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, 12 insertions, 3 deletions

diff --git a/src/pgm_sender.hpp b/src/pgm_sender.hpp
index 89f81bf..5a808b6 100644
--- a/src/pgm_sender.hpp
+++ b/src/pgm_sender.hpp
@@ -84,12 +84,21 @@ namespace xs
         handle_t rdata_notify_handle;
         handle_t pending_notify_handle;
 
-        //  Output buffer from pgm_socket.
+        //  Output buffer and size for pgm_socket.
         unsigned char *out_buffer;
-        
-        //  Output buffer size.
         size_t out_buffer_size;
 
+        //  Size of header in each datagram.
+        size_t header_size;
+
+        //  Encoder buffer and size, adjusted from output buffer by size of
+        //  datagram header(s).
+        unsigned char *encode_buffer;
+        size_t encode_buffer_size;
+
+        //  Position of offset to first message in output buffer.
+        unsigned char *offset_p;
+
         //  Number of bytes in the buffer to be written to the socket.
         //  If zero, there are no data to be sent.
         size_t write_size;