GLStateTracker code review:

 - using LinkedList as stack replacement for non index based push/pop
 - increased initial map size since the default values already exceeds the default mapsize
 - size()==0 -> isEmpty() (can be significantly faster if the deque impl would change in future)
 - map copy with initial size
 - minor other changes

src/jogl/classes/jogamp/opengl/GLStateTracker.java

@@ -39,56 +39,58 @@
 
 package jogamp.opengl;
 
-import java.util.List;
-import java.util.ArrayList;
 import javax.media.opengl.*;
 import com.jogamp.common.util.IntIntHashMap;
+import java.nio.IntBuffer;
+import java.util.LinkedList;
 
 /**
  * Tracks as closely as possible OpenGL states.
  * GLStateTracker objects are allocated on a per-OpenGL-context basis.
  * <p>
  * Currently supported states: PixelStorei
  */
-
 public class GLStateTracker {
-  private static final boolean DEBUG = Debug.debug("GLStateTracker");
+
+//  private static final boolean DEBUG = Debug.debug("GLStateTracker");
 
   private volatile boolean enabled = true;
 
   private IntIntHashMap pixelStateMap;
+  private final LinkedList<SavedState> stack; // would be used as Deque interface in jdk6
+
+  private static class SavedState {
 
-  static class SavedState {
     /**
      * Empty pixel-store state
      */ 
-    SavedState() {
-        this.pixelStateMap = null;
-    }
+    private IntIntHashMap pixelStateMap;
 
     /**
      * set (client) pixel-store state
      */ 
-    void putPixelStateMap(IntIntHashMap pixelStateMap) {
-        this.pixelStateMap = new IntIntHashMap();
+    private void putPixelStateMap(IntIntHashMap pixelStateMap) {
+        //TODO add copy constructor to primitive hashmaps
+        this.pixelStateMap = new IntIntHashMap(Math.max(16, pixelStateMap.size()));
         this.pixelStateMap.setKeyNotFoundValue(-1);
         this.pixelStateMap.putAll(pixelStateMap);
     }
 
     /**
      * get (client) pixel-store state
      */ 
-    IntIntHashMap getPixelStateMap() { return pixelStateMap; }
+    private IntIntHashMap getPixelStateMap() { return pixelStateMap; }
 
-    private IntIntHashMap pixelStateMap;
-    // private Map otherStateMap;
   }
-  private List/*<SavedState>*/ stack = new ArrayList();
+
 
   public GLStateTracker() {
-    pixelStateMap = new IntIntHashMap();
+
+    pixelStateMap = new IntIntHashMap(32);
     pixelStateMap.setKeyNotFoundValue(-1);
     resetStates();
+
+    stack = new LinkedList<SavedState>();
   }
 
   public void clearStates(boolean enable) {
@@ -119,7 +121,7 @@ public boolean getInt(int pname, int[] params, int params_offset) {
 
   /** @return true if found in our map, otherwise false, 
    *  which forces the caller to query GL. */
-  public boolean getInt(int pname, java.nio.IntBuffer params, int dummy) {
+  public boolean getInt(int pname, IntBuffer params, int dummy) {
     if(enabled) {
         int value = pixelStateMap.get(pname);
         if(0 <= value) {
@@ -143,16 +145,16 @@ public void pushAttrib(int flags) {
             // save client pixel-store state
             state.putPixelStateMap(pixelStateMap);
         }
-        stack.add(0, state); // push
+        stack.addFirst(state); // push
     }
   }
 
   public void popAttrib() {
     if(enabled) {
-        if(stack.size()==0) {
+        if(stack.isEmpty()) {
             throw new GLException("stack contains no elements");
         }
-        SavedState state = (SavedState) stack.remove(0); // pop
+        SavedState state = stack.pollFirst(); // pop
         if(null==state) {
             throw new GLException("null stack element (remaining stack size "+stack.size()+")");
         }
@@ -168,17 +170,17 @@ private void resetStates() {
     pixelStateMap.clear();
 
     pixelStateMap.put(GL.GL_PACK_ALIGNMENT,          4);
-    pixelStateMap.put(GL2GL3.GL_PACK_SWAP_BYTES,     0 /* GL_FALSE */);
-    pixelStateMap.put(GL2GL3.GL_PACK_LSB_FIRST,      0 /* GL_FALSE */);
+    pixelStateMap.put(GL2GL3.GL_PACK_SWAP_BYTES,     GL.GL_FALSE);
+    pixelStateMap.put(GL2GL3.GL_PACK_LSB_FIRST,      GL.GL_FALSE);
     pixelStateMap.put(GL2GL3.GL_PACK_ROW_LENGTH,     0);
     pixelStateMap.put(GL2GL3.GL_PACK_SKIP_ROWS,      0);
     pixelStateMap.put(GL2GL3.GL_PACK_SKIP_PIXELS,    0);
     pixelStateMap.put(GL2GL3.GL_PACK_IMAGE_HEIGHT,   0);
     pixelStateMap.put(GL2GL3.GL_PACK_SKIP_IMAGES,    0);
 
     pixelStateMap.put(GL.GL_UNPACK_ALIGNMENT,        4);
-    pixelStateMap.put(GL2GL3.GL_UNPACK_SWAP_BYTES,   0 /* GL_FALSE */);
-    pixelStateMap.put(GL2GL3.GL_UNPACK_LSB_FIRST,    0 /* GL_FALSE */);
+    pixelStateMap.put(GL2GL3.GL_UNPACK_SWAP_BYTES,   GL.GL_FALSE);
+    pixelStateMap.put(GL2GL3.GL_UNPACK_LSB_FIRST,    GL.GL_FALSE);
     pixelStateMap.put(GL2GL3.GL_UNPACK_ROW_LENGTH,   0);
     pixelStateMap.put(GL2GL3.GL_UNPACK_SKIP_ROWS,    0);
     pixelStateMap.put(GL2GL3.GL_UNPACK_SKIP_PIXELS,  0);