Implement SP wire protocol

Implements the SP wire protocol, and infrastructure for legacy wire
protocol support.

Also added an XS_SERVICE_ID socket option to set the service id and renamed
the XS_PROTOCOL option to XS_PATTERN_VERSION.

The following pattern versions are supported:

PAIR:     v3
PUBSUB:   v1 (legacy), v4
REQREP:   v2
PIPELINE: v3
SURVEY:   v2

Note that all existing pattern versions have been bumped by 1 to allow for
use of legacy protocols (otherwise there would be no way to distinguish
between e.g. PUBSUB v3 and PUBSUB v3 using SP).

Signed-off-by: Martin Lucina <martin@lucina.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/stream_engine.hpp b/src/stream_engine.hpp
index 46a6080..70c9ddb 100644
--- a/src/stream_engine.hpp
+++ b/src/stream_engine.hpp
@@ -30,6 +30,7 @@
 #include "encoder.hpp"
 #include "decoder.hpp"
 #include "options.hpp"
+#include "wire.hpp"
 
 namespace xs
 {
@@ -98,6 +99,22 @@ namespace xs
 
         bool plugged;
 
+        //  Outgoing protocol header.
+        sp_header_t out_header;
+
+        //  Desired protocol header.
+        sp_header_t desired_header;
+
+        //  Incoming protocol header.
+        sp_header_t in_header;
+
+        unsigned char *header_pos;
+        size_t header_remaining;
+
+        //  Protocol header has been received/sent.
+        bool header_received;
+        bool header_sent;
+
         stream_engine_t (const stream_engine_t&);
         const stream_engine_t &operator = (const stream_engine_t&);
     };