENCODER_HPP_INCLUDED__
+
+#include <stdint.h>
+
+namespace zmq
+{
+
+    //  Forward declaration
+    class i_msg_source;
+
+    //  Interface to be implemented by message encoder.
+
+    struct i_encoder
+    {
+        virtual ~i_encoder () {}
+
+        //  Set message producer.
+        virtual void set_msg_source (i_msg_source *msg_source_) = 0;
+
+        //  The function returns a batch of binary data. The data
+        //  are filled to a supplied buffer. If no buffer is supplied (data_
+        //  is NULL) encoder will provide buffer of its own.
+        //  If offset is not NULL, it is filled by offset of the first message
+        //  in the batch.If there's no beginning of a message in the batch,
+        //  offset is set to -1.
+        virtual void get_data (unsigned char **data_, size_t *size_,
+            int *offset_ = NULL) = 0;
+
+    };
+
+}
+
+#endif