Implement new message encoder/decoder

This is supposed to become part of the ZMTP/1.1.

The main differences from the ZMTP/1.0 framing protocol are:
- flags field comes first, followed by the length field
- long messages are signaled using a flag rather then 0xff escape
- length field does not include the flags field, 0 is a valid value

src/v1_encoder.hpp

@@ -0,0 +1,60 @@
+/*
+    Copyright (c) 2009-2011 250bpm s.r.o.
+    Copyright (c) 2007-2012 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_V1_ENCODER_HPP_INCLUDED__
+#define __ZMQ_V1_ENCODER_HPP_INCLUDED__
+
+#include "msg.hpp"
+#include "i_msg_source.hpp"
+#include "encoder.hpp"
+
+namespace zmq
+{
+
+    class i_msg_source;
+
+    //  Encoder for 0MQ framing protocol. Converts messages into data stream.
+
+    class v1_encoder_t : public encoder_base_t <v1_encoder_t>
+    {
+    public:
+
+        v1_encoder_t (size_t bufsize_, i_msg_source *msg_source_);
+        virtual ~v1_encoder_t ();
+
+        virtual void set_msg_source (i_msg_source *msg_source_);
+
+    private:
+
+        bool size_ready ();
+        bool message_ready ();
+
+        i_msg_source *msg_source;
+        msg_t in_progress;
+        unsigned char tmpbuf [9];
+
+        v1_encoder_t (const v1_encoder_t&);
+        const v1_encoder_t &operator = (const v1_encoder_t&);
+    };
+}
+
+#endif
+