MP2017.2 changes

Support for short int encoded values (32 bits with 16 bit for ID and 16 bits for value)

Added extra debugging options
1. Debug level
  bit 1 - loopback (show your own model as an MP model)
  bit 2 - dump outgoing packets
  bit 3 - dump incoming packets
  bit 4 - hexdump outgoing packets

2. Update property (/simwith packet
- configurable debug (loopback, packet trace (in,out), packet dump)
- prevent properties from being visible to V1 clients - to ensure reliable compatibility, with just the basic position message being processed. This allows more changes to the V2 protocol whilst giving basic V1 support
- add debug

src/MultiPlayer/mpmessages.hxx

@@ -71,7 +71,7 @@ struct T_MsgHdr {
     xdr_data_t  Version;                // Protocoll version
     xdr_data_t  MsgId;                  // Message identifier 
     xdr_data_t  MsgLen;                 // absolute length of message
-	xdr_data_t  MsgLen2;                // Used to be - ReplyAddress;           // (player's receiver address
+	xdr_data_t  RequestedRangeNm;       // start of second partition of message 
     xdr_data_t  ReplyPort;              // player's receiver port
     char Callsign[MAX_CALLSIGN_LEN];    // Callsign used by the player
 };

src/MultiPlayer/multiplaymgr.hxx

@@ -74,14 +74,11 @@ private:
   }
   int getProtocolToUse()
   {
-	  return mProtocolVersion;
-  }
-  void setProtocolToUse(int protocolVersion)
-  {
-	  if (protocolVersion >= MIN_MP_PROTOCOL_VERSION && protocolVersion <= MAX_MP_PROTOCOL_VERSION)
-		  mProtocolVersion = protocolVersion;
-	  else
-		  mProtocolVersion = MIN_MP_PROTOCOL_VERSION;
+      int protocolVersion = pProtocolVersion->getIntValue();
+      if (protocolVersion >= MIN_MP_PROTOCOL_VERSION && protocolVersion <= MAX_MP_PROTOCOL_VERSION)
+          return protocolVersion;
+      else
+          return MIN_MP_PROTOCOL_VERSION;
   }
 
   void findProperties();
@@ -113,12 +110,15 @@ private:
   // and the property nodes
   typedef std::map<unsigned int, SGSharedPtr<SGPropertyNode> > PropertyMap;
   PropertyMap mPropertyMap;
+  SGPropertyNode *pProtocolVersion;
+  SGPropertyNode *pXmitLen;
+  SGPropertyNode *pMultiPlayDebugLevel;
+  SGPropertyNode *pMultiPlayRange;
 
   typedef std::map<unsigned int, const struct IdPropertyList*> PropertyDefinitionMap;
   PropertyDefinitionMap mPropertyDefinition;
 
   bool mPropertiesChanged;
-  int mProtocolVersion;
 
   MPPropertyListener* mListener;
   

src/MultiPlayer/tiny_xdr.cxx

@@ -73,6 +73,34 @@ XDR_encode_int32 ( const int32_t & n_Val )
     return (SWAP32(static_cast<xdr_data_t> (n_Val)));
 }
 
+static short convert_int_to_short(int v1)
+{
+	if (v1 < -32767)
+		v1 = -32767;
+
+	if (v1 > 32767) 
+		v1 = 32767;
+
+	return (short)v1;
+}
+
+/*
+ * Pack two 16bit shorts into a 32 bit int. By convention v1 is packed in the highword
+ */
+xdr_data_t XDR_encode_shortints32(const int v1, const int v2)
+{
+	return XDR_encode_uint32( (convert_int_to_short(v1) << 16) | (convert_int_to_short(v2)));
+}
+/* Decode packed shorts into two ints. V1 in the highword ($V1..V2..)*/
+void            XDR_decode_shortints32(const xdr_data_t & n_Val, int &v1, int &v2)
+{
+	int _v1 = XDR_decode_int32(n_Val);
+	short s2 = (short)(_v1 & 0xffff);
+	short s1 = (short)(_v1  >> 16);
+	v1 = s1;
+	v2 = s2;
+}
+
 xdr_data_t
 XDR_encode_uint32 ( const uint32_t & n_Val )
 {

src/MultiPlayer/tiny_xdr.hxx

@@ -54,6 +54,9 @@ xdr_data2_t     XDR_encode_uint64   ( const uint64_t & n_Val );
 int64_t         XDR_decode_int64    ( const xdr_data2_t & n_Val );
 uint64_t        XDR_decode_uint64   ( const xdr_data2_t & n_Val );
 
+xdr_data_t      XDR_encode_shortints32(const int v1, const int v2);
+void            XDR_decode_shortints32(const xdr_data_t & n_Val, int &v1, int &v2);
+
 //////////////////////////////////////////////////
 //
 //  FIXME: #1 these funtions must be fixed for