Changed memory usage of page widgets by dynamically allocating in chu…

…nks rather than a big static array
jhhoward · Jul 23, 2021 · 5501acd · 5501acd
1 parent a6b8cb4
commit 5501acd
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Showing 2 changed files with 75 additions and 10 deletions.
diff --git a/src/Page.cpp b/src/Page.cpp
@@ -22,7 +22,7 @@
 
 #define TOP_MARGIN_PADDING 1
 
-Page::Page(App& inApp) : app(inApp)
+Page::Page(App& inApp) : app(inApp), widgets(allocator)
 {
 	Reset();
 }
@@ -34,7 +34,7 @@ void Page::Reset()
 	numFinishedWidgets = 0;
 	pageWidth = Platform::video->windowWidth;
 	pageHeight = 0;
-	numWidgets = 0;
+	widgets.Clear();
 	needLeadingWhiteSpace = false;
 	pendingVerticalPadding = 0;
 	widgetURL = NULL;
@@ -185,10 +185,9 @@ Widget* Page::CreateWidget(Widget::Type type)
 		FinishCurrentWidget();
 	}
 
-	if (numWidgets < MAX_PAGE_WIDGETS)
+	if (widgets.Allocate())
 	{
-		currentWidgetIndex = numWidgets;
-		numWidgets++;
+		currentWidgetIndex = widgets.Count() - 1;
 
 		Widget& current = widgets[currentWidgetIndex];
 		current.type = type;
@@ -257,7 +256,7 @@ void Page::FinishCurrentLine(bool includeCurrentWidget)
 	{
 		int lineWidth = 0;
 		int lineHeight = 0;
-		int lineEndWidget = numWidgets;
+		int lineEndWidget = widgets.Count();
 
 		// If there is a bullet point right before the line start then treat it as part of the line finishing shuffling:
 		if (currentLineStartWidgetIndex > 0 && widgets[currentLineStartWidgetIndex - 1].type == Widget::BulletPoint)
@@ -269,7 +268,7 @@ void Page::FinishCurrentLine(bool includeCurrentWidget)
 
 		if (!includeCurrentWidget && currentWidgetIndex != -1)
 		{
-			lineEndWidget = numWidgets - 1;
+			lineEndWidget = widgets.Count() - 1;
 		}
 
 		for (int n = currentLineStartWidgetIndex; n < lineEndWidget; n++)
@@ -525,7 +524,7 @@ void Page::SetTitle(const char* inTitle)
 
 Widget* Page::GetWidget(int x, int y)
 {
-	for (int n = 0; n < numWidgets; n++)
+	for (int n = 0; n < widgets.Count(); n++)
 	{
 		Widget* widget = &widgets[n];
 
@@ -554,3 +553,41 @@ void Page::SetFormData(WidgetFormData* inFormData)
 {
 	formData = inFormData;
 }
+
+WidgetContainer::WidgetContainer(LinearAllocator& inAllocator) : allocator(inAllocator), numAllocated(0)
+{
+}
+
+bool WidgetContainer::Allocate()
+{
+	int chunkIndex = WIDGET_INDEX_TO_CHUNK_INDEX(numAllocated);
+	int indexInChunk = WIDGET_INDEX_TO_INDEX_IN_CHUNK(numAllocated);
+
+	if (chunkIndex > MAX_WIDGET_CHUNKS)
+	{
+		return false;
+	}
+
+	if (indexInChunk == 0)
+	{
+		// Need to allocate a new chunk
+		chunks[chunkIndex] = allocator.Alloc<WidgetContainer::Chunk>();
+		if (chunks[chunkIndex] == NULL)
+		{
+			return false;
+		}
+	}
+
+	numAllocated++;
+	return true;
+}
+
+void WidgetContainer::Clear()
+{
+	numAllocated = 0;
+}
+
+Widget& WidgetContainer::operator[](int index)
+{
+	return chunks[WIDGET_INDEX_TO_CHUNK_INDEX(index)]->widgets[WIDGET_INDEX_TO_INDEX_IN_CHUNK(index)];
+}
diff --git a/src/Page.h b/src/Page.h
@@ -22,8 +22,37 @@
 #define MAX_PAGE_STYLE_STACK_SIZE 32
 #define MAX_TEXT_BUFFER_SIZE 128
 
+#define MAX_WIDGET_CHUNKS 256
+#define WIDGETS_PER_CHUNK 64
+#define WIDGET_INDEX_TO_CHUNK_INDEX(index) ((index) >> 6)
+#define WIDGET_INDEX_TO_INDEX_IN_CHUNK(index) ((index) & 0x3f)
+
 class App;
 
+class WidgetContainer
+{
+public:
+	WidgetContainer(LinearAllocator& inAllocator);
+
+	bool Allocate();
+	void Clear();
+
+	int Count() const { return numAllocated; }
+
+	Widget& operator[](int index);
+
+private:
+	LinearAllocator& allocator;
+	int numAllocated;
+
+	struct Chunk
+	{
+		Widget widgets[WIDGETS_PER_CHUNK];
+	};
+
+	Chunk* chunks[MAX_WIDGET_CHUNKS];
+};
+
 class Page
 {
 public:
@@ -85,8 +114,7 @@ class Page
 
 	bool needLeadingWhiteSpace;
 
-	Widget widgets[MAX_PAGE_WIDGETS];
-	int numWidgets;
+	WidgetContainer widgets;
 
 	WidgetStyle styleStack[MAX_PAGE_STYLE_STACK_SIZE];
 	uint8_t styleStackSize;