From 4d005a7dbbbe21df83cef4838ba5907bc9b742d8 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Wed, 11 Aug 2010 16:18:38 +0000
Subject: [PATCH] Implement a naive garbage collector.

---
 src/asset.cpp    |  4 ++--
 src/asset.h      |  3 ++-
 src/editor.cpp   | 14 +++++++-------
 src/gtkvideo.cpp |  4 ++--
 src/map.cpp      |  1 -
 src/test-map.cpp |  6 +++---
 src/ticker.cpp   | 45 ++++++++++++++++++++++++++++++---------------
 src/tiler.cpp    |  7 +++----
 src/tileset.cpp  |  4 ++--
 9 files changed, 51 insertions(+), 37 deletions(-)

diff --git a/src/asset.cpp b/src/asset.cpp
index 54ce5bbc..3bee580c 100644
--- a/src/asset.cpp
+++ b/src/asset.cpp
@@ -1,5 +1,5 @@
 
-#include <malloc.h>
+#include <cstdlib>
 
 #include "asset.h"
 #include "ticker.h"
@@ -9,7 +9,7 @@
  */
 
 Asset::Asset() :
-    index(0),
+    next(0),
     ref(0),
     destroy(0)
 {
diff --git a/src/asset.h b/src/asset.h
index 4616603a..329b93bd 100644
--- a/src/asset.h
+++ b/src/asset.h
@@ -23,7 +23,8 @@ public:
     virtual int Unref();
 
 protected:
-    int index, ref, destroy;
+    Asset *next;
+    int ref, destroy;
 };
 
 #endif // __DH_ASSET_H__
diff --git a/src/editor.cpp b/src/editor.cpp
index 1f99f450..b3115be6 100644
--- a/src/editor.cpp
+++ b/src/editor.cpp
@@ -1,17 +1,17 @@
-#include <SDL.h>
 
-#include <stdio.h>
-#include <math.h>
+#include <cstdio>
+#include <cmath>
 
-#include "gtkvideo.h"
-#include "ticker.h"
-#include "game.h"
+#include <SDL.h>
 
-#include <math.h>
 #include <gtk/gtk.h>
 #include <gtkgl/gtkglarea.h>
 #include <GL/gl.h>
 
+#include "gtkvideo.h"
+#include "ticker.h"
+#include "game.h"
+
 volatile int quit = 0;
 
 static gint main_quit(GtkWidget *widget, GdkEventExpose *event)
diff --git a/src/gtkvideo.cpp b/src/gtkvideo.cpp
index 06a10bef..47783e31 100644
--- a/src/gtkvideo.cpp
+++ b/src/gtkvideo.cpp
@@ -1,4 +1,6 @@
 
+#include <cstdlib>
+
 #include <gtk/gtk.h>
 #include <gtkgl/gtkglarea.h>
 
@@ -13,8 +15,6 @@
 #   include <GL/gl.h>
 #endif
 
-#include <stdlib.h>
-
 #include "gtkvideo.h"
 
 /*
diff --git a/src/map.cpp b/src/map.cpp
index 31c5c871..f40c8142 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -2,7 +2,6 @@
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
-#include <malloc.h>
 #include <ctype.h>
 
 #include "map.h"
diff --git a/src/test-map.cpp b/src/test-map.cpp
index 24ef9208..0458b5b7 100644
--- a/src/test-map.cpp
+++ b/src/test-map.cpp
@@ -1,9 +1,9 @@
 // Test stuff
 
-#include <SDL.h>
+#include <cstdio>
+#include <cmath>
 
-#include <stdio.h>
-#include <math.h>
+#include <SDL.h>
 
 #include "sdlvideo.h"
 #include "game.h"
diff --git a/src/ticker.cpp b/src/ticker.cpp
index 3f606ae7..97dd8094 100644
--- a/src/ticker.cpp
+++ b/src/ticker.cpp
@@ -3,8 +3,9 @@
  * The ticker
  */
 
+#include <cstdlib>
+#include <cstdio>
 #include <stdint.h>
-#include <stdlib.h>
 
 #include "ticker.h"
 #include "asset.h"
@@ -19,19 +20,19 @@ static class TickerData
 
 public:
     TickerData() :
-        assets(0),
+        list(0),
         nassets(0)
     {
-        /* Nothing to do */
     }
 
     ~TickerData()
     {
-        free(assets);
+        if (nassets)
+            fprintf(stderr, "ERROR: still %i assets in ticker\n", nassets);
     }
 
 private:
-    Asset **assets;
+    Asset *list;
     int nassets;
 }
 tickerdata;
@@ -44,23 +45,37 @@ static TickerData * const data = &tickerdata;
 
 void Ticker::Register(Asset *asset)
 {
-    int tmp = data->nassets++;
-    data->assets = (Asset **)realloc(data->assets,
-                                     data->nassets * sizeof(Asset *));
-    data->assets[tmp] = asset;
-
-    asset->index = tmp;
+    asset->next = data->list;
+    data->list = asset;
+    data->nassets++;
 }
 
 void Ticker::TickGame(float delta_time)
 {
-    for (int i = 0; i < data->nassets; i++)
-        data->assets[i]->TickGame(delta_time);
+    /* Garbage collect objects that can be destroyed */
+    for (Asset *asset = data->list, *prev = NULL;
+         asset;
+         prev = asset, asset = asset->next)
+        if (asset->destroy)
+        {
+            if (prev)
+                prev->next = asset->next;
+            else
+                data->list = asset->next;
+
+            data->nassets--;
+            delete asset;
+        }
+
+    /* Tick objects for the game loop */
+    for (Asset *asset = data->list; asset; asset = asset->next)
+        asset->TickGame(delta_time);
 }
 
 void Ticker::TickRender(float delta_time)
 {
-    for (int i = 0; i < data->nassets; i++)
-        data->assets[i]->TickRender(delta_time);
+    /* Tick objects for the render loop */
+    for (Asset *asset = data->list; asset; asset = asset->next)
+        asset->TickRender(delta_time);
 }
 
diff --git a/src/tiler.cpp b/src/tiler.cpp
index 5c50e7a6..496067d1 100644
--- a/src/tiler.cpp
+++ b/src/tiler.cpp
@@ -1,7 +1,7 @@
 
 #include <cstring>
 #include <cstdio>
-#include <stdlib.h>
+#include <cstdlib>
 
 #include "tiler.h"
 #include "tileset.h"
@@ -28,6 +28,8 @@ public:
 
     ~TilerData()
     {
+        if (ntilesets)
+            fprintf(stderr, "ERROR: still %i tilesets in tiler\n", ntilesets);
         free(tilesets);
     }
 
@@ -81,10 +83,7 @@ void Tiler::Deregister(int id)
     --id; /* ID 0 is for the empty tileset */
 
     if (data->tilesets[id]->Unref() == 0)
-    {
-        delete data->tilesets[id];
         data->tilesets[id] = NULL;
-    }
 }
 
 void Tiler::Render(uint32_t code, int x, int y)
diff --git a/src/tileset.cpp b/src/tileset.cpp
index c5cc1147..12550cb2 100644
--- a/src/tileset.cpp
+++ b/src/tileset.cpp
@@ -1,4 +1,6 @@
 
+#include <cstdlib>
+
 #ifdef WIN32
 #   define WIN32_LEAN_AND_MEAN
 #   include <windows.h>
@@ -13,8 +15,6 @@
 #include <SDL.h>
 #include <SDL_image.h>
 
-#include <malloc.h>
-
 #include "tileset.h"
 
 /*