Improved Object signature assignment and made sure there will be no duplicates; Also used short-ranged values only so Demo system won't screw up

CHANGELOG.txt

@@ -7,6 +7,7 @@ main/newdemo.c: Added a new code to properly re-record view/cockpit-events at be
 arch/sdl/window.c, main/automap.c, main/game.c, main/gamecntl.c, main/kconfig.c, main/menu.c, main/net_ipx.c, main/net_udp.c, main/newmenu.c: Make response to EVENT_WINDOW_CLOSE conform to 'handling' system - returning 1 means abort closing
 main/kconfig.c, main/newmenu.c: Tidy up newmenu_show/hide_cursor calls
 main/newmenu.c: Allow user to abort close, for whatever reason (helps with my next commit)
+main/gamesave.c, main/newdemo.c, main/object.c, main/object.h, main/state.c: Improved Object signature assignment and made sure there will be no duplicates; Also used short-ranged values only so Demo system won't screw up
 
 20100127
 --------

main/gamesave.c

@@ -898,7 +898,7 @@ int load_game_data(CFILE *LoadFile)
 	}
 
 	//===================== READ PLAYER INFO ==========================
-	Object_next_signature = 0;
+
 
 	//===================== READ OBJECT INFO ==========================
 
@@ -913,7 +913,7 @@ int load_game_data(CFILE *LoadFile)
 			memset(&(Objects[i]), 0, sizeof(object));
 			read_object(&Objects[i],LoadFile,game_top_fileinfo.fileinfo_version);
 
-			Objects[i].signature = Object_next_signature++;
+			Objects[i].signature = obj_get_signature();
 			verify_object( &Objects[i] );
 		}
 

main/newdemo.c

@@ -439,6 +439,7 @@ static int shareware = 0;	// reading shareware demo?
 void nd_read_object(object *obj)
 {
 	memset(obj, 0, sizeof(object));
+	short shortsig = 0;
 
 	/*
 	 * Do render type first, since with render_type == RT_NONE, we
@@ -451,20 +452,8 @@ void nd_read_object(object *obj)
 
 	nd_read_byte((sbyte *) &(obj->id));
 	nd_read_byte((sbyte *) &(obj->flags));
-	nd_read_short((short *)&(obj->signature));
-
-	    /* This doesn't make sense, since the object signature is supposed to 
-	       be an int, but a short is probably half the size on many platforms.
-	       The problem then is that probably only half the signature will be
-	       initialized. This is definitely not portable.
-
-	       See the typedef struct object's signature field in object.h to see
-	       what I mean. The compiler warning with my gcc 4.2.3 seems to be 
-	       warranted. 
-	       
-	       Kip (kip@thevertigo.com)
-	    */
-
+	nd_read_short(&shortsig);
+	obj->signature = shortsig; // It's OKAY! We made sure, obj->signature is never has a value which short cannot handle!!! We cannot do this otherwise, without breaking the demo format!
 	nd_read_shortpos(obj);
 
 	obj->attached_obj = -1;
@@ -667,6 +656,7 @@ void nd_read_object(object *obj)
 void nd_write_object(object *obj)
 {
 	int life;
+	short shortsig = 0;
 
 	/*
 	 * Do render_type first so on read, we can make determination of
@@ -679,7 +669,8 @@ void nd_write_object(object *obj)
 
 	nd_write_byte(obj->id);
 	nd_write_byte(obj->flags);
-	nd_write_short((short)obj->signature);
+	shortsig = obj->signature;  // It's OKAY! We made sure, obj->signature is never has a value which short cannot handle!!! We cannot do this otherwise, without breaking the demo format!
+	nd_write_short(shortsig);
 	nd_write_shortpos(obj);
 
 	if ((obj->type != OBJ_HOSTAGE) && (obj->type != OBJ_ROBOT) && (obj->type != OBJ_PLAYER) && (obj->type != OBJ_POWERUP) && (obj->type != OBJ_CLUTTER)) {

main/object.c

@@ -879,7 +879,30 @@ void obj_unlink(int objnum)
 	Assert(Objects[0].prev != 0);
 }
 
-int Object_next_signature = 0;
+// Returns a new, unique signature for a new object
+int obj_get_signature()
+{
+	static short sig = 0; // Yes! Short! a) We do not need higher values b) the demo system only stores shorts
+	int free = 0, i = 0;
+
+	while (!free)
+	{
+		free = 1;
+		sig++;
+		if (sig < 0)
+			sig = 0;
+		for (i = 0; i <= MAX_OBJECTS; i++)
+		{
+			if ((sig == Objects[i].signature) && (Objects[i].type != OBJ_NONE))
+			{
+				free = 0;
+			}
+		}
+	}
+
+	return sig;
+}
+
 
 int Debris_object_count=0;
 
@@ -1053,7 +1076,7 @@ int obj_create(ubyte type,ubyte id,int segnum,vms_vector *pos,
 	// in uninitialized fields.
 	memset( obj, 0, sizeof(object) );
 
-	obj->signature				= Object_next_signature++;
+	obj->signature				= obj_get_signature();
 	obj->type 					= type;
 	obj->id 						= id;
 	obj->last_pos				= *pos;
@@ -1141,7 +1164,7 @@ int obj_create_copy(int objnum, vms_vector *new_pos, int newsegnum)
 
 	obj_link(newobjnum,newsegnum);
 
-	obj->signature				= Object_next_signature++;
+	obj->signature				= obj_get_signature();
 
 	//we probably should initialize sub-structures here
 

main/object.h

@@ -408,6 +408,9 @@ extern void create_shorterpos(shorterpos *spp, object *objp);
 //if clear_all is set, clear even proximity bombs
 void clear_transient_objects(int clear_all);
 
+// Returns a new, unique signature for a new object
+int obj_get_signature();
+
 //returns the number of a free object, updating Highest_object_index.
 //Generally, obj_create() should be called to get an object, since it
 //fills in important fields and does the linking.

main/state.c

@@ -763,7 +763,6 @@ RetryObjectLoading:
 			}
 		}
 	
-		Object_next_signature = 0;
 		for (i=0; i<=Highest_object_index; i++ )	{
 			obj = &Objects[i];
 			obj->rtype.pobj_info.alt_textures = -1;
@@ -779,12 +778,9 @@ RetryObjectLoading:
 					}
 				}
 				obj_link(i,segnum);
-				if ( obj->signature > Object_next_signature )
-					Object_next_signature = obj->signature;
 			}
 		}	
 		special_reset_objects();
-		Object_next_signature++;
 	
 		//Restore wall info
 		Num_walls = PHYSFSX_readSXE32(fp, swap);