Fix compression ratio stats in decoder

We need to count the number of bytes received, not what's been put in
the temporary output buffer. The two are not the same for all decoders.

Author: CendioOssman

common/rfb/DecodeManager.cxx

@@ -149,6 +149,8 @@ bool DecodeManager::decodeRect(const core::Rect& r, int encoding,
     partialEntry->server = &conn->server;
     partialEntry->pb = pb;
     partialEntry->bufferStream = bufferStream;
+
+    beforePos = conn->getInStream()->pos();
   } else {
     assert(partialEntry->rect == r);
     assert(partialEntry->encoding == encoding);
@@ -170,7 +172,7 @@ bool DecodeManager::decodeRect(const core::Rect& r, int encoding,
     &partialEntry->affectedRegion);
 
   stats[encoding].rects++;
-  stats[encoding].bytes += 12 + partialEntry->bufferStream->length();
+  stats[encoding].bytes += 12 + conn->getInStream()->pos() - beforePos;
   stats[encoding].pixels += r.area();
   equiv = 12 + r.area() * (conn->server.pf().bpp/8);
   stats[encoding].equivalent += equiv;

common/rfb/DecodeManager.h

@@ -71,6 +71,7 @@ namespace rfb {
     };
 
     DecoderStats stats[encodingMax+1];
+    size_t beforePos;
 
     struct QueueEntry {
       bool active;