ReportDescriptor: fix wrong list indexing by changing list to stack (#13)

Author: benedekkupper

HidSharp/Reports/ReportDescriptor.cs

@@ -163,11 +163,11 @@ void ParseEncodedItem(EncodedItem item)
                     switch (item.TagForGlobal)
                     {
                         case GlobalItemTag.Push:
-                            State.GlobalItemStateStack.Add(new Dictionary<GlobalItemTag, EncodedItem>(State.GlobalItemState));
+                            State.GlobalItemStateStack.Push(new Dictionary<GlobalItemTag, EncodedItem>(State.GlobalItemState));
                             break;
 
                         case GlobalItemTag.Pop:
-                            State.GlobalItemStateStack.RemoveAt(State.GlobalItemState.Count - 1);
+                            State.GlobalItemStateStack.Pop();
                             break;
 
                         case GlobalItemTag.ReportID:

HidSharp/Reports/ReportDescriptorParseState.cs

@@ -27,7 +27,7 @@ sealed class ReportDescriptorParseState
         public ReportDescriptorParseState()
         {
             RootItem = new DescriptorCollectionItem();
-            GlobalItemStateStack = new List<IDictionary<GlobalItemTag, EncodedItem>>();
+            GlobalItemStateStack = new Stack<IDictionary<GlobalItemTag, EncodedItem>>();
             LocalItemState = new List<KeyValuePair<LocalItemTag, uint>>();
             Reset();
         }
@@ -39,7 +39,7 @@ public void Reset()
             RootItem.CollectionType = 0;
 
             GlobalItemStateStack.Clear();
-            GlobalItemStateStack.Add(new Dictionary<GlobalItemTag, EncodedItem>());
+            GlobalItemStateStack.Push(new Dictionary<GlobalItemTag, EncodedItem>());
             LocalItemState.Clear();
         }
 
@@ -75,10 +75,10 @@ public DescriptorCollectionItem RootItem
 
         public IDictionary<GlobalItemTag, EncodedItem> GlobalItemState
         {
-            get { return GlobalItemStateStack[GlobalItemStateStack.Count - 1]; }
+            get { return GlobalItemStateStack.Peek(); }
         }
 
-        public IList<IDictionary<GlobalItemTag, EncodedItem>> GlobalItemStateStack
+        public Stack<IDictionary<GlobalItemTag, EncodedItem>> GlobalItemStateStack
         {
             get;
             private set;