Changeset 385

Timestamp:

Dec 5, 2007, 12:05:46 AM (17 years ago)

Author:

scheusso

Message:

extended GameStateManager:
added functions

• encode (takes two gamestates and returns a diffed and compressed gamestate)
• decode (opposite of encode)
• compress (called by encode) — not yet implemented
• decompress (called by decode) — not yet implemented
• diff (called by en/decode)

Location:

code/branches/FICN/src/network

Files:

• GameStateManager.cc (modified) (2 diffs)
• GameStateManager.h (modified) (2 diffs)

code/branches/FICN/src/network/GameStateManager.cc

@@ -118 +118 @@
  * @return iterator pointing to the next object in the list
  */
-// orxonox::Iterator<Synchronisable> removeObject(orxonox::Iterator<Synchronisable> it){
 void GameStateManager::removeObject(orxonox::Iterator<Synchronisable> &it){
   orxonox::Iterator<Synchronisable> temp=it;
@@ -126 +125 @@
 }
 
+GameState GameStateManager::encode(GameState a, GameState b){
+  GameState r = diff(a,b);
+  return compress(r);
+}
+
+GameState GameStateManager::decode(GameState a, GameState x){
+  GameState t = decompress(x);
+  return diff(a, t);
+}
+
+GameState GameStateManager::diff(GameState a, GameState b){
+  unsigned char *ap = a.data, *bp = b.data;
+  int of=0; // pointers offset
+  int dest_length=0;
+  if(a.size>=b.size)
+    dest_length=a.size;
+  else
+    dest_length=b.size;
+  unsigned char *dp = (unsigned char *)malloc(dest_length*sizeof(unsigned char));
+  while(of<a.size && of<b.size){
+    *(dp+of)=*(ap+of)^*(bp+of); // do the xor
+    ++of;
+  }
+  if(a.size!=b.size){ // do we have to fill up ?
+    unsigned char n=0;
+    if(a.size<b.size){
+      while(of<dest_length){
+        *(dp+of)=n^*(bp+of);
+        of++;
+      }
+    } else{
+      while(of<dest_length){
+        *(dp+of)=*(ap+of)^n;
+        of++;
+      }
+    }
+  }
+  // should be finished now
+  GameState r = {b.id, dest_length, dp};
+  return r;
+}
+
+GameState GameStateManager::compress(GameState a){
+  // to be implemented !!!!!!!!!!!!!!
+  return a;
+}
+
+GameState GameStateManager::decompress(GameState a){
+  // to be implemented !!!!!!!!!!!!!!
+  return a;
+}
 
 }

code/branches/FICN/src/network/GameStateManager.h

@@ -35 +35 @@
  * - writing gamestates to universe
  * - diffing gamestates ?
+ * 
+ * EN/DECODATION:
+ * a: last Gamestate a client has received
+ * b: new Gamestate
+ * x: diffed and compressed gamestate
+ * x=(a^b)
+ * b=(a^x)
+ * diff(a,diff(a,x))=x (hope this is correct)
  * @author Oliver Scheuss
 */
@@ -43 +51 @@
   GameState getSnapshot(int id);
   bool loadSnapshot(GameState state);
+  GameState encode(GameState a, GameState b);
+  GameState decode(GameState a, GameState x);
 private:
   void removeObject(orxonox::Iterator<Synchronisable> &it);
-
+  GameState diff(GameState a, GameState b);
+  GameState compress(GameState a);
+  GameState decompress(GameState a);
 };